Expanding the spectrum of IDH1 mutations in gliomas.

Mutations in isocitrate dehydrogenase -1 or -2 (IDH1 or IDH2) are found in the majority of WHO grade II and III diffuse gliomas and secondary glioblastomas. IDH mutation screening is rapidly becoming part of the routine pathological work up of human brain tumors, providing both diagnostic and prognostic information. Here, we characterize four rare and novel IDH1 mutations identified in surgical human glioma samples: two instances of an IDH1 p.