ABSTRACT Original Article Background and Objectives

Quantitation of BCR-ABL mRNA is emerging as the standard of care to monitor the status of chronic myeloid leukemia (CML). Peripheral blood plasma was ana-lyzed in this study because of previous detection of nucleic acids and proteins from tumor cells in plasma samples. Design and Methods Reverse transcriptase polymerase chain reaction was used to establish ratios of BCR-ABL:ABL mRNA in peripheral blood cells and plasma, and absolute levels of BCR-ABL mRNA per unit volume of plasma. Samples from 160 CML patients and 180 control individuals without CML were tested. Cells and plasma samples from 93 of the CML patients were re-analyzed 3-12 months after imatinib treatment. Results Ratios of BCR-ABL:ABL mRNA in paired cell and plasma samples of the 160 CML patients correlated significantly (r=0.83; p<0.001). When results were compared directly using the sign test, the pre-therapy plasma results were significantly dif-ferent from those from peripheral blood cells (p=0.028), but not bone marro