TP53 and glioblastoma: Consistent with the data obtained with Real time PCR analysis (RT-PCR), challenging GBM cells with EB54 and EB148 for 16 h led to a slight but significant increase in p53 protein levels (Figure 9A and 9B); a wash-out period of 16 h brought p53 accumulation to control levels in EB54-treated cells.