BCL-2 AND C-MYC EXPRESSION, CELL-CYCLE KINETICS AND APOPTOSIS DURING THE PROGRESSION OF CHRONIC MYELOGENOUS LEUKEMIA FROM DIAGNOSIS TO BLASTIC PHASE

Chronic myelogenous leukemia (CML) has a progressive course but little is known about the biologic characteristics of disease progression. T his study was designed to assess the changes in cell proliferative cha racteristics, apoptosis, the expression of the bcl-2 and c-myc genes b etween the time of initial diagnosis and entrance into the blastic pha se of the disease. We observed that the rate of cell proliferation dec reased and the cell death rate did not significantly change as the dis ease accelerated. The level of bcl-2 expression was significantly high er in accelerated/blastic phase cells than in the chronic phase cells in the population as a whole, however, the bcl-2 expression level did not change in blast cell subpopulation. c-myc Expression was significa ntly higher in the blast cell subpopulation of accelerated/blastic pha se than in that of earlier phases of the disease. in conclusion, the c haracteristics of CML cells, namely proliferation rate, c-myc and bcl- 2 change during the course of the disease. It is possible that the cha nge in c-myc expression plays a causative role in evolution of the bla stic phase from the chronic phase. (C) 1997 Elsevier Science Ltd.