Recently, accumulating evidence has demonstrated the cross-talk between ER and HER2 signaling is able to help identify new therapeutic strategies, including the use of aromatase inhibitors, dual blockade (trastuzumab/perstuzumab), and CDK4/6 inhibitors, to treat various different breast cancer subtypes [14,15,16,17]. Here, CYP19A1 is linked to breast carcinoma.