TERT and brain neoplasm: Genetic characteristics of brain tumors such as the co-deletion of chromosomes 1p and 19q [29,30,31], mutations in isocitrate dehydrogenase 1/2 (IDH1/2) genes [31,32], amplification or mutation of the epidermal growth factor receptor (EGFR) gene [33,34], mutations of the promoter region of the telomerase reverse transcriptase (TERT) gene [35], and deletion of the phosphatase and tensin homolog (PTEN) gene [33,34,35,36] have refined the classification of brain tumor subtypes.