p53 and MDM2 induction in B-CLL and in normal cells in response to nutlin-3. B-CLL cells (A) and normal CD19⁺ B lymphocytes, PBMCs, and BMMCs (B) were incubated with or without nutlin-3 (10 μM) for 24 hours before analysis of p53 and MDM2 by Western blot. (A) Representative samples from patients characterized by absent/low (nos. 1, 10, 19, 26, and 27) and intermediate/high (nos. 6, 11, 14, 22, 25) ZAP-70 levels, showing a variable induction of p53 and a low frequency of MDM2 induction (nos. 26, 25), are reported. High constitutive and unmodified level in patient no. 27 indicates p53 mutation. (B) Representative results of 3 to 6 independent experiments are shown.