Expression of functional CXCR4 has been reported in various types of cancer cells [9-12], but also in immune cells such as peripheral blood lymphocytes, unprimed T cells, dendritic cells and lymphocytic leukemia B cells, where CXCR4 mediates spontaneous migration beneath bone marrow and stromal cells [13]. This evidence concerns the gene CXCR4 and lymphoid leukemia.