Considerations of Gut Microbiome and Cancer—Part 1: Exploring Its Role in Tumorigenesis and Treatment Responses

Abstract

The gut microbiota is a pivotal determinant of human health, influencing both local and systemic physiological processes. Understanding its composition and function is crucial for exploring its impact on diseases, including cancer. Dysbiosis—or imbalances in the gut microbiota linked to negative health outcomes—is increasingly implicated in the pathogenesis of various cancers through mechanisms such as chronic inflammation, immune modulation, and metabolic interactions. The gut microbiome plays a fundamental role in maintaining host health by influencing gut integrity, metabolism, and immune function, with accumulating evidence suggesting a direct impact on cancer development and also cancer drug metabolism, modulating both treatment efficacy and toxicity. This manuscript explores the interactions between the gut microbiome and cancer, focusing on its role in tumorigenesis and its influence on the efficacy of cancer treatments. We review the underlying mechanisms by which specific bacterial species promote tumour development and discuss the microbiome’s role in modulating chemotherapy, immunotherapy and radiotherapy outcomes. The complex interplay between the gut microbiome and cancer therapy continues to reveal new avenues for improving treatment outcomes, and as microbiome science becomes increasingly integrated into oncology, future research should focus on identifying specific microbial signatures predictive of treatment response, developing targeted microbiome-modulating interventions, and incorporating microbiome profiling into clinical trial design.