BIRC2 and neoplasm: Considering that S2/IAPinh and SW IV-134 only differ with regard to affecting cIAP-2 protein levels in pancreatic (HPAC) and ovarian cancer cell lines (OVCAR8), we conclude that the overall mechanistic properties of each drug conjugate, in the context of a given tumor type, are consistent with the activity profile of its related cargo, i.e. cIAP-1/2 degradation with SW IV-134 via its cargo (SW IV-52, SMAC mimetic) but only cIAP-1 degradation with S2/IAPinh via its cargo (LCL161, IAPinh).