MC3817 is a selective DNMT inhibitor, with IC50 values of 0.044 µM for DNMT1 and greater than 10 µM for DNMT3A/3L. It inhibits P53-dependent cancer cell proliferation, induces apoptosis and DNA damage, and elevates the levels of cleaved Caspase 3, P53, and gammaH2AX. MC3817 is applicable in research on non-small cell lung cancer, colon cancer, cervical cancer, triple-negative breast cancer, and histiocytic lymphoma.