Association between IDH1/2 mutations and brain glioma grade

Abstract

Isocitrate dehydrogenase 1/2 (IDH)1/2 mutations are frequently detected in glioma. The aim of the present study was to investigate the association between IDH1/2 mutations and glioma grades. The current study was retrospective and used samples from 206 patients with brain glioma and 9 patients with spinal cord glioma as a control. Patients were diagnosed and graded according to the World Health Organization classification of tumors of the central nervous system. The association of patient age with glioma grade was evaluated, and IDH1/2 mutations were also examined and analyzed in different grades. On average, brain glioma grade tended to increase with increasing patient age; patients with grade IV (primary) gliomas had a significantly higher mean age than those with grades I and II (P<0.05), and patients with grade II glioma had a significantly lower mean age than those with grade III (P<0.05). The majority of brain gliomas with mutations in IDH1/2 in grade II, II-III and III occurred in adults, rather than adolescents. IDH1/2 mutations occurred most frequently in grade II, II-III and III gliomas, and these mutation frequencies differed significantly between brain glioma grades (P<0.001). In summary, mutations in IDH1/2 were associated with grade II, II-III and III brain gliomas, and possibly with the progression of brain glioma from grade II to grade III.

Keywords: age; brain glioma; isocitrate dehydrogenase 1/2; mutation; spinal cord glioma.

Figure 1.

Examples of IDH1 and IDH2 sequencing results. (A) Substitution in IDH1 at amino acid residue 132 (R132H). (B) Substitution in IDH2 at amino acid residue 172 (R172K). IDH, isocitrate dehydrogenase.