A new review explains how the human microbiome—the trillions of microbes living in the gut, mouth, and skin—can influence cancer development and treatment outcomes. When balanced, these microbes help regulate immunity and metabolism, but when disrupted, they can cause chronic inflammation that damages DNA and promotes tumor growth.
Specific bacteria have been linked to different cancers. Some oral and gut microbes are associated with oral, colorectal, liver, pancreatic, lung, breast, and gastric cancers by producing toxins, triggering inflammation, or weakening immune defenses. In some cases, bacteria can even reduce the effectiveness of chemotherapy.
The microbiome also affects cancer therapy response. Patients with greater gut microbial diversity tend to respond better to immunotherapy and CAR-T treatments, while antibiotics may reduce treatment benefits by disrupting helpful bacteria.
Researchers are exploring nanotechnology-based strategies to address these issues, including nanoparticles that target harmful bacteria, neutralize toxins, and deliver probiotics more safely. However, challenges such as safety, manufacturing complexity, and patient variability remain before clinical use.