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World J Gastrointest Oncol. Sep 15, 2022; 14(9): 1665-1674
Published online Sep 15, 2022. doi: 10.4251/wjgo.v14.i9.1665
Implication of gut microbiome in immunotherapy for colorectal cancer
Evangelos Koustas, Eleni-Myrto Trifylli, Panagiotis Sarantis, Nikolaos Papadopoulos, Georgios Aloizos, Ariadne Tsagarakis, Christos Damaskos, Nikolaos Garmpis, Anna Garmpi, Athanasios G Papavassiliou, Michalis V Karamouzis
Evangelos Koustas, Eleni-Myrto Trifylli, Panagiotis Sarantis, Athanasios G Papavassiliou, Michalis V Karamouzis, Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens 11527, Greece
Nikolaos Papadopoulos, Georgios Aloizos, 1st Department of Internal Medicine, 417 Army Share Fund Hospital of Athens, Athens 11521, Attica, Greece
Ariadne Tsagarakis, Beth Israel Deaconess Medical Center, Boston, MA 02215, United States
Christos Damaskos, N.S. Christeas Laboratory of Experimental Surgery and Surgical Research, Medical School, National and Kapodistrian University of Athens, Athens 11527, Greece
Nikolaos Garmpis, Second Department of Propedeutic Surgery, Laiko General Hospital, Medical School, National and Kapodistrian University of Athens, Athens 11527, Greece
Anna Garmpi, First Department of Pathology, Medical School, National and Kapodistrian University of Athens, Athens 11527, Greece
Author contributions: All authors participated in the writing and editing of the manuscript.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Evangelos Koustas, MD, PhD, Doctor, Senior Research Fellow, Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 75 M. Asias Street, Athens 11527, Greece. vang.koustas@gmail.com
Received: March 20, 2022
Peer-review started: March 20, 2022
First decision: April 17, 2022
Revised: May 9, 2022
Accepted: July 31, 2022
Article in press: July 31, 2022
Published online: September 15, 2022
Abstract

Colorectal cancer (CRC) constitutes the third most frequently reported malignancy in the male population and the second most common in women in the last two decades. Colon carcinogenesis is a complex, multifactorial event, resulting from genetic and epigenetic aberrations, the impact of environmental factors, as well as the disturbance of the gut microbial ecosystem. The relationship between the intestinal microbiome and carcinogenesis was relatively undervalued in the last decade. However, its remarkable effect on metabolic and immune functions on the host has been in the spotlight as of recent years. There is a strong relationship between gut microbiome dysbiosis, bowel pathogenicity and responsiveness to anti-cancer treatment; including immunotherapy. Modifications of bacteriome consistency are closely associated with the immunologic response to immunotherapeutic agents. This condition that implies the necessity of gut microbiome manipulation. Thus, creatingan optimal response for CRC patients to immunotherapeutic agents. In this paper, we will review the current literature observing how gut microbiota influence the response of immunotherapy on CRC patients.

Keywords: Colorectal cancer, Gut microbiome, Immunotherapy, Checkpoint inhibitors, Tumor microenvironment

Core Tip: Colorectal cancer (CRC) constitutes the third most frequent malignancy. CRC is a complex, multistep process. The impact of environmental factors as well as the disturbance of the gut microbial ecosystem is associated with CRC development. There is a strong relationship between the gut microbiome and resistance to immunotherapy.