Some long noncoding RNAs (lncRNAs) play important roles in the regulation of gene expression by acting as competing endogenous RNAs (ceRNAs). However, the roles of lncRNA associated-ceRNAs in oncogenesis are not fully understood. Here, based on lncRNA microarray data of gastric cancer, bioinformatic algorithm miRcode and microRNA (miRNA) targets database TarBase, we first constructed an lncRNA-miRNA-mRNA network. Then, we confirmed it by data of six types of other cancer including head and neck squamous cell carcinoma, prostate cancer, papillary thyroid carcinoma, pituitary gonadotrope tumors, ovarian cancer, and chronic lymphocytic leukemia. The results showed a clear cancer-associated ceRNA network. Eight lncRNAs (AC009499.1, GACAT1, GACAT3, H19, LINC00152, AP000288.2, FER1L4, and RP4-620F22.3) and nine miRNAs (miR-18a-5p, miR-18b-5p, miR-19a-3p, miR-20b-5p, miR-106a-5p, miR-106b-5p, miR-31-5p, miR-139-5p, and miR-195-5p) were involved. For instance, through its miRNA response elements (MREs) to compete for miR-106a-5p, lncRNA-FER1L4 regulates the expression of PTEN, RB1, RUNX1, VEGFA, CDKN1A, E2F1, HIPK3, IL-10, and PAK7. Furthermore, cellular experimental results indicated that FER1L4-small interfering RNA (siRNA) simultaneously suppressed FER1L4 and RB1 mRNA level. These results suggest that lncRNAs harbor MREs and play important roles in post-transcriptional regulation in cancer.

BACKGROUND & AIMS:We performed a systematic review and meta-analysis to comprehensively estimate adenoma miss rate (AMR) and advanced AMR (AAMR) and explore associated factors. METHODS: We searched the PubMed, Web of Science, and Ovid EMBASE databases for studies published through April 2018 on tandem colonoscopies, with AMR and AAMR as the primary outcomes. We performed meta-regression analyses to identify risk factors and factors associated with outcome. Primary outcomes were AMR and AAMR and secondary outcomes were AMR and AAMR for different locations, sizes, pathologies, morphologies, and populations. RESULTS: In a meta-analysis of 43 publications and more than 15,000 tandem colonoscopies, we calculated miss rates of 26% for adenomas (95% confidence interval [CI] 23%-30%), 9% for advanced adenomas (95% CI 4%-16%), and 27% for serrated polyps (95% CI 16%-40%). Miss rates were high for proximal advanced adenomas (14%; 95% CI 5%-26%), serrated polyps (27%; 95% CI 16%-40%), flat adenomas (34%; 95% CI 24%-45%), and in patients at high risk for colorectal cancer (33%; 95% CI 26%-41%). Miss rates could be decreased by adequate bowel preparation and auxiliary techniques (P ¼ .06; P ¼ .04, and P ¼ .01, respectively). The adenoma detection rate (ADR), adenomas per index colonoscopy, and adenomas per positive index colonoscopy (APPC) were independently associated with AMR (P ¼ .02, P ¼ .01, and P ¼ .008, respectively), whereas APPC was the only factor independently associated with AAMR (P ¼ .006). An APPC value greater than 1.8 was more effective in monitoring AMR (31% vs 15% for AMR P < .0001) than an ADR value of at least 34% (27% vs 17% for AMR; P ¼ .008). The AAMR of colonoscopies with an APPC value below 1.7 was 35%, vs 2% for colonoscopies with an APPC value of at least 1.7 (P ¼ .0005). CONCLUSIONS: In a systematic review and meta-analysis, we found that adenomas and advanced adenomas are missed (based on AMR and AAMR) more frequently than previously believed. In addition to ADR,

BackgroundLong non-coding RNAs (lncRNAs) are prevalently transcribed in the genome yet their potential roles in human cancers are not well understood. The aim of the present study was to determine the lncRNA expression profile in gastric cancer and its potential clinical value.MethodsThe global lncRNA expression profile in gastric cancer was measured by lncRNA microarray. Levels of two representative lncRNAs, H19 and uc001lsz, were confirmed by real-time reverse transcriptase-polymerase chain reaction. The relationship between their levels and clinicopathological factors of patients with gastric cancer was explored. A receiver operating characteristic (ROC) curve was constructed for differentiating gastric cancer from benign gastric diseases.ResultsTotal of 135 lncRNAs, which differential expression levels between tumor and non-tumorous tissues were more than twofold, were found (GEO No. GSE47850). The most down-regulated lncRNAs in gastric cancer tissues were FER1L4, uc001lsz, BG491697, AF131784, uc009ycs, BG981369, AF147447, HMlincRNA1600, and AK054588; while the most up-regulated ones were H19, HMlincRNA717, BM709340, BQ213083, AK054978, and DB077273. H19 was found highly expressed in stomach and liver cancer cell lines, while lowly expressed in lung cancer and prostate cancer cell lines. Uc001lsz was lowly expressed in gastric, lung and liver cancer cell lines, while highly expressed in prostate cancer. The areas under ROC curves were up to 0.613, 0.751, and 0.761 for H19, uc001lsz, and the combination, respectively.ConclusionsThe lncRNA expression profile in gastric cancer suggests the potential roles of lncRNAs in gastric cancer occurrence and development. The overexpression of H19 in gastric cancer suggests that H19 may be participated in gastric cancer. The reduced expression of uc001lsz in gastric cancer cell lines and tissues, its associations with TNM stage, and its dysregulation in early cancer and precancerous lesions suggest that uc001lsz may be a potential marker for the diagnosis of early gastric cancer.

