PIK3CA and oligodendroglioma: In summary, our results indicated that oligodendroglioma has great heterogeneity during gene evolution and suggested that several well‐known signaling pathways and genes play an important role in tumor evolution, including the SHh signaling pathway, PI3K/AKT signaling pathway, Notch1 signaling pathway, and MMR proteins (MSH2 and MSH6).