Representative results of three colorimetric DNA fragmentation assays. AML cells were incubated with anti-Fas MoAb control; top, 200 ng/mL; center, 1,000 ng/mL; bottom). X axis shows intensity of fluorescence caused by PI. (A) Count and linear PI, (B) count and logarithmic PI, and (C) FS and logarithmic PI. UPN, unique patient number. Dose-dependent induction of Fas-induced apoptosis is demonstrated.