In addition, several potential pathologic hallmarks of glioma have been investigated, which include 1p/19q codeletion, IDH, EGFR, p53, PTEN/Akt pathway, Rb, Ras/MAPK pathway, extrachromosomal DNA, MGMT, TERT, and ATRX (5, 10, 12, 16). This evidence concerns the gene RB1 and central nervous system cancer.