Estimation of the relationship between caspase-3 expression and clinical outcome of Burkitt's and Burkitt-like lymphoma.

Burkitt's lymphoma and atypical Burkitt/Burkitt-like lymphoma (BL/BLL) are considered highly aggressive B-cell lymphomas with a rapid proliferative rate and high rate of apoptosis. The aim of the present study was to confirm whether apoptotic and cell proliferative factors affect BL/BLL clinical outcomes. We retrospectively analyzed the relationship between the clinical and immunophenotypic features of 43 BL/BLL patients by immunohistochemical staining for bcl-2 and double staining for Ki-67 plus caspase-3. In double staining experiments, all patients were divided into high and low groups for the expression of caspase-3, Ki-67, and both Ki-67 and caspase-3, by using the medians of their percentages as limits. The 43 BL/BLL patients were divided into high caspase-3 (n = 19) and low caspase-3 (n = 24) groups. There was a significant difference in the overall survival between the high (77%) and low caspase-3 (33%) groups; the survival rate of patients in the low caspase-3 group who received aggressive short-term chemotherapy (58%) was significantly better than that of patients who received cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP) therapy (17%). All patients positive for bcl-2 were in the low caspase-3 group (high caspase-3 group, 0%; low caspase-3 group, 42%). The overall survival tended to be better in the high caspase-3 and bcl-2-negative group (76%) than in the low caspase-3 and bcl-2-negative (50%) group. In addition, the low caspase-3 and bcl-2-positive group tended to show the worst prognosis (16%). We suggest that caspase-3 may function as an indicator of the prognosis of BL/BLL. Furthermore, intensive short-term chemotherapeutic regimens may improve the prognosis of the patients in the low caspase-3 group.