EZH2 and cancer: Enhancer of zeste homolog 2 (EZH2), a methyltransferase and the core catalytic element of the polycomb repressive complex 2 (PRC2), can induce the genome-wide histone H3 lysine 27 trimethylation (H3K27me3) and acts as an oncogene via the repression of tumor suppressor genes in human cancers [9, 10].