IDH1 and central nervous system cancer: Second, we have included IDH and 1p/19q in this study as they are the two most important factors in classification of glioma since the WHO 2016 guidelines.1 However, as per the recent WHO 2021 guidelines,2 knowledge of telomerase reverse transcriptase (TERT) promoter methylation, epidermal growth factor receptor (EGFR) gene amplification, and combined chromosome 7 gain/chromosome 10 loss status are also required for classifying IDH-wt grade 2/3 gliomas into “Glioblastoma, IDH-wildtype” or “NEC (not elsewhere classified)” classes.