Commensal Microbes and Their Metabolites: Influence on Host Pathways in Health and Cancer

Commensal microbial homeostasis has been associated with the health of an individual for centuries. Microbial dysbiosis (alteration of microbial composition, with expectation of adverse outcome) in disease, infection, and chronic metabolic disorders are associated with distinct comorbidities, hitherto known, and yet poorly understood. With extensive use of sequence-based molecular phylogeny, we now understand the commensal microbial association with the diseases, their manifestation, and pathogenesis. Microbiome and its metabolic products continuously interact with the host, both immunologically and biochemically in health and disease. This interaction can be beneficial or adversarial, depending on its nature of participation in the host metabolic process. In this chapter, we have discussed the major microbial metabolites that dominate the metabolic landscape of gut microbiota (the cancer microbiome) and influence cancer pathogenesis and chemotherapeutic efficacy.