Fecal immunochemical tests from population-based colorectal cancer screening programs support prospective microbiome...

Area of Science:

• Microbiome research
• Gastroenterology
• Oncology

Background:

• Prospective studies on the gut microbiome's role in colorectal cancer (CRC) risk are essential.
• This study utilized residual fecal immunochemical tests (FIT) from a CRC screening program in Turin, Italy.
• It represents one of the largest population-based case-control studies across the adenoma-carcinoma sequence.

Purpose of the Study:

• To evaluate the gut microbiome composition and its association with colorectal neoplasms.
• To investigate the relationship between microbial diversity, specific bacterial species, genes, and pathways, and CRC risk.

Main Methods:

• DNA extraction from residual FIT stool samples.
• Whole-genome shotgun sequencing for microbiome analysis.
• Multivariable logistic regression to assess associations with colorectal neoplasms.

Main Results:

• Reduced alpha diversity was inversely associated with colorectal neoplasms, especially early adenomas.
• Oral pathogens (e.g., Parvimonas micra) and bacteria (e.g., Escherichia coli, Bacteroides fragilis) were linked to increased odds of CRC and other colorectal neoplasms.
• Specific microbial genes and pathways showed associations with colorectal neoplasms.

Conclusions:

• Findings support the gut microbiome's association with colorectal cancer risk.
• CRC screening programs offer valuable opportunities for large-scale prospective microbiome research.
• This study validates previous findings in a larger population setting.