We identified KMT2C p.K2797fs as a frequently mutated mutation in Chinese breast cancer but not in the MSKCC cohort (2% versus 0%, FDR < 0.05) (Supplementary Fig. 5a), and this finding was particularly true in the HR+/HER2− subtype (Supplementary Fig. 5b, top left). Here, HR is linked to breast carcinoma.