A new method for studying cell cycle characteristics in ANLL using double-labeling with BrdU and 3HTdr.

Ten patients with acute nonlymphocytic leukemia (ANLL) received bromodeoxyuridine (BrdU) at 100 mg/M2 intravenously over 1 h. BrdU is incorporated into the DNA by S-phase cells and was detected by using a monoclonal anti-BrdU antibody in the bone marrow aspirate (BM) and biopsy specimens obtained at the end of the infusion. Additionally, BM was incubated in vitro with tritiated thymidine (3HTdr) and processed by our previously described double-label method. This allowed us to measure the duration of S-phase (Ts) and total cell cycle time (Tc) of myeloblasts. Data revealed a higher number of S-phase cells from biopsies (21%) than BM (5%). The Ts ranged from 9 to 35 h and Tc ranged between 36 and 152 h in different patients. Using this method, data are available within 48 h and if shown to be clinically relevant, may be useful for prospective planning of therapy in individual patients.