The Oncomicrobiotics and the influence of the microbiota in the carcinogenesis

Abstract

The microbiome also known as “The forgotten organ” embraces the collective genome of all bacteria, archaea, fungi, protists, and viruses found in the host body surfaces and cavities. It is acknowledged that the microbiota has a role in many physiological functions such as the regulation of inflammation, immune response or haematopoiesis among others. The involvement of dysbiosis (alteration of the homeostatic microbiota) in the development of many pathologies like depression or cancer is a current topic of interest. On the other hand, carcinogenesis results as an accumulation of genetic and epigenetic alterations which are favoured by risk factors such as lifestyle, diet or dysbiosis. The latter has recently been discovered to either contribute or prevent carcinogenesis by modulating tumour or host cell microenvironment, respectively. Moreover, the microbiota has been found to influence chemotherapy, radiotherapy and immunotherapy efficacy and toxicity. Therefore, in this dissertation it is discussed the role of the microbiota as the cause, consequence or both of carcinogenesis as well as the mechanisms and the bacterial species that are involved in the efficacy or toxicity of certain anticancer drugs. It is relevant because it opens new strategies to prevent cancer or to enhance therapeutic agents against cancer which could result in positive clinical outcomes for cancer patients. One new strategy is the oncomicrobiotics, a select “cocktail of bacteria and/or bacterial products” as an adjunctive therapy to cancer with the intention of improving the immune response through optimizing the gut microbiota.