CDKN2A and glioblastoma: Due to their proximity to genes with significantly differentially altered copy numbers as well as their established connection to GBM [10], the rates of gains/amplifications (log2 ratio > 0.25/0.8) and losses/deletions (log2 ratio < 0.25/0.8) in EGFR, CDKN2A, and CDKN2B were investigated in the two response groups.