| 1. |
- Ahnström Waltersson, Marie, 1976-, et al.
(författare)
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Role of cyclin D1 in ErbB2-positive breast cancer and tamoxifen resistance.
- 2005
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Ingår i: Breast Cancer Research and Treatment. - : Springer Science and Business Media LLC. - 0167-6806 .- 1573-7217. ; 91:2, s. 145-151
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Tidskriftsartikel (refereegranskat)abstract
- Cyclin D1 plays an important role in the regulation of the G1 phase in the cell cycle. In mammary epithelial cells the expression of cyclin D1 is regulated through the oestrogen receptor and via ErbB2 signalling. Here we investigated the prognostic significance of cyclin D1 among 230 breast cancer patients randomised for tamoxifen, CMF chemotherapy and radiotherapy. The importance of combined cyclin D1 and ErbB2 overexpression was also analysed. Immunohistochemical analysis of the cyclin D1 expression resulted in 69 (29.8%) weakly positive, 107 (46.5%) moderately positive and 54 (23.7%) strongly positive cases. The prognostic importance of ErbB2 was significantly greater for patients whose tumours overexpressed cyclin D1 than for other patients (p = 0.026). In the former group, ErbB2 overexpression was strongly associated with increased risk of recurrence (RR = 4.7; 95% CI, 2.1-10.4) and breast cancer death (RR = 5.4; 95% CI, 2.3-12.6). This result is in accordance with experimental studies demonstrating a link between cyclin D1 and ErbB2 in oncogenesis. Among oestrogen receptor positive patients, those with moderate cyclin D1 expression significantly did benefit from tamoxifen treatment (RR = 0.42; 95% CI, 0.21-0.82) whereas those with weak or strong expression did not. Therefore cyclin D1 might be a predictive marker for tamoxifen resistance.
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| 2. |
- Bostner, Josefine, et al.
(författare)
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Activation of Akt, mTOR, and the estrogen receptor as a signature to predict tamoxifen treatment benefit
- 2013
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Ingår i: Breast Cancer Research and Treatment. - : Springer Verlag (Germany). - 0167-6806 .- 1573-7217. ; 137:2, s. 397-406
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Tidskriftsartikel (refereegranskat)abstract
- The frequent alterations of the PI3K/Akt/mTOR-growth signaling pathway are proposed mechanisms for resistance to endocrine therapy in breast cancer, partly through regulation of estrogen receptor alpha (ER) activity. Reliable biomarkers for treatment prediction are required for improved individualized treatment. We performed a retrospective immunohistochemical analysis of primary tumors from 912 postmenopausal patients with node-negative breast cancer, randomized to either tamoxifen or no adjuvant treatment. Phosphorylated (p) Akt-serine (s) 473, p-mTOR-s2448, and ER phosphorylations-s167 and -s305 were evaluated as potential biomarkers of prognosis and tamoxifen treatment efficacy. High expression of p-mTOR indicated a reduced response to tamoxifen, most pronounced in the ER+/progesterone receptor (PgR) + subgroup (tamoxifen vs. no tamoxifen: hazard ratio (HR), 0.86; 95 % confidence interval (CI), 0.31-2.38; P = 0.78), whereas low p-mTOR expression predicted tamoxifen benefit (HR, 0.29; 95 % CI, 0.18-0.49; P = 0.000002). In addition, nuclear p-Akt-s473 as well as p-ER at -s167 and/or -s305 showed interaction with tamoxifen efficacy with borderline statistical significance. A combination score of positive pathway markers including p-Akt, p-mTOR, and p-ER showed significant association with tamoxifen benefit (test for interaction; P = 0.029). Cross-talk between growth signaling pathways and ER-signaling has been proposed to affect tamoxifen response in hormone receptor-positive breast cancer. The results support this hypothesis, as an overactive pathway was significantly associated with reduced response to tamoxifen. A clinical pre-treatment test for cross-talk markers would be a step toward individualized adjuvant endocrine treatment with or without the addition of PI3K/Akt/mTOR pathway inhibitors.
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| 3. |
- Khoshnoud, Mahmoud R., et al.
(författare)
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Immunohistochemistry compared to cytosol assays for determination of estrogen receptor and prediction of the long-term effect of adjuvant tamoxifen
- 2011
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Ingår i: Breast Cancer Research and Treatment. - : Springer Science and Business Media LLC. - 0167-6806 .- 1573-7217. ; 126:2, s. 421-430
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study is to compare immunohistochemistry (IHC) and cytosol-based assays for determination of estrogen receptor (ER) and prediction of response to adjuvant tamoxifen treatment in postmenopausal women with early-stage invasive breast cancer. The Stockholm Breast Cancer Study Group conducted a randomized trial during 1976 through 1990 comparing adjuvant tamoxifen versus control. The patients were stratified according to tumor size and lymph node status in high-risk and low-risk groups. In this study we evaluated 683 patients with "low risk" breast cancer (size a parts per thousand currency sign30 mm, lymph node-negative) for whom ER status had been determined by both the cytosol assays and IHC at one pathology laboratory. The median follow-up was 17 years. Six hundred eighty-three patients had tumors with ER determined by both methods, 536 (78.5%) were ER-positive by cytosol assays using the cutoff level at a parts per thousand yen0.05 fmol/mu g DNA and 539 patients were ER-positive (79%) by IHC using the cutoff level at a parts per thousand yen10% cell stained. Thirty-nine tumors (5.7%) were ER-positive by cytosol but not by IHC, whereas the opposite pattern was found for 42 cases (6.1%). Only seven tumors had stained cells between 0 and 9% by IHC. The concordance between IHC and cytosol assays was high (88%). The kappa statistic was 0.65, 95% CI 0.58-0.72. Among patients classified as ER-negative no therapeutic benefit from tamoxifen was observed. Among patients with ER-expressing tumors, tamoxifen resulted in significantly better recurrence-free survival irrespective of the method (IHC: HR, 0.53, P < 0.001; cytosol: HR, 0.53, P < 0.001). The effect on overall survival was not statistically significant probably due to the limited sample size. Both IHC and cytosol assay accurately predict long-term response to adjuvant tamoxifen.
