ERBB2 and breast cancer: Women with ER- tumours had worse survival outcomes compared to women with ER + tumours, while luminal B, HER2-enriched and TNBC subtypes were associated with significantly higher risks of BC death (adjusted HRs of 2.04, 1.95 and 3.93 respectively, compared to luminal A tumours) (Supplementary Tables 1 and 2).