CASP7 and cancer: Our data showed that those cancer cell lines with higher levels of XIAP:CASP7 (e.g. MCF-7, BT-483, MDA-MB-468, and ZR-75-1) were hypersensitive to 643943 (Fig. 5A, B), consistent with that 643943 disrupts the XIAP:CASP7 complexes.