influence of Bcl-2 and myeloid antigen expression on response to therapy in childhood acute lymphoblastic leukemia

ABSTRACT

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