Whereas CCR6 seems to be required for retention of LCH-cells in the various tissues, our in vitro experiments support a role for CXCR4 in the distribution of blood-borne CD1a+CD11c+CXCR4+‘LCH-cell like’ myeloid cells in analogy to both immune cells and tumor cells.21 The gene discussed is CXCR4; the disease is neoplasm.