Multiple myeloma and other differentiated B-cell disorders.

Molecular genetic techniques that are used to define the myeloma precursor cell and find its origin are generating new insights into the biology of this generally incurable malignancy. In the absence of curative therapy, new techniques to distinguish between myeloma and more benign plasma cell disorders are particularly valuable. The increasing application of myeloablative therapy as early consolidation therapy is improving survival in myeloma. Interferon alpha maintenance therapy prolongs plateau phase in patients responding to conventional induction therapy and prolongs both remission duration and survival in patients who have received myeloablative consolidation therapy. Patients who show early resistance to induction chemotherapy may particularly benefit from myeloablative therapy. The role of allogeneic bone marrow transplantation in myeloma therapy remains undefined. Attempts to modulate cytotoxic drug resistance seem likely to be clinically successful in the near future. Insights into the roles of cytokines such as interleukin-1 and interleukin-6 will lead to new therapies. Clonal plasma cell expansion results in the plasma cell disorders including overt malignancy, multiple myeloma, plasma cell leukemia, solitary plasmacytoma of bone, or more indolent disorders including monoclonal gammopathy of undetermined significance. Selected important data on the biology and therapy of these disorders are highlighted.