CCL2 and neoplasm: Because decreased tumor growth in mice co-treated with DFMO and Trimer PTI was associated with increased T-cell IFN-γ production as measured by ELISpot assay as well as increased levels of IL-10, MCP-1 and IFN-γ, we hypothesized that PBT anti-tumorigenic properties may be dependent on host immune system competence.