The IHC clone used was anti-IDH1 R132H (Dianova, USA Clone: H09-unconj) in dilution of 1:25. Immunoreactions were scored positive for mutated IDH1 protein when a majority of tumor cells showed strong cytoplasmic positivity with or without nuclear staining.[16 (link)] Normal/residual glial cells and vascular endothelial cells served as an internal negative control.