Our group carried out a retrospective, observational analysis of T‐DM1 clinical activity in 250 HER2‐positive metastatic BC patients.23 Overall, our results were compared to those from randomized trials and, similarly to what was found in those studies, no differences in clinical outcomes emerged when we analyzed our population by HRs status (p = 0.29). Here, ERBB2 is linked to breast cancer.