Effect of p53 expression in D283 on apoptotic response after irradiation. Bar graph summarizing the subdiploid, apoptotic fraction of D283 clones, mp53.1, mp53.3, and vec.1 2 days after treatment with 0 or 5 Gy. Each bar represents the mean ± SD of the results of three independent experiments. In each experiment, a minimum of 2 × 104 cells were counted.