Next, we used Q-PCR to detect PHGDH mRNA expression levels in detect the PHGDH mRNA expression of 40 glioma tissues (10 grade I astrocytomas, 10 grade II astrocytomas, 10 anaplastic astrocytomas and 10 glioblastomas) and 10 normal brain tissues. The gene discussed is PHGDH; the disease is astrocytoma (excluding glioblastoma).