Monitoring BCR-ABL in the treatment of chronic myeloid leukemia by polymerase chain reaction.

The sensitive detection of minimal residual disease by the polymerase chain reaction (PCR) has revolutionized our ability to follow treatment response and predict relapse. Examples of how the detection of minimal residual disease can drive clinical research are best found in chronic myeloid leukemia (CML). The use of PCR to detect the BCR-ABL chimeric transcript in CML has been found to predict relapse in the transplant setting, and more recently, has been found in trials of imatinib to be a strong measure in predicting progression-free survival. In addition, clinical trials are now under way using the quantitative assessment of BCR-ABL as a surrogate outcome marker, potentially reducing the time and cost of clinical trials.