| 1. |
- Aguilar, Helena, et al.
(författare)
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VAV3 mediates resistance to breast cancer endocrine therapy
- 2014
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Ingår i: Breast Cancer Research. - : BioMed Central. - 1465-5411 .- 1465-542X. ; 16:3, s. R53-
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Endocrine therapies targeting cell proliferation and survival mediated by estrogen receptor alpha (ERalpha) are among the most effective systemic treatments for ERalpha-positive breast cancer. However, most tumors initially responsive to these therapies acquire resistance through mechanisms that involve ERalpha transcriptional regulatory plasticity. Here, we identify VAV3 as a critical component in this process.METHODS: A cell-based chemical compound screen was carried out to identify therapeutic strategies against resistance to endocrine therapy. Binding to ERalpha was evaluated by molecular docking analyses, an agonist fluoligand assay, and short-hairpin (sh) RNA-mediated protein depletion. Microarray analyses were performed to identify altered gene expression. Western blot of signaling and proliferation markers and shRNA-mediated protein depletion in viability and clonogenic assays were performed to delineate the role of VAV3. Genetic variation in VAV3 was assessed for association with the response to tamoxifen. Immunohistochemical analyses of VAV3 were carried out to determine the association with therapy response and different tumor markers. An analysis of gene expression association with drug sensitivity was carried out to identify a potential therapeutic approach based on differential VAV3 expression.RESULTS: The compound YC-1 was found to comparatively reduce the viability of cell models of acquired resistance. This effect was probably not due to activation of its canonical target (soluble guanylyl cyclase) but instead a result of binding to ERalpha. VAV3 was selectively reduced upon exposure to YC-1 or ERalpha depletion and, accordingly, VAV3 depletion comparatively reduced the viability of cell models of acquired resistance. In the clinical scenario, germline variation in VAV3 was associated with response to tamoxifen in Japanese breast cancer patients (rs10494071 combined P value = 8.4 x 10-4). The allele association combined with gene expression analyses indicated that low VAV3 expression predicts better clinical outcome. Conversely, high nuclear VAV3 expression in tumor cells was associated with poorer endocrine therapy response. Based on VAV3 expression levels and the response to erlotinib in cancer cell lines, targeting EGFR signaling may be a promising therapeutic strategy.CONCLUSIONS: This study proposes VAV3 as a biomarker and rationale signaling target to prevent and/or overcome resistance to endocrine therapy in breast cancer.
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| 2. |
- Bostner, Josefine, et al.
(författare)
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S6 kinase signaling and tamoxifen response in breast cancer cells and in two randomized breast cancer cohorts
- 2013
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Detecting signals in the mammalian target of rapamycin (mTOR), and the estrogen receptor (ER) pathways for prediction of treatment response may be a future clinical tool in primary breast cancer. Here, we investigated the validity and value of the mTOR targets p70-S6 kinase (S6K) 1 and 2 as biomarkers for tamoxifen sensitivity in vitro and in two independent tamoxifen randomized postmenopausal breast cancer cohorts. In addition, the prognostic value of the S6Ks was evaluated. A simultaneous knockdown of the S6Ks in ER-positive breast cancer cells resulted in G1 arrest, and tamoxifen-induced G1 arrest was in part S6K1+S6K2 dependent, suggesting separate roles in proliferation and in tamoxifen response. We found S6K1 to correlate with HER2 and cytoplasmic Akt activity, whereas S6K2 and phosphorylated S6K were closer connected with ER positivity, low proliferation and nucleic p-Akt. Treatment prediction and prognosis were evaluated by immunohistochemical staining. Nuclear accumulation of S6K1 was indicative of a reduced tamoxifen treatment effect, compared with a significant benefit from tamoxifen treatment in patients without tumor S6K1 nuclear accumulation. Patients with a combination of S6K1 nuclear accumulation and S6K2 cytoplasmic accumulation in the tumor cells had no tamoxifen benefit. Also, S6K1 and S6K2 activation, indicated by p-S6K-t389 expression, was associated with low benefit from tamoxifen compared with untreated patients. In addition, high protein expression of S6K1, independent of localization, predicted worse prognosis. This was not evident for variations in S6K2 or p-S6K-t389 expression.In conclusion, the mTOR targeted kinases S6K1 and S6K2 interfere with proliferation and response to tamoxifen. Monitoring their activity andintracellular localization may provide biomarkers for breast cancer treatment, allowing for identification of a group of patients less likely tobenefit from tamoxifen and thus in need of an alternative or additional treatment.
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| 3. |
- Bostner, Josefine, et al.
(författare)
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S6 kinase signaling: tamoxifen response and prognostic indication in two breast cancer cohorts
- 2015
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Ingår i: Endocrine-Related Cancer. - : BioScientifica. - 1351-0088 .- 1479-6821. ; 22:3, s. 331-343
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Tidskriftsartikel (refereegranskat)abstract
- Detection of signals in the mammalian target of rapamycin (mTOR) and the estrogen receptor (ER) pathways may be a future clinical tool for the prediction of adjuvant treatment response in primary breast cancer. Using immunohistological staining, we investigated the value of the mTOR targets p70-S6 kinase (S6K) 1 and 2 as biomarkers for tamoxifen benefit in two independent clinical trials comparing adjuvant tamoxifen with no tamoxifen or 5 years versus 2 years of tamoxifen treatment. In addition, the prognostic value of the S6Ks was evaluated. We found that S6K1 correlated with proliferation, HER2 status, and cytoplasmic AKT activity, whereas high protein expression levels of S6K2 and phosphorylated (p) S6K were more common in ER-positive, and low-proliferative tumors with pAKT-s473 localized to the nucelus. Nuclear accumulation of S6K1 was indicative of a reduced tamoxifen effect (hazard ratio (HR): 1.07, 95% CI: 0.53-2.81, P=0.84), compared with a significant benefit from tamoxifen treatment in patients without tumor S6K1 nuclear accumulation (HR: 0.42, 95% CI: 0.29-0.62, Pless than0.00001). Also S6K1 and S6K2 activation, indicated by pS6K-t389 expression, was associated with low benefit from tamoxifen (HR: 0.97, 95% CI: 0.50-1.87, P=0.92). In addition, high protein expression of S6K1, independent of localization, predicted worse prognosis in a multivariate analysis, P=0.00041 (cytoplasm), P=0.016 (nucleus). In conclusion, the mTOR-activated kinases S6K1 and S6K2 interfere with proliferation and response to tamoxifen. Monitoring their activity and intracellular localization may provide biomarkers for breast cancer treatment, allowing the identification of a group of patients less likely to benefit from tamoxifen and thus in need of an alternative or additional targeted treatment.
