ESR1 and breast cancer: Notably, pathways such as estrogen receptor (ER), human epidermal growth factor receptor 2 (HER2), PI3K/Akt/mTOR, Wnt/β‐catenin, Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3), Notch, and Hedgehog (Hh) signaling have been analyzed to elucidate their roles in BC progression [11, 12].