Epigenetic changes in tumors are commonly seen in the methylation of CpG island in the promoter region of tumor suppressor genes. Histone acetylation, methylation, phosphorylation, ubiquitination, ADP ribosylation, and noncoding RNA can all affect the transcriptional activity of genes. Epigenetic groups have become new targets for individualized treatment of tumors. It can be used in combination with HDACi, BETi, IDHi, DOTi, EZH2 inhibitor, LSD1 inhibitor and DNMT inhibitor. respectively. The gene discussed is DNMT1; the disease is neoplasm.