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| 4. |
- Linderholm, Barbro, 1959, et al.
(författare)
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Vascular endothelial growth factor receptor 2 and downstream p38 mitogen-activated protein kinase are possible candidate markers of intrinsic resistance to adjuvant endocrine treatment in steroid receptor positive breast cancer.
- 2011
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Ingår i: Breast cancer research and treatment. - : Springer Science and Business Media LLC. - 1573-7217 .- 0167-6806. ; 125:2, s. 457-65
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Tidskriftsartikel (refereegranskat)abstract
- A cross talk between tyrosine kinase receptors and mitogen-activated protein kinases (MAPKs) is proposed as involved in endocrine resistance. We wanted to investigate intratumoral levels of vascular endothelial growth factor receptor 2 (VEGFR2) and p38 MAPK in relation to relapse-free (RFS) and breast cancer corrected survival (BCCS) after adjuvant endocrine treatment, mainly tamoxifen for 2 or 5 years. We also wanted to investigate these markers in relation to early and late recurrences. VEGFR2 (n = 381) and p38 (n = 174) were determined by enzyme-linked immuno-sorbent assays in tumor homogenates from primary BC diagnosed 1993-1996. Wide ranges of VEGFR2 and p38 proteins were found; median 0.72 pg/μg DNA (range 0.0-11.66), and 0.04 pg/μg DNA (range 0.0-6.79), respectively. Detectable levels of p38 were registered in 65% and classified positive. Higher VEGFR2 were correlated to higher VEGF (P = 0.005), p38 MAPK (P = 0.018), negative ER (P = 0.008), larger tumors (P = 0.001), histopathological grade III (P = 0.018), distant metastasis (P = 0.044), shorter RFS (P = 0.013), and shorter BCCS (P = 0.017). Expression of p38 was significantly correlated with negative PgR (P = 0.044) and with early relapses (P = 0.021), while no difference was seen during the later follow-up period (P = 0.73). Higher VEGFR2 had a significant negative impact on both early (P = 0.029) and later recurrences (P = 0.018), while VEGF only predicted later relapses (P = 0.037). Our preliminary results suggest higher intratumoral levels of VEGFR2 and p38 MAPK as candidate markers of intrinsic resistance for adjuvant endocrine therapy.
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| 5. |
- 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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| 6. |
- Sjöström, Martin, et al.
(författare)
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Lack of G protein-coupled estrogen receptor (GPER) in the plasma membrane is associated with excellent long-term prognosis in breast cancer
- 2014
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Ingår i: Breast Cancer Research and Treatment. - : Springer Verlag (Germany). - 0167-6806 .- 1573-7217. ; 145:1, s. 61-71
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Tidskriftsartikel (refereegranskat)abstract
- G protein-coupled estrogen receptor (GPER), or GPR30, is a membrane receptor reported to mediate non-genomic estrogen responses. Tamoxifen is a partial agonist at GPER in vitro. Here, we investigated if GPER expression is prognostic in primary breast cancer, if the receptor is treatment-predictive for adjuvant tamoxifen, and if receptor subcellular localization has any impact on the prognostic value. Total and plasma membrane (PM) GPER expression was analyzed by immunohistochemistry in breast tumors from 742 postmenopausal lymph node-negative patients subsequently randomized for tamoxifen treatment for 2-5 years versus no systemic treatment, regardless of estrogen receptor (ER) status, and with a median follow-up of 17 years for patients free of event. PM GPER expression was a strong independent prognostic factor for poor prognosis in breast cancer without treatment-predictive information for tamoxifen. In the tamoxifen-treated ER-positive and progesterone receptor (PgR)-positive patient subgroup, the absence of PM GPER (53 % of all ER-positive tumors) predicted 91 % 20-year distant disease-free survival, compared to 73 % in the presence of GPER (p = 0.001). Total GPER expression showed positive correlations with ER and PgR and negative correlation with histological grade, but the correlations were biphasic. On the other hand, PM GPER expression showed strong negative correlations with ER and PgR, and strong positive correlation with HER2 overexpression and high histological grade. GPER overexpression and PM localization are critical events in breast cancer progression, and lack of GPER in the PM is associated with excellent long-term prognosis in ER-positive and PgR-positive tamoxifen-treated primary breast cancer.
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