Microbiota in pancreatic cancer: Roles in tumor initiation and progression (Review).

Pancreatic cancer is a highly aggressive malignancy with limited therapeutic options and poor survival outcomes, highlighting the need for an improved understanding of its underlying biology. Advances have positioned the human microbiome as a critical regulator of the initiation and progression of pancreatic cancer. Microbial communities across the oral-gut-tumor axis contribute to tumor initiation through coordinated mechanisms, including the induction of genotoxic stress, chronic inflammation and activation of oncogenic signaling pathways. During tumor progression, microbiota dynamically shape the tumor microenvironment by modulating immune responses, metabolic reprogramming and stromal remodeling. Notably, microbial influences are bidirectional, as tumor-promoting and tumor-suppressive taxa exert opposing effects that converge on shared regulatory pathways within the tumor ecosystem. The present study reviews the current understanding of microbiome involvement in pancreatic cancer, focusing on its mechanistic roles in tumor initiation and progression. Furthermore, the key challenges in the field are discussed, and the emerging opportunities for therapeutic intervention are highlighted. These insights provide a conceptual framework for integrating microbiome research into precision oncology for pancreatic cancer.