Tumor-associated microbiota

The tumor-associated microbiota consists of the diverse populations of bacteria, fungi, and viruses that reside within tumor tissues or at associated mucosal sites, significantly influencing cancer progression and treatment response (Sepich-Poore et al., Nature 2020). These microbial communities function as an integral component of the tumor microenvironment, where they can promote chronic inflammation, induce DNA damage through the release of toxins, and modulate local immune cell activity (Bullman et al., Science 2017). For instance, certain bacteria like Fusobacterium nucleatum are known to promote chemoresistance and metastasis in colorectal cancer by activating specific signaling pathways and suppressing T-cell infiltration. Furthermore, the microbiota can directly interfere with drug efficacy; some species express enzymes like cytidine deaminase that degrade chemotherapeutic agents such as gemcitabine (Geller et al., Science 2017). Conversely, the presence of specific beneficial microbes is required for the optimal activity of immune checkpoint inhibitors, leading to the development of fecal microbiota transplants (FMT) and microbial consortia as adjunct therapies (Gopalakrishnan et al., Science 2018). Targeting the tumor-associated microbiota represents a novel frontier in oncology, aiming to reprogram the microbial landscape to enhance the host's anti-tumor immunity and overcome therapeutic resistance.

Other names

Intratumoral microbiotaCancer microbiomeOncomicrobiomeTumor microbiomeTumor-resident bacteria

Modulation of the tumor microenvironment (TME) through the production of metabolites (e.g., short-chain fatty acids), enzymatic degradation of chemotherapeutic agents, activation of Toll-like receptors (TLRs), and regulation of systemic and local immune cell infiltration and activation.