PSPH and cancer: The high energetic demand of cancer cells involves the anabolic pathway of serine biosynthesis where the enzyme phosphoglycerate dehydrogenase (PHGDH) converts 3-phospho- glycerate generated from glycolysis into the precursor 3-phosphohydroxypyruvate; subsequently the enzymes phosphoserine aminotransferase 1 (PSAT1) and phosphoserine phosphatase (PSPH) convert the 3-phosphohydroxypyruvate into serine [53].