Abstract
The cytophotometric technic employing the Feulgen reagent was used to determine the relative amount of DNA in the nuclei of individual myeloma and plasma cells aspirated from the bone marrow. Individual myeloma cells were found to contain markedly elevated amounts of DNA as compared to that in the plasma cells of non-specific plasmacytoses. Myeloma cells were found to contain geometric multiples (2, 4, 8) of the amount of DNA present in normal lymphocytes, and the degree of DNA "ploidy" was related to the morphologic stage of immaturity. Polyploid DNA values were not found in the non-specific plasmacytoses. The possible mechanisms of formation were discussed. The findings are interpreted as suggesting the presence of a basic alteration in the quantitative DNA-chromosome relationship in myeloma cells, and they offer additional support for the separation of the myeloma plasmacytoses from nonspecific plasmacytoses.
