p53-depleted UKF-NB-3 cells were substantially more resistant to irradiation than UKF-NB-3 cells (Figure 6b), but, notably, YM155 increased the anti-neuroblastoma effects of irradiation in UKF-NB-3 cells and p53-depleted UKF-NB-3 cells (Figure 6c). This evidence concerns the gene TP53 and neuroblastoma.