DNA values in myeloma

The DNA content of interphase nuclei of cells in the peripheral blood and bone marrow in myeloma has been measured using a microspectrophoto-metric technique after Feulgen staining. Twenty-two patients had DNA values measured on peripheral blood mononuclear cells, and 22 had DNA measurements on marrow cells. In 20 patients, DNA studies were made on both peripheral blood and marrow samples obtained at the same time. Twelve patients had a broad scatter of DNA values about the primary mode in peripheral blood nucleated cells, and an additional three patients had a broad scatter about the primary mode in marrow cells. Three patients had significant numbers of cells with marked hypodiploidy in the bone marrow. One patient in the terminal stages of the disease had a major mode in the tetraploid range and other modes at the diploid and octoploid levels. The results are discussed, with particular reference to the possible explanations for these findings, their relationship to chromosome studies previously reported, and the evidence for the presence of circulating abnormal nucleated cells in this disease.