Note: worth reading; covers a variety of concerns
IN BRIEF
- Accounting for around 5%–10% of all breast cancers, harmful mutations in BRCA1 or BRCA2 increase a woman’s chance of developing breast cancer over their lifetime by approximately five times compared to the normal population.
- Carriers of the harmful BRCA1/2 mutations are also approximately 10–30 times more likely to develop ovarian cancer, with these mutations accounting for around 10% of all ovarian cancers.
- There is no single BRCA mutation, but a wide variety of mutations on these two genes, many of which have yet to be recorded. Only some have been demonstrated to be harmful.
- BRCA mutations can also raise the risk of other cancers, including gastric, pancreatic, colon and prostate cancer, as well as melanoma and male breast cancer.
- Other ‘cancer genes’ include mutated APC genes, responsible for familial adenomatous polyposis, which lead to colon cancer, and mutated MLH1, MSH2 MSH6, or PMS2 genes, which are associated with hereditary non-polyposis colon cancer (HNPCC) (Lynch Syndrome), a syndrome that also raises the risk of endometrial (uterine), stomach, ovarian, small bowel (intestinal), urinary tract, liver, and bile duct cancers.
