RAC1 and acute lymphoblastic leukemia: Although it has been reported that RhoGDI2 positively regulates the activation of Rac1 and Cdc42 (20), we find the phosphorylation on 24 and 153 tyrosine complex less RhoA or RhoC in human T-ALL cell lines (Figure 3), raising a possibility to release the negative regulatory role of RhoGDI2 in T-ALL cell migration toward CXCL12 (Figure 4).