Women with a strong family history for BRCA2 genetic mutations in close relatives, but who test negative for the family-specific mutation, may feel like they’ve dodged a bullet.
Prior studies have suggested that women with close family ties for certain mutations, but who undergo genetic testing and test negative, have the same risk as someone in the general population, according to the U.S. National Cancer Institute.
However British researchers at the University of Manchester had different findings. Contrary to earlier belief, they saw that women who are from BRCA2 families but who test negative may have still about a 40 percent greater lifetime risk for developing breast cancer compared with the general population.
This is according to a new study published online Nov. 27, 2013 in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.
“We found that women who test negative for family-specific BRCA2 mutations have more than four times the risk for developing breast cancer than the general population and that any increased risk for breast cancer is largely limited to BRCA2 families with strong family history and other genetic factors,” said Gareth R. Evans, M.B.B.S., M.D., M.R.C.P., F.R.C.P., honorary professor of medical genetics and cancer epidemiology at the University of Manchester in the UK.
Female carriers of family-specific BRCA1 or BRCA2 (BReast CAncer type 1 or 2) mutation genes have substantial risk (40-65 percent) for developing breast cancer in their lifetime when compared with the general population. In the United States that's about 5-10 percent of the diagnosed breast cancers, according to the American Cancer Society.
Female BRCA1/2 carriers are at much higher risk for developing ovarian cancer and other types of cancer, too.
Genetic testing for the BRCA gene is available only to people with a personal or family history that’s likely to have an inherited mutation, or who have specific types of breast cancer.