CDKN2A and glioblastoma: Recently, Johansson et al. performed a drug library screen using a large cohort of GBM patient-derived cell lines and found a correlation between TP53 (Tumor Protein 53) and CDKN2A/CDKN2B (Cyclin Dependent Kinase Inhibitor 2A and 2B) mutational and functional status and cell line sensitivity to proteasome inhibitors [17].