PSPH and neoplasm: For example, under the stress condition of nutrients deprivation such as glucose or glutamine, tumor cells activate oncogene c-Myc to support the survival of tumor cells by regulating the expression of metabolic enzymes such as PHGDH, PSAT1, PSPH and other metabolic enzymes in the serine synthesis pathway and enhancing the de novo synthesis of serine and maintaining redox homeostasis [22].