Presenting recently at the 2016 San Antonio Breast Cancer Symposium, researchers from the Mayo Clinic described how inherited pathogenic variants in the protein coding genes BARD1 and RAD51D increase a woman's likelihood of developing breast cancer. Pathogenic variants are changes in DNA that have an adverse impact on a gene's ability to function properly.
"The BARD1 and RAD51D genes, have been included in clinical testing panels to determine breast cancer risk," explained lead study author Fergus Couch, Ph.D., a geneticist at Mayo Clinic. "However, the genes were identified as 'breast cancer' genes through very small studies, so there has never been strong evidence indicating that they are important in driving breast cancer risk."
In a presentation entitled “Breast cancer risks associated with mutations in cancer predisposition genes identified by clinical genetic testing of 60,000 breast cancer patients,” Dr. Couch described how he and his colleagues studied data from a large group of women with breast cancer to obtain risk estimates associated with 21 cancer predisposition genes from testing panels. The researchers found that pathogenic variants in individual genes, such as BARD1 and RAD51D, caused moderately increased risks of breast cancer.
Additionally, the Mayo researchers confirmed the involvement of the ATM, CHEK2, and PALB2 genes in breast cancer. They also found that the RAD50 and MRE11A genes did not increase risks of breast cancer.
"Our findings are important because genes that do not increase the risk of breast cancer can now be ignored and potentially removed from clinical testing panels," Dr. Couch remarked. "I am hopeful this work will lead to a much better interpretation of results from clinical, hereditary, and genetic testing."