Dynamics of the gut microbiome in FAP patients undergoing intensive endoscopic removal of polyps

Abstract To elucidate the intestinal environment in patients with familial adenomatous polyposis (FAP) and any association of the microbiome with high-risk factors for developing colorectal cancer, we performed shotgun metagenomic sequencing and metabolome analyses on a total of 287 fecal samples collected from 130 FAP patients without colectomy and 53 healthy subjects. Partial resemblance with the microbiome of other inflammatory bowel diseases was established. Notably, colorectal cancer-associated bacteria such as Fusobacterium nucleatum, Solobacterium moorei , and Gemella morbillorum were also increased along with tumor progression. Furthermore, FAP with high histological grade of polyps, large polyp size, and high polyp density was associated with the Prevotella -dominated gut microbiome. This first comprehensive analysis of the relationship between pre-cancerous lesions and intestinal microbiota in FAP provided novel insights into gut microbiome's roles in colorectal cancer.