Systematic Reviews
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Mar 15, 2022; 14(3): 734-745
Published online Mar 15, 2022. doi: 10.4251/wjgo.v14.i3.734
Association of Blastocystis hominis with colorectal cancer: A systematic review of in vitro and in vivo evidences
Vinoth Kumarasamy, Wahib Mohammed Atroosh, Deepa Anbazhagan, Mona Mohamed Ibrahim Abdalla, Meram Azzani
Vinoth Kumarasamy, Deepa Anbazhagan, Department of Microbiology and Parasitology, Faculty of Medicine, Bioscience and Nursing, MAHSA University, Jenjarom 42610, Selangor, Malaysia
Vinoth Kumarasamy, Department of Preclinical Sciences, Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Kajang 43000, Selangor, Malaysia
Wahib Mohammed Atroosh, Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Wilayah Persekutuan, Malaysia
Wahib Mohammed Atroosh, Department of Microbiology and Parasitology, Faculty of Medicine and Health Sciences, University of Aden, Aden 00, Yemen
Mona Mohamed Ibrahim Abdalla, Human Biology Department, International Medical University, Bukit Jalil 57000, Kuala Lumpur, Malaysia
Meram Azzani, Department of Community Medicine, Faculty of Medicine, Bioscience and Nursing, MAHSA University, Jenjarom 42610, Selangor, Malaysia
Author contributions: Azzani M designed the research, performed the literature search and extracted the data; Kumarasamy V wrote the discussion and extracted the data; Atroosh WM wrote the methodology and extracted the data; Anbazhagan D wrote the results and extracted the data; Abdalla M wrote the introduction and extracted the data; All authors read and approved the final manuscript.
Conflict-of-interest statement: Dr. Azzani has nothing to disclose.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
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: Meram Azzani, PhD, Senior Lecturer, Department of Community Medicine, Faculty of Medicine, Bioscience and Nursing, MAHSA University, Bandar Saujana Putra, Jenjarom 42610, Selangor, Malaysia. dr_memeazzani@yahoo.com
Received: May 17, 2021
Peer-review started: May 17, 2021
First decision: July 4, 2021
Revised: July 16, 2021
Accepted: February 22, 2022
Article in press: February 22, 2022
Published online: March 15, 2022
ARTICLE HIGHLIGHTS
Research background

Intestinal colonisation of Blastocystis hominis (Blastocystis) as a risk factor to the worsening of colorectal cancer (CRC).

Research motivation

There has been an increase in the prevalence of Blastocystis in CRC patients. Besides, various in vitro and in vivo studies have highlighted Blastocystis as an important risk factor for the worsening of CRC.

Research objectives

To perform a systematic review on all evidence on the association between CRC and Blastocystis.

Research methods

A systematic review of the literature was performed by searching PubMed, Science Direct, Scopus and Google scholar databases up to February 2020.

Research results

Out of 12 studies selected for this systematic review, seven studies have confirmed the prevalence of Blastocystis. A total of four studies employing in vitro human colorectal carcinoma cell line study models showed significant cytopathic and immunological effects of Blastocystis. One in vivo experimental animal model study showed that there was a significant effect of infection with Blastocystis on exacerbation of colorectal carcinogenesis.

Research conclusions

Blastocystis is a commonly identified microorganisms in CRC patients. These studies have provided supportive data that Blastocystis could exacerbate existing CRC via alteration in host immune response and increased oxidative damage.

Research perspectives

Future studies of CRC and Blastocystis should attempt to determine the various stages of CRC that are most likely to be associated with Blastocystis and its association with other intestinal diseases.