The Influence of Bcl-2 and Myeloid Antigen Expression on Response to Therapy in Childhood Acute Lymphoblastic Leukemia

The possible prognostic significance of the expression of a variety of markers has been investigated in acute lymphoblastic leukemia (ALL). In the present study we investigated the prognostic significance of CD13 and CD33 myeloid antigens (MY) aberrantly expressed on the blasts of ALL patients and Bcl-2 anti- apoptotic molecule expression in childhood ALL. Aberrant expression of MY occurred in 8.8% of cases. Variant levels of Bcl-2 were expressed in patients (44.2±25.5%), with more than 20% positivity for Bcl-2 in 64.7% of patients. Bcl-2+ patients survived 959±242 days compared to 1059+230 days for Bcl-2- patients (P=0.2). Corresponding data for complete remission duration was 682±170 and 716±173 days (P=0.3), respectively, indicating no significant association between survival and complete remission duration of patients with expression of the Bcl-2 molecule. Analysis of clinical response according to MY expression, however, showed significant association with survival and complete remission duration. MY+ patients had shorter complete remission duration (383±58 days) and survival (473±68 days) than MY- patients (complete remission duration, 724±144 days; survival, 1045±186 days; P<0.001). Expression of Bcl-2 along with MY was not associated with a significant decrease in survival or complete remission duration Results of this study indicated that expression of MY was a poor prognostic factor in childhood ALL. Bcl-2 expression in MY+ patients could not influence the response to therapy.