We therefore analysed IDH1 and IDH2 statusat codon 132 of IDH1 and codon 172 of IDH2 by direct sequencing and anti-IDH1-R132H immunohistochemistry in 53 paired samples and their recurrences, including 29 low- grade gliomas, 16 anaplastic gliomas and 8 Glioblastomas. The gene discussed is IDH1; the disease is central nervous system cancer.