Methodology of premature chromosome condensation and its potential for relapse prediction in acute leukemia of children and adolescents

Abstract Premature chromosome condensation has been examined as a method for measuring the proliferative potential of bone marrow cells derived from children with acute leukemia with the intention of finding a predictor of relapse. A proliferative potential index (PPI) has been determined for patients with active disease at diagnosis and relapse, as well as at onset of remission and at extramedullary relapse. A modification of the technique established by Hittelman is described, which can be easily performed by the leukemia cytogeneticist. A PPI of 35% or greater is usually obtained for patients at diagnosis or in relapse. At the onset of remission, the PPI declines to values significantly below 35% and during extramedullary relapse the value of the PPI is near normal (12%). The method for the determination of the PPI is given in detail.