Next, we examined CXCR4 and CD5 expression on leukemic cells in different stages of the cell cycle by overlaying the G0, G1, and S/G2/M fractions, revealing that while G0 and G1 cell fractions displayed similar levels of CXCR4, S/G2/M cells expressed significantly higher levels of both CXCR4 and CD5 (Figure 3D,E) mirroring our findings in human CLL cells. This evidence concerns the gene CXCR4 and B-cell chronic lymphocytic leukemia.