Relationship between gut microbiota and prognosis, clinical characteristics of colorectal cancer based on 16S rRNA sequencing

Purpose Colorectal cancer is a high incidence tumor, immunotherapy has become a hot topic of research in recent years, at the same time, the dysregulation of intestinal microbiota is also gaining attention because it can lead to changes in body immunity. So, we want to explore the relationship between gut microbiota and colorectal cancer. Methods We performed 16S rRNA high-throughput sequencing of tumors and paraneoplastic tissues from 30 patients, followed by at least 5 years of follow-up. Microbiome analysis, survival analysis, and then immunohistochemistry and its correlation with microbiota were performed in 19 of these patients. Results OTU13530 and OTU17086, both representing g_Sediminibacterium, showed significant differences in normalized abundance in tumor and paraneoplastic tissues (FDR 2FC > 1). Both of them correlated with T-stage (p = 0.016, p = 0.024) and Her-2 expression (p = 0.034, p = 0.001). The former correlated with HIF expression (p = 0.017), and the latter with EGFR expression (p = 0.003). OTU3504, representing o_Myxococcales, had a correlation with patient survival (p = 0.015, HR = 28.5(1.9–425.0)), its abundance correlated with tumor neural invasion (p = 0.005) and vascular invasion (p = 0.005). Conclusion There is no statistical difference in the diversity and homogeneity of the microbiota between tumor and paraneoplastic tissues. But the abundance of some specific microbiota differed significantly between tumor and paraneoplastic tissues, and these microbiota correlated with patient survival, Her-2, HIF and other proteins expression, T-stage, neurovascular invasion and other clinical traits.