The microbiome and cancer

Evidence suggests that microbes located within the gastrointestinal tract and other anatomical locations influence the development and progression of diseases such as cancer (1):

• clinical and preclinical evidence suggests that microbes in the gastrointestinal tract and other anatomical locations, such as the respiratory tract, may affect carcinogenesis, development of metastases, cancer treatment response, and cancer treatment–related adverse effects
• within tumors of patients with cancer, microbes may affect response to treatment, and therapies that reduce or eliminate these microbes may improve outcomes in patients with cancer
• modulating gastrointestinal tract (gut) microbes through faecal microbiota transplant and other strategies such as dietary intervention (eg, high-fibre diet intervention) has improved outcomes in small studies of patients treated with cancer immunotherapy
• disruption of the gut microbiota by receipt of broad-spectrum antibiotics prior to treatment with cancer immunotherapy has been associated with poorer overall survival and higher rates of adverse effects in patients treated with immune checkpoint blockade for solid tumours and also with chimeric antigen receptor T-cell therapy for hematologic malignancies

Study authors state (1):

• microbes in the gut and other locations in the body may influence the development and progression of cancer and may affect the response to adverse effects from cancer therapy

Reference:

1. Fernandez E, Wargo JA, Helmink BA. The Microbiome and Cancer: A Translational Science Review. JAMA. Published online May 12, 2025.