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| 4. |
- Dar, Huma, et al.
(författare)
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Assessment of 25-Year Survival of Women With Estrogen Receptor-Positive/ERBB2-Negative Breast Cancer Treated With and Without Tamoxifen Therapy A Secondary Analysis of Data From the Stockholm Tamoxifen Randomized Clinical Trial
- 2021
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Ingår i: JAMA Network Open. - : American Medical Association. - 2574-3805. ; 4:6
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE Clinically used breast cancer markers, such as tumor size, tumor grade, progesterone receptor (PR) status, and Ki-67 status, are known to be associated with short-term survival, but the association of these markers with long-term (25-year) survival is unclear. OBJECTIVE To assess the association of clinically used breast cancer markers with long-term survival and treatment benefit among postmenopausal women with lymph node-negative, estrogen receptor [ER]-positive and ERBB2-negative breast cancer who received tamoxifen therapy. DESIGN, SETTING, AND PARTICIPANTS This study was a secondary analysis of data from a subset of 565 women with ER-positive/ERBB2-negative breast cancer who participated in the Stockholm tamoxifen (STO-3) randomized clinical trial. The STO-3 clinical trial was conducted from 1976 to 1990 and comprised 1780 postmenopausal women with lymph node-negative breast cancer who were randomized to receive adjuvant tamoxifen therapy or no endocrine therapy. Complete 25-year follow-up data through December 31, 2016, were obtained from Swedish national registers. Immunohistochemical markers were reannotated in 2014. Data were analyzed from April to December 2020. INTERVENTIONS Patients in the original STO-3 clinical trial were randomized to receive 2 years of tamoxifen therapy vs no endocrine therapy. In 1983, patients who received tamoxifen therapy without cancer recurrence during the 2-year treatment and who consented to continued participation in the STO-3 study were further randomized to receive 3 additional years of tamoxifen therapy or no endocrine therapy. MAIN OUTCOMES AND MEASURES Distant recurrence-free interval (DRFI) by clinically used breast cancer markers was assessed using Kaplan-Meier and multivariable Cox proportional hazards analyses adjusted for age, period of primary diagnosis, tumor size (T1a and T1b [T1a/b], T1c, and T2), tumor grade (1-3), PR status (positive vs negative), Ki-67 status (low vs medium to high), and STO-3 clinical trial arm (tamoxifen treatment vs no adjuvant treatment). A recursive partitioning analysis was performed to evaluate which markers were able to best estimate long-term DRFI. RESULTS The study population comprised 565 postmenopausal women (mean [SD] age, 62.0 [5.3] years) with lymph node-negative, ER-positive/ERBB2-negative breast cancer. A statistically significant difference in long-term DRFI was observed by tumor size (88% for T1a/b vs 76% for T1c vs 63% for T2 tumors; log-rank P <.001) and tumor grade (81% for grade 1 vs 77% for grade 2 vs 65% for grade 3 tumors; log-rank P =.02) but not by PR status or Ki-67 status. Patients with smaller tumors (hazard ratio [HR], 0.31 [95% CI, 0.17-0.55] for T1a/b tumors and 0.58 [95% CI, 0.38-0.88] for T1c tumors) and grade 1 tumors (HR, 0.48; 95% CI, 0.24-0.95) experienced a significant reduction in the long-term risk of distant recurrence compared with patients with larger (T2) tumors and grade 3 tumors, respectively. A significant tamoxifen treatment benefitwas observed among patients with larger tumors (HR, 0.53 [95% CI, 0.32-0.89] for T1c tumors and 0.34 [95% CI, 0.16-0.73] for T2 tumors), lower tumor grades (HR, 0.24 [95% CI, 0.07-0.82] for grade 1 tumors and 0.50 [95% CI, 0.31-0.80] for grade 2 tumors), and PR-positive status (HR, 0.38; 95% CI, 0.24-0.62). The recursive partitioning analysis revealed that tumor sizewas the most important characteristic associated with long-term survival, followed by clinical trial arm among patients with larger tumors. CONCLUSIONS AND RELEVANCE This secondary analysis of data from the STO-3 clinical trial indicated that, among the selected subgroup of patients, tumor size followed by tumor grade were the markers most significantly associated with long-term survival. Furthermore, a significant long-term tamoxifen treatment benefit was observed among patients with larger tumors, lower tumor grades, and PR-positive tumors.
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| 5. |
- Ellegård, Sander, et al.
(författare)
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ERBB2 and PTPN2 gene copy numbers as prognostic factors in HER2-positive metastatic breast cancer treated with trastuzumab
- 2019
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Ingår i: Oncology Letters. - Athens, Greece : Spandidos Publications. - 1792-1074 .- 1792-1082. ; 17:3, s. 3371-3381
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Tidskriftsartikel (refereegranskat)abstract
- Trastuzumab has markedly improved the treatment and long-term prognosis of patients with HER2-positive breast cancer. A frequent clinical challenge in patients with relapsing and/or metastatic disease is de novo or acquired trastuzumab resistance, and to date no predictive biomarkers for palliative trastuzumab have been established. In the present study, the prognostic values of factors involved in the HER2-associated PI3K/Akt signalling pathway were explored. The first 46 consecutive patients treated at the Department of Oncology, Linkoping University Hospital between 2000 and 2007 with trastuzumab for HER2-positive metastatic breast cancer were retrospectively included. The gene copy number variation and protein expression of several components of the PI3K/Akt pathway were assessed in the tumour tissue and biopsy samples using droplet digital polymerase chain reaction and immunohistochemistry. Patients with tumours displaying a high-grade ERBB2 (HER2) amplification level of amp;gt;= 6 copies had a significantly improved overall survival hazard ratio [(HR)=0.4; 95%, confidence interval (CI): 0.2-0.9] and progression-free survival (HR=0.3; 95% CI: 0.1-0.7) compared with patients with tumours harbouring fewer ERBB2 copies. High-grade ERBB2 amplification was significantly associated with the development of central nervous system metastases during palliative treatment. Copy gain (amp;gt;= 3 copies) of the gene encoding the tyrosine phosphatase PTPN2 was associated with a shorter overall survival (HR=2.0; 95% CI: 1.0-4.0) and shorter progression-free survival (HR=2.1; 95% CI: 1.0-4.1). In conclusion, high ERBB2 amplification level is a potential positive prognostic factor in trastuzumab-treated HER2-positive metastatic breast cancer, whereas PTPN2 gain is a potential negative prognostic factor. Further studies are warranted on the role of PTPN2 in HER2 signalling.
