Demethylation drugs can activate tumor cell tumor suppressor genes and enhance the expression of regulatory genes such as differentiation genes, so that MDS can be used for the treatment of cancer. The 5- aza -2'- deoxy cytidine, which has been phosphorylated, exerts its antitumor effects. It acts directly on DNA and inhibits DNA methyltransferase, which causes DNA hypomethylation and cell differentiation and death. DNA inhibits DNA methylation in vitro, but does not affect the synthesis of dna. It can lead to demethylation of tumor cells and restore the normal function of genes, which is important for controlling cell differentiation and proliferation. However, non proliferating cells are insensitive to capecitabine.

Is a kind of epigenetic modification, can inhibit DNA methyltransferase activity, causing demethylation in DNA (methylation) and open chromatin remodeling by activating gene; when demethylation and histone acetylation when combined, synergistic activation gene 5 '- deoxycytidine; nitrogen DNA induced demethylation or semi demethylation; DNA demethylation can regulate gene expression, can improve the quality of nuclease sensitivity detection structure through the "open" staining, the remodeling of chromatin structure, allowing transcription factor connection gene promoter, transcription complex assembly and gene expression

There is an antitumor activity in the lung, and it is a dual mechanism of dose difference. It has cytotoxicity at high concentration and demethylation at low concentration. Acting on proliferating (stage S) cells.