TP53 and glioblastoma: Pretreatment with general caspase inhibitor (z-VAD-fmk) significantly reduced the apoptosis rate from 50.12 ± 3.42 to 16.92 ± 1.30 (P < 0.01) indicating that PLAB proceeds apoptosis in U87 glioblastoma cells mainly through caspase activation.Apart from caspase inhibitor, PFTα, a p53 inhibitor, also reduced the apoptosis rate from 50.12 ± 3.42 to 33.42 ± 2.85 indicating the involvement of p53 in PLAB-induced apoptosis in U87 glioblastoma cells (Figure 4).