THE CLINICAL-SIGNIFICANCE OF RESIDUAL DISEASE IN CHILDHOOD ACUTE LYMPHOBLASTIC-LEUKEMIA AS DETECTED BY POLYMERASE CHAIN-REACTION AMPLIFICATION OF ANTIGEN-RECEPTOR GENE-SEQUENCES

The polymerase chain reaction (PCR) has been applied to detect occult leukemia cells in children with acute lymphoblastic leukemia who are o therwise considered in complete remission by traditional morphological examination of bone marrow specimens. To determine whether PCR provid es unique prognostic information of use for the clinical investigator, we reviewed the 20 clinical studies published to date. From this revi ew, it is evident that discrepancies exist for the detection of residu al disease for patients who remain in complete remission and for those who relapse. However, because of the fundamentally different approach es used to apply the PCR method to each of these studies, an entirely different interpretation can be reached when critical technical factor s are considered. The combined data from the various studies suggest t hat a consistent pattern for residual disease disappearance over many months exists for patients who remain in extended complete remission a nd a pattern of residual disease persistence and reappearance precedin g clinical findings exists for the majority of those who ultimately re lapse in the bone marrow.