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| 6. |
- Falivelli, Giulia, et al.
(författare)
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Attenuation of eph receptor kinase activation in cancer cells by coexpressed ephrin ligands
- 2013
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Ingår i: PLOS ONE. - San Francisco, CA, United States : Public Library of Science. - 1932-6203. ; 8:11, s. e81445-
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Tidskriftsartikel (refereegranskat)abstract
- The Eph receptor tyrosine kinases mediate juxtacrine signals by interacting "in trans" with ligands anchored to the surface of neighboring cells via a GPI-anchor (ephrin-As) or a transmembrane segment (ephrin-Bs), which leads to receptor clustering and increased kinase activity. Additionally, soluble forms of the ephrin-A ligands released from the cell surface by matrix metalloproteases can also activate EphA receptor signaling. Besides these trans interactions, recent studies have revealed that Eph receptors and ephrins coexpressed in neurons can also engage in lateral "cis" associations that attenuate receptor activation by ephrins in trans with critical functional consequences. Despite the importance of the Eph/ephrin system in tumorigenesis, Eph receptor-ephrin cis interactions have not been previously investigated in cancer cells. Here we show that in cancer cells, coexpressed ephrin-A3 can inhibit the ability of EphA2 and EphA3 to bind ephrins in trans and become activated, while ephrin-B2 can inhibit not only EphB4 but also EphA3. The cis inhibition of EphA3 by ephrin-B2 implies that in some cases ephrins that cannot activate a particular Eph receptor in trans can nevertheless inhibit its signaling ability through cis association. We also found that an EphA3 mutation identified in lung cancer enhances cis interaction with ephrin-A3. These results suggest a novel mechanism that may contribute to cancer pathogenesis by attenuating the tumor suppressing effects of Eph receptor signaling pathways activated by ephrins in trans.
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| 7. |
- Fohlin, Helena, et al.
(författare)
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Akt2 expression is associated with good long-term prognosis in oestrogen receptor positive breast cancer
- 2013
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Ingår i: European Journal of Cancer. - : Elsevier. - 0959-8049 .- 1879-0852. ; 49:6, s. 1196-1204
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionAkt is a signalling modulator for many cellular processes, including metabolism, cell proliferation, cell survival and cell growth. Three isoforms of Akt have been identified, but only a few studies have concerned the isoform-specific roles in the prognosis of breast cancer patients. The aim of this study was to investigate the prognostic value of v-akt murine thymoma viral oncogene homologue 1 (Akt1) and v-akt murine thymoma viral oncogene homologue 2 (Akt2) in oestrogen receptor positive (ER+) and oestrogen receptor negative (ER–) breast cancer with long-term follow-up.Material and methodsThe expression of Akt in tumour tissue was analysed with immunohistochemistry in a cohort of 272 postmenopausal patients with stage II breast cancer. The median follow-up time was 19 years. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using the Cox’s proportional hazards model.ResultsThe risk of distant recurrence was reduced for patients with ER+ tumours expressing Akt2 compared to patients with no Akt2 expression (HR = 0.49, 95% CI 0.29–0.82, p = 0.007). When adjusting for important clinical tumour characteristics and treatment, Akt2 was still an independent prognostic factor (HR = 0.38, 95% CI 0.21–0.68, p = 0.001) and the association remained long-term. The prognostic value of Akt2 increased with higher oestrogen receptor levels from no effect among patients with ER– tumours to 68% risk reduction for the group with high ER-levels (P for trend = 0.042). Akt1 showed no significant prognostic information.ConclusionOur results indicate that Akt2 expression is associated with a lower distant recurrence rate for patients with ER+ tumours and that this association remains long-term. The prognostic value of Akt2 increases with higher oestrogen receptor expression, motivating further mechanistic studies on the role of Akt2 in ER+ breast cancer.
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| 8. |
- Husa, Anna-Maria, et al.
(författare)
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EPH/ephrin profile and EPHB2 expression predicts patient survival in breast cancer
- 2016
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Ingår i: Oncotarget. - : IMPACT JOURNALS LLC. - 1949-2553. ; 7:16, s. 21362-21380
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Tidskriftsartikel (refereegranskat)abstract
- The EPH and ephrins function as both receptor and ligands and the output on their complex signaling is currently investigated in cancer. Previous work shows that some EPH family members have clinical value in breast cancer, suggesting that this family could be a source of novel clinical targets. Here we quantified the mRNA expression levels of EPH receptors and their ligands, ephrins, in 65 node positive breast cancer samples by RT-PCR with TaqMan (R) Micro Fluidics Cards Microarray. Upon hierarchical clustering of the mRNA expression levels, we identified a subgroup of patients with high expression, and poor clinical outcome. EPHA2, EPHA4, EFNB1, EFNB2, EPHB2 and EPHB6 were significantly correlated with the cluster groups and particularly EPHB2 was an independent prognostic factor in multivariate analysis and in four public databases. The EPHB2 protein expression was also analyzed by immunohistochemistry in paraffin embedded material (cohort 2). EPHB2 was detected in the membrane and cytoplasmic cell compartments and there was an inverse correlation between membranous and cytoplasmic EPHB2. Membranous EPHB2 predicted longer breast cancer survival in both univariate and multivariate analysis while cytoplasmic EPHB2 indicated shorter breast cancer survival in univariate analysis. Concluding: the EPH/EFN cluster analysis revealed that high EPH/EFN mRNA expression is an independent prognostic factor for poor survival. Especially EPHB2 predicted poor breast cancer survival in several materials and EPHB2 protein expression has also prognostic value depending on cell localization.
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| 9. |
- Johansson, Annelie, et al.
