New Breast Cancer Gene Found
April 22, 2002 -- A newly identified gene known as CHEK2 may account for up to 1% of all breast cancers in women and 9% of breast cancers in men. Researchers say the discovery may lead to a better understanding of what genetic factors affect a person's risk of developing breast cancer.
Mutations in the BRCA1 and BRCA2 genes have already been shown to increase the risk of breast and ovarian cancer, but these genetic abnormalities account for only a small fraction of all breast cancer cases. Nevertheless, the finding has prompted researchers to search for other genes that may play a role in breast cancer.
To find other genetic risk factors, a group of European and American researchers screened individuals from 718 families with a history of breast cancer, but without the BRCA1 or BRCA2 mutations.
They found that a mutation in the gene CHEK2 confers a twofold increase in the risk of breast cancer in women and a tenfold increase in men. Their results are published in today's issue of Nature Genetics.
Researchers say having the CHEK2 mutation does not increase the risk of breast cancer in people who also carry the BRCA1 or BRCA2 variations. That suggests that the genes may operate in the same way -- along the same biological pathway -- to increase breast cancer risk, the researchers say.
The CHEK2 protein is involved in the process of cell proliferation and growth. It acts like a brake to stop cell division when the cell's genetic material becomes damaged. This allows time to repair the error before it gets passed on to other cells. Researchers say a mutation in the CHEK2 gene has been shown to disrupt this braking action -- so mutations can be passed on to many cells, potentially causing cancer.