PRDM9 and neoplasm: Specifically, the histone methyltransferase (HMTase) G9a, which catalyzes H3K9 mono and di-methylation (H3K9me1/2), was linked to self-renewal and tumor initiation in several neoplasms including leukemia, melanoma, lung tumors, as well as head and neck carcinomas [16–19].