BIRC2 and neoplasm: By comparison, the moderately potent compound, 15 (Ki value against cIAP1-BIR3 = 3.2 μM), showed modest cytotoxicity against PC-3 tumor cells with EC50 values of 5.3 and 3.7 μM for TNF and LT-α, respectively (Fig 5) [all data shown in Fig 5 can be found in S1 Prism].