IDH1 and glioma: Furthermore, higher expression of BIRC5 was positively correlates with adverse clinicopathologic features of glioma, including the tumor grade, histological subtype, isocitrate dehydrogenase 1 (IDH1) mutation, 1p/19q chromosomal co-deletion, chemotherapy status, and O[6]-methylguanine-DNA methyltransferase (MGMT) promoter methylation status (Figure 3).