Detection of minimal residual disease in acute leukemia.

A significant proportion of patients with acute leukemia who achieve remission subsequently experience frank relapse of their disease, and their ultimate prognosis is typically poor. Although such disease recurrences have been impossible to predict using standard laboratory techniques, new methods have been studied that identify patients destined to relapse. Sensitive polymerase chain reaction analyses of unique breakpoint fusion regions, and, in cases of acute lymphoblastic leukemia, patient-specific gene rearrangements have been used to detect minimal residual disease. Multiparameter flow cytometry has also been used to identify rare leukemia cells among populations of predominantly normal cells. Because these types of studies in pediatric acute lymphoblastic leukemia have convincingly demonstrated that patients with evidence of minimal residual disease during remission have a much higher incidence of relapse, therapeutic protocols have been initiated that intensify therapy for patients with minimal residual disease detected during remission.