Basic Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 21, 2017; 23(47): 8345-8354
Published online Dec 21, 2017. doi: 10.3748/wjg.v23.i47.8345
Circular RNA circ-LDLRAD3 as a biomarker in diagnosis of pancreatic cancer
Fan Yang, Dong-Yan Liu, Jin-Tao Guo, Nan Ge, Ping Zhu, Xiang Liu, Sheng Wang, Guo-Xin Wang, Si-Yu Sun
Fan Yang, Jin-Tao Guo, Nan Ge, Ping Zhu, Xiang Liu, Sheng Wang, Guo-Xin Wang, Si-Yu Sun, Endoscopy Center, Shengjing Hospital of China Medical University, Shenyang 110004, Liaoning Province, China
Dong-Yan Liu, Medical Research Center, Shengjing Hospital of China Medical University, Benxi 117000, Liaoning Province, China
Author contributions: Yang F and Sun SY were involved in the study conception and design; Yang F drafted the article and analyzed and interpreted the data; Guo JT and Ge N performed critical revision of the article for important intellectual content and collected the data; Liu X performed statistical analysis; Zhu P and Wang S conducted the evaluation of TNM stage of pancreatic cancer; all authors performed the final approval of the article.
Supported by Natural Science Foundation of Liaoning Province, No. 20170541024; and the Shengjing Free Researcher Project Foundation, No. 200812.
Institutional review board statement: The study was reviewed and approved by the Ethics Committee of Shengjing Hospital of China Medical University (No. 2016PS277K).
Informed consent statement: All cancer specimen and blood samples from the patients and healthy volunteers were taken after informed written consent and ethical permission were obtained prior to study enrollment.
Conflict-of-interest statement: The authors have no conflicts of interest to declare.
Data sharing statement: No additional data are available for this study. All data are included in the paper itself.
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/
Correspondence to: Si-Yu Sun, MD, PhD, Chief, Professor, Endoscopy Center, Shengjing Hospital of China Medical University, No. 36, Sanhao Street, Shenyang 110004, Liaoning Province, China. sun-siyu@163.com
Telephone: +86-24-96615-26111 Fax: +86-24-23892617
Received: November 3, 2017
Peer-review started: November 4, 2017
First decision: November 14, 2017
Revised: November 17, 2017
Accepted: November 27, 2017
Article in press: November 27, 2017
Published online: December 21, 2017
Processing time: 46 Days and 9.9 Hours
ARTICLE HIGHLIGHTS
Research background

Pancreatic cancer is a malignancy with a very poor prognosis. There have been few recent therapeutic advances in the treatment of pancreatic cancer for more than 10 years. The key to improving the prognosis of pancreatic cancer mostly lies in early diagnosis and early treatment. Circular RNAs (circRNAs) are a class of noncoding RNAs characterized by stable ring structure formed by a covalently closed continuous loop, which makes them stable in cells, tissues, and body fluid. Therefore, they can serve as ideal biomarkers for detection of diseases, especially cancer. This study indicates that circ-LDLRAD3 has potential as a novel biomarker indicative of tumor invasion capacity in the diagnosis of pancreatic cancer.

Research motivation

This study aimed to analyze and evaluate the diagnostic value of a new circular RNA, circ-LDLRAD3, in pancreatic cancer. And research data suggest that circ-LDLRAD3 may be used as a biomarker in pancreatic cancer diagnosis.

Research objectives

The main objectives in this study were pancreatic cancer and a new circular RNA, circ-LDLRAD3. The results showed that the expression level of circ-LDLRAD3 was up-regulated in pancreatic cancer and it can serve as a biomarker in pancreatic cancer.

Research methods

The expression levels of circ-LDLRAD3 were detected using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) in pancreatic cancer cell lines, normal pancreatic cell lines, paired pancreatic cancer tissues and adjacent non-tumorous tissues, and plasma samples from patients with pancreatic cancer and healthy volunteers. The relationship between circ-LDLRAD3 expression and patients’ clinicopathological factors was analyzed, the diagnostic value of circ-LDLRAD3 was further calculated alone and combined with CA19-9.

Research results

Our study found that expression levels of circ-LDLRAD3 were up-regulated in pancreatic cell lines, pancreatic cancer tissues, and plasma samples from pancreatic cancer patients. It may serve as a new biomarker in the diagnosis of pancreatic cancer. Studies utilizing a large number of samples in multiple centers should be implemented in future. The study of circ-LDLRAD3 function in pancreatic cancer is also likely to improve the understanding of the occurrence and progression mechanisms of pancreatic cancer.

Research conclusions

This study indicated that the expression of a new circular RNA, circ-LDLRAD3, was significantly up-regulated in pancreatic cancer cell lines, pancreatic cancer tissues, and pancreatic cancer plasma samples. Furthermore, circ-LDLRAD3 expression was correlated with lymphatic invasion, venous invasion, and metastasis. Therefore, circ-LDLRAD3 has potential as a novel biomarker indicative of tumor invasion capacity in the diagnosis of pancreatic cancer. It is highly believed that the key to improving the prognosis of pancreatic cancer mostly lies in early diagnosis and early treatment. Therefore, searching for ideal biomarkers is essential. Circular RNAs are a class of non-coding RNAs which are stable because of their unique circular structure. Previous studies have confirmed that some circRNAs can serve as biomarkers in certain diseases. In this study, we focused a new circular RNA, circ-LDLRAD3, and hypothesized that expression levels of circ-LDLRAD3 were up-regulated in pancreatic cancer. Moreover, this study verified the hypothesis and found that expression levels of circ-LDLRAD3 were significantly up-regulated in pancreatic cancer cell lines, pancreatic cancer tissues, and pancreatic cancer plasma samples, whose expression levels were correlated with lymphatic invasion, venous invasion, and metastasis. Therefore, circ-LDLRAD3 may be a new biomarker in the diagnosis of pancreatic cancer.

Research perspectives

This is the first study to report the expression pattern of circ-LDLRAD3 and its diagnostic value in pancreatic cancer and provides a new avenue for the early diagnosis of pancreatic cancer. However, due to the limited number of available tissue and plasma samples from patients with pancreatic cancer, studies utilizing a large number of samples in multiple centers should be implemented in future. The study of circ-LDLRAD3 function in pancreatic cancer is also likely to improve the understanding of the occurrence and progression mechanisms of pancreatic cancer. And more types of circular RNAs and their relationship with pancreatic cancer should be verified in the future research.