The question is why these mutations (in BRCA1 and BRCA2, etc.)yield increased risks of cancer in a tissue-specific manner (breast, ovary, and to a much lesser extent, pancreas, prostate, etc.), whereas the genes themselves, both BRCA1 and BRCA2, are expressed ubiquitously, with any predilection for certain tissues. This evidence concerns the gene BRCA2 and cancer.