Basic Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jul 7, 2022; 28(25): 2920-2936
Published online Jul 7, 2022. doi: 10.3748/wjg.v28.i25.2920
Fecal gene detection based on next generation sequencing for colorectal cancer diagnosis
Si-Yu He, Ying-Chun Li, Yong Wang, Hai-Lin Peng, Cheng-Lin Zhou, Chuan-Meng Zhang, Sheng-Lan Chen, Jian-Feng Yin, Mei Lin
Si-Yu He, Hai-Lin Peng, Cheng-Lin Zhou, Mei Lin, Department of Clinical Laboratory, Taizhou People's Hospital (Postgraduate Training Base of Dalian Medical University), Taizhou 225300, Jiangsu Province, China
Si-Yu He, Department of Clinical Laboratory, The First People's Hospital of Tianmen City, Tianmen 431700, Hubei Province, China
Ying-Chun Li, Yong Wang, Department of General Surgery, Taizhou People's Hospital (Postgraduate Training Base of Dalian Medical University), Taizhou 225300, Jiangsu Province, China
Chuan-Meng Zhang, Central Laboratory, Taizhou People's Hospital (Postgraduate training base of Dalian Medical University), Taizhou 225300, Jiangsu Province, China
Sheng-Lan Chen, Department of Laboratory, Taizhou Genewill Medical Laboratory Company Limited, Taizhou 225300, Jiangsu Province, China
Jian-Feng Yin, Department of Laboratory, Jiangsu CoWin Biotech Co., Ltd., Taizhou 225300, Jiangsu Province, China
Author contributions: He SY performed most of the experiments, analyzed some data, and drafted the manuscript; Li YC and Wang Y provided specimens for the study; Peng HL and Zhou CL gave constructive guidance on the study; Zhang CM contributed to the statistics; Chen SL and Yin JF performed some of the experiments; Lin M designed and supervised the study and edited the manuscript; all authors approved the final version of the article.
Supported by Taizhou Social Development Plan, No. TS202004; Natural Science Foundation of Nanjing University of Chinese Medicine China, No. XZR2020093; and Taizhou People's Hospital Medical Innovation Team Foundation, No. CXTDA201901.
Institutional review board statement: This study was reviewed and approved by the Ethics Committee of Taizhou people's Hospital in Jiangsu Province (No. KY201912501).
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Data sharing statement: No additional data are available.
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: Mei Lin, MD, PhD, Senior Scientist, Department of Clinical Laboratory, Taizhou People's Hospital (Postgraduate Training Base of Dalian Medical University), No. 366 Taihu Road, Taizhou 225300, Jiangsu Province, China. l_mei@163.com
Received: January 16, 2022
Peer-review started: January 16, 2022
First decision: March 8, 2022
Revised: March 18, 2022
Accepted: May 27, 2022
Article in press: May 27, 2022
Published online: July 7, 2022
Processing time: 168 Days and 21.5 Hours
ARTICLE HIGHLIGHTS
Research background

Colorectal cancer (CRC) is currently a health problem of global concern. In recent years, the incidence of CRC presents a trend of gradual increase. Most patients have unobvious early symptoms, and they are commonly in mid and advanced stages when the symptoms become evident, with rather high mortalities. Featuring high throughput, fastness, and rich information, next generation sequencing (NGS) can greatly shorten the detection time, which is a research hotspot at home and abroad at present.

Research motivation

As we all know, histopathological examination is the gold standard of diagnosis, but its invasiveness limits its development. Therefore, it is imperative to explore the screening, diagnosis, and prognosis of CRC by strong specificity, high sensitivity, and non-invasive methods.

Research objectives

In this study, NGS technology was used to conduct genetic testing on stool samples of CRC patients, and the results were compared with the corresponding tumor tissue genetic testing results. The aim was to find genes or gene combinations with high specificity and sensitivity in the stool and establish a technical platform for CRC screening and diagnosis and curative effect monitoring through fecal DNA detection, providing a strong basis and support for personalized diagnosis and treatment of CRC.

Research methods

NGS was used to sequence the DNA in stools of patients with CRC, which were then compared with the genetic testing results of the stool samples of normal control and benign intestinal disease groups, as well as the tumor tissues of CRC patients. Specific genes or gene combinations in fecal DNA suitable for diagnosis and prognostic prediction of CRC were screened, and their significance in diagnosing CRC and predicting patients' prognosis was comprehensively evaluated.

Research results

High mutation frequencies of TP53, APC, and KRAS were detected in the stools and tumor tissues of CRC patients prior to surgery. Contrastively, no pathogenic mutations of the above three genes were noted in the postoperative stools, or two control groups. This indicates that the tumor-specific DNA was detectable in the preoperative stools of CRC patients. Compared to the postoperative stools and the stools in the two control groups, the pathogenic mutation frequencies of TP53 and KRAS were significantly higher for the preoperative stools (P < 0.05), suggesting that fecal TP53 and KRAS genes can be used for CRC screening, diagnosis, and prognostic prediction. No significant difference in the pathogenic mutation frequency of the APC gene was found from the postoperative stools or the two control groups (P > 0.05), so further analysis with larger sample size is required. In 27 preoperative stools of CRC patients, the sensitivity and negative predictive value of TP53- KRAS gene combination detection were higher than those of TP53 mutation or KRAS mutation alone, suggesting that TP53-KRAS gene combination detection can improve the detection rate of CRC. The "undetected" mutation sites found in preoperative stools and tumor tissues may be new mutation types in the occurrence and development of CRC, which need to be further studied. In addition, some mutations of "unknown clinical significance" were found, and their clinical value is worth further study.

Research conclusions

NGS-based fecal genetic testing can be used as a complementary technique for the CRC diagnosis. Fecal TP53 and KRAS can be used as specific genes for the screening, diagnosis, prognostic prediction, and recurrence monitoring of CRC. Moreover, the combined testing of TP53 and KRAS genes can improve the CRC detection rate.

Research perspectives

Fecal genetic detection is a new method for CRC diagnosis, which has the advantages of non-invasiveness, convenient sampling, and dynamic monitoring. Although the sensitivity of fecal genetic test in CRC screening is low, it is certain that it has great potential and broad prospects in the diagnosis and prognosis assessment of CRC. In addition, the "undetected" mutation sites in preoperative stools of CRC patients and the "unknown clinical significance" mutation sites are related to the occurrence and development of CRC, which requires further research and exploration.