Immunohistochemically, the tumor cells were diffusely positive for GFAP (Fig. 4c), S100 (Fig. 4d), olig2 (Fig. 4e), synaptophysin, and vimentin, but negative for EMA (Fig. 4f), CD31, CD34 (Fig. 4g, h), NeuN, inhibin-α, D2-40, and IDH1 (Fig. 4i). This evidence concerns the gene IDH1 and neoplasm.