PHGDH and central nervous system cancer: Recent reports in tumors have shown that PHGDH is highly expressed in breast cancer, melanoma, non-small cell lung cancer, hepatocellular carcinoma, pancreatic cancer, glioma, and gastric cancer tissues compared to normal tissues [24, 26–34] and that PHGDH overexpression accelerates cancer progression and promotes drug resistance by activating serine synthesis [35–37].