TP53 and neoplasm: Recent studies employing multiple biopsies of a single patient’s tumor have shown that multiple distinct GBM subtypes (i.e., mesenchymal, neural, etc.)exist within the same tumor (Sottoriva et al., 2013; Tang et al., 2015), that genetic heterogeneity even in early driver mutations such as TP53 occurs (Kumar et al., 2014), and that a genetically heterogeneous population of malignant cells survives initial treatment (Heimberger et al., 2003; Swartz et al., 2014).