However, tumor cells from neu+, neu+Ccl2-/-, and neu+Ccr2-/- mice grow at similar rates in culture (Fig 7A), and adding neutralizing CCL2 antibodies to wild type tumor cells or exogenous CCL2 to Ccl2-/- tumor cells did not affect their proliferation (Fig 7B). This evidence concerns the gene CCL2 and neoplasm.