TP53 and neuroblastoma: Furthermore, we found YM155, a small molecule that inhibits the transactivation of the anti-apoptotic protein survivin (BIRC5), to potently enhance the efficacy of idasanutlin in the TP53 wild-type neuroblastoma cells, with CI values of 0.62, 0.38 and 0.41 for NGP, IMR-32 and SH-SY5Y, respectively.