CXCR4 and B-cell chronic lymphocytic leukemia: As shown in Figure 2A and Supplementary Figure S2, inhibition of PI3Ks using a PI3K-δ specific inhibitor (Idelalisib) [14] or a pan-PI3K inhibitor (LY294002) [36], hindered BCR-dependent CXCR4 decrease in stimulated CLL cells.