PTEN and central nervous system cancer: An analysis of interactions between genes showed that KRAS and TP53 (Pearson's correlation: 0.36) as well as PTEN and TP53 (Pearson's correlation: 0.32) exhibited co-expression in the GBM samples in the study of Brennan CW (Table 6), while CDKN2A and TP53 (p-value<0.001) as well as EGFR and TP53 (p-value=0.001) exhibited mutual exclusivity (Table 7), suggesting a central axis function for TP53 under TMZ control in the glioma pathway.