The Feasibility Study Of LncRNAs As Tumor Markers For Gastric Cancer Early Diagnosis

Objective: To demonstrate whether LINC00152 is a gastric cancer related-lncRNA, we first detected the levels of this lncRNA in gastric cancer cell lines and tissues. Then, to explore the feasibility of LINC00152 as a tumor marker for gastric cancer early diagnosis, we detected the levels of plasma LINC00152 of patients with early gastric cancer and with advanced cancer. At last, to explore the existing way of LINC00152 in plasma, we detected its levels in exosomes extracted from plasma.Methods:(1) We detected the expression levels of LINC00152 in four human gastric cancer cell lines, one normal gastric epithelial cell line, pairs of gastric cancer tissues and adjacent nontumorous tissues using quantitative reverse transcription-polymerase chain reaction(qRT-PCR).(2) We used qRT-PCR to detect the levels of LINC00152 in plasma samples of patients with gastric cancer, containing pre- and postoperative ones, and of patients with gastric epithelial dysplasia, and then compared their LINC00152 levels with thoese of healthy controls. At last, we used receiver operating characteristic(ROC) curve to examine the diagnostic value of plasma LINC00152.(3) We compared the levels of LINC00152 in plasma and in exosomes, which were extracted from the same volume of same plasma and confirmed by transmission electron microscopy.Results:(1) We found that LINC00152 was up-regulated in gastric cancer cell lines, MGC-803, SGC-7901, and BGC-823.(2) LINC00152 also up-regulated in cancer tissues.(3) The levels of plasma LINC00152 were significantly elevated in gastric cancer patients.(4) Early gastric cancer patients also showed higher levels of LINC00152 in their plasma.(5) There were no significant differences of plasma LINC00152 levels between gastric epithelial dysplasia patients and healthy controls.(6) LINC00152 levels in postoperative plasma samples were singnificantly different from those in preoperative ones.(7) The sensitivity and specificity of plasma LINC00152 as a tumor marker were 48.1% and 85.2%, respectively.(8) Exosomes can protect lncRNAs existing in plasma.Conclusion: LINC00152, as one of the gastric cancer related lncRNAs, has possibility to be a novel gastric cancer biomarker applied in early diagnosis. The possible mechanism of its stably existing in blood was protected by exosomes. This feature may be helpful for the clinical analysis of lncRNA-typed tumor markers.