Variation in expression of 8 apoptotic proteins in PRED, VCR, and ASP (PVA)-sensitive and -resistant childhood ALL. Protein levels of Apaf-1, procaspases-2, -3, -6, -7, -8, -10, and PARP of leukemic cells from 10 patients compared by Western blot analysis. Arrows indicate the positions of full-length procaspase-2 (48 kDa), procaspase-3 (32 kDa), procaspase-6 (33 kDa), procaspase-7 (35 kDa), procaspase-8 (50/55 kDa), procaspase-10 (58 kDa), full-length and cleaved PARP (116/89 kDa), and Apaf-1 (140 kDa). The in vitro drug responsiveness of each patient is indicated below each lane; R indicates in vitro resistant and S indicates in vitro sensitive toward PRED, VCR, and ASP (PVA), as explained in “Materials and methods.”