Genetics and Breast Cancer Subtypes Among African American and Caucasian Patients

Inherited genetic variants play a role in the development of different breast cancer subtypes among African American and Caucasian patients, according to an article published in JAMA Oncology.¹

Breast cancer — the most common tumor among women — is diagnosed among similar numbers of African American and Caucasian women of European descent, though mortality rates are 42% higher in the former. This may be explained by more frequent basal-like, triple-negative, and HER2-positive cancers among African Americans, though whether there are genetic reasons for this are unknown.

For this study, researchers used data from The Cancer Genome Atlas to analyze genetic and molecular information as well as recurrence and survival rates among African American and Caucasian women.

Of the 930 included patients, 776 were Caucasian and 154 were African American. African American patients had worse disease-free survival, greater likelihood of basal-like or HER2-positive disease, more TP53 mutations, and fewer PIK3CA mutations than Caucasian patients.

Of 9232 genes differentially expressed between the 2 groups, 142 were used to develop a gene expression signature after adjusting for disease subtype. The signature was used to effectively distinguish cancers of African American patients.

The authors concluded that a “modest number of genomic differences” were noted by this analysis between African American and Caucasian patients with breast cancer. Genetically personalized assessments may optimize treatment by predicting which patients require aggressive treatment.

Reference

1. Huo D, Hu H, Rhie SK, et al. Comparison of breast cancer molecular features and survival by African and European Ancestry in The Cancer Genome Atlas. JAMA Oncol. doi: 10.1001/jamaoncol.2017.0595 [Epub ahead of print]