Frequency and spectrum of mutations across 94 cancer predisposition genes in African American women with invasive breast cancer.

African American women are at increased risk of being diagnosed at a young age and/or with triple negative breast cancer, both factors which are included in current guidelines for identifying women who may benefit from genetic testing. Commercial breast cancer predisposition genetic panels, based largely on data derived from women of European ancestry, may not capture the full spectrum of cancer predisposition genes associated with breast cancer in African American women. Between 2001 and 2018, 488 unselected African American women with invasive breast cancer enrolled in the Clinical Breast Care Project. National Comprehensive Cancer Network (NCCN) Hereditary Cancer testing criteria version 1.2020 were applied to determine genetic risk. Targeted sequencing was performed using the TruSight Cancer panel and variants classified using the ClinVar database. Using NCCN criteria, 64.1% of African American women would be eligible for genetic testing. Fifty pathogenic or likely pathogenic mutations were detected in 19 genes with the highest frequencies in BRCA2 (29.4%) and BRCA1 (15.7%). Mutation frequencies in test-eligible and test-ineligible women were 13.1% and 3.5%, respectively. One-third of women harbored variants that could not be classified. While these data do not suggest a need to expand current commercial gene panels, NCCN criteria would fail to identify 12.5% of African American women with mutations in hereditary cancer predisposing genes.

Racial and Ethnic Differences in Breast Cancer Survival: Mediating Effect of Tumor Characteristics and Sociodemographic and Treatment Factors.

PURPOSE: To evaluate the relationship between race/ethnicity and breast cancer-specific survival according to subtype and explore mediating factors. PATIENTS AND METHODS: Participants were women presenting with stage I to III breast cancer between January 2000 and December 2007 at National Comprehensive Cancer Network centers with survival follow-up through December 2009. Cox proportional hazards regression was used to compare breast cancer-specific survival among Asians (n = 533), Hispanics (n = 1,122), and blacks (n = 1,345) with that among whites (n = 14,268), overall and stratified by subtype (luminal A like, luminal B like, human epidermal growth factor receptor 2 type, and triple negative). Model estimates were used to derive mediation proportion and 95% CI for selected risk factors. RESULTS: In multivariable adjusted models, overall, blacks had 21% higher risk of breast cancer-specific death (hazard ratio [HR], 1.21; 95% CI, 1.00 to 1.45). For estrogen receptor-positive tumors, black and white survival differences were greatest within 2 years of diagnosis (years 0 to 2: HR, 2.65; 95% CI, 1.34 to 5.24; year 2 to end of follow-up: HR, 1.50; 95% CI, 1.12 to 2.00). Blacks were 76% and 56% more likely to die as a result of luminal A-like and luminal B-like tumors, respectively. No disparities were observed for triple-negative or human epidermal growth factor receptor 2-type tumors. Asians and Hispanics were less likely to die as a result of breast cancer compared with whites (Asians: HR, 0.56; 95% CI, 0.37 to 0.85; Hispanics: HR, 0.74; 95% CI, 0.58 to 0.95). For blacks, tumor characteristics and stage at diagnosis were significant disparity mediators. Body mass index was an important mediator for blacks and Asians. CONCLUSION: Racial disparities in breast cancer survival vary by tumor subtype. Interventions are needed to reduce disparities, particularly in the first 2 years after diagnosis among black women with estrogen receptor-positive tumors.