ERBB2 and breast cancer: Supplementary Figure S5 illustrated the association within these genes. We further analyzed the predictive effects of our five-signature model in different subtypes of BC from the TCGA-BRCA cohort (Supplementary Figure S6). In the luminal (p < 0.001) and HER2-overexpressing (p = 0.002) subtypes, Kaplan–Meier analysis revealed that the low-risk group had a greater chance of survival than the other group, while there was no significant difference in survival in triple-negative BC.