Based on our findings, we revealed that METTL3 plays a protective role in HR+HER2− BC and regulates the CDKN1A/EMT and BAX/caspase3/8/9 axes in an m6A-dependent manner, which could be novel pathways involved in a potential mechanism of HR+HER2− BC chemoresistance (Fig. 6H). Here, ERBB2 is linked to breast cancer.