Salmonella-based Anticancer Vaccines and their Efficacy

Surgery, chemotherapy, and radiotherapy are successfully used to treat patients with tumors or cancers. However, the innovation of more potent therapeutic modalities is essential for the efficient treatment of patients with advanced cancers. More than two centuries ago, bacteria have been observed to have beneficial effects in some cancer patients. Virulence factors of some bacteria and their infectious behavior in the body suggest their effectiveness in tumor suppression. At present, bacillus calmette-guérin (BCG), a live attenuated strain of Mycobacterium bovis, is currently used to treat bladder cancer. Some other bacteria have also been found to have antitumor activities. Anaerobic bacteria can colonize solid tumors and exert an intrinsic antitumor effect. Salmonella is the most studied bacterium in the field of bacterial anticancer therapy in preclinical studies. In this article, we discuss progress in the development of bacterial anticancer vaccines, especially Salmonella-based vaccines, their antitumor efficacy, and mechanisms involved in vaccine-mediated cancer cell death.