The genetics of inherited breast cancer.

The isolation of BRCA1 and BRCA2 has greatly increased our understanding of the genetics of inherited breast and ovarian cancer although the functions of these genes are not yet fully understood. We will discuss the current state of knowledge about the function of BRCA1 and BRCA2 and summarize the cancer risks in women carrying a BRCA1 or BRCA2 mutation. We review the evidence for gene-gene and gene-environment interaction in modifying that risk, and discuss the contribution of BRCA1 and BRCA2 and other high penetrance genes to both inherited and sporadic breast cancer.