Current concepts of leukemia and lymphoma: etiology, pathogenesis, and therapy.

The cellular change (phenotypic) leading to leukemia may involve a disorder of leukocyte maturation, but the etiologic molecular change (genotypic) remains unknown. We present evidence here that human leukemic cells contain type-C viral information and consider the possible significance of this observation in the context of a working hypothesis. We reexamine reticuloendothelial neoplasms in the light of newer immunologic, cytochemical, and ultrastructural methods for identifying cells of the T-lymphocytic, B-lymphocytic, and monocyte-macrophage systems. Use of these methods has led to a challenging concept of malignant lymphomas as neoplasms of various anatomic and functional compartments of the immune system. Functional studies, although still in their inception, have already provided provocative clues in the etiology and pathophysiology of these disorders. Advances in laboratory research have been paralled by dramatic changes in clinical oncology, as evidenced by trends in the treatment of acute lymphocytic leukemia, acute myelogenous leukemia, Hodgkin's disease, and diffuse histocyte lymphoma.