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

Alpha diversity of cancerous tissue from CRC patients was significantly lower than that of fecal samples.

• 30 CRC patients contributed cancerous tissue samples, paracancerous tissue samples, and fecal samples each, plus 30 healthy volunteers contributed fecal samples
• Microbial communities were analyzed using 16S rRNA sequencing
• The difference in alpha diversity between cancerous tissue and fecal samples was statistically significant (p < 0.05)

The intestinal microbiota of CRC patients was statistically different from that of healthy individuals.

• Comparison was made between CRC patients and 30 healthy volunteers
• The difference was statistically significant (p < 0.01)
• Both alpha and beta diversity metrics were used in the evaluation

Beta diversity differed significantly between cancerous tissue and fecal gut microbiota of CRC patients.

• Beta diversity comparison was performed between cancerous tissue samples and fecal samples from the same CRC patients
• The difference was statistically significant (p < 0.01)
• This indicates distinct microbial community compositions between tumor tissue and fecal microbiota

Paracancerous tissues had significantly higher Gut Microbiome Health Index (GMHI) scores than cancerous tissues.

• GMHI was used to evaluate gut microbiome health status
• Paracancerous tissue microbiota exhibited significantly higher GMHIs than cancerous tissues
• Healthy individuals demonstrated better gut health than individuals with CRC based on GMHI
• Fecal samples from CRC patients had a higher GMHI than cancerous tissues, and this difference was statistically significant (p < 0.001)

The Microbial Dysbiosis Index (MDI) showed a reversed trend compared to GMHI across sample types.

• MDI was used as a complementary measure to GMHI
• Where GMHI was higher (indicating better health), MDI trended lower, and vice versa
• This inverse relationship suggests MDI and GMHI capture complementary aspects of microbiome health

Escherichia coli abundance showed a statistically significant positive correlation with tumor size.

• Correlation analysis was performed between specific bacterial taxa and clinical tumor indicators
• The positive correlation between Escherichia coli and tumor size was statistically significant (p < 0.05)

Methylobacterium/Methylorubrum abundance showed a statistically significant positive correlation with tumor stage.

• Methylobacterium/Methylorubrum was identified as a taxon of clinical relevance
• The positive correlation with tumor stage was statistically significant (p < 0.05)

Blautia and Faecalibacterium were more abundant in feces of healthy individuals and paracancerous tissues, while Escherichia-Shigella, Bacteroides, Enterococcus, and Fusobacterium were more abundant in cancerous tissues.

• Species difference analysis was used to identify differentially abundant taxa across sample types
• Blautia and Faecalibacterium were identified as potentially protective flora with higher abundances in healthy and paracancerous contexts
• Escherichia-Shigella, Bacteroides, Enterococcus, and Fusobacterium were enriched in colorectal cancer tissue samples
• This pattern is consistent with enrichment of pathogenic bacteria and reduction of protective flora in CRC