Fig. 2
From: The microbiota and microbiome in pancreatic cancer: more influential than expected
Summary of Possible Mechanisms by Which Microbiota Affect PDAC. 1) Persistent inflammation or infections acts as a central facilitator. Microbes activate inflammatory responses and ultimately lead to molecular alterations and neoplastic transformation. 2) Modulation of immune therapy in PDAC: promoting immune activation or suppression. Gut bacteria activate specific immune cells and increase their antitumor effects. Besides, the enrichment of specific strains of gut and intrapancreatic bacteria induces a tolerogenic immunosuppressive microenvironment that favors cancer progression and resistance to immunotherapies. Here, we cite an example of microorganisms within PDAC to exemplify the concrete mechanism involving TLRs, MyD88, TRIF, NF-κB and MAPK. 3) The gut microbiota serves as a critical regulator of metabolism in PDAC carcinogenesis, and obesity-associated dysbiosis is a representative pattern. 4) The microbiota is a component of the PDAC tumor microenvironment and may interact with PSCs. 5) The development of virus-associated cancers and provide a model of bacteria-virus interaction for carcinogenesis