CDKN2A and central nervous system cancer: The genetically engineered mouse models of glioma used by Akkari et al. to examine the combined therapeutic efficacy of CSF-1R inhibitor and radiotherapy were generated in an Ink4a/Arf-deficient background (platelet-derived growth factor-driven Ink4a/Arf KO), which was previously reported to closely resemble the proneural subtype of GBM [2, 47].