SILVER BANDS IN CHRONIC GRANULOCYTIC-LEUKEMIA .1. INCREASED BANDING ASSOCIATED WITH BLASTIC TRANSFORMATION

The proposal that the level of Ag banding in leukemic cells of Ph1 + chronic granulocytic leukemia (CGL) patients increases as the disease progresses was tested. Blood and/or bone marrow cells from 14 patients were cultured for 24 h before banding. In all but 1 case, there were 2 populations of mitoses, those with Ag bands on their nucleolar organizing regions (NOR) and those without. The percentage of cells that banded was higher, on average, in cultures from 7 patients in blastic transformation (80%) than in 8 chronic cases (36%) or in 1 accelerated phase (49%). The mean number of NOR stained in banded cells was higher in blastic phase (6.9) compared with chronic phase cells (4.4). Hyperdiploid cell lines were present in 4 cases of myeloblastic transformation. All such cells were Ag banded, and the mean fraction of NOR banded in them was relatively high. An increase in Ag banding with time was shown in 2 of the patients. Ag banding most likely increases in CGL cells as the disease progresses. This may arise either through an increase in the rate of ribosomal RNA [rRNA] synthesis in leukemic cells present in the blastic phase or possibly by a decrease in the rate of degradation (or processing) of newly synthesized rRNA.