Predicting relapse of human leukemia by means of premature chromosome condensation

We attempted to determine whether the technique of premature chromosome condensation (PCC) could be used to predict relapse in patients with acute leukemia in complete remission. Nineteen patients received chemotherapy and were studied serially with the PCC technique. Of the 19 patients in this pilot study, 14 relapsed, and the PCC technique predicted relapse in 11 of these 14. The median time from an elevation in the fraction of G1 cells in the late G1 phase (a high proliferative-potential index) to the development of clinical evidence of relapse was 3.5 months. On the other hand, the median time from a low proliferative-potential index to relapse or to the end of the study was eight months. The incidense of false-positive or false-negative measurements was low. Two patients had high index values just before chemotherapy, and remission was estimated to be prolonged by 2.5 and six months by our therapeutic protocol. These results suggest that the PCC technique is useful and accurate in the early prediction of relapse in human leukemia.