p53-dependent target gene activation in response to nutlin-3 and fludarabine. Samples from 4 patients with B-CLL were treated with nutlin-3 and fludarabine (both used at 10 μM) for 24 hours. The levels of p53 and Ser¹⁵ phosphorylated-p53 (P-p53) (A) as well as p53-related gene expression (B) were assessed by Western blot and cDNA microarray analysis, respectively. (A) The effect of nutlin-3 and fludarabine treatments on cell viability is also reported for each patient analyzed. (B) Ratios represent nutlin-3 or fludarabine values divided by untreated values. Results are expressed as means plus or minus SD of the 4 B-CLL samples analyzed. *Genes significantly upmodulated by the treatments (above the cut-off of 2-fold of induction).