Noncanonical (Non-R132H) IDH-Mutated Gliomas

Abstract

Mutations in IDH1 or IDH2 confer a significant survival advantage compared to their isocitrate dehydrogenase (IDH) wild-type counterparts and, as such, are the most significant prognostic factors in this group. The mutations in the IDH1 gene are heterozygous and almost always involve only a single residue (arginine 132), which is replaced by histidine in roughly 90% of tumors. Regardless, the non-p.R132H (noncanonical) mutations in the IDH1 gene were also documented in around 20% of mutated glioma. The noncanonical IDH mutations have distinguishing radiological and histological features. The existence of such tumors seems to be associated with a genetic predisposition to cancer development.