LEF-1 is a prosurvival factor in CLL cells. (A) Detection of LEF1 mRNA levels by quantitative PCR in B cells from a CLL patient 24 hours after siRNA treatment. (B) Intracellular flow cytometry measurements of LEF-1 expression with indicated change in mean fluorescence intensity (ΔMFI) 72 hours after siRNA treatment in 9 CLL samples. *P < .0001. **P < .0001. Horizontal lines indicate the mean of the group. (C) CLL percentage survival 72 hours after siRNA treatment in 9 samples (left panel), and the average fold change in survival normalized to control siRNA treatment (right panel). *P = .0001. **P = .0002. Error bars represent the SEM.