IDH2 and central nervous system cancer: Of the eight possible combinations based on the presence or absence of the three tumor genetic markers, five could be used to classify most of the 471 (93.3%) gliomas: triple-positive (80, 17.0%), mutations in both TERT and IDH (14, 3.0%), mutation in IDH only (91, 19.3%), triple-negative (143, 30.4%), and mutation in TERT only (143, 30.4%).