Of 320 124 women diagnosed with breast cancer from 2010 to 2016, 232 558 (72.6%) had luminal A, 35 869 (11.2%) had luminal B, 15 472 (4.8%) had ERBB2-enriched, and 36 225 (11.3%) had triple-negative breast cancer subtypes. The gene discussed is ERBB2; the disease is breast cancer.