Abstract

Introduction: Cancer is known to be a major cause of morbidity and mortality, making it vital to deepen cancer research. Colorectal cancer is one of the most common cancers and represents the fourth most common cause of death from cancer worldwide. It is a multifactorial disease associated with environmental exposure, DNA mutations, lifestyle, inflammation and recently, microbiota.
Aim: The aim of this review is to discuss the most recent scientific advances in the establishment of a causality link between intestinal microbiota and colorectal cancer, as well as explore the underlying physiopathological mechanisms and theories. It will also be discussed the clinical relevance of the subject.
Results: Most of the studies corroborate a relationship between the microbiota changes and tumorigenesis. However, the existence of a causal relation has not yet been fully clarified. More and more evidence suggests a collective and multifactorial role of the microbiome. Nevertheless, some microorganisms appear to play a prominent role, such as Fusobacterium nucleatum, Escherichia coli and Enteroxigenic Bacteroides fragilis. There has been increasing interest in the clinical potentials of this association, namely by microbiome modulation and creation of potential screening biomarkers.
Conclusions: There is solid evidence of the relationship between microbiome and colorectal cancer. However, it’s not entirely clear yet the causal nature of this relationship, as well as the mechanisms and interactions that characterize it to its fullest extent. The most consistently associated microorganism, and therefore with the greatest clinical potential is Fusobacterium nucleatum. For now, the clinical application of these findings is not a reality, but the potentialities are huge.

Keywords: Microbiome; Microbiota; Cancer; Colorectal; Dysbiosis