Tumor-Promoting Gut Microbes in Colorectal Cancer: Mechanisms and Translational Perspectives

Colorectal cancer (CRC) represents a predominant global malignancy, characterized by increasing incidence and mortality rates. Recent investigations have underscored the gut microbiota as a pivotal element in the pathogenesis and progression of CRC. This review synthesizes current evidence regarding the association between gut microbial dysbiosis and CRC, with a particular emphasis on pathogenic bacteria such as Fusobacterium nucleatum, enterotoxigenic Bacteroides fragilis, pks⁺ Escherichia coli, and Enterococcus faecalis, among others. The mechanisms through which these microbes contribute to tumorigenesis include the induction of DNA damage, the promotion of chronic inflammation, and the induction of immunosuppression, and the production of oncogenic metabolites. Additionally, the review examines the clinical implications of gut microbiota, highlighting their potential as non-invasive biomarkers for early CRC detection and their impact on the efficacy and toxicity of chemotherapy, radiotherapy, and immunotherapy. Furthermore, emerging microbiota-targeted interventions, such as fecal microbiota transplantation, dietary modification, and probiotics, are evaluated for their therapeutic potential. Despite substantial progress, challenges remain in standardizing microbial markers and optimizing individualized microbiota modulation strategies. Future studies integrating multi-omics and machine learning approaches may pave the way for microbiome-based precision medicine in CRC.