EZH2 and breast cancer: The role of EZH2 in carcinogenesis has been extensively documented in numerous studies showing that EZH2 upregulation, or gain-of-function mutation, is often correlated with an adverse prognosis in various cancer types, including melanoma, prostate cancer, breast cancer, and others [21,89,90,91,92,93,94,95,96,97,98].