IDH1 and glioblastoma: Third, it was observed that PTGFRN expression was found to be significantly upregulated: in classical and mesenchymal subtypes as compared to neural and pro-neural subtypes (Fig. 1D), in wild type IDH1 tumors as compared to mutant IDH1 tumors, and in G-CIMP– tumors as compared to G-CIMP+ tumors of GBM (Fig. 1E).