MYCN and neuroblastoma: To examine further the ability of MYCN expression to influence sensitivity to PARP inhibition and to test the influence of trapping, the cytotoxicity of three PARP inhibitors, talazoparib, olaparib and veliparib, was compared by MTT assay in the NB cell lines, IMR-32 (MYCN-amplified) and SHEP-1 (non-MYCN-amplified).