What Does Bacteria Have to Do with Cancer? The Influence of the Body's Microbiota on Cancer in Cats and Dogs

The body's microbiota plays a fundamental role in maintaining homeostasis and influences immune function, metabolism, and tissue integrity. A growing body of research suggests that fluctuations in the composition and abundance of individual microbiota populations may influence cancer development and the effectiveness of therapy. The condition of microbiota dysbiosis has been demonstrated to induce chronic inflammation, immune system dysregulation, and, most significantly, modulation of molecular pathways that promote tumorigenesis. The efficacy and toxicity of cancer treatment can be influenced by the composition of the microbiota. Bacteria can modify the effectiveness and toxicity of chemotherapy and immunotherapy by affecting drug metabolism and the body's immune response. In contrast, the development of anticancer therapies that utilize bacteria is gaining increasing interest. This alternative to conventional treatment utilizes the natural ability of certain bacterial species to selectively colonize hypoxic and necrotic environments. The exploration of natural and genetically modified bacteria as vectors for the delivery of cytotoxins, immunomodulators, or therapeutic genes in the combat of cancer is a current area of research. In addition, their capacity to stimulate an antitumor immune response is also exploited. Preclinical investigations in animals have demonstrated the efficacy of this therapeutic approach, underscoring the promise of bacterial therapies as either an adjunct to conventional treatment or as a standalone strategy for combating cancer. This article synthesizes the current knowledge regarding the role of microbiota in carcinogenesis in animals and discusses recent developments in the field of bacterial therapies. The text also addresses the challenges, safety considerations, and future perspectives associated with translating microbiota-targeted and bacterial therapies into veterinary and comparative oncology.