long non-coding rnas in gastric cancer: the most significant associated markers

Gastric Cancer (GC) as a major health problem is the fourth common cancer in the world and second cause related to cancers. Although the global incidence of gastric cancer has been decreased dramatically in recent decades, north and northwest of Iran have the highest incidence rate of gastric cancer. Long non-coding RNAs (lncRNAs) are kind of non-coding RNA > 200 nucleotides that havelimitation in protein coding ability, and act as new modulators in different biological processes, especially in different type of cancers. In last decades, many researches have reported several up- or down regulated lncRNAs that seem to be important as diagnostic or prognostic markers. Some studies done in blood, tissue or even gastric juice samples to assess the most effectiveness marker in detecting, prognosis or screening gastric cancer thus this review supposed to find the best lncRNA markers in gastric cancer.TCGA Atlas of Non-coding RNAs in Cancer (TANRIC) database expressed total of 452 differentially lncRNAs among GC and matched normal tissues, of which 76 lncRNAs were identified to be gastric cancer-specific from a pan-cancer analysis of different kinds of human cancer. From these 76 gastric cancer-specific lncRNAs, lncRNA H19, LINC00152, AA174084 and Fer-1-like protein 4 (FER1L4) were the most significant associated markers with gastric cancer. H19 upregulates in GCserum and can be use in identifying gastric cancer in early stages with sensitivity 85.5 % and specificity of 80.1 %. Plasma LINC00152 is a noninvasive biomarker for GC screening with a sensitivity of 48.1 % and a specificity of 85.2 %. AA174084 in digestive fluids is a diagnostic marker with a low sensitivity (46%), but high specificity (93%), although its plasma level could not be used to identify GC. FER1L4as a prognostic marker down-regulates in GC tissues with sensitivity and specificity 67.2 and 80.3 percent.Overall, specificity and sensitivity of any unique tumor-associated circulating lncRNA is poorand it seems that combination different types of lncRNAs with each other being more helpful. Combination of CUDR, LSINCT-5 and PTENP1 is the best known combination with sensitivity of 74.1 % and specificity of 100 % to diagnose GC patients from healthy people. Also combination of these three lncRNAs have sensitivity of 77.8 % and specificity of 97.0 % for early gastric cancer detection. Thus combination of CUDR, LSINCT-5 and PTENP1 is a novel biomarker marker for GC detection.All together clinical and biological studies are required to validate these findings.