It has been reported that IDH-mutant astrocytomas have co-occurring TP53 mutations in 94% of cases and loss of ATRX expression in 86% of cases [10].We sought to assess the added value of performing ATRX immunohistochemistry over and above an ATRX prediction metric based upon the status of IDH and TP53 alterations as determined by Oncomine alone in the adult population within our cohort. This evidence concerns the gene IDH2 and astrocytoma (excluding glioblastoma).