NCIt definition : A nutritional supplement that is synthesized from adenosine triphosphate (ATP) and
the amino acid methionine by the endogenous essential enzyme methionine adenosyltransferase
(MAT), with potential antineoplastic activity. Upon administration, S-adenosylmethionine
acts as a methyl donor for various transmethylation reactions. In cancer cells, this
agent induces the methylation of tumor promoting genes, reverses DNA hypomethylation,
and leads to the suppression of oncogene transcription. This induces apoptosis in
and inhibits proliferation of susceptible tumor cells.;