CC-115 and mTOR inhibitors block proliferation of CLL cells. (A) CFSE-labeled CLL cells were cultured on fibroblast expressing CD40L with (black line) or without (gray) IL-21 and cotreated with 1 µM CC-115 (thick black line). After 4 days, CFSE was measured by FACS. Results are shown as representative histograms for 2 patients. (B) Division index was calculated with the FlowJo program. Results are shown as mean ± SEM (n = 11; patients 2C, 19B, 20, 35B, 71, and 78-82). *P < .05, **P < .01, ***P < .001 (1-way ANOVA).