Familial breast cancer.

Since the localization and discovery of the first high-risk breast cancer (BC) genes in 1990, there has been a substantial progress in unravelling its familial component. Increasing numbers of women at risk of BC are coming forward requesting advice on their risk and what they can do about it. Three groups of genetic predisposition alleles have so far been identified with high-risk genes conferring 40-85% lifetime risk including BRCA1, BRCA2 and TP53. Moderate risk genes (20-40% risk) including PALB1, BRIP, ATM and CHEK2, and a host of low-risk common alleles identified largely through genome-wide association studies. Currently, only BRCA1, BRCA2 and TP53 are used in clinical practice on a wide scale, although testing of up to 50-100 gene loci may be possible in the future utilizing next-generation technology.