These effects were typical for the other tumor cell lines tested, independently of their p53 status and none of these reductions in PE reached statistical significance with the exception of the BRCA1-defective cell line, MDA-MB-436 [27], where PE was reduced by niraparib from 11.5 ± 1.1% to 2.5 ± 0.9% (p=0.004). The gene discussed is TP53; the disease is neoplasm.