In the past, most PCR-based MRD tests used semiquantitative methods for the detection of clone-specific translocations or IG or TCR gene rearrangements.44 46 Standard PCR techniques have the ability to amplify target DNA to a plateau of amplification, so that after 35 to 40 cycles it is not possible to precisely define the initial amount of target DNA. Semiquantitative methods, such as dot-blot hybridization using a patient-specific VDJ region probe, competitive PCR, and limiting dilution PCR, are similarly based on post-PCR endpoint analysis.54 These techniques require serial dilutions and the analysis of multiple replicates, both of which introduce variability and cost, and are too difficult and too time-consuming to be performed routinely in the clinical laboratory. Real-time quantitative PCR technology (RQ-PCR) circumvents these problems and allows for quantitative assessment of residual disease. The amount of DNA can be normalized to quantitative amplification of a control gene.54
Was this article helpful?