Comparison of p53 and MDM2 steady-state mRNA levels between B-CLL cells and normal CD19⁺ B lymphocytes. RNA from samples of purified normal CD19⁺ B lymphocytes (n = 5) and from B-CLL cells (n = 12) were quantitatively analyzed by p53 and MDM2 RT-PCR after normalization to the level of GAPDH mRNA. Each sample was determined in duplicate. Horizontal bars are median; upper and lower edges of box are 75th and 25th percentiles; lines extending from box are 10th and 90th percentiles. *Significance at P < .01.