(författare)
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Clinical and molecular characteristics of estrogen receptor-positive ultralow risk breast cancer tumors identified by the 70-gene signature
- 2022
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 150:12, s. 2072-2082
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Tidskriftsartikel (refereegranskat)abstract
- The metastatic potential of estrogen receptor (ER)-positive breast cancers is heterogeneous and distant recurrences occur months to decades after primary diagnosis. We have previously shown that patients with tumors classified as ultralow risk by the 70-gene signature have a minimal long-term risk of fatal breast cancer. Here, we evaluate the previously unexplored underlying clinical and molecular characteristics of ultralow risk tumors in 538 ER-positive patients from the Stockholm tamoxifen randomized trial (STO-3). Out of the 98 ultralow risk tumors, 89% were luminal A molecular subtype, whereas 26% of luminal A tumors were of ultralow risk. Compared to other ER-positive tumors, ultralow risk tumors were significantly (Fishers test, P < .05) more likely to be of smaller tumor size, lower grade, progesterone receptor (PR)-positive, human epidermal growth factor 2 (HER2)-negative and have low Ki-67 levels (proliferation-marker). Moreover, ultralow risk tumors showed significantly lower expression scores of multi-gene modules associated with the AKT/mTOR-pathway, proliferation (AURKA), HER2/ERBB2-signaling, IGF1-pathway, PTEN-loss and immune response (IMMUNE1 and IMMUNE2) and higher expression scores of the PIK3CA-mutation-associated module. Furthermore, 706 genes were significantly (FDR < 0.001) differentially expressed in ultralow risk tumors, including lower expression of genes involved in immune response, PI3K/Akt/mTOR-pathway, histones, cell cycle, DNA repair, apoptosis and higher expression of genes coding for epithelial-to-mesenchymal transition and homeobox proteins, among others. In conclusion, ultralow risk tumors, associated with minimal long-term risk of fatal disease, differ from other ER-positive tumors, including luminal A molecular subtype tumors. Identification of these characteristics is important to improve our prediction of nonfatal vs fatal breast cancer.
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| 10. |
- Johansson, Annelie, et al.
(författare)
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Twenty-Year Benefit From Adjuvant Goserelin and Tamoxifen in Premenopausal Patients With Breast Cancer in a Controlled Randomized Clinical Trial
- 2022
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Ingår i: Journal of Clinical Oncology. - : Lippincott, Williams & Wilkins. - 0732-183X .- 1527-7755. ; 40:35, s. 4071-4082
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSETo assess the long-term (20-year) endocrine therapy benefit in premenopausal patients with breast cancer.METHODSSecondary analysis of the Stockholm trial (STO-5, 1990-1997) randomly assigning 924 premenopausal patients to 2 years of goserelin (3.6 mg subcutaneously once every 28 days), tamoxifen (40 mg orally once daily), combined goserelin and tamoxifen, or no adjuvant endocrine therapy (control) is performed. Random assignment was stratified by lymph node status; lymph node-positive patients (n = 459) were allocated to standard chemotherapy (cyclophosphamide, methotrexate, and fluorouracil). Primary tumor immunohistochemistry (n = 731) and gene expression profiling (n = 586) were conducted in 2020. The 70-gene signature identified genomic low-risk and high-risk patients. Kaplan-Meier analysis, multivariable Cox proportional hazard regression, and multivariable time-varying flexible parametric modeling assessed the long-term distant recurrence-free interval (DRFI). Swedish high-quality registries allowed a complete follow-up of 20 years.RESULTSIn estrogen receptor-positive patients (n = 584, median age 47 years), goserelin, tamoxifen, and the combination significantly improved long-term distant recurrence-free interval compared with control (multivariable hazard ratio [HR], 0.49; 95% CI, 0.32 to 0.75, HR, 0.57; 95% CI, 0.38 to 0.87, and HR, 0.63; 95% CI, 0.42 to 0.94, respectively). Significant goserelin-tamoxifen interaction was observed (P = .016). Genomic low-risk patients (n = 305) significantly benefitted from tamoxifen (HR, 0.24; 95% CI, 0.10 to 0.60), and genomic high-risk patients (n = 158) from goserelin (HR, 0.24; 95% CI, 0.10 to 0.54). Increased risk from the addition of tamoxifen to goserelin was seen in genomic high-risk patients (HR, 3.36; 95% CI, 1.39 to 8.07). Moreover, long-lasting 20-year tamoxifen benefit was seen in genomic low-risk patients, whereas genomic high-risk patients had early goserelin benefit.CONCLUSIONThis study shows 20-year benefit from 2 years of adjuvant endocrine therapy in estrogen receptor-positive premenopausal patients and suggests differential treatment benefit on the basis of tumor genomic characteristics. Combined goserelin and tamoxifen therapy showed no benefit over single treatment. Long-term follow-up to assess treatment benefit is critical.
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| 11. |
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| 12. |
- Karlsson, Elin, et al.
(författare)
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High-Resolution Genomic Analysis of the 11q13 Amplicon in Breast Cancers Identifies Synergy with 8p12 Amplification, Involving the mTOR Targets S6K2 and 4EBP1
- 2011
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Ingår i: Genes, Chromosomes and Cancer. - : Wiley-Blackwell. - 1045-2257 .- 1098-2264. ; 50:10, s. 775-787
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Tidskriftsartikel (refereegranskat)abstract
- The chromosomal region 11q13 is amplified in 15-20% of breast cancers; an event not only associated with estrogen receptor (ER) expression but also implicated in resistance to endocrine therapy. Coamplifications of the 11q13 and 8p12 regions are common, suggesting synergy between the amplicons. The aim was to identify candidate oncogenes in the 11q13 region based on recurrent amplification patterns and correlations to mRNA expression levels. Furthermore, the 11q13/8p12 coamplification and its prognostic value, was evaluated at the DNA and the mRNA levels. Affymetrix 250K NspI arrays were used for whole-genome screening of DNA copy number changes in 29 breast tumors. To identify amplicon cores at 11q13 and 8p12, genomic identification of significant targets in cancer (GISTIC) was applied. The mRNA expression levels of candidate oncogenes in the amplicons [ RAD9A, RPS6KB2 (S6K2), CCND1, FGF19, FGF4, FGF3, PAK1, GAB2 (11q13); EIF4EBP1 (4EBP1), PPAPDC1B, and FGFR1 (8p12)] were evaluated using real-time PCR. Resulting data revealed three main amplification cores at 11q13. ER expression was associated with the central 11q13 amplification core, encompassing CCND1, whereas 8p12 amplification/gene expression correlated to S6K2 in a proximal 11q13 core. Amplification of 8p12 and high expression of 4EBP1 or FGFR1 was associated with a poor outcome in the group. In conclusion, single nucleotide polymorphism arrays have enabled mapping of the 11q13 amplicon in breast tumors with high resolution. A proximal 11q13 core including S6K2 was identified as involved in the coamplification/coexpression with 8p12, suggesting synergy between the mTOR targets S6K2 and 4EBP1 in breast cancer development and progression.
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| 13. |
- Karlsson, Elin, et al.