It has been known that differential expression of long non-coding RNA (lncRNA) plays critical roles in carcinogenesis. However, the significance of lncRNA, especially long intergenic ncRNA (lincRNA, the main type of lncRNA family), in the diagnosis of gastric cancer is largely unknown. The aim of this study was to determine the expression level of LINC00152, a newfound lincRNA, in gastric carcinoma and its clinical association. The expression of LINC00152 in 71 pairs of tumorous and adjacent normal tissues from patients with gastric cancer was detected by quantitative real-time reverse transcription-polymerase chain reaction. And then, the potential associations between its level in gastric cancer tissue and the clinicopathological features were analyzed. Finally, a receiver operating characteristic (ROC) curve was constructed for differentiating patients with gastric cancer from patients with benign gastric diseases. The results showed that the expression level of LINC00152 in gastric carcinoma was significantly increased, compared with matched normal tissue (P=0.045) and normal mucosa from health control (P=0.004), respectively. Levels of LINC00152 in gastric cancer cell lines, BGC-823, MGC-803, and SGC-7901, were significantly higher than those in human normal gastric epithelial cell line GES-1. In addition, high expression of LINC00152 was correlated with invasion (P=0.042). LINC00152 levels in gastric juice from patients with gastric cancer were further found significantly higher than those from normal controls (P=0.002). Moreover, the area under the ROC curve (AUC) was up to 0.645 (95 % CI=0.559-0.740, P=0.003). This study highlights that lincRNA LINC00152 might be a novel biomarker for predicting gastric cancer.

BACKGROUND: MicroRNAs (miRNAs) play a crucial role in carcinogenesis; however, it largely remains unclear whether miRNAs in gastric juice, which is specific for gastric tissues, can be used as biomarkers for gastric cancer. The objective of the current study was to investigate the feasibility of using gastric juice miRNAs as potential biomarkers to assist in screening for gastric cancer. METHODS: Gastric juice samples were collected from 141 patients who underwent upper gastrointestinal endoscopy examination between September 2010 and December 2011. Gastric cancer and adjacent normal biopsy specimens also were collected. The existence and stability of miRNAs in gastric juices were determined by real-time reverse transcriptase-quantitative polymerase chain reaction (RTqPCR) and sequencing. miRNA levels in tissues and gastric juices were detected by RT-qPCR. A receiver operating characteristic (ROC) curve was constructed for differentiating gastric cancer from benign gastric diseases. RESULTS: Levels of miRNA-21 (miR-21) and miR-106a in gastric cancer tissues were significantly higher compared with the levels in adjacent tissues (P ¼ .006 and P ¼ .001, respectively). Patients who had gastric cancer had significantly different levels of gastric juice miR-21 and miR-106a compared with patients who had benign gastric diseases (both P < .001). There were significant correlations between miR-21/miR-106a levels and Borrmann types. miR-21 levels in intestinal type gastric cancer specimens were higher than that in diffuse (P ¼ .003) or mixed (P < .001) gastric cancer types. The area under the ROC curve was up to 0.969 for miR-21 and 0.871 for miR-106a. CONCLUSIONS:The current results indicated that certain miRNAs in gastric juice are potential biomarkers that can assist in screening for gastric cancer.

Aberrantly expressed long noncoding RNAs (lncRNAs) are associated with various cancers. However, the roles of lncRNAs in the pathogenesis of most cancers are unclear. Here, we report that the lncRNA FER1L4 (fer-1-like family member 4, pseudogene) acts as a competing endogenous RNA (ceRNA) to regulate the expression of PTEN (a well-known tumor suppressor gene) by taking up miR-106a-5p in gastric cancer. We observed that FER1L4 was downregulated in gastric cancer and that its level corresponded with that of PTEN mRNA. Both FER1L4 and PTEN mRNA were targets of miR-106a-5p. Further experiments demonstrated that FER1L4 downregulation liberates miR-106a-5p and decreases the abundances of PTEN mRNA and protein. More importantly, FER1L4 downregulation accelerated cell proliferation by promoting the G0/G1 to S phase transition. We conclude that one mechanism by which lncRNAs function in in tumorigenesis is as ceRNAs for tumor suppressor mRNAs.

Non-coding RNAs (ncRNAs) play key roles in