Stabilization of the estrogen receptor through the ERα/FKBP5 complex in breast cancer cells mediates endocrine therapy resistance53; whereas, in endometrial cancer, it exerts its anti-cancer function by degrading the proto-oncoprotein C-MYC protein through the ubiquitination pathway of the E3 ligase TRIM2854. This evidence concerns the gene ESR1 and endometrial cancer.