In the light of the new WHO 2016 brain tumor classification system, we performed an in-depth comparison of oligodendrogliomas (IDH-mutant and 1p/19q co-deleted) represented by our 1p/19q subgroup to astrocytomas (vast majority IDH-mutant) represented by our IDHme subgroup. The gene discussed is IDH1; the disease is oligodendroglioma.