DNMT1 and lung cancer: Compared with DNMT1 and DNMT3a, DNMT3b was significantly overexpressed in tumor tissues.50 Overexpression of DNMT1, DNMT3a, and DNMT3b has been observed in multiple cancers, including AML, CML, glioma, and breast, gastric, colorectal, hepatocellular, pancreatic, prostate, and lung cancers.