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What is BRCA?
“BRCA” is an abbreviation for “Breast Cancer gene.” BRCA1 and BRCA2 are two different genes which everyone has that produce tumor suppressor proteins. These act to repair DNA faults which can lead to cancer and uncontrolled growth of tumours. However, in some people these tumour suppression proteins do not work properly. They are said to be altered or mutated.
What is the difference between BRCA1 and BRCA2?
Estimates of risk are different for BRCA1 and BRCA2 mutations. Women who have a BRCA1 mutation have an estimated 60-90% lifetime risk of breast cancer and 40-60% lifetime risk of ovarian cancer. Women who have a BRCA2 gene mutation have an estimated 45-85% lifetime risk of breast canvcer and 10-30% lifetime risk of ovarian cancer.
BRCA gene mutations are also linked to an increased risk of male breast cancer and prostate cancer, though the estimated lifetime risk is higher for men with a BRCA2 mutation.
How are BRCA Mutations inherited?
We inherit two copies of every gene; one from our mother and one from our father. If either parent has a BRCA gene mutation, then there is a 50% chance that it will be passed on to their children.
Who should get tested for the BRCA gene?
Men and women with a personal or strong family history of breast, ovarian or prostate cancer. People who have a family member that has already been identified as a BRCA mutation carrier, could also be eligible for genetic testing.
BRCA-associated cancers are also more common amongst people with Ashkenazi Jewish ancestry - it is estimated that 1 in 40 Ashkenazi Jews have a BRCA 1/2 mutation relative to 1 in 400 in the general population.