Differential nucleolus organizer activity in normal and leukemic bone marrow.

A cytochemical technique that uses silver nitrate staining has been used to study the nucleolus organizer activity in bone marrow cells from 13 patients with acute lymphocytic leukemia (ALL), 11 patients with chronic myelogenous leukemia (CML), 7 patients with acute myelogenous leukemia (AML), and 4 healthy persons. Our results indicate that the nucleolus organizer region (NOR) activity was significantly lower in the control group than in the ALL patients. The NOR activity level was significantly lower in both the CML patients in chronic phase and the AML patients than in the ALL group and similar to the control group. These disease-related differences in NOR activity as detected by silver staining can be used as diagnostic procedure in evaluating human leukemias.