Roles for both tumour-presenting and antigen-presenting cells have been described in mediation of nucleic acid sensing.48 A link between Nod1 and colorectal tumourigenesis has been described, in which the bacterial sensor Nod1 exerts immunosuppressive potential via arginase activity, thereby promoting tumourigenesis by creating a tumour-permissive microenvironment.49 These alterations are in line with chronic inflammation, one of the hallmarks of cancer,50 which can stimulate neoplastic transformation and sustain disease progression. The gene discussed is NOD1; the disease is neoplasm.