Harnessing the microbiome for cancer therapy.

The microbiome is increasingly recognized as a key player in cancer pathogenesis and treatment response, acting through both local and systemic mechanisms. Microbial communities and their metabolites can directly influence drug metabolism, shape the immune landscape, and alter transcriptional and epigenetic programmes in the gut, systemically and in the tumour microenvironment. Emerging data support the potential of microbiome-targeted interventions (such as faecal microbiota transplantation, diet, prebiotics and probiotics) as adjuncts to conventional cancer therapies, with the goal of enhancing efficacy and reducing toxicity. This Review highlights the promise of the microbiome as a prognostic and predictive biomarker, a modifiable factor in cancer care and prevention, and a therapeutic target. We also discuss major knowledge gaps, limitations in current study designs, and the need for mechanism-guided, personalized strategies to advance clinical translation.