MTAP and cancer: For example, methylthio-DADMe-immucillin-A ((3R,4S)-1-[(4-amino-5H-pyrrolo [3,2-d]pyrimidin-7-yl)methyl]-4-[(methylthio)methyl]-3-pyrrolidinol, MT-DADMe-ImmA), a potent transition state inhibitor (Ki = 1.7 nM) analogue of 5′-methylthioadenosine phosphorylase (MTAP; the rate-limiting enzyme of the l-methionine salvage pathway), possesses anti-cancer properties in several in vitro cancer cell lines and in in vivo mouse models of human cancers [84,85].