PIK3CA and oligodendroglioma: The relative expression levels of biomarkers in the TP53 pathway (Fig. 4I) and RTK-PI3K pathway (Fig. 4K) were mostly higher in oligodendroglioma, except for FGFR2 and PTPN11. Astrocytoma exhibited increased or increased signals of expression of RB pathway biomarkers (Fig. 4J).