MDM2 antagonists induce mRNA accumulation of p53 target genes. Cells from B-CLL patients with wild-type p53 (patients 20, 3, and 15) and mutant p53 (patients 16 and 17) were untreated or treated with 5 μM nutlin-3a (□), 0.8 μM doxorubicin (▦), or 3 μM fludarabine (▪) for 48 hours. Cells were lysed, and expression of p53 target genes was analyzed by quantitative PCR as described in “Patients, materials, and methods.” The results are shown as fold induction relative to untreated cells.