FEASIBILITY OF ORAL AND DUODENAL MICROBIOTA ANALYSIS OF PANCREATIC CANCER PATIENTS AND CONTROLS

Aims Periodontal disease is a risk factor for pancreatic cancer (PDAC) onset and, recently, there has been evidence for gut bacteria being able to migrate into the pancreas and have a protumorigenic effect. The duodenal microbiota of PDAC cases has been described only in patients with tumor of the head, without taking into considerations the changes of the microbiome due to impaired exocrine pancreatic function or bile flow, thus being a consequence and not a cause of the tumor. The aim of our study was to evaluate the feasibility of oral and duodenal microbiome evaluation in a selected cohort of PDAC patients and controls.

Methods Patients with PDAC not obstructing the bile or pancreatic duct and healthy controls were enrolled with collection of the saliva and duodenal mucosal brushing (through either diagnostic EUS or upper GI endoscopy) in dedicated stabilizing solutions. Bacterial 16S RNA gene was extracted, amplified through polymerase chain reaction (PCR) and underwent Next Generation Sequencing (NGS). Results were analyzed and compared through Qiime2 software.

Results 7 PDAC patients and 3 healthy controls were enrolled. Bacterial 16S RNA gene was successfully extracted and sequenced through NGS in all cases (technical success=100%). Rarefaction data show that all samples were adequate for analysis, with increased observed Operational Taxonomic Units (OTUs) in PDAC cases saliva and duodenal brush, although not significant. In terms of Alpha and beta-diversity there was no difference in paired samples, probably due to the small sample size.

Conclusions Extraction and NGS analysis of saliva and duodenal microbiome of PDAC cases and healthy controls has a 100% of technical success. No significant differences were seen among samples in terms of alpha and beta-diversity, despite in the rarefaction data the observed OTUs were increased in the samples deriving from PDAC cases. Further studies on a larger population are advocated.