[Recent progress in non-Hodgkin's lymphoma study in Japan].

Great progress has been made in clinical research on non-Hodgkin's lymphoma during the last 15 years. Surface marker and DNA analyses of immunoglobulin and T-cell receptor genes are essential for new classification of the disease according to the cellular origin of tumor cells. This approach resulted in the establishment of new disease entities such as adult T-cell leukemia/lymphoma(ATL), immunoblastic lymphoadenopathy (IBL)-like T-cell lymphoma, and the pleural B-lymphoma occurring in long-standing pyothorax. New retrovirus, HTLV-I, was found during studies on ATL. Prevention of HTLV-I infection is an important project. HTLV-I negative ATL was also found and is of particular interest in understanding leukemogenesis of ATL. An oncogen such as bcl-2 is important for characterization of follicular lymphoma. Prognostic factors of patients with T-lymphoma are completely different from those of B-lymphoma. Risk grouping by combination of major prognostic factors is useful for the selection of the best treatment modality and the accurate estimation of prognosis of patients at initial presentation. The effect of combination chemotherapy should be evaluated separately between T- and B-lymphomas because of the difference in response rate and prognostic factors.