CDK4 and central nervous system cancer: Many of these regions contain tumor suppressor genes such as TP53 or XRCC1, as well as putative proto-oncogenes BCL3, CDK4, and HIF3A. The fact that no CNAs were more common in high grade IDHwt gliomas than in lower grade IDHwt gliomas supports the concept that the recurring copy number aberrations seen in IDHwt GBM are likely to be present in grade II–III precursor tumors.