Knockdown of SPRY2 increases proliferation of CLL cells from good-prognosis patients. To determine the effect of SPRY2 knockdown on human CLL cells, we used Mec-1 cells and primary CLL cells from good-prognosis CLL patients. (A) Mean bar graph of 3 repeats showing Ki-67 staining of Mec-1 cells after SPRY2 knockdown with anti-IgM and anti-IgD antibody stimulation (left) and scanned western blot (right), showing decrease in SPRY2 protein levels after siRNAs treatment. (B) Dot plot of patient’s sample CLL-1 showing an increase in proliferation after SPRY2 knockdown using two different siRNA. (C) CLL cells were isolated from PB of different good-prognosis CLL patients (n = 7). CLL cells were nucleofected with scramble, siRNA A and siRNA B, and coculture on S-17 stromal layer. After 48 hours, CLL cells were stained with Ki-67 stain and proliferation was measured. Displayed bar graph is fold in the rate of proliferation of CLL cells. (D) Mean fold change of (C) showing significant (P = .01) increase in proliferation after SPRY2 knockdown with siRNA B.