| 1. |
- Gruvberger, Sofia, et al.
(författare)
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Estrogen receptor beta expression is associated with tamoxifen response in ER alpha-negative breast carcinoma
- 2007
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Ingår i: Clinical Cancer Research. - 1078-0432. ; 13:7, s. 1987-1994
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Endocrine therapies, such as tamoxifen, are commonly given to most patients with estrogen receptor (ERalpha)-positive breast carcinoma but are not indicated for persons with ERalpha-negative cancer. The factors responsible for response to tamoxifen in 5% to 10% of patients with ERalpha-negative tumors are not clear. The aim of the present study was to elucidate the biology and prognostic role of the second ER, ERbeta, in patients treated with adjuvant tamoxifen.EXPERIMENTAL DESIGN: We investigated ERbeta by immunohistochemistry in 353 stage II primary breast tumors from patients treated with 2 years adjuvant tamoxifen, and generated gene expression profiles for a representative subset of 88 tumors.RESULTS: ERbeta was associated with increased survival (distant disease-free survival, P = 0.01; overall survival, P = 0.22), and in particular within ERalpha-negative patients (P = 0.003; P = 0.04), but not in the ERalpha-positive subgroup (P = 0.49; P = 0.88). Lack of ERbeta conferred early relapse (hazard ratio, 14; 95% confidence interval, 1.8-106; P = 0.01) within the ERalpha-negative subgroup even after adjustment for other markers. ERalpha was an independent marker only within the ERbeta-negative tumors (hazard ratio, 0.44; 95% confidence interval, 0.21-0.89; P = 0.02). An ERbeta gene expression profile was identified and was markedly different from the ERalpha signature.CONCLUSION: Expression of ERbeta is an independent marker for favorable prognosis after adjuvant tamoxifen treatment in ERalpha-negative breast cancer patients and involves a gene expression program distinct from ERalpha. These results may be highly clinically significant, because in the United States alone, approximately 10,000 women are diagnosed annually with ERalpha-negative/ERbeta-positive breast carcinoma and may benefit from adjuvant tamoxifen.
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| 2. |
- Honeth, Gabriella, et al.
(författare)
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The CD44(+)/CD24(-) phenotype is enriched in basal-like breast tumors
- 2008
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Ingår i: Breast Cancer Research. - : Springer Science and Business Media LLC. - 1465-5411 .- 1465-542X. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Human breast tumors are heterogeneous and consist of phenotypically diverse cells. Breast cancer cells with a CD44(+)/CD24(-) phenotype have been suggested to have tumor-initiating properties with stem cell-like and invasive features, although it is unclear whether their presence within a tumor has clinical implications. There is also a large heterogeneity between tumors, illustrated by reproducible stratification into various subtypes based on gene expression profiles or histopathological features. We have explored the prevalence of cells with different CD44/CD24 phenotypes within breast cancer subtypes. Methods Double-staining immunohistochemistry was used to quantify CD44 and CD24 expression in 240 human breast tumors for which information on other tumor markers and clinical characteristics was available. Gene expression data were also accessible for a cohort of the material. Results A considerable heterogeneity in CD44 and CD24 expression was seen both between and within tumors. A complete lack of both proteins was evident in 35% of the tumors, while 13% contained cells of more than one of the CD44(+)/CD24(-), CD44(-)/CD24(+) and CD44(+)/CD24(+) phenotypes. CD44(+)/CD24(-) cells were detected in 31% of the tumors, ranging in proportion from only a few to close to 100% of tumor cells. The CD44(+)/CD24(-) phenotype was most common in the basal-like subgroup-characterized as negative for the estrogen and progesterone receptors as well as for HER2, and as positive for cytokeratin 5/14 and/or epidermal growth factor receptor, and particularly common in BRCA1 hereditary tumors, of which 94% contained CD44(+)/CD24(-) cells. The CD44(+)/CD24(-) phenotype was surprisingly scarce in HER2+ tumors, which had a predominantly CD24(+) status. A CD44(+)/CD24(-) gene expression signature was generated, which included CD44 and alpha(6)-integrin (CD49f) among the top-ranked overexpressed genes. Conclusion We demonstrate an association between basal-like and particularly BRCA1 hereditary breast cancer and the presence of CD44(+)/CD24(-) cells. Not all basal-like tumors and very few HER2+ tumors, however, contain CD44(+)/CD24(-) cells, emphasizing that a putative tumorigenic ability may not be confined to cells of this phenotype and that other breast cancer stem cell markers remain to be identified.
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| 3. |
- Persson, Oscar, et al.
(författare)
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Microarray analysis of gliomas reveals chromosomal position-associated gene expression patterns and identifies potential immunotherapy targets.
- 2007
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Ingår i: Journal of Neuro-Oncology. - : Springer Science and Business Media LLC. - 1573-7373 .- 0167-594X. ; 85:J1, s. 11-24
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Tidskriftsartikel (refereegranskat)abstract
- Gliomas are among the most aggressive malignant tumors and the most refractory to therapy, in part due to the propensity for malignant cells to disseminate diffusely throughout the brain. Here, we have used 27 K cDNA microarrays to investigate global gene expression changes between normal brain and high-grade glioma (glioblastoma multiforme) to try and better understand gliomagenesis and to identify new therapeutic targets. We have also included smaller groups of grade II and grade III tumors of mixed astrocytic and oligodendroglial origin as comparison. We found that the expression of hundreds of genes was significantly correlated to each group, and employed a naive Bayesian classifier with leave-one-out cross-validation to accurately classify the samples. We developed a novel algorithm to analyze the gene expression data from the perspective of chromosomal position, and identified distinct regions of the genome that displayed coordinated expression patterns that correlated significantly to tumor grade. The regions identified corresponded to previously known genetic copy number changes in glioma (e.g. 10q23, 10q25, 7q, 7p) as well as regions not previously associated significantly with glioma (e.g. 1p13, 6p22). Furthermore, to enrich for more suitable targets for therapy, we took a bioinformatics approach and annotated our signatures with two published datasets that identified membrane/secreted genes from cytosolic genes. The resulting focused list of 31 genes included interesting novel potential targets as well as several proteins already being investigated for immunotherapy (e.g. CD44 and tenascin-C). Software for the chromosome analysis was developed and is freely available at http://base.thep.lu.se.
