IDH1 and central nervous system cancer: In a preliminary study (unpublished) in our laboratory, mutation profiling by Sanger sequencing of hot-spot regions of four glioma-related genes (Idh1, Idh2, Braf, and Egfr) identified point mutations in Egfr gene in 55% (6/11) of the gliomas from chemical-exposed HSD: Sprague Dawley® SD rats.