CXCR4 and neoplasm: B cell malignancies with widespread dissemination to the lymph nodes, such as B-cell chronic lymphocytic leukemia (B-CLL) [145], express high levels of CCR7, which mediates B cell entry into the lymphoid tissue, while neoplasms that experience little metastasis to the lymph nodes, such as multiple myeloma or hairy cell leukemia [145], express low levels of CCR7 and low to moderate levels of CXCR4 [144].