(författare)
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Loss of protein tyrosine phosphatase, non-receptor type 2 is associated with activation of AKT and tamoxifen resistance in breast cancer
- 2015
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Ingår i: Breast Cancer Research and Treatment. - : Springer Verlag (Germany). - 0167-6806 .- 1573-7217. ; 153:1, s. 31-40
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Tidskriftsartikel (refereegranskat)abstract
- Breast cancer is a heterogeneous disease and new clinical markers are needed to individualise disease management and therapy further. Alterations in the PI3K/AKT pathway, mainly PIK3CA mutations, have been shown frequently especially in the luminal breast cancer subtypes, suggesting a cross-talk between ER and PI3K/AKT. Aberrant PI3K/AKT signalling has been connected to poor response to anti-oestrogen therapies. In vitro studies have shown protein tyrosine phosphatase, non-receptor type 2 (PTPN2) as a previously unknown negative regulator of the PI3K/AKT pathway. Here, we evaluate possible genomic alterations in the PTPN2 gene and its potential as a new prognostic and treatment predictive marker for endocrine therapy benefit in breast cancer. PTPN2 gene copy number was assessed by real-time PCR in 215 tumour samples from a treatment randomised study consisting of postmenopausal patients diagnosed with stage II breast cancer 1976-1990. Corresponding mRNA expression levels of PTPN2 were evaluated in 86 available samples by the same methodology. Gene copy loss of PTPN2 was detected in 16 % (34/215) of the tumours and this was significantly correlated with lower levels of PTPN2 mRNA. PTPN2 gene loss and lower mRNA levels were associated with activation of AKT and a poor prognosis. Furthermore, PTPN2 gene loss was a significant predictive marker of poor benefit from tamoxifen treatment. In conclusion, genomic loss of PTPN2 may be a previously unknown mechanism of PI3K/AKT upregulation in breast cancer. PTPN2 status is a potential new clinical marker of endocrine treatment benefit which could guide further individualised therapies in breast cancer.
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| 14. |
- Karlsson, Elin, et al.
(författare)
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The mTOR effectors 4EBP1 and S6K2 are frequently coexpressed, and associated with a poor prognosis and endocrine resistance in breast cancer : a retrospective study including patients from the randomised Stockholm tamoxifen trials.
- 2013
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Ingår i: Breast Cancer Research. - : BioMed Central. - 1465-5411 .- 1465-542X. ; 15:5, s. R96-
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: mTOR and its downstream effectors the 4E-binding protein 1 (4EBP1) and the p70 ribosomal S6 kinases (S6K1 and S6K2) are frequently upregulated in breast cancer, and assumed to be driving forces in tumourigenesis, in close connection with oestrogen receptor (ER) networks. Here, we investigated these factors as clinical markers in five different cohorts of breast cancer patients.METHODS: The prognostic significance of 4EBP1, S6K1 and S6K2 mRNA expression was assessed with real-time PCR in 93 tumours from the treatment randomised Stockholm trials, encompassing postmenopausal patients enrolled between 1976 and 1990. Three publicly available breast cancer cohorts were used to confirm the results. Furthermore, the predictive values of 4EBP1 and p4EBP1_S65 protein expression for both prognosis and endocrine treatment benefit were assessed by immunohistochemical analysis of 912 node-negative breast cancers from the Stockholm trials.RESULTS: S6K2 and 4EBP1 mRNA expression levels showed significant correlation and were associated with a poor outcome in all cohorts investigated. 4EBP1 protein was confirmed as an independent prognostic factor, especially in progesterone receptor (PgR)-expressing cancers. 4EBP1 protein expression was also associated with a poor response to endocrine treatment in the ER/PgR positive group. Cross-talk to genomic as well as non-genomic ER/PgR signalling may be involved and the results further support a combination of ER and mTOR signalling targeted therapies.CONCLUSION: This study suggests S6K2 and 4EBP1 as important factors for breast tumourigenesis, interplaying with hormone receptor signalling. We propose S6K2 and 4EBP1 as new potential clinical markers for prognosis and endocrine therapy response in breast cancer.
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| 15. |
- Magic, Zeljana, et al.
(författare)
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Ephrin-B2 inhibits cell proliferation and motility in vitro and predicts longer metastasis-free survival in breast cancer
- 2019
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Ingår i: International Journal of Oncology. - : SPANDIDOS PUBL LTD. - 1019-6439 .- 1791-2423. ; 55:6, s. 1275-1286
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Tidskriftsartikel (refereegranskat)abstract
- The tyrosine kinase receptor EphB4 and its ligand ephrin-B2 interact through cell-to-cell contacts. Upon interaction, EphB4 transmits bidirectional signals. A forward signal inside EphB4-expressing cells is believed to suppress tumor growth, while inside the ephrin-expressing cells, an oncogenic reverse signal arises. In breast cancer cells with a high EphB4 receptor expression the forward signal is low, in part due to the low expression of the ligand ephrin-B2. Therefore, we hypothesized that by re-introducing the ligand in EphB4-positive cells, tumor suppression could be induced by the stimulation of the forward signal. This question was addressed in vitro by the stable lentiviral infection of breast cancer cells with either wild-type EFNB2 or with a mutant EFNB2-5F, unable to transmit reverse signaling. Furthermore, we investigated ephrin-B and EphB4 protein expression in 216 paraffin-embedded tumors using immunohistochemistry. The in vitro results indicated that ephrin-B2 expression was associated with a lower cell proliferation, migration and motility compared with the control cells. These effects were more pronounced when the cells lacked the ability to transmit the reverse signal (B2-5F). In clinical material, ephrin-B protein expression was associated with a positive estrogen receptor (ER) status, a low HER-2 expression and was negatively associated with Nottingham histologic grade (NHG) III. Ephrin-B expression indicated a good prognosis, whereas EphB4 expression was associated with a shorter metastasis-free survival in univariate and multivariate analysis. Furthermore, the prognostic value of EFNB2 and EPHB4 was confirmed at the gene expression level in public datasets. Thus, on the whole, the findings of this study suggest that ephrin-B2 expression is associated with less proliferation and lower motility of breast cancer cells and with a longer patient survival in breast cancer.
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| 16. |
- Miller, Todd W, et al.
