Enhancer of zeste homolog 2 (EZH2), a histone methyltransferase served as a catalytic subunit of PRC2, has been known to catalyze tri-methylation of histone H3 at Lys 27 (H3K27me3) by its SET (Su(var)3-9, Enhancer-of-zeste and Trithorax) domain in C-terminus, leading to silencing its target genes involved in cell cycle regulation, cell proliferation, cell differentiation, and cancer progression [2]. The gene discussed is EZH2; the disease is cancer.