Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Normal human mammary tissues from BRCA1 mutation carriers, non-BRCA1/2 mutation carriers and normal women

ABSTRACT: Gene expression profiles of normal human mammary tissue from BRCA1 mutation carriers, non-BRCA1/2 mutation carriers and normal women. RNA was prepared from normal breast tissue (confirmed by pathology) from reduction mammoplasties (n=5) and prophylactic mastectomies of known BRCA1 (n=7) and non-BRCA1/2 mutation carriers (n=8). non-BRCA1/2 carriers were individuals with a strong family history of breast cancer (kConFab Category 1 (http://www.kconfab.org/Collection/Eligibility.shtml) where no mutation in BRCA1 or BRCA2 has been identified in the family by high sensitivity testing (http://www.kconfab.org/Progress/Sensitivity.shtml) of any individual affected by breast or ovarian cancer. Normal breast samples refer to reduction mammoplasty specimens, where family history is generally not known. Microarray expression profiles were obtained from whole pre-neoplastic breast tissue from three categories of patient, as described in the summary. Samples were checked for keratin gene expression levels as a marker for epithelium tissue, and a number of samples were removed because two or more keratin genes lacked detectable expression (BeadStudio detection p-value 0.01). One other sample was removed because its expression profile appeared abnormal. Out of 36 samples initially profiled, 20 passed the quality filters and were used for the final analysis.

ORGANISM(S): Homo sapiens

SUBMITTER: Jane Visvader

PROVIDER: E-GEOD-17072 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Aberrant luminal progenitors as the candidate target population for basal tumor development in BRCA1 mutation carriers.

Lim Elgene E Vaillant François F Wu Di D Forrest Natasha C NC Pal Bhupinder B Hart Adam H AH Asselin-Labat Marie-Liesse ML Gyorki David E DE Ward Teresa T Partanen Audrey A Feleppa Frank F Huschtscha Lily I LI Thorne Heather J HJ Fox Stephen B SB Yan Max M French Juliet D JD Brown Melissa A MA Smyth Gordon K GK Visvader Jane E JE Lindeman Geoffrey J GJ

Nature medicine 20090802 8

Basal-like breast cancers arising in women carrying mutations in the BRCA1 gene, encoding the tumor suppressor protein BRCA1, are thought to develop from the mammary stem cell. To explore early cellular changes that occur in BRCA1 mutation carriers, we have prospectively isolated distinct epithelial subpopulations from normal mammary tissue and preneoplastic specimens from individuals heterozygous for a BRCA1 mutation. We describe three epithelial subsets including basal stem/progenitor, luminal ...[more]

PMID: 19648928

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Project description:Pathogenic germline mutations in BRCA1 or BRCA2 are detected in less than one third of families with a strong history of breast cancer. It is therefore expected that mutations still remain undetected by currently used screening methods. In addition, a growing number of BRCA1/2 sequence variants of unclear pathogen significance are found in the families, constituting an increasing clinical challenge. New methods are therefore needed to improve the detection rate and aid the interpretation of the clinically uncertain variants. In this study we analyzed a series of 33 BRCA1, 22 BRCA2, and 128 sporadic tumors by RNA profiling to investigate the classification potential of RNA profiles to predict BRCA1/2 mutation status. We found that breast tumors from BRCA1 and BRCA2 mutation carriers display characteristic RNA expression patterns, allowing them to be distinguished from sporadic tumors. The majority of BRCA1 tumors were basal-like while BRCA2 tumors were mainly luminal B. Using RNA profiles, we were able to distinguish BRCA1 tumors from sporadic tumors among basal-like tumors with 83% accuracy and BRCA2 from sporadic tumors among luminal B tumors with 89% accuracy. Furthermore, subtype-specific BRCA1/2 gene signatures were successfully validated in two independent data sets with high accuracies. Although additional validation studies are required, indication of BRCA1/2 involvement (“BRCAness”) by RNA profiling could potentially be valuable as a tool for distinguishing pathogenic mutations from benign variants, for identification of undetected mutation carriers, and for selecting patients sensitive to new therapeutics such as PARP inhibitors. Gene expression profiling of 183 breast tumor samples. Breast tumors from hereditary breast cancer patients carrying a pathogenic BRCA1 (n=33) or BRCA2 (n=22) germ-line mutation were included in the study. Serving as a representative control group, primary breast tumor samples (n=128) were randomly selected. The study was conducted using Agilent-029949 Custom SurePrint G3 Human GE 8x60K Microarray platform. For cross-platform validation, a subset of the tumor samples (92 of the 183 samples) were analyzed by our in-house spotted microarray platform.

Dataset Information

Normal human mammary tissues from BRCA1 mutation carriers, non-BRCA1/2 mutation carriers and normal women

Publications

Aberrant luminal progenitors as the candidate target population for basal tumor development in BRCA1 mutation carriers.

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