Draaisma et al. [9] reported CDKN2A/B results on a mixed population of WHO Grade 2–4 gliomas: astrocytoma (68.6%), GBM (14.8%, not included in meta-analysis), oligodendroglioma (ODG, 2.5%, not included in meta-analysis), the histological status of the remaining samples (13.9%) was inconclusive. This evidence concerns the gene CDKN2A and oligodendroglioma.