Consistent with host survival and tumor growth in vivo (Fig 1), tumors from wild type and Ccl2-/- mice showed similar patterns of gradually increasing Ki-67 staining of tumor cells (identified morphologically) while neu+Ccr2-/- tumors showed much higher levels of Ki-67 staining starting abruptly at 100 days (Fig 9A). This evidence concerns the gene CCR2 and neoplasm.