MGMT and glioma: O6-methylguanine-DNA methyltransferase (MGMT)-initiated methylation, loss of heterozygosity in 1p/19q, isocitrate dehydrogenase-1 (IDH1) gene mutation, and loss of ATRX expression have become important molecular biomarkers in the pathological diagnosis of gliomas and enrich people's understanding of tumor gene variation [10, 11].