DNA repair in human leukemic leucocytes treated with neocarzinostatin

Neocarzinostatin, an antineoplastic agent which is effective against human leukemia, induced unscheduled DNA synthesis in human leukemic leucocytes. This indicated the existence of repair process against at least a part of DNA damage caused by the agent. The extent of unscheduled DNA synthesis increased in parallel with the concentration of Neocarzinostatin up to 5 microgram/ml, followed by a decline at more than 5 microgram/ml. Leucocytes from patients with chronic myelogenous leukemia had higher repair synthesis after Neocarzinostatin treatment compared to those from patients with acute leukemia. The amount of repair synthesis correlated well with the proportion of immature leucocytes among chronic myelogenous leukemia samples, but such correlation was not found among acute leukemia samples.