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Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Nov 26, 2019; 7(22): 3683-3697
Published online Nov 26, 2019. doi: 10.12998/wjcc.v7.i22.3683
Colorectal cancer: The epigenetic role of microbiome
Hussein Sabit, Emre Cevik, Huseyin Tombuloglu
Hussein Sabit, Emre Cevik, Huseyin Tombuloglu, Department of Genetics, Institute for Medical Research and Consultations, Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia
Author contributions: Sabit H conceptualized the idea and wrote the manuscript; Cevik E made all the figures and illustrations; Tombuloglu H revised the manuscript.
Conflict-of-interest statement: The authors declare no conflicts of interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Hussein Sabit, Professor of Cancer Epigenetics, Department of Genetics, Institute for Medical Research and Consultations, Imam Abdulrahman Bin Faisal University, PO Box 1982, Dammam 31441, Saudi Arabia. hhsabit@iau.edu.sa
Telephone: +966-54-6177974 Fax: +966-13-3330333
Received: April 1, 2019
Peer-review started: April 1, 2019
First decision: May 30, 2019
Revised: October 23, 2019
Accepted: October 30, 2019
Article in press: October 29, 2019
Published online: November 26, 2019
Abstract

Colorectal cancer (CRC) is the third most common cancer in men (746000 cases per year) and the second most common cancer in women globally (614000 cases per year). The incidence rate of CRC in developed countries (737000 cases per year) is higher than that in less developed countries (624000 cases per year). CRC can arise from genetic causes such as chromosomal instability and microsatellite instability. Several etiologic factors underlie CRC including age, diet, and lifestyle. Gut microbiota represent a proven cause of the disease, where they play pivotal roles in modulating and reshaping the host epigenome. Several active microbial metabolites have been found to drive carcinogenesis, invasion, and metastasis via modifying both the methylation landscape along with histone structure in intestinal cells. Gut microbiota, in response to diet, can exert both beneficial and harmful functions in humans, according to the intestinal balance of number and types of these bacteria. Although the intestinal microbial community is diverse among individuals, these microbes cumulatively produce 100-fold more proteins than the human genome itself, which calls for further studies to elaborate on the complicated interaction between these microorganisms and intestinal cells. Therefore, understanding the exact role that gut microbiota play in inducing CRC will help attain reliable strategies to precisely diagnose and treat this fatal disease.

Keywords: Colorectal, Cancer, Colorectal cancer, Epigenetics, Gut, Microbiota

Core tip: Colorectal cancer is serious disease that affects males and females late in their lives. Several etiologic factors trigger colorectal cancer; however, the gut microbiome is responsible of most of the cases. Gut bacteria can produce a variety of chemical compounds that affect intestinal cells and might transform them into malignant ones. In this review, we describe the main mechanisms by which gut microbiota exert these functions.