Somatic mutations of genes involved in epigenetic functions and chromatin remodeling such as PHF6 (11%), KMT2D(MLL2) (12%), DNMT3A (5%), TET2 (5%), SUZ12 (5%), and EP300 (5%) have been identified in T-ALL [5,11,24,34]. The gene discussed is DNMT3A; the disease is acute lymphoblastic leukemia.