Characteristics and function of the gut microbiota in patients with rectal neuroendocrine tumors.

The gut microbiota plays a significant role in the initiation and progression of tumors, but its role in rectal neuroendocrine tumors (rNETs) remains unclear. Fecal samples were collected from 19 healthy individuals and 21 rNET patients,with the rNET cohort further divided into metastatic (rNETs-M) and non-metastatic (rNETs-nM) groups. Using metagenomic high-throughput sequencing, we analyzed the diversity, species composition, and functional characteristics of the gut microbiota. We applied a random forest model to identify potential microbial biomarkers for predicting rNET and specifically distinguishing rNETs-M cases. Alpha diversity analysis revealed that species diversity was lower in the rNETs group than in the control group. In contrast, the rNETs-M group exhibited higher species diversity than the rNETs-nM group. Beta diversity analysis demonstrated significant differences in community structure between the rNETs and control groups between the rNET-M and rNETs-nM groups. Notably, in the rNETs group, the abundance of potential pathogens such as Escherichia coli and Shigella was elevated.Furthermore, the rNETs-M group exhibited an increased abundance of potential pathogens such as Alistipes. KEGG enrichment analysis indicated that these distinct microbiota play a significant role in environmental information processing, genetic information processing, and metabolic pathways. Random forest analysis and ROC curve results identified Lachnospira pectinoschiza (AUC=0.885), Parasutterella muris (AUC=0.862), Sodaliphilus pleomorphus(AUC=0.956), Methylobacterium iners (AUC=0.971) as biomarkers with significant discriminatory value.