IL22 and neoplasm: Commensal and pathogenic bacteria (Citrobacter rodentium and Bacteroides fragilis) and their products can engage with Toll-like receptors (TLRs) on tumour infiltrating myeloid cells and activate MyD88 mediated production of IL-23 and tumour promoting inflammatory cytokines such as IL-17A, IL-6, and IL-22 [114].