Association analysis of the differences in intestinal flora and clinical tumor indicators among colorectal cancer patients.

Background: Colorectal cancer (CRC) is the third most common malignant tumor globally, and its development is closely related to intestinal flora dysbiosis. However, the heterogeneity of cancerous tissues, paracancerous tissues, and fecal flora, and their clinical significance, has not been fully elucidated. Aim: This study aimed to systematically analyze the diversity, composition, and functional differences of intestinal flora in patients with CRC compared to healthy individuals, and to reveal potential associations between the characteristics of these microbial communities and tumorigenesis and development. Methods: Thirty CRC patients (30 cancerous tissue samples, 30 paracancerous tissue samples, and 30 fecal samples) and 30 healthy volunteers (30 fecal samples) were enrolled in the study. The microbial communities were analyzed using 16S rRNA sequencing, and the status of the bacterial flora was evaluated by combining alpha and beta diversity, species difference analysis, the Gut Microbiome Health Index (GMHI), and the Gut Microbiome Dysbiosis Index (MDI). The correlation of these factors with clinical parameters was then analyzed. Results: The alpha diversity of the cancerous tissue from patients with CRC was significantly lower than that of the fecal samples ( Conclusion: The intestinal flora of CRC patients is characterized by decreased diversity, an enrichment of pathogenic bacteria, and a reduction in protective flora. these microbial alterations are associated with tumor progression, potentially via inflammatory and metabolic pathways, although causal mechanisms remain to be functionally validated. The flora health index and dysbiosis index have potential for use as adjunctive diagnostic tools. However, individualized preventive intervention strategies need to be developed in the future by combining multi-omics data.