For instance, under the stress condition of nutrient deprivation, such as that of glucose or glutamine, tumor cells activate the oncogene c-Myc to support the survival of tumor cells by controlling the expression of metabolic enzymes like PHGDH (phosphoglycerate dehydrogenase), PSAT1 (phosphoserine aminotransferase 1), PSPH (phosphoserine phosphatase), and other metabolic enzymes in the serine synthesis pathway, promoting the de novo synthesis of serine, and sustaining redox homeostasis (32). The gene discussed is PHGDH; the disease is neoplasm.