Minimal residual disease in hematologic disorders

In almost no other area of medical oncology has the introduction of new dru gs, combinations of chemotherapeutic agents, and novel biologic treatments caused such dramatic responses as it has in the treatment of malignant hema tologic disorders. However, despite some therapeutic success, many patients relapse and die from recurrence of their disease. The implications of mini mal residual disease (MRD), a term referring to disease that is undetectabl e by conventional morphologic methods, have therefore attracted increasing attention in recent years. New and powerful laboratory tools such as polyme rase chain reaction assays have extraordinary sensitivity and provide excit ing new insights into the detection, nature, quantification, and kinetics o f MRD. This article summarizes methods used in the identification of MRD an d its importance as exemplified in the case of acute leukemias and chronic myelogenous leukemia.