Abstract:

Objective To investigate the relative expression of serum long noncoding RNA（lncRNA） colon cancer-associated transcript 2（CCAT2） in patients with gastric cancer（GC） and its role in the early diagnosis and prognosis monitoring of GC. Methods A total of 40 GC patients diagnosed by pathology department were enrolled from the Affiliated Hospital of Nantong University,and their preoperative and postoperative serum samples were collected. Totally,30 patients with gastric benign lesions（gastric ulcers and gastric polyps） and 43 age-matched healthy subjects（healthy control group） were enrolled. The relative expression of CCAT2 was determined by real-time fluorescence quantitation polymerase chain reaction（PCR）,and chemiluminescence immunoassay was used to determine carcinoembryonic antigen（CEA）and carbohydrate antigen 19-9（CA19-9）. Receiver operating characteristic（ROC） curve was used to evaluate the diagnostic efficiency of CCAT2. Results Comparing with gastric benign lesion and healthy control groups,the relative expression of CCAT2 were higher in GC group（P<0.01）,and there was no statistical significance between gastric benign lesion and healthy control groups（P>0.05）. The preoperative relative expression of CCAT2 was higher than postoperative one with statistical significance（P<0.01）. High expression levels of CCAT2 were correlated with tumor size（P=0.028）,TNM stage（P=0.012） and lymph node metastasis（P=0.034）,and there was no correlation with age and sex（P>0.05）. The area under ROC curve（AUC） of CCAT2 was 0.851 [95% confidence interval（CI） 0.772-0.930,P<0.05] for the differential diagnosis of GC patients from healthy subjects. For the differential diagnosis of GC from gastric benign lesions,the AUC was 0.808（95% CI 0.701-0.916,P<0.05） as the cut-off value of 1.125. The combined determination of CCAT2 with CEA and CA19-9 can improve the sensitivity（98%）. There was no correlation between relative expression of CCAT2 and CEA,CA19-9 in GC group. Conclusions As a new biological marker,CCAT2 plays a role in the diagnosis and prognosis monitoring of GC,and it can improve the diagnostic efficiency combined with CEA and CA19-9 in GC patients.

Key words: Gastric cancer, Long noncoding RNA, Colon cancer-associated transcript 2, Early diagnosis