Fecal microbiota transplantation for immune regulation: improving ulcerative colitis and enhancing cancer immunotherapy.

The gut microbiota plays an integral role in maintaining health and regulating various host functions, including immune responses. Fecal microbiota transplantation (FMT) has emerged as a promising therapeutic approach to restore gut microbial balance. Although widely recognized for its efficacy in treating ulcerative colitis (UC), FMT is now being investigated as an adjuvant therapy to enhance the efficacy of immune checkpoint inhibitors (ICIs) in cancer treatment. This review summarizes the clinical applications of FMT in UC treatment and its potential role in cancer immunotherapy. FMT exhibits varying degrees of efficacy in the treatment of UC, with differences in outcomes attributed to variations in administration methods and donor selection. In cancer therapy, FMT has demonstrated the potential to improve ICI responses, particularly in patients with melanoma. However, its effects on other cancers remain unclear. Although FMT holds promise for UC and cancer immunotherapy, challenges such as inconsistent clinical outcomes and methodological variations persist. Standardized protocols and mechanistic studies are crucial to optimize FMT-based therapeutic strategies, and further research is required to establish its efficacy under diverse clinical conditions.