CRB3 and breast cancer: While only nine representative tamoxifen‐resistant metastatic tissues and matched primary tumours were examined, and the mechanism whereby CRB3 regulates β‐catenin signalling‐dependent tamoxifen resistance remains to be investigated, we believe that CRB3‐regulated stemness of breast cancer might shed a light in treatment of breast cancer patients who develop resistance to tamoxifen during the course of the treatment.