BRCA-1 gene lies on chromosome
Refer Robbins page no 1054 Mutations in BRCA1 and BRCA2 are responsible for 80% to 90% of "single gene" familial breast cancers and about 3% of all breast cancers. Penetrance (the percentage of carriers who develop breast cancer) varies from 30% to 90% depending on the specific mutation present. Mutations in BRCA1 also markedly increase the risk of developing ovarian carcinoma, which occurs in as many as 20% to 40% of carriers. BRCA2 confers a smaller risk for ovarian carci- noma (10% to 20%) but is associated more frequently with male breast cancer. BRCA1 and BRCA2 carriers are also at higher risk for other epithelial cancers, such as prostatic and pancreatic carcinomas. BRCA1 (on chromosome 17q21) and BRCA2 (on chro- mosome 13q12.3) are both large genes, and hundreds of different mutations distributed throughout their coding regions have been associated with familial breast cancers.
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