Second, CO-dependent inhibition of CBS in cancer cell lines triggers upregulation of remethylation metabolites [e.g., methionine (Met), S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH) in Fig. 2]; changes in these metabolites determine cellular contents of polyamines that regulate cancer metastasis, and regulate protein methylation and epigenetics [39–41]. The gene discussed is CBS; the disease is cancer.