CXCR2 and neoplasm: Lastly, we injected Cl66-Luc cells intracardially in the wild type and Cxcr2−/− mice and observed the lower seeding of tumor cells in the bones of Cxcr2−/− in comparison with the wild type, thereby suggesting that the expression of CXCR2 in the host determines its inhabitation by tumor cells and establishment of bone metastasis.