Modulation of Notch1 mRNA by Nutlin-3 in primary B-CLL patient samples. After exposure to Nutlin-3 for 24 hours, samples from B-CLL and from normal PBLs were analyzed for Notch1 mRNA levels (A) and for p53 accumulation (B). (A) Levels of Notch1 mRNA were analyzed by quantitative RT-PCR. After normalization to the level of GAPDH mRNA, results were expressed as fold of Notch1 mRNA induction in Nutlin-3–treated cultures with respect to the control untreated cultures. Data are reported as means ± SD of results from experiments each performed in triplicate. *TP53^mutated B-CLL samples. (B) p53 protein levels, analyzed by Western blot, are shown for representative B-CLL and normal PBL samples. Tubulin staining is shown as loading control.