ASSOCIATION OF BCL-2, BAX, BCL-XL AND INTEULEUKIN-1-BETA-CONVERTING ENZYME EXPRESSION WITH INITIAL RESPONSE TO CHEMOTHERAPY IN ACUTE MYELOID-LEUKEMIA

Bcl-2 expression is able to confer drug resistance to chemotherapy-ind uced programmed cell death. Bax, a partner protein of bcl-2 with exten sive aminoacid homology, is a promoter of apoptosis. Apparently the eq uilibrium of bcl-2 and bax hetero- and homodimers is important for the susceptibility of cells for stimuli inducing apoptosis. In this study we determined the role of bcl-2 to bax expression ratio, bcl-xL and I CE expression level for predicting clinical response to chemotherapy i n acute myeloid leukemia (AML). Bone marrow samples from 14 patients w ith AML were examined using an immunophosphatase staining method. Init ial bone marrow blast portion was over 80% in all cases. Clinical resp onse was defined by bone marrow aspiration 4 weeks after treatment ini tiation. There was a significant correlation between bcl-2 to bar expr ession ratio and clinical response (P < 0.005). No patients with a bcl -2/bax ratio > 1.0 achieved complete remission after induction therapy . No significant correlation between bcl-2- and p-glycoprotein-express ion was observed in this group. Conversely a high expression of ICE in dicated a good clinical response (P < 0.01), whereas expression of bcl -xL had no influence on therapeutic success in this group.