Using a lethal irradiation/bone marrow transplantation approach, with isogeneic WT or IL-23p19−/− hosts and WT or IL-23p19−/− donor hematopoietic cells, we sought to address whether bone marrow-derived myeloid cells infiltrate colon tissue and influence TLR9-dependently chronic inflammation and tumor progression in the colon. This evidence concerns the gene TLR9 and neoplasm.