Bacteria and Bacteria-Based Products in Cancer Therapy: Current Status and Future Advances

Cancer is one of the most frequent causes of global mortality with about ten million deaths reported in 2020, according to the World Health Organization (WHO). The present-day cancer armamentarium typically possesses limitations viz. lack of specificity, high toxicity, multidrug resistance, and other threatening side effects. Thus, there remains a need for novel antitumor drugs with high efficacy and minimum side effects. The use of live oncolytic bacteria has emerged as a plausible approach to meet these challenges. These tumor-targeted bacteria can proliferate in the cancer cells, initiate the immune response, and suppress the cancers. In addition, microbes also produce a variety of peptides, enzymes, toxins, other proteins, and several secondary metabolites, which have emerged as promising candidates for cancer therapy. The present chapter elaborates upon the various attributes of these bio-drugs such as sources, mode of action, targeted cancers, toxicity issues, and clinical status. In addition, the recent approaches to improve the efficacy and safety of therapeutic bacteria and their products are briefly discussed.