Primary ER-positive Breast Cancer Treated with Neoadjuvant Letrozole
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ABSTRACT:
PROVIDER: PRJNA272564 | ENA |
REPOSITORIES: ENA
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Project description:<p>These are tumor biopsies and corresponding normal samples from patients with early stage ER+/HER2- breast cancer who had received the aromatase inhibitor letrozole for 10-21 days prior to surgery.</p>
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Project description:Transcriptome of ER+ breast tumors treated with letrozole were profiled by RNA-seq
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Project description:Biopsies were collected from post-menopausal women with ER+ HER2- breast cancer who were subsequently treated with either letrozole or letrozole plus bevacizumab.
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Project description:Acquired resistance to aromatase inhibitor (AI) therapy is a major clinical problem in the treatment of breast cancer. The detailed mechanisms of how tumour cells develop this resistance remain unclear. Here estrogen receptor ChIPseq analysis identifies adaptations of the ER in response to prolonged letrozole treatment.
2016-03-21 | GSE54592 | GEO
Project description:Diagnostic samples from female breast cancer patients with ER-positive and HER2-normal tumors selected for neoadjuvant chemotehrapy.
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Project description:Trastuzumab, a humanized monoclonal antibody directed to the HER2 protein, is the standard-of-care treatment for patients with HER2 positive breast cancer, reducing the risk of relapse and death in patients. Nonetheless, some patients do not benefit from this treatment, underscoring the need to identify patients for whom chemotherapy + trastuzumab is adequate versus patients requiring additional drugs. The series comprised 24 incisional biopsies of breast carcinomas derived from patients that received neoadjuvant trastuzumab based therapy. Gene expression profiling was performed using RNA from frozen core biopsies from 24 patients with primary HER2-positive (HER2+) tumors treated with neoadjuvant chemotherapy and trastuzumab.
2016-03-31 | E-GEOD-62327 | biostudies-arrayexpress
Project description:The purpose of the present study was to investigate the association of glutathione S-transferase P1 (GSTP1) expression with resistance to neoadjuvant paclitaxel followed by 5-fluorouracil/epirubicin/cyclophosphamide (P-FEC) in human breast cancers. The relationship of GSTP1 expression and GSTP1 promoter hypermethylation with intrinsic subtypes was also investigated. In this study, primary breast cancer patients (n = 123, stage II-III) treated with neoadjuvant P-FEC were analyzed. Tumor samples were obtained by vacuum-assisted core biopsy before P-FEC. GSTP1 expression was determined using immunohistochemistry, GSTP1 promoter methylation index (MI) using bisulfite methylation assay and intrinsic subtypes using DNA microarray. The pathological complete response (pCR) rate was significantly higher in GSTP1-negative tumors (80.0%) than GSTP1-positive tumors (30.6%) (P = 0.009) among estrogen receptor (ER)-negative tumors but not among ER-positive tumors (P = 0.267). Multivariate analysis showed that GSTP1 was the only predictive factor for pCR (P = 0.013) among ER-negative tumors. Luminal A, luminal B and HER2-enriched tumors showed a significantly lower GSTP1 positivity than basal-like tumors (P = 0.002, P < 0.001 and P = 0.009, respectively), while luminal A, luminal B and HER2-enriched tumors showed a higher GSTP1 MI than basal-like tumors (P = 0.076, P < 0.001 and P < 0.001, respectively). In conclusion, these results suggest the possibility that GSTP1 expression can predict pathological response to P-FEC in ER-negative tumors but not in ER-positive tumors. Additionally, GSTP1 promoter hypermethylation might be implicated more importantly in the pathogenesis of luminal A, luminal B and HER2-enriched tumors than basal-like tumors. Fresh frozen tumor samples obtained by vacuum-assisted core biopsy from one hundred and fifteen patients were subjected to RNA extraction and hybridization on Affymetrix microarrays.
2012-03-20 | E-GEOD-32646 | biostudies-arrayexpress
Project description:The purpose of the present study was to investigate the association of glutathione S-transferase P1 (GSTP1) expression with resistance to neoadjuvant paclitaxel followed by 5-fluorouracil/epirubicin/cyclophosphamide (P-FEC) in human breast cancers. The relationship of GSTP1 expression and GSTP1 promoter hypermethylation with intrinsic subtypes was also investigated. In this study, primary breast cancer patients (n = 123, stage II-III) treated with neoadjuvant P-FEC were analyzed. Tumor samples were obtained by vacuum-assisted core biopsy before P-FEC. GSTP1 expression was determined using immunohistochemistry, GSTP1 promoter methylation index (MI) using bisulfite methylation assay and intrinsic subtypes using DNA microarray. The pathological complete response (pCR) rate was significantly higher in GSTP1-negative tumors (80.0%) than GSTP1-positive tumors (30.6%) (P = 0.009) among estrogen receptor (ER)-negative tumors but not among ER-positive tumors (P = 0.267). Multivariate analysis showed that GSTP1 was the only predictive factor for pCR (P = 0.013) among ER-negative tumors. Luminal A, luminal B and HER2-enriched tumors showed a significantly lower GSTP1 positivity than basal-like tumors (P = 0.002, P < 0.001 and P = 0.009, respectively), while luminal A, luminal B and HER2-enriched tumors showed a higher GSTP1 MI than basal-like tumors (P = 0.076, P < 0.001 and P < 0.001, respectively). In conclusion, these results suggest the possibility that GSTP1 expression can predict pathological response to P-FEC in ER-negative tumors but not in ER-positive tumors. Additionally, GSTP1 promoter hypermethylation might be implicated more importantly in the pathogenesis of luminal A, luminal B and HER2-enriched tumors than basal-like tumors.
2012-03-20 | GSE32646 | GEO
Project description:A large-panel gene expression analysis was conducted to identify biomarkers associated with the effectiveness of adding palbociclib to letrozole Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors have demonstrated significant activity in estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-) advanced breast cancer. Further biomarkers to refine the population beyond ER+/HER2- that benefits remain to be identified. We performed a comprehensive biomarker analysis using patient tissues from PALOMA-2, a randomized phase 3 study of palbociclib-letrozole versus placebo-letrozole, to determine markers of sensitivity and resistance to the combination.
2020-05-31 | GSE133394 | GEO
Project description:Primary ER-positive Breast Cancer Treated with Neoadjuvant Letrozole
| PRJNA272565 | ENA