Prevalence of Germline Mutations among Young Women with Breast Cancer in Louisiana by Cancer Subtype and Race.

OBJECTIVE

Black women in Louisiana have an increased breast cancer incidence. In addition, mortality and incidence of breast cancer in younger patients are on the rise, regardless of race or germline mutations. Most available germline mutation data in breast cancer are based primarily on White patient populations. We sought to evaluate the relationship between race, pathogenic germline mutations, and breast cancer subtypes among young women (younger than 40 years old) diagnosed as having breast cancer in Louisiana.

METHODS

We collected and reviewed a 10-year retrospective database from 2012 to 2022 of 773 women younger than age 40 years diagnosed as having breast cancer in a Louisiana-based regional health system. Associations between subtypes and germline mutations were assessed using the χ2 test.

RESULTS

In total, 632 patients had available genetics data: 38% of patients with pathogenic germline mutations were Black or African American and 62% were White, 53% of Black or African American patients had a variant of uncertain significance (VUS) vs 47% of White patients. The association between pathogenic germline mutations and triple-negative breast cancer (estrogen receptor [ER]-/human epidermal growth factor receptor 2 [HER2]-) was noted with P = 0.0122. The presence of VUS was not statistically significant when compared with no mutation in the triple-negative cohort (odds ratio [OR] 1.13; 95% confidence interval [CI] 0.70-1.83; P = 0.6224). No statistically significant difference was noted in the prevalence of germline mutations among ER+/HER2- and ER-/HER2+ cancers. Evaluation of the germline mutations demonstrated an association between germline mutation and race (P = 0.0045). VUS was twofold in Black or African American patients compared with no mutation (OR 2.12; 95% CI 1.35-3.34; P = 0.0012). The presence of a pathogenic germline mutation was 1.19 times as common in Black or African American patients compared with no mutation (OR 1.19; 95% CI 0.79-1.79; P = 0.4018].

CONCLUSIONS

These data demonstrate that triple-negative breast cancer continues to have a significant association with germline mutations in a young patient population. Pathogenic germline mutations and VUS may be more common in younger Black or African American patients as demonstrated by our research, however.