Breast Cancer Gene: An Overview of Genes
Genes are nature's blueprints for every living thing. Genes come in pairs: one set of genes is passed down (or inherited) from your mother and the other set from your father. Genes determine how your body will function and grow, as well as the color of your hair and eyes.
Some genes do not function properly because there is a mistake in them. If a gene has a mistake, it is said to be mutated or altered. In fact, all people have altered forms of some genes. Some alterations can increase your risk for certain illnesses such as cancer. In recent years, gene alterations have been found in some families with a history of
breast cancer.
BRCA1 and BRCA2 Breast Cancer Genes
These alterations are most often found in genes named BRCA1 and BRCA2 (BReast CAncer Gene 1 and BReast CAncer Gene 2). Both men and women have BRCA1 and BRCA2 genes, so alterations in these genes can be passed down from either the mother or the father. It is likely that more genes like these will be discovered in the future.
Altered Genes in Women
A woman with a BRCA1 or BRCA2 alteration is more likely to develop breast cancer than is a woman without an alteration. However, not every woman who has an altered BRCA1 or BRCA2 gene will get breast cancer, because genes are not the only factor that affect a person's risk for breast cancer. Therefore, an altered gene by itself is not sufficient to cause cancer.
Most cases of breast cancer do not involve an altered BRCA1 or BRCA2 gene. At most, 1 in 10 breast cancer cases involves an inherited altered gene, and not all inherited breast cancer involves BRCA1 or BRCA2.