Intra‑tumoral Microbiome Found to Influence Cancer Immunity and Treatment

Tumors are not sterile; they host complex communities of bacteria, fungi and viruses that actively shape disease progression, immune responses and the effectiveness of therapies. These intra‑tumoral microbes can either promote cancer growth or boost the body’s anti‑tumor immunity, creating a dual role in oncology. The composition of these microbial ecosystems varies widely between cancer types and even among individual tumors, driven by tissue environment, immune status and microbial origin. By interacting with both innate and adaptive immune cells, the microbiota modulate signaling pathways, alter immune cell behavior and produce metabolites that can suppress or activate anti‑tumor responses, thereby reshaping the tumor microenvironment.

Therapeutic strategies are emerging to exploit this knowledge: engineered bacteria, targeted antibiotics, bacteriophages and oncolytic viruses are being investigated to remodel the tumor niche, enhance immune activity and overcome resistance to conventional treatments. While promising, these approaches face challenges related to safety, targeting precision and the complexity of microbial ecosystems.