Ancestry-Specific Risks of Triple-Negative Breast Cancer and Genetic Mutations

By: Kayci Reyer
Posted: Wednesday, July 20, 2022

Research presented at the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 10517) suggests that the risk of triple-negative breast cancer among patients with germline pathogenic variants may vary slightly based on ancestry, but it tends to remain comparable across racial/ethnic groups. This risk was evaluated among women of African, European, Asian, and Latinx ancestries.

“The reason to ask this is we know triple-negative breast cancer is a lot more common in African American women,” noted Michael J. Hall, MD, of the Fox Chase Cancer Center, Philadelphia, in an institutional press release. “While in general we think these high-risk genetic mutations are evenly distributed in the population by race/ethnicity, we wanted to see if variations in race/ethnicity-specific risks existed and could be explained by gene-specific variability in risk.”

The study relied on clinical and genetic records from 627,219 women who underwent multigene panel testing for hereditary cancer predisposition between September 2013 and May 2020. Among the 115,337 women (18.4%) with a personal history of breast cancer, 17,951 (15.6%) had experienced triple-negative breast cancer. Triple-negative breast cancer was reported most often by women of African ancestry (26.9%), followed by women of Latinx (14.9%), European (13.9%), or Asian (11.7%) ancestry.

Triple-negative breast cancer odds ratios across all four groups were comparable among women who were carriers of BRCA1, BRCA2, or PALB2. Whole-group, Asian ancestry, African ancestry, Latinx ancestry, and European ancestry odds ratios were 21.23, 26.27, 19.40, 25.23, and 22.84 among BRCA1 carriers; 4.43, 3.93, 4.85, 5.68, and 4.68 among BRCA2 carriers; and 5.29, 7.79, 5.14, 3.46, and 5.71 among PALB2 carriers. Comparable rates were also observed for carriers of BARD1, RAD51C, and RAD51D, though data were insufficient or not available for some ancestry groups (Latinx, Asian, and Asian plus Latinx, respectively).

“While small [sample] sizes limit some gene-specific analyses, comparable ancestry-specific risks of [triple-negative breast cancer] were seen across the racial/ethnic groups examined here,” concluded the authors.

Disclosure: For full disclosures of the study authors, visit coi.asco.org.

2022 ASCO Annual Meeting

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