EZH2 and lung cancer: With respect to lung cancer, two histone modifications implicated in the formation of a transcriptionally repressive chromatin state involve trimethylation at Lysine 27 and dimethylation at Lysine 9 of histone H3 (H3K27me3 and H3K9me2) via S-adenosyl-methionine-dependent methylation catalyzed by the histone methyltransferases (HMTs) EZH2 and G9a.