TP53 and glioblastoma: For example, in a subtype of glioblastoma multiforme (GBM) known as primary GBM, 70% of glioma cells express wildtype p53 and these cells have been observed to have a selective impairment of the apoptotic functions of WT p53, while still being able to regulate p53 control over DNA repair and control of cell cycle (Shu et al., 1998).