[Molecular evidence for a single clonal origin in a patient with multiple myeloma and non-Hodgkin's lymphoma].

A 49-year old man was admitted in November 1989, because of anemia, abnormal shadowing on chest X ray and hyperproteinemia. Biclonal gammopathy (IgG kappa + IgA kappa) was shown in serum, and Bence Jones protein in urine. The bone marrow examination showed an increased number of abnormal plasma cells (15.7%) and no evidence of lymphoma, A diagnosis of multiple myeloma (MM) was made. In April 1990, while the patient was treated with the modified M2 regiman, swelling of the right cervical lymph node was observed. Lymph node biopsy revealed that he had non-Hodgkin's Lymphoma (:NHL, diffuse, mixed, B cell type). He was retreated with the CHOP regimen for both disease, but died of respiratory failure in October. 1991. To establish the clonal origin of this case of concominant MM and B-cell NHL, the immunoglobulin gene rearrangements in his lymph node and bone marrow were analyzed. Southern blot analysis with the JH probe and Ck probe showed one common band and one different band in the two samples. Our data suggest that two B-cell malignancies may have arisen from a single B-cell progenitor.