Among African-American women with breast cancer referred for genetic counseling, one in five had an inherited mutation in at least one of the 18 genes that are linked with breast cancer susceptibility. The frequency of gene mutations was even higher in certain subgroups of these women. These results were presented at the 2013 Annual Meeting of the American Society of Clinical Oncology (ASCO).
Inherited mutations in certain genes are known to increase a woman’s risk of breast cancer. The best known of these genes are BRCA1 and BRCA2, but several other genes also affect breast cancer risk. If a woman is found to have a gene mutation that puts her at high risk of breast cancer, she has options to reduce or manage her risk; these options include preventive surgery to remove the breasts and/or ovaries before cancer develops, use of medication that reduces cancer risk, and more intensive cancer screening.
To evaluate the range and frequency of breast cancer-related gene mutations in African American women with breast cancer, researchers conducted a study among 249 unrelated women who were referred for genetic counseling. Women were tested for mutations in 18 different genes that have been associated with breast cancer risk.
- Overall, 22% of the women had an inherited, cancer-associated gene mutation. The genes that were involved were BRCA1, BRCA2, CHEK2, PALB2, ATM, and PTEN.
- Gene mutations were particularly frequent in certain subgroups of women. Mutations were found in 30% of women with triple-negative breast cancer, 27% of women diagnosed with breast cancer before the age of 45, and 30% of women who had a close relative with breast or ovarian cancer.
Because the study focused on women with breast cancer who were referred for genetic counseling, the frequency of gene mutations is likely to be higher than in the general population of African American women. Even so, the frequency of mutations was higher than the researchers had expected. Mutations were particularly common among women who had been diagnosed with breast cancer at a young age, women who had triple-negative breast cancer, and women who had a family history of breast or ovarian cancer.
For African American women with breast cancer and a high likelihood of a cancer-associated gene mutation, increased use of genetic testing could provide important benefits to family members. If a woman is found to carry a gene mutation, her family members could also be tested. Those who also carry the gene mutation would then have the option to make use of available breast cancer prevention strategies.
Reference: Churpek JE, Walsh T, Zheng Y et al. Inherited mutations in breast cancer genes in African American breast cancer patients revealed by targeted genomic capture and next generation sequencing. Presented at the 49th Annual Meeting of the American Society of Clinical Oncology. May 31-June 4, 2013; Chicago, IL. Abstract CRA1501.
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