Antioxidant treatment inhibits BACH2 promotion of chemotherapy-induced cell death. Control (pDL2; panel A) and BACH2-overexpressing (no. 67; panel B) RAJI clones were seeded (1 × 10⁵/mL) in 96-well plates 1 day before the experiments. Cells were treated with catalase 50 U/mL for 1 hour. Then 2 μg/mL VP16, 0.2 μg/mL DNR, or 0.1 μg/mL Ara-C was added to the suspension, and the cells were incubated at 37°C in 5% CO₂ for 40 hours. After incubation, MTT (5 mg/mL, 10 μL/well) was added to each well, and the absorbance was measured. A statistically significant difference in cell viability was observed (*P < .01 or **P < .05). The results are representative of 3 separate experiments. Error bars represent standard deviation.