Gene expression profiling of GTPases and GEFs in CLL and healthy B cells revealed loss of the Rac activator Tiam1 in CLL. (A-E) Relative gene expression profile of GTPase family members in sorted peripheral blood-derived CLL cells compared with normal B lymphocytes. Real-time PCR was performed using TaqMan primers and probes, as described in Materials and methods. (A) RhoA mRNA expression in healthy B (n = 3) and CLL (n = 18) cells, RhoB in healthy B (n = 7) and CLL (n = 8) cells, and RhoC in healthy B (n = 7) and CLL (n = 8) cells. (B) RhoH expression in healthy B (n = 7) and CLL (n = 8) cells. (C) Rac1, Rac2, and Rac3 in healthy B (n = 3) and CLL (n = 18) cells. (D) CDC42 expression in healthy B (n = 3) and CLL (n = 18) cells. (E) Tiam1 expression in healthy B (n = 7) and CLL (n = 8) cells and Vav1 and Dock2 expression in healthy B (n = 3) and CLL (n = 18) cells. All data represent means ± standard deviation (SD).