Median number of mutations also did not vary significantly when corrected for disease subtype, possibly due to the small sample size (hormone receptor positive (HR+): BM median 2 mutations, non-BM 2; HER2+:BM 3, non-BM 2; triple negative breast cancer (TNBC): BM 3, non-BM 1). The gene discussed is ERBB2; the disease is triple-negative breast carcinoma.