In an attempt to delineate the contribution of these cells to the pathogenesis of prostate cancer, we used a chimera system in which the Luc+ CCR2+ tumor cells (C1-TRAMP) were administered into CCR2−/− immunocompetent mice, which subsequently, were, or were not reconstituted with CCR2+ CD11b+ BM cells, or with CCR2−/− CD11b+ BM cells. The gene discussed is CCR2; the disease is prostate carcinoma.