Role of minimal residual disease evaluation in leukemia therapy.

In patients with acute leukemia, measurements of minimal residual disease (MRD) provide unique information on response to treatment. The most useful currently available MRD assays are polymerase chain reaction amplification of fusion transcripts and rearranged antigen-receptor genes and flow cytometric detection of aberrant immunophenotypes. Many studies in children and adults with acute lymphoblastic leukemia and acute myeloid leukemia have demonstrated a strong association between the presence of MRD and risk of relapse. Therefore, the use of information on MRD to adjust the intensity of therapy holds great potential for improving long-term clinical outcome. This article discusses the methodologies available for productive MRD testing and the clinical significance of the results.