Abstract
BACKGROUND AND OBJECTIVES: The objective of this study was to investigate the changes in fecal microbial diversity and metabolic product levels in patients with stage IV colorectal cancer (CRC). The aim was to provide new research strategies for the diagnosis and treatment of CRC. METHODS: Fecal and blood samples were collected from both stage IV CRC patients and healthy individuals. Fecal samples were subjected to 16S and 18S tests to analyze microbial diversity. Short chain fatty acids were measured in both fecal and blood samples. Blood metabolomics analysis was also performed. RESULTS: The data from this study showed that Sutterella, Anaerostipes, and Coprococcus in the fecal bacteria of stage IV CRC patients were significantly reduced, while Auricularia, Botryotrichum, and Themoascus in fungi were significantly reduced. Although there was no significant change in short chain fatty acid levels in the feces of stage IV CRC patients compared to healthy individuals, propionic acid in the blood was significantly increased, while hexanoic acid was significantly reduced. Moreover, there were significant differences in the blood metabolome between stage IV CRC patients and healthy individuals. CONCLUSION: The research results indicate that changes in the diversity of fecal bacteria and fungi in stage IV CRC patients may be detrimental to their health, and treatments targeting gut bacteria and fungi may help improve their health. Additionally, changes in fecal bacteria and fungi, as well as changes in blood short chain fatty acids and metabolites, may be potential targets for diagnosing and treating stage IV CRC.