BRCA1 and BRCA2 are human genes that produce proteins known to suppress tumors, according to the National Cancer Institute. These cells are responsible for repairing damage to DNA and ensure the stability of a cell's genetic material.
When BRCA1 or BRCA2 genes are mutated or altered, the protein within is unable to function correctly. As a result, DNA is not repaired properly, and cells are more likely to develop genetic anomalies that lead to cancer, reports the National Cancer Institute.
Particular inherited abnormalities in these genes are proven to increase the risk of cancer in breast and ovarian tissues. Mutations in BRCA1 and BRCA2 are responsible for between 20 and 25 percent of all hereditary breast cancer cases, while a mutation in these genes is responsible for about 15 percent of all ovarian cancers, states the National Cancer Institute.
Mutations are inherited from either side of the gene pool, and the effects of any irregularities are evident even when the person's second copy of either gene is normal. Every child of a parent with an affected BRCA gene has a 50 percent chance of inheriting the mutation, says the National Cancer Institute.
BRCA1 and BRCA2 irregularities are also known to increase the risk of additional cancers. Men with harmful BRCA1 or BRCA2 mutations have a higher risk of prostate cancer, while women with BRCA1 mutations have a higher risk of developing fallopian tube cancer, notes the National Cancer Institute.