TP53 and glioblastoma: The frequency of TP53 mutations is known to be significantly different when compared between primary and recurrent glioblastomas,51 and that the frequency of TP53 mutations also differs across different subtypes of GBM, accounting for 54%, 32%, 21% and 0% of Proneural, Interstitial, Neuro and Classical GBM, respectively.52