Clinical Trials Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 7, 2019; 25(1): 138-150
Published online Jan 7, 2019. doi: 10.3748/wjg.v25.i1.138
Molecular detection of epithelial-mesenchymal transition markers in circulating tumor cells from pancreatic cancer patients: Potential role in clinical practice
Xiao-Hui Zhao, Zai-Rui Wang, Chang-Long Chen, Ling Di, Zhuo-Fei Bi, Zhi-Hua Li, Yi-Min Liu
Xiao-Hui Zhao, Zai-Rui Wang, Chang-Long Chen, Ling Di, Zhuo-Fei Bi, Zhi-Hua Li, Yi-Min Liu, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China
Xiao-Hui Zhao, Zai-Rui Wang, Chang-Long Chen, Ling Di, Zhuo-Fei Bi, Yi-Min Liu, Department of Radiotherapy, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China
Zhi-Hua Li, Department of Medical Oncology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China
Author contributions: Liu YM, Zhao XH, and Li ZH designed the research, analyzed and interpreted the data, and wrote the paper; Wang ZR and Chen CL analyzed and interpreted the data; Bi ZF, Ding L, and Qing L wrote the paper.
Supported by Guangdong Natural Science Foundation, No. 2016A030313312.
Institutional review board statement: The study protocol was reviewed and approved by Institutional Review Board of Sun Yat-sen Memorial Hospital.
Clinical trial registration statement: The study is registered at www.chictr.org.cn and the registration identification number is chiCTR1800018513.
Informed consent statement: All participants signed an informed consent form prior to study enrollment.
Conflict-of-interest statement: The authors do not have any conflict of interest to disclose.
Data sharing statement: No additional data are available.
CONSORT 2010 statement: We complied with CONSORT 2010 during the period of the study.
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: Yi-Min Liu, MA, Associate Specialist, Professor, Department of Radiotherapy, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yan-Jiang Xi Road, Guangzhou 510120, Guangdong Province, China. liuyimin1995@sina.com
Telephone: +86-13828401190 Fax: +86-21-81332533
Received: October 13, 2018
Peer-review started: October 15, 2018
First decision: November 7, 2018
Revised: December 5, 2018
Accepted: December 6, 2018
Article in press: December 6, 2018
Published online: January 7, 2019
Processing time: 93 Days and 18.9 Hours
ARTICLE HIGHLIGHTS
Research background

Circulating tumor cells (CTCs) have been demonstrated to be a prognostic indicator in numerous cancers. However, in pancreatic ductal adenocarcinoma (PDAC), CTCs remain to be studied. Here, we report for the first time the prognostic utility of CTCs, as detected by CanPatrol CTC enrichment technique, in patients with PDAC. Our data support the potential clinical value of PDAC CTCs. Both total CTC number and CTC epithelial-to-mesenchymal transition (EMT) phenotype may act as potential biomarkers for PDAC prognosis.

Research motivation

In the present study, we explored the relationships between clinicopathological parameters and the relative abundance of three circulating EMT-CTC subpopulations. We found that CTC status correlated with lymph node metastasis, TNM stage, distant metastasis, blood lymphocyte counts, and the neutrophil-to-lymphocyte ratio (NLR). Kaplan-Meier survival analysis showed that patients with ≥ 6 total CTCs had significantly decreased OS and PFS compared to patients with < 6 total CTCs. The presence of M-CTCs was positively correlated with TNM stage and distant metastasis. Additionally, lymphocyte counts and NLR in patients without CTCs were significantly different from those in patients testing positive for each CTC subpopulation. Our data support the potential clinical value of PDAC CTCs. Furthermore, our data also provide support for further large well-designed clinical trials to explore CTC counts as indicators of PDAC progression.

Research objectives

The objective of this research was to explore the relationships between clinicopathological parameters and the relative abundance of the three circulating EMT-CTC subpopulations in PDAC. This research demonstrated that positive CTC status was significantly correlated with lymph node metastasis, distant metastasis, late TNM stage, and poor patient prognosis. Meanwhile, M-CTCs were most common in patients with advanced cancer. These results demonstrated that classifying CTCs by EMT markers helps to identify the more aggressive CTC subpopulations and provides useful evidence for determining a suitable clinical approach.

Research Methods

This research utilized the cell size- and phenotype-based CanPatrol CTC filtration system to isolate CTCs. CTC subpopulations were identified using a multiplex RNA-ISH assay. Four epithelial biomarkers (epithelial cell adhesion molecule and cytokeratin 8/18/19), two mesenchymal biomarkers (vimentin and twist), and a leukocyte biomarker, CD45, were applied to capture and characterize the CTCs.

Research results

This research indicated that the presence of CTCs was significantly associated with PDAC poor prognosis. Moreover, M-CTCs were most common in patients with advanced cancer. These results demonstrate that CTCs are promising biomarker for PDAC prognosis and identification of EMT markers in CTCs provide more information on tumor progression.

Research conclusions

In the present study, a novel technology called CanPatrol CTC filtration system applying a combination of epithelial and mesenchymal markers was used to detect CTCs in peripheral blood from 107 patients with PDAC. We found that CTC positivity was correlated with clinicopathologic variables and outcomes. Meanwhile, the presence M-CTCs was associated with advanced stage and distant metastasis. These results demonstrate that CTC enumeration and classification show promise as a prognostic biomarker and may provide useful evidence for determining a suitable clinical approach.

Research perspectives

This research supports the potential clinical value of PDAC CTCs. Both total CTC number and CTC EMT phenotype may act as potential biomarkers for PDAC prognosis. However, our study suffered from a small sample size, and the results should be interpreted with caution. Large well-designed clinical trials are required to elucidate the potential value of EMT markers in CTCs.