Observational Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Jun 6, 2021; 9(16): 3880-3894
Published online Jun 6, 2021. doi: 10.12998/wjcc.v9.i16.3880
Differential analysis revealing APOC1 to be a diagnostic and prognostic marker for liver metastases of colorectal cancer
Hai-Yu Shen, Fang-Ze Wei, Qian Liu
Hai-Yu Shen, Fang-Ze Wei, Qian Liu, Department of Colorectal Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
Author contributions: Shen HY, Wei FZ, and Liu Q designed the research, collected and analyzed the data, and drafted and revised the article; all authors have read and approved the final manuscript.
Supported by National Key Research and Development (R&D) Program Project, No. 2019YFC1315705.
Institutional review board statement: The study was reviewed and approved by the Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College Institutional Review Board (approval No. 17-116/1439).
Informed consent statement: All study participants, or their legal guardian, provided informed written consent prior to study enrollment.
Conflict-of-interest statement: The authors declare that there is no conflict of interest in regard to this research.
Data sharing statement: Technical appendix, statistical code, and dataset available from the corresponding author at fcwpumch@163.com.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
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: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Qian Liu, MD, Chief Doctor, Department of Colorectal Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 17 Panjiayuan Nanli, Chaoyang District, Beijing 100021, China. fcwpumch@163.com
Received: January 22, 2021
Peer-review started: January 22, 2021
First decision: February 28, 2021
Revised: March 10, 2021
Accepted: March 23, 2021
Article in press: March 23, 2021
Published online: June 6, 2021
Processing time: 112 Days and 1 Hours
Abstract
BACKGROUND

Colorectal cancer (CRC) is one of the most malignant gastrointestinal cancers worldwide. The liver is the most important metastatic target organ, and liver metastasis is the leading cause of death in patients with CRC. Owing to the lack of sensitive biomarkers and unclear molecular mechanism, the occurrence of liver metastases cannot be predicted and the clinical outcomes are bad for liver metastases. Therefore, it is very important to identify the diagnostic or prognostic markers for liver metastases of CRC.

AIM

To investigate the highly differentially expressed genes (HDEGs) and prognostic marker for liver metastases of CRC.

METHODS

Data from three NCBI Gene Expression Omnibus (GEO) datasets were used to show HDEGs between liver metastases of CRC and tumour or normal samples. These significantly HDEGs of the three GEO datasets take the interactions. And these genes were screened through an online tool to explore the prognostic value. Then, TIMER and R package were utilized to investigate the immunity functions of the HDEGs and gene set enrichment analysis was used to explore their potential functions.

RESULTS

Based on the selection criteria, three CRC datasets for exploration (GSE14297, GSE41258, and GSE49355) were chosen. Venn diagrams were used to show HDEGs common to the six groups and 47 HDEGs were obtained. The HDEGs were shown by using STRING and Cytoscape software. Based on the TCGA database, APOC1 showed significantly different expression between N2 and N0, and N2 and N1. And there was also a significant difference in expression between T2 and T4, and between T2 and T3. In 20 paired CRC and normal tissues, quantitative real-time polymerase chain reaction illustrated that the APOC1 mRNA was strongly upregulated in CRC tissues (P = 0.014). PrognoScan and GEPIA2 revealed the prognostic value of APOC1 for overall survival and disease-free survival in CRC (P < 0.05). TIMER showed that APOC1 has a close relationship with immune infiltration (P < 0.05).

CONCLUSION

APOC1 is a biomarker that is associated with both the diagnosis and prognosis of liver metastases of CRC.

Keywords: APOC1; Liver metastases; Colorectal cancer; Differentially expressed genes; Marker

Core Tip: It is important to identify the diagnostic or prognostic markers for liver metastasis (LM) of colorectal cancer (CRC). Three datasets from NCBI Gene Expression Omnibus (GEO) were used to identify highly differentially expressed genes (HDEGs) between LM and tumor or normal samples. Then, HDEGs of the three GEO datasets take the intersections. The prognostic value of these genes was analyzed through online tools, which finally showed that APOC1 was associated with the prognosis of CRC. Analysis of the relationship with immune infiltration and tumor microenvironment and GSEA of APOC1 demonstrated that APOC1 was strongly associated with CRC development. In conclusion, APOC1 is a biomarker associated with both the diagnosis and prognosis of LM of CRC.