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| 4. |
- Saal, Lao, et al.
(författare)
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PIK3CA mutations correlate with hormone receptors, node metastasis, and ERBB2, and are mutually exclusive with PTEN loss in human breast carcinoma
- 2005
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Ingår i: Cancer Research. - 1538-7445. ; 65:7, s. 2554-2559
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Tidskriftsartikel (refereegranskat)abstract
- Deregulation of the phosphatidylinositol 3-kinase (PI3K) pathway either through loss of PTEN or mutation of the catalytic subunit alpha of PI3K (PIK3CA) occurs frequently in human cancer. We identified PIK3CA mutations in 26% of 342 human breast tumor samples and cell lines at about equal frequency in tumor stages I to IV. To investigate the relationship between PTEN and PIK3CA, we generated a cohort of tumors that had lost PTEN expression and compared it with a matched control set that had retained PTEN. A highly significant association between PIK3CA mutations and retention of PTEN protein expression was observed. In addition, PIK3CA mutations were associated with expression of estrogen and progesterone receptors (ER/PR), lymph node metastasis, and ERBB2 overexpression. The fact that PIK3CA mutations and PTEN loss are nearly mutually exclusive implies that deregulated phosphatidylinositol-3,4,5-triphosphate WIN is critical for tumorigenesis in a significant fraction of breast cancers and that loss Of PIP3 homeostasis by abrogation of either PIK3CA or PTEN relieves selective pressure for targeting of the other gene. The correlation of PIK3CA mutation to ER/PR-positive tumors and PTEN loss to ER/PR-negative tumors argues for disparate branches of tumor evolution. Furthermore, the association between ERBB2 overexpression and PIK3CA mutation implies that more than one input activating the PI3K/AKT pathway may be required to overcome intact PTEN. Thus, mutation of PIK3CA is frequent, occurs early in carcinoma development, and has prognostic and therapeutic implications.
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| 5. |
- Saal, Lao, et al.
(författare)
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Poor prognosis in carcinoma is associated with a gene expression signature of aberrant PTEN tumor suppressor pathway activity
- 2007
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Ingår i: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 104:18, s. 7564-7569
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Tidskriftsartikel (refereegranskat)abstract
- Pathway-specific therapy is the future of cancer management. The oncogenic phosphatidylinositol 3-kinase (P13K) pathway is frequently activated in solid tumors; however, currently, no reliable test for P13K pathway activation exists for human tumors. Taking advantage of the observation that loss of PTEN, the negative regulator of P13K, results in robust activation of this pathway, we developed and validated a microarray gene expression signature for immunohistochemistry (IHC)-detectable PTEN loss in breast cancer (IBC). The most significant signature gene was PTEN itself, indicating that PTEN mRNA levels are the primary determinant of PTEN protein levels in BC. Some PTEN IHC-positive BCs exhibited the signature of PTEN loss, which was associated to moderately reduced PTEN mRNA levels cooperating with specific types of PIK3CA mutations and/or amplification of HER2. This demonstrates that the signature is more sensitive than PTEN IHC for identifying tumors with pathway activation. In independent data sets of breast, prostate, and bladder carcinoma, prediction of pathway activity by the signature correlated significantly to poor patient outcome. Stathmin, encoded by the signature gene STMN1, was an accurate IHC marker of the signature and had prognostic significance in BC. Stathmin was also pathway-pharmacodynamic in vitro and in vivo. Thus, the signature or its components such as stathmin may be clinically useful tests for stratification of patients for anti-P13K pathway therapy and monitoring therapeutic efficacy. This study indicates that aberrant P13K pathway signaling is strongly associated with metastasis and poor survival across carcinoma types, highlighting the enormous potential impact on patient survival that pathway inhibition could achieve.
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| 6. |
- Saal, Lao, et al.
(författare)
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Recurrent gross mutations of the PTEN tumor suppressor gene in breast cancers with deficient DSB repair
- 2008
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 40:1, s. 102-107
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Tidskriftsartikel (refereegranskat)abstract
- Basal-like breast cancer (BBC) is a subtype of breast cancer with poor prognosis1, 2, 3. Inherited mutations of BRCA1, a cancer susceptibility gene involved in double-strand DNA break (DSB) repair, lead to breast cancers that are nearly always of the BBC subtype3, 4, 5; however, the precise molecular lesions and oncogenic consequences of BRCA1 dysfunction are poorly understood. Here we show that heterozygous inactivation of the tumor suppressor gene Pten leads to the formation of basal-like mammary tumors in mice, and that loss of PTEN expression is significantly associated with the BBC subtype in human sporadic and BRCA1-associated hereditary breast cancers. In addition, we identify frequent gross PTEN mutations, involving intragenic chromosome breaks, inversions, deletions and micro copy number aberrations, specifically in BRCA1-deficient tumors. These data provide an example of a specific and recurrent oncogenic consequence of BRCA1-dependent dysfunction in DNA repair and provide insight into the pathogenesis of BBC with therapeutic implications. These findings also argue that obtaining an accurate census of genes mutated in cancer will require a systematic examination for gross gene rearrangements, particularly in tumors with deficient DSB repair.
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