Heritable Susceptibility to Breast Cancer among African-American Women in the Detroit Research on Cancer Survivors Study

Background: African-American women have high rates of breast cancer associated with hereditary features. However, no studies have reported the prevalence of inherited variation across all genes known to be breast cancer risk factors among African-American patients with breast cancer not selected for high-risk characteristics. Methods: We evaluated 182 African-American women diagnosed with invasive breast cancer in metropolitan Detroit via targeted capture and multiplex sequencing of 13 well-established breast cancer risk genes and five suggested breast cancer risk genes. Results: We identified 24 pathogenic variants in 23 women [12.6%; 95% confidence interval (CI), 8.2%-18.4%] and five genes (BRCA2, BRCA1, ATM, RAD50, CDH1). BRCA1 and BRCA2 accounted for 58.3% of all pathogenic variants. An additional six pathogenic variants were found in suggested breast cancer risk genes (MSH6, MUTYH, NF1, BRIP1). Conclusions: The prevalence of germline pathogenic variants is relatively high among African-American patients with breast cancer unselected for high-risk characteristics across a broad spectrum of genes. Impact: This study helps to define the genomic landscape of breast cancer susceptibility in African-American women who could benefit from enhanced surveillance and screening.