Sensitivity to ABT-737 does not correlate with the expression pattern of Bcl-2 family proteins. (A) Protein expression of Bcl-2 family proteins was determined by Western blot analysis using lysates from untreated myeloma cell lines. Membranes were probed with specific pAbs against the indicated Bcl-2 family members as described in “Western blot analysis” and “Antibodies.” Actin was used as a loading control. (B) Change in the expression of Bcl-2 proteins after treatment with 0.4μM ABT-737 for 24 hours was determined by Western blot analysis.