Onkológia 5/2016

Human microbiome and colorectal cancer

Slovak Republic is among the countries with the highest incidence of colorectal cancer worldwide. The high incidence and colorectal cancer mortality brings the need for discovery of new possibilities in the prevention, diagnosis and therapy. The study of gut microbiota role in etiology of several diseases, including colorectal cancer is now coming to the forefront of research in numerous experimental institutes. Commensal bacteria provide several benefits to its host, playing an important role in the development and function of the intestinal immune system, involving in the development and maturation of the intestinal mucosa, preventing the infections caused by pathogenic bacteria, and degradating the metabolic products. Sustaining of microbial symbiosis is necessary for human health. Analysis of bacterial composition in healthy subjects and patients has confirmed that the change of composition and structure of the intestinal microflora can lead to the development of colorectal pre-malignities. The mechanisms by which organisms contribute to the initiation or development of the disease include the chronic inflammation induction; biosynthesis of genotoxic agents that interfere with cell cycle regulatory mechanisms; toxic metabolites production and activation of carcinogenic dietary components. According to the experimental and clinical studies bacterial dysbiosis can be modulated by administration of probiotics and intestinal microflora transplantation. Animal models revealed the ability of intestinal bacteria to enhance the immune response against tumor cells. Uncovering the role of microorganisms in tumorigenesis is therefore not only important for the prevention, but also for cancer treatment.

Keywords: colorectal cancer, microbiome, dysbiosis of gut microflora, probiotics, cancer prevention and treatment