BRCA1

The BRCA1 gene belongs to a class of genes known as tumor suppressor genes. Like many other tumor suppressors, the protein produced from the BRCA1 gene helps prevent cells from growing and dividing too rapidly or in an uncontrolled way.

The BRCA1 gene provides instructions for making a protein that is directly involved in repairing damaged DNA. In the nucleus of many types of normal cells, the BRCA1 protein interacts with several other proteins, including the proteins produced from the RAD51 and BARD1 genes, to mend breaks in DNA. These breaks can be caused by natural and medical radiation or other environmental exposures, and also occur when chromosomes exchange genetic material in preparation for cell division. By helping repair DNA, BRCA1 plays a role in maintaining the stability of a cell's genetic information.

Research suggests that the BRCA1 protein also regulates the activity of other genes and plays a critical role in embryonic development. To carry out these functions, the BRCA1 protein interacts with many other proteins, including other tumor suppressors and proteins that regulate cell division.

breast cancer - increased risk from variations of the BRCA1 gene

Researchers have identified more than 1,000 mutations in the BRCA1 gene, many of which are associated with an increased risk of cancer (particularly breast cancer in women). Most of these mutations lead to the production of an abnormally short version of the BRCA1 protein, or prevent any protein from being made from one copy of the gene. Other BRCA1 mutations change single protein building blocks (amino acids) in the protein or delete large segments of DNA from the BRCA1 gene. Researchers believe that a defective or missing BRCA1 protein is unable to help repair damaged DNA or fix mutations that occur in other genes. As these defects accumulate, they can allow cells to grow and divide uncontrollably and form a tumor.

other cancers - increased risk from variations of the BRCA1 gene

In addition to female breast cancer, mutations in the BRCA1 gene also increase the risk of several other types of cancer including fallopian tube cancer, male breast cancer, and pancreatic cancer. Many of these mutations change one of the amino acids used to make the BRCA1 protein, resulting in a protein that cannot perform its normal DNA repair function.