Microbial metabolites may promote or suppress cancer progression through inflammation, DNA damage, or immune modulation

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Frontiers in Medicine Published June 5, 2026 Medically reviewed June 5, 2026 DOI ↗ By Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

Key Takeaway

Microbial metabolites may drive or suppress cancer progression via inflammation or immune modulation, but causality needs establishment.

This narrative review explores the potential impact of microbial metabolites on carcinogenesis and cancer progression. The scope covers a broad range of conditions including colorectal cancer, pancreatic cancer, breast cancer, liver cancer, head and neck cancer, and hematologic malignancies. The authors do not report specific sample sizes or numerical outcomes for these conditions.

The authors synthesize findings indicating that pro-carcinogenic metabolites drive malignancy through mechanisms such as chronic inflammation, direct DNA damage, and oncogenic signaling. Conversely, protective metabolites are described as countering cancer progression through immune modulation, selective apoptosis, and epigenetic regulation. No specific effect sizes or absolute numbers are reported for these outcomes.

The review highlights the emerging role of metabolites as diagnostic and prognostic biomarkers. It also discusses their capacity to modulate the efficacy and toxicity of chemotherapy and immunotherapy. However, the authors acknowledge significant limitations, including the need for standardization and the requirement for established causality before clinical application.

Practice relevance is framed cautiously as an emerging area. The review does not provide data on adverse events or tolerability. Clinicians should interpret these findings as hypotheses requiring further validation rather than established clinical guidelines.

Study Details

Study typeSystematic review

EvidenceLevel 1

PublishedMay 2026

View Original Abstract ↓

Cancer is increasingly recognized to involve profound metabolic reprogramming, where the resident human microbiome acts as a “second genome” that fundamentally influences health and disease. At the intersection of oncology and microbiology lies the microbial metabolome, a comprehensive set of small-molecule metabolites that serve as the primary functional effectors between the microbiome and the host. We synthesize mechanistic evidence across hematologic malignancies as well as solid tumors including colorectal, pancreatic, breast, liver, and head and neck cancers. Pro-carcinogenic metabolites, such as secondary bile acids and bacterial genotoxins like colibactin, drive malignancy through chronic inflammation, direct DNA damage, and oncogenic signaling. Conversely, protective metabolites, predominantly short-chain fatty acids like butyrate, counteract cancer progression through immune modulation, selective apoptosis, and epigenetic regulation. This review examines the microbial metabolome as a “double-edged sword” in carcinogenesis, detailing how these molecules can either promote or suppress tumorigenesis depending on their identity, concentration, and the host environment. The review further explores the translational potential of microbial metabolomics in clinical oncology. We highlight the emerging role of metabolites as diagnostic and prognostic biomarkers and their capacity to modulate the efficacy and toxicity of chemotherapy and immunotherapy. Finally, we address critical methodological hurdles, including the need for standardization and established causality while providing a roadmap for integrating metabolomic profiling into a new era of personalized precision oncology.