The effects of Microbiota on cancer

Introduction: The interaction between host genetic elements and the environmental factors, impacts on cancer as a complex disease. One of the reciprocal factors is a group of 1014 bacteria, eukaryotes and viruses existing in the gastrointestinal tract and known as the gut microbiota. Although their main role is still unclear, they play crucial roles in many physiological processes, particularly in inflammatory and immune reactions. Recently studies have shown significant microbial differences between cancer and healthy patients.Description: Using Keywords including gut microbiota, cancer microbiome, through PubMed and Google scholar search engines, 78 articles were investigated between 2010 to the end of 2018. The results overviewed in the context of this article.Discussion and conclusion: Gut microbiota stimulate the production of cytokines against potential pathogens by their antigens and metabolic products. Helicobacter pylori, hepatitis B and C viruses, and human papillomaviruses that count as infectious agents, have been recognized as carcinogenic factors in 20% of all cancers. Dysbiosis _changes in gut microbiota profiles_ is associated with several mechanisms that are not explained yet. One of the most important mechanisms that are related to cancer development, is their effects on the secretion of inflammatory cytokines and immune system. Bacterial signals modify immunity response and simultaneously alert immune cells, to hit the right target. The gut microbiome influences the pathogenesis of stomach cancer by Helicobacter pylori, Colorectal Carcinoma by Escherichia coli, and Bladder Carcinoma by Salmonella enterica typhi. It seems that an active strategy to fight cancer is the microbiota as a holistic hub point for cancer development and improve therapeutic approach. It however, must be proven whether gut microbiota can be used as a biomarker to differentiate healthy and tumor patients?