On the other hand, apoptosis could be induced in pancreatic carcinoma, breast tumor, and HCC cell lines by supplementing growth media with the on-pathway MSP product of ADI1GP oxidation, MTOB.[32-34] Furthermore, other upstream metabolites (e.g. MTA, SAM) also induce apoptosis.[24, 32, 34, 35] Ornithine decarboxylase 1 (ODC), an enzyme from the polyamine biosynthesis pathway, also inhibits tumor growth.[22, 36] As such, further investigations are needed to confirm that enhanced apoptosis and tumor inhibition with elevated ADI1GP expression levels are truly independent of metal binding. This evidence concerns the gene ODC1 and hepatocellular carcinoma.