image: Tumor-associated Bacterial Effectors: Novel Frontiers in Tumor Biology and Immunity
Credit: ©Science Bulletin
A growing body of research has shown that bacteria are not only present in the gut and respiratory tract, but can also exist inside primary and metastatic tumors. These tumor associated bacteria are increasingly recognized as important players in cancer development, tumor progression and immune regulation. However, divergent results regarding enriched bacteria have been reported across studies of the same cancer type, suggesting that the bacterial taxonomic identity may not fully explain their role in cancer.
Instead, researchers are now paying more attention to what these bacteria do. Functional metagenomic studies have revealed that although bacterial taxonomic identity may vary between patient groups, their biological functions can be surprisingly conserved. These findings suggest that the functional repertoire of the bacterial communities, rather than their taxonomic identity, constitutes the core determinant of tumor progression.
Research on bacterial functional effectors remains in its infancy and is largely constrained by the diversity and complexity of tumor-associated bacterial constituents. Against this background, a research team led by Professor Na Liu from Sun Yat-sen University Cancer Center proposes the unified nomenclature of bacterial functional constituents as “tumor-associated bacterial effectors” (TABEs), categorizing them into six functional classes according to their chemical nature, conserved structural features, and analogous mechanisms of action in regulating host cells, including:
- Virulence factors
- Microbe-associated molecular patterns
- Bacterial metabolites
- Biotransformative enzymes
- Cross-reactive antigens
- Non-coding RNAs
According to the article, the research team systematically summarizes the multiple functions and mechanisms by which TABEs influence tumor progression and immune regulation. Based on these insights, they propose multi-dimensional potential therapeutic strategies targeting different functional stages of TABEs. Such approaches could complement existing cancer treatments and open new directions in precision oncology.
The research team also outlines several key directions for future research, including:
- Using multi-omics technologies (metagenomics, metatranscriptomics, metaproteomics, and metabolomics) to investigate the dynamic functional evolution of tumor-associated bacteria.
- Systematically isolating and culturing bacterial strains from clinical tissues using culturomics to reveal TABE heterogeneity between different strain lineages.
- Defining the operational determinants and conditions of TABEs, such as concentration, spatial localization, structural variations, and experimental model systems.
- Exploring intermicrobial synergistic cross-talk to understand TABE mechanisms from a community perspective.
- Re-exploring host–bacteria interactions at single-cell and spatial resolution to move from correlation to causation.
- Conducting rigorous preclinical evaluations and standardized clinical trials to validate the long-term safety and efficacy of TABE-based therapies.
Collectively, the TABEs-centered framework establishes a foundation for harnessing bacterial effectors as next-generation biomarkers and therapeutic targets, ultimately paving the way toward precision oncology that incorporates the field of tumor-associated bacteria. In the coming decade, integrating TABEs-based interventions into existing treatment frameworks will provide endless opportunities for advancing more effective strategies in cancer therapy, potentially revolutionizing current practices in clinical oncology.