Silver-stained nucleolar organizer regions in bone marrow cells and peripheral blood lymphocytes of Philadelphia chromosome-positive chronic myelocytic leukemia patients.

Silver-stained nucleolar organizer regions (Ag-NOR) in bone marrow cells and/or phytohemagglutinin-stimulated peripheral blood lymphocytes were compared between six normal healthy persons as controls and 22 Philadelphia chromosome (Ph)-positive chronic myelocytic leukemia (CML) patients, to examine if any disease associated changes occur in the expression of Ag-NOR. Although the frequency of Ag-NOR-positive cells and the number of Ag-NOR per cell were generally greater in lymphocytes than in bone marrow cells in both controls and CML patients, the Ag-stainability of these cell types in CML patients was considerably heterogeneous, compared with that found in controls. The peripheral lymphocytes of CML patients in the chronic phase, but not in the blastic phase, exhibited a significantly lowered Ag-stainability when compared with those of controls. while no such difference was observed between bone marrow cells of controls and leukemia patients in both phases of CML. In the blastic phase, however, the occurrence of Ag-NOR on the Ph of CML bone marrow cells was significantly less than expected. The present findings are discussed in relation to the existing data on the Ag-NOR expression in both normal and neoplastic cells.