A Negative BRCA Test May Still Suggest Higher Breast Cancer Risk
BRCA2 gene mutation may mean a four times higher risk (November 27)
Women who have family members with BRCA2 genetic mutations but who test negative for the family-specific BRCA2 mutations may be at greater risk for the development of breast cancer compared with women in the general population, according to a study published in Cancer Epidemiology, Biomarkers & Prevention.
Women with certain mutations in their BRCA1 or BRCA2 genes are at increased risk for breast cancer. If a woman whose relatives have the mutated BRCA gene has negative testing results for her family-specific BRCA mutation, her risk for breast cancer is generally considered to be the same as someone in the general population. The new study, however, suggests that this might not always be true.
Dr. Gareth Evans from the University of Manchester in the United Kingdom said that women who test negative for family-specific BRCA2 mutations have more than four times the risk for developing breast cancer than those in the general population. He added that it is likely that these women inherit genetic factors other than BRCA-related genes that increase their risk.
He explained that about 77 single nucleotide polymorphisms (SNPs), or genetic variations that can help track the inheritance of disease genes within families, are linked to the risk. Identifying additional SNPs is necessary to understand why some of the BRCA-negative women from BRCA families are at higher risk.
The authors suggested that specialists use caution when stating that a woman’s breast cancer risk is the same as that of the general population after a negative genetic test. The study was funded by the National Institute for Health Research.[Source: American Association for Cancer Research, November 27, 2013.]