J Cancer 2015; 6(2):105-110. doi:10.7150/jca.10568

Research Paper

Colon Cancer Associated Transcript-1 (CCAT1) Expression in Adenocarcinoma of the Stomach

Ido Mizrahi1*, Haggi Mazeh1*, Ronit Grinbaum1, Nahum Beglaibter1, Michael Wilschanski2, Vera Pavlov2, Muchamad Adileh3, Alexander Stojadinovic4, Itzhak Avital4, Ali Osmay Gure5, David Halle2, Aviram Nissan2,3 ✉

1. Department of Surgery, Hadassah-Hebrew University Medical Center, Mount Scopus, Jerusalem, Israel;
2. The Surgical Oncology Laboratory, Department of Surgery, Hadassah-Hebrew University Medical Center, Mount Scopus, Jerusalem, Israel;
3. Department of Surgery, Hadassah-Hebrew University Medical Center, Ein Kerem, Jerusalem, Israel;
4. Bon Secours Cancer Institute, Richmond, VA, USA;
5. Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey.
* Both authors contributed equally to the preparation of this study.

This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY-NC) License. See http://ivyspring.com/terms for full terms and conditions.
Mizrahi I, Mazeh H, Grinbaum R, Beglaibter N, Wilschanski M, Pavlov V, Adileh M, Stojadinovic A, Avital I, Gure AO, Halle D, Nissan A. Colon Cancer Associated Transcript-1 (CCAT1) Expression in Adenocarcinoma of the Stomach. J Cancer 2015; 6(2):105-110. doi:10.7150/jca.10568. Available from http://www.jcancer.org/v06p0105.htm

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Background: Long non-coding RNAs (lncRNAs) have been shown to have functional roles in cancer biology and are dys-regulated in many tumors. Colon Cancer Associated Transcript -1 (CCAT1) is a lncRNA, previously shown to be significantly up-regulated in colon cancer. The aim of this study is to determine expression levels of CCAT1 in gastric carcinoma (GC).

Methods: Tissue samples were obtained from patients undergoing resection for gastric carcinoma (n=19). For each patient, tumor tissue and normal appearing gastric mucosa were taken. Normal gastric tissues obtained from morbidly obese patients, undergoing laparoscopic sleeve gastrectomy served as normal controls (n=19). A human gastric carcinoma cell line (AGS) served as positive control. RNA was extracted from all tissue samples and CCAT1 expression was analyzed using quantitative real time-PCR (qRT-PCR).

Results: Low expression of CCAT1 was identified in normal gastric mucosa samples obtained from morbidly obese patients [mean Relative Quantity (RQ) = 1.95±0.4]. AGS human gastric carcinoma cell line showed an elevated level of CCAT1 expression (RQ=8.02). Expression levels of CCAT1 were approximately 10.8 fold higher in GC samples than in samples taken from the negative control group (RQ=21.1±5 vs. RQ=1.95±0.4, respectively, p<0.001). Interestingly, CCAT1 expression was significantly overexpressed in adjacent normal tissues when compared to the negative control group (RQ = 15.25±2 vs. RQ=1.95±0.4, respectively, p<0.001). Tissues obtained from recurrent GC cases showed the highest expression levels (RQ = 88.8±31; p<0.001). Expression levels increased with tumor stage (T4- 36.4±15, T3- 16.1±6, T2- 4.7±1), however this did not reach statistical significance (p=0.2). There was no difference in CCAT1 expression between intestinal and diffuse type GC (RQ=22.4±7 vs. 22.4±16, respectively, p=0.9). Within the normal gastric tissue samples, no significant difference in CCAT1 expression was observed in helicobacter pylori negative and positive patients (RQ= 2.4±0.9 vs. 0.93±0.2, respectively, p=0.13).

Conclusion: CCAT1 is up-regulated in gastric cancer, and may serve as a potential bio-marker for early detection and surveillance.

Keywords: Gastric cancer, CCAT1, gastrectomy, biomarker, long non-coding RNA.