Statistically, they are responsible for most of the population's genetic susceptibility to breast cancer, and are fertile targets for research. High-risk variants of the BRCA1 and BRCA2 genes are not common in the general population. A blood test can identify whether a person has a known high-risk variant of the BRCA1 or BRCA2 gene. Whether or not to be tested is a complicated decision. Talk to your physician or a genetic counselor .
Some university hospitals have specialized clinics for members of cancer families.
A recent study found that breast cancer can result not only from variations in the BRCA1 gene itself, but from chemical changes in DNA near the BRCA1 gene. You may want to discuss this further with your physician or a genetic counselor . Some, like radiation, can clearly contribute to breast cancer, but are rare in the population. Sex hormones and reproductive history are important environmental influences. Hormone replacement after the menopause raises risk.