What it is: BRCA1/2 genes encode proteins that help repair damage to both DNA chains through genetic recombination. If BRCA1/2 are non-functional then DNA damage accumulates.
BRCA1 and BRCA2 mutations can result from either gene (inherited) or somatic mutations.
Why the test is done::
1. Ovarian cancer. The presence of mutations that inactivate the BRCA1/2 genes  predict sensitivity to PARP inhibitors.
2. Breast cancer. Women with BRCA mutation-associated breast cancer have up to a 40% chance of developing a new primary breast cancer within 10 years of diagnosis if untreated.
Frequency:
1. Approximately 25% of high-grade malignant serous carcinomas of the ovary
2. The frequency of BRCA1/2 mutations in breast cancer are found in 5-7% in the community.