(författare)
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Loss of Phosphatase and Tensin Homologue Deleted on Chromosome 10 Engages ErbB3 and Insulin-Like Growth Factor-I Receptor Signaling to Promote Antiestrogen Resistance in Breast Cancer
- 2009
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Ingår i: CANCER RESEARCH. - 0008-5472. ; 69:10, s. 4192-4201
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Tidskriftsartikel (refereegranskat)abstract
- Knockdown of the tumor suppressor phosphatase Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) with shRNA in three estrogen receptor (ER)-positive breast cancer cell lines resulted in increased phosphatidylinositol-3 kinase (PI3K) and AKT activities, resistance to tamoxifen and fulvestrant, and hormone-independent growth. PTEN knockdown induced the up-regulation of ER transcriptional activity in MCF-7 cells but decreased ER protein levels and transcriptional activity in T47D and MDA-361 cells. Tamoxifen and fulvestrant treatment inhibited estradiol-induced Ell transcriptional activity in all shPTEN cell lines but did not abrogate the increased cell proliferation induced by PTEN knockdown. PTEN knockdown increased basal and ligand-induced activation of the insulin-like growth factor-I (IGF-I) and ErbB3 receptor tyrosine kinases, and prolonged the association of the p85 PI3K subunit with the IGF-I receptor (IGF-IR) effector insulin receptor substrate-1 and with ErbB3, implicating VITA in the modulation of Signaling upstream of PI3K. Consistent with these data, PTEN levels inversely correlated with levels of tyrosine-phosphorylated IGF-IR in tissue lysate arrays of primary breast cancers. Inhibition of IGF-IR and/or ErbB2-mediated activation of ErbB3 with tyrosine kinase inhibitors restored hormone dependence and the growth inhibitory effect of tamoxifen and fulvestrant. oil shPTEN cells, suggesting that cotargeting both Ell and receptor tyrosine kinase pathways holds promise for the treatment of patients with ER+, PTEN-deficient breast cancers.
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| 17. |
- Pérez-Tenorio, Gizeh, 1971-, et al.
(författare)
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Activation of AKT/PKB in breast cancer predicts a worse outcome among endocrine treated patients
- 2002
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Ingår i: British Journal of Cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 86:4, s. 540-545
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Tidskriftsartikel (refereegranskat)abstract
- Akt/PKB is a serine/threonine protein kinase that regulates cell cycle progression, apoptosis and growth factor mediated cell survival in association with tyrosine kinase receptors. The protein is a downstream effector of erbB-2 with implications in breast cancer progression and drug resistance in vitro. We aimed to examine the role of Akt-1 in breast cancer patients, by determining whether the expression (Akt-1) and/or activation (pAkt) were related to prognostic markers and survival. The expression of erbB-2, heregulin β1 and Bcl-2 was also assessed by flow cytometry or immunohistochemistry. This study comprised 93 patients, aged < 50 who were treated with tamoxifen and/or goserelin. We found that pAkt was associated with lower S-phase fraction (P = 0.001) and the presence of heregulin β1-expressing stromal cells (P = 0.017). Neither Akt-1 nor pAkt was related with other factors Turnout cells-derived heregulin β1 was found mainly in oestrogen receptor negative (P = 0.026) and node negative (P = 0.005) cases. Survival analysis revealed that pAkt positive patients were more prone to relapse with distant metastasis, independently of S-phase fraction and nodal status (multivariate analysis; P = 0.004). The results suggest that activation of Akt may have prognostic relevance in breast cancer
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| 18. |
- Pérez-Tenorio, Gizeh, 1971-
(författare)
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Alterations in the PI3K/AKT Signaling Pathway and Response to Adjuvant Treatment in Breast Cancer
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- (PI3K)/AKT signaling pathway could be a cause of therapeutic resistance in breast cancer. The PI3K/AKT pathway controls cell proliferation, cell growth and survival, and its members include oncogenes and tumor suppressor genes. Alterations in this pathway are frequent in cancer. In this thesis, we aimed to study the biological significance of some of these alterations in a tumor context as well as their clinical value. PIK3CA gene, encoding the PI3K catalytic subunit, was examined for mutations. The tumor suppressor PTEN, that counteracts PI3Kmediated effects, was studied at the protein level whereas amplification of RPS6KB1 (S6K1) and RPS6KB2 (S6K2) genes, encoding two substrates of the mammalian target of rapamycin (mTOR) acting downstream PI3K/AKT, was also inspected. AKT phosphorylation or activation (pAKT) was determined by immunohistochemistry. Other factors related with this pathway, such as HER-2, heregulin (HRG) β1, the cell cycle inhibitor p21WAF1/CIP1, the pro-apoptotic factor Bcl-2, and cyclin D1, were also considered. These studies were perfomed in two patient materials consisting of premenopausal patients that received endocrine treatment (paper I) and postmenopausal patients randomized to receive radiotherapy (RT) or chemotherapy (CMF) in combination with tamoxifen (Tam) or no endocrine treatment (papers II-IV). In the first material, we found that pAKT indicated higher risk of distant recurrence among endocrine treated patients. In the second material HRGβ1 induced accumulation cytoplasmic p21 in vitro and pAKT was associated with cytoplasmic p21 in the tumors. In addition, p21 cellular location identified subgroups of ER+ patients with different responses to tamoxifen. Other alterations such as PIK3CA mutations and PTEN loss were positively associated in this material. PIK3CA mutations lowered the risk for local recurrences while PTEN loss conferred radiosensitivity as a single variable or combined with mutated PIK3CA. PIK3CA mutations and/or PTEN loss was associated with lower S-phase (SPF). Nevertheless, among patients with low proliferating tumors, these alterations predicted higher risk of recurrence in contrast to those with high proliferating tumors. Finally, we found amplification of the S6K1 and S6K2 genes. S6K2 amplification was associated with cyclin D1 gene amplification, predicted poor recurrence-free survival and breast cancer death, and indicated benefit from tamoxifen. On the other hand, S6K1 amplification was associated with HER-2 amplification/overexpression, indicated higher risk of recurrence and was a predictor of poor response to radiotherapy. These results indicate the potential of this pathway as therapeutic source.
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| 19. |
- Perez-Tenorio, Gizeh, et al.
(författare)
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Clinical potential of the mTOR targets S6K1 and S6K2 in breast cancer
- 2011
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Ingår i: Breast Cancer Research and Treatment. - : Springer Science Business Media. - 0167-6806 .- 1573-7217. ; 128:3, s. 713-723
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Tidskriftsartikel (refereegranskat)abstract
- The mammalian target of rapamycin (mTOR) and its substrates S6K1 and S6K2 regulate cell growth, proliferation, and metabolism through translational control. RPS6KB1 (S6K1) and RPS6KB2 (S6K2) are situated in the commonly amplified 17q21-23 and 11q13 regions. S6K1 amplification and protein overexpression have earlier been associated with a worse outcome in breast cancer, but information regarding S6K2 is scarce. The aim of this study was to evaluate the prognostic and treatment predictive relevance of S6K1/S6K2 gene amplification, as well as S6K2 protein expression in breast cancer. S6K1/S6K2 gene copy number was determined by real-time PCR in 207 stage II breast tumors and S6K2 protein expression was investigated by immunohistochemistry in 792 node-negative breast cancers. S6K1 amplification/gain was detected in 10.7%/21.4% and S6K2 amplification/gain in 4.3%/21.3% of the tumors. S6K2 protein was detected in the nucleus (38%) and cytoplasm (76%) of the tumor cells. S6K1 amplification was significantly associated with HER2 gene amplification and protein expression. S6K2 amplification correlated significantly with high S6K2 mRNA levels, ER+ status and CCND1 amplification. S6K1 and S6K2 gene amplification was associated with a worse prognosis independent of HER2 and CCND1. S6K2 gain and nuclear S6K2 expression was related to an improved benefit from tamoxifen among patients with ER+, respectively ER+/PgR+ tumors. In the ER+/PgR- subgroup, nuclear S6K2 rather indicated decreased tamoxifen responsiveness. S6K1 amplification predicted reduced benefit from radiotherapy. This is the first study showing that S6K2 amplification and overexpression, like S6K1 amplification, have prognostic and treatment predictive significance in breast cancer.
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| 20. |
- Perez-Tenorio, Gizeh, 1971-, et al.
(författare)
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Clinical Value of RPS6KB1 and RPS6KB2 Gene Amplification in Postmenopausal Breast Cancer
- 2008
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Tidskriftsartikel (refereegranskat)abstract
- The mammalian target of rapamycin (mTOR) and its substrates the ribosomal S6 kinases (S6K)1 and 2 integrate nutrient and hormonal/growth factor mediated signals and are implicated indiabetes, obesity and cancer. The genes encoding S6K1 (RPS6KB1) and S6K2 (RPS6KB2) aresituated close to well known amplicons but information regarding its expression and clinicalvalue is scarce. In this study we quantified RPS6KB1/2 gene copy number, establishedassociations with other clinical factors and explored their clinical value in breast cancer. RPS6KB1/2 copy number was determined by fast real-time PCR in 207 breast tumors.RPS6KB1 was amplified (≥ 4 copies) in 10.7% (22/206) and RPS6KB2 in 4.3% (9/207) of thetumors. Amplification of RPS6KB1 was associated with HER2 gene amplification (P=0.025)and protein expression (P=0.014) while RPS6KB2 correlated with ER+ status (P=0.046) and CCND1 amplification (P<0.00001). In a multivariate analysis, both genes were independentprognostic factors indicating higher risk to develop recurrences. In terms of loco regionalcontrol, amplification of the RPS6KB1 gene predicted less response to radiotherapy (P=0.035) while RPS6KB2 gene copy gain (≥ 3 copies) indicated increased benefit from tamoxifen (P=0.03) among ER+ patients. S6K1/2 gene amplification could be used as an indicator oftherapy response among postmenopausal breast cancer patients.
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| 21. |
- Perez-Tenorio, Gizeh, 1971-, et al.
(författare)
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Cytoplasmic p21WAF1/CIP1 correlates with Akt activation and poor response to tamoxifen in breast cancer
- 2006
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Ingår i: International Journal of Oncology. - 1019-6439 .- 1791-2423. ; 28:5, s. 1031-1042
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Tidskriftsartikel (refereegranskat)abstract
- P21WAF1/Cip1 (p21) translocates to the cytoplasm inducing cell cycle progression and survival upon Akt/PKB activation. We studied whether heregulin beta1 (HRGbeta1), that activates the PI3K/Akt and MAPK pathways, also misallocates p21. We also explored whether HRGbeta1 interferes with the effects of tamoxifen. The clinical material studied helped us to clarify whether p21 was associated with phosphorylated Akt, recurrence-free survival and response to tamoxifen. MCF-7 cells treated with HRGbeta1 -/+ E2 were analyzed by flow cytometry to observe how the different compounds affected tamoxifen-induced cell cycle arrest and apoptosis. Total cell lysate and nuclear and cytoplasmic fractions were used to detect p21, phospho-Akt and other proteins by Western blotting. Immunofluorescence was used to visualize p21+ cells upon HRGbeta1 and E2 stimulation. The localization of p21 in breast cancer was studied by immunohistochemistry in frozen tumor sections from 280 patients. In MCF-7 we found that HRGbeta1 counteracted the inhibition of p21 expression by tamoxifen and caused p21 cytoplasmic accumulation. HRGbeta1 partially counteracted the cytostatic effect of tamoxifen but abrogated its cytotoxic effect. The clinical material revealed that nuclear p21 (P=0.022) and cytoplasmic p21 (P=0.00001) were associated with phospho-Akt. Based on p21 cell location, we identified 3 subgroups of ER+ patients: the p21N+/C- group for whom tamoxifen was needed otherwise the survival was poor (P=0.0082), the p21N+/C+ or p21N-/C- group, that responded to tamoxifen (P=0.034), and the p21C+/N- group, that might not benefit from this treatment (P=0.7). In conclusion, HRGbeta1 inhibits tamoxifen-induced apoptosis, contributes to p21 cytoplasmic expression while the cellular localization of p21 interacts with the benefit from tamoxifen treatment.
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| 22. |
- Pérez-Tenorio, Gizeh, 1971-, et al.
(författare)
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PIK3CA mutations and PTEN loss correlate with similar prognostic factors and are not mutually exclusive in breast cancer
- 2007
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Ingår i: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 13:12, s. 3577-3584
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The phosphatidylinositol 3'-kinase/Akt pathway is frequently altered in breast cancer. PTEN, a phosphatase that opposes the effect of phosphatidylinositol 3'-kinase, can be mutated or lost, whereas the PIK3CA gene is mutated. These have been proposed as alternative mechanisms, and their clinicalpathology significance is under discussion. In this study, we aimed to explore whether PIK3CA mutations and PTEN loss are mutually exclusive mechanisms, correlate with other known clinicopathologic markers, or have clinical implication in breast cancer. Experimental Design: Exons 9 and 20 of the PIK3CA gene were analyzed in 270 breast tumors, and mutations were detected by single-stranded conformational analysis followed by sequencing. The expression of PTEN was evaluated by immunohistochemistry in 201 tumors. Results: PIK3CA mutations were found in 24% of the tumors and associated with estrogen receptor(+) status, small size, negative HER2 status, high Akt1, and high cyclin D1 protein expression. PTEN was negative in 37% of the cases and PTEN loss was associated with PIK3CA mutations (P = 0.0024). Tumors presenting PTEN loss or both alterations were often estrogen receptor(+), small in size, and HER2(-). PIK3CA mutations predicted for longer local recurrence-free survival. Moreover, PTEN loss by itself or combined with mutated PIK3CA tended to confer radiosensitivity. In addition, the patients with high S-phase fraction had longer recurrence-free survival if they carried mutations in the PIK3CA gene and/or had lost PTEN, whereas the same alterations were associated with shorter recurrence-free survival among patients with low S-phase fraction. Conclusions: PIK3CA mutations and PTEN loss were not mutually exclusive events and associated with similar prognostic factors.
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| 23. |
- Pousette, Jenny, et al.
(författare)
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Prognostic and Predictive Significance of Stromal Tumor-Infiltrating Lymphocytes (sTILs) in ER-Positive/HER2-Negative Postmenopausal Breast Cancer Patients
- 2022
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Ingår i: Cancers. - : MDPI. - 2072-6694. ; 14:19
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Tidskriftsartikel (refereegranskat)abstract
- The clinical impact of tumor-infiltrating lymphocytes (TILs) is less known for breast cancer patients with the estrogen receptor-positive (ER+)/human epidermal growth factor receptor-negative (HER−) subtype. Here, we explored the prognostic and predictive value of TILs regarding distant recurrence-free interval (DRFI) and breast cancer-specific survival (BCSS) in 763 postmenopausal patients randomized to receive tamoxifen vs. no systemic treatment. TILs were assessed in whole section tumor samples stained with H&E and divided into low (<10%), intermediate (10–39%), or high (≥40%). High TILs were associated with poor prognostic variables and good prognoses for all patients, but not within the ER+/HER2− group. Within the ER+/HER2− group, high gene expression of CD19 and PD-L1 and high IMMUNE1 score indicated good prognosis in multivariable analysis while high CD8 and CD19 gene expression and high IMMUNE1 score were associated with less tamoxifen benefit. These results indicate that within the ER+/HER2− subtype there could be subsets of patients where expression of specific TIL markers might be used to reveal candidates for immune therapy interventions upon failure of the endocrine therapy.
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| 24. |
- Sandström, Josefine, et al.
(författare)
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IP6K2 predicts favorable clinical outcome of primary breast cancer
- 2021
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Ingår i: Molecular and clinical oncology. - : Spandidos Publication Ltd. - 2049-9450 .- 2049-9469. ; 14:5
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Tidskriftsartikel (refereegranskat)abstract
- The inositol hexakisphosphate kinase (IP6K) 1 and 2 genes are localized at 3p21.31, a highly altered gene-dense chromosomal region in cancer. The IP6Ks convert IP6 to IP7, which inhibits activation of the tumor-promoting PI3K/Akt/mTOR signaling pathway. IP6K2 has been suggested to be involved in p53-induced apoptosis, while IP6K1 may stimulate tumor growth and migration. The present study aimed to elucidate the role of the two IP6Ks in predicting outcome in patients with breast cancer. To the best of our knowledge, the role of IP6K was analyzed for the first time in tumors from three cohorts of patients with breast cancer; one Swedish low-risk cohort, one Dutch cohort and the TCGA dataset. Analyses of gene -and protein expression and subcellular localization were included. IP6K2 gene expression was associated with ER positivity and nuclear p-Akt. Improved prognosis was detected with high IP6K2 gene expression compared with low IP6K2 gene expression in systemically untreated patients in the Swedish low-risk and Dutch cohorts. In the TCGA dataset, IP6K2 prognostic value was significant when selecting for tumors with wild-type TP53. A multivariable analysis testing IP6K2 against other cancer-related genes at 3p.21.31, including IP6K1 and clinical biomarkers, revealed that IP6K2 was associated with decreased risk of distant recurrence. IP6K1 was associated with increased risk of distant recurrence in the multivariable test and protein analysis revealed trends of worse prognosis with high IP6K1 in the cytoplasm. The expression levels of IP6K1 and IP6K2 were associated to a high extent; however, a diverging prognostic value of the two genes was observed in breast cancer. The present data suggest that IP6K2 can be a favorable prognostic factor, while IP6K1 may not be.
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| 25. |
- Stål, Olle, et al.
(författare)
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Akt kinases in breast cancer and the results of adjuvant therapy
- 2003
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Ingår i: Breast Cancer Research. - : Springer Science and Business Media LLC. - 1465-5411 .- 1465-542X. ; 5:2, s. R37-R44
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe serine/threonine kinase Akt, or protein kinase B, has recently been a focus of interest because of its activity to inhibit apoptosis. It mediates cell survival by acting as a transducer of signals from growth factor receptors that activate phosphatidylinositol 3-kinase.MethodsWe analysed the expression of the isoforms Akt1 and Akt2 as well as phosphorylated Akt (pAkt) by immunohistochemistry in frozen tumour samples from 280 postmenopausal patients who participated in a randomised trial comparing cyclophosphamide–methotrexate–5-fluorouracil chemotherapy and postoperative radiotherapy. The patients were simultaneously randomised to tamoxifen or to no endocrine treatment.ResultsMarked staining was found in 24% of the tumours for Akt1, but in only 4% for Akt2. A low frequency of Akt2-positive cells (1–10%) was observed in another 26% of the tumours. pAkt was significantly associated with both Akt1 and Akt2 expression. Overexpression of erbB2 correlated significantly with pAkt (P = 0.0028). The benefit from tamoxifen was analysed in oestrogen receptor (ER)-positive patients. Patients with a negative status of Akt (no overexpression of Akt1, Akt2 or pAkt) showed significant benefit from tamoxifen. The relative rate of distant recurrence, with versus without tamoxifen, was 0.44 (95% confidence interval [CI], 0.25–0.79) for ER+/Akt1- patients, while it was 0.72 (95% CI, 0.34–1.53) for ER+/Akt1+ patients. The difference in rate ratio did not reach statistical significance. The rate of locoregional recurrence was significantly decreased with radiotherapy versus chemotherapy for Akt-negative patients (rate ratio, 0.23; 95% CI, 0.08–0.67; P = 0.0074), while no benefit was evident for the Akt-positive subgroup (rate ratio, 0.77; 95% CI, 0.31–1.9; P = 0.58). The interaction between Akt and the efficacy of radiotherapy was significant in multivariate analysis (P = 0.042).ConclusionActivation of the Akt pathway is correlated with erbB2 overexpression in breast cancer. The results suggest that Akt may predict the local control benefit from radiotherapy.
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