The gut microbiota in cancer immunity and immunotherapy

Abstract The human gastrointestinal tract harbors trillions of microorganisms, including bacteria, fungi, and viruses, to form the gut microbiota. Cumulative evidence has demonstrated the critical impact of gut microbes on cancer immunity. In cancer, an altered gut microbiota enriched with pathogenic bacteria can actively promote immune evasion and disrupt antitumor immunity, thereby supporting tumor growth and survival. Conversely, beneficial commensal bacteria (e.g., Lactobacillus and Bifidobacterium ) have emerged as therapeutic probiotics for cancer prevention and as adjuvants for cancer therapy. The gut microbiota is also closely linked to the efficacy of immunotherapy. This review summarizes the effects…