Viability of L1210 (A, B) and A20 cells (C, D) after DFX treatment with or without FeCl₃, according to treatment time (24 vs. 48 hr) and DFX concentration (3.125-75 µM). Experiments were performed in triplicate. All data are presented as the mean±standard error (^a)P<0.05, ^b)P<0.01).