Analysis of microbiota patterns linked to pancreatic cancer and their role in host inflammation, oxidative stress, and immune status

ENG- Pancreatic cancer (PDAC) is becoming more common, especially in developed countries, due to risk factors like smoking and alcohol-related chronic pancreatitis (CP). Its hidden location often causes late-stage diagnosis, resulting in high mortality rates close to its incidence. Limited diagnostic tools mean research focuses on new biomarkers to enable earlier detection. Currently, diagnosis depends on imaging and biopsies, with CA19-9 antigen as the sole biomarker, though it lacks accuracy. This doctoral thesis explores potential serological biomarkers linked to inflammation, oxidative stress, and intestinal permeability, as well as microbiome markers to aid PDAC and CP diagnosis and improve patient prognosis. Key findings include reduced superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities in PDAC and CP patients, respectively, and increased levels of the lipid peroxidation marker (MDA) in CP patients. However, large genetic cohort analyses suggested that oxidative stress related markers may not have potential for disease prevention. Yet, further research is encouraged to assess their viability as non-invasive tools for early diagnosis, particularly in pre-diagnostic CP populations. Microbiome analysis revealed a reduction in Lachnospiraceae and Oscillospiraceae in both diseases, and an increase in Enterobacteriaceae in PDAC. PDAC patients also showed an enrichment of Streptococcus in the oral microbiome and similarities between oral and intestinal microbiota, indicating potential bacterial translocation. Additionally, bacteriophages like CrAssphages, which interact with bacteria capable of causing DNA damage, could play a role in disease progression. This study underscores the importance of continued research into microbiome and serological biomarkers for better PDAC and CP diagnosis and management, focusing on the roles of bacteriophages, oxidative stress, and bacterial interactions