Micro-and mycobiota dysbiosis in pancreatic ductal adenocarcinoma development

Abstract

Background: Dysbiosis of the intestinal flora has emerged as an oncogenic contributor in different malignancies. Recent findings suggest a crucial tumor-promoting role of micro-and my-cobiome alterations also in the development of pancreatic ductal adenocarcinoma (PDAC). Meth-ods: To summarize the current knowledge about this topic, a systematic literature search of articles published until October 2020 was performed in MEDLINE (PubMed). Results: An increasing num-ber of publications describe associations between bacterial and fungal species and PDAC develop-ment. Despite the high inter-individual variability of the commensal flora, some studies identify specific microbial signatures in PDAC patients, including oral commensals like Porphyromonas gin-givalis and Fusobacterium nucleatum or Gram-negative bacteria like Proteobacteria. The role of Helico-bacter spp. remains unclear. Recent isolation of Malassezia globosa from PDAC tissue suggest also the mycobiota as a crucial player of tumorigenesis. Based on described molecular mechanisms and interactions between the pancreatic tissue and the immune system this review proposes a model of how the micro-and the mycobial dysbiosis could contribute to tumorigenesis in PDAC. Conclu-sions: The presence of micro-and mycobial dysbiosis in pancreatic tumor tissue opens a fascinating perspective on PDAC oncogenesis. Further studies will pave the way for novel tumor markers and treatment strategies.