HSF1 and breast cancer: Since the initial observation that S326 phosphorylation affects heat stress‐induced HSF1 activity [8], five kinases have been observed to phosphorylate S326, including mTORC1 [33, 37], MEK1 [38], p38 [34], DYRK2 [40] and AKT1, which our work previously identified can phosphorylate S326 in breast cancer [15].