In serine/glycine metabolism, tumor cells synthesize and utilize serine/glycine by a phosphoglycerate dehydrogenase (PHGDH)/phosphoserine aminotransferase 1 (PSAT1)/phosphoserine phosphatase (PSPH)/hydroxymethyltransferase (SHMT)-mediated continuous enzymatic reaction. Here, PHGDH is linked to neoplasm.