PHGDH and breast cancer: Phosphoglycerate dehydrogenase (PHGDH), the first enzyme of the SGOC pathway, is amplified in breast cancer and melanomas.12,13 NRF2 and Myc activate the expression of genes in serine synthesis pathway in cancer.14,15 HER2 and p53 regulate the expression of PHGDH.9 Thus, serine biosynthesis pathway is regulated by many oncogenes and tumor suppressor genes.