G9a was overexpressed in breast, gastric, ovarian, cervical, endometrial, prostate, lung, colorectal, liver, urinary bladder, and brain cancers, as well as in hematological malignancies, melanoma, and cholangiocarcinoma, leading to aberrant H3K9 methylation [109,110,111,112,113,114,115,116,117,118,119,120,121,122]. The gene discussed is EHMT2; the disease is melanoma.