Among 12 765 beneficiaries with ERBB2-positive breast cancer (median [IQR] age, 74 [69-80] years; 99.2% female), 8.1% were of Black, 6.9% Hispanic, and 85.0% White race and ethnicity, and 54.2% received ERBB2-targeted therapy. This evidence concerns the gene ERBB2 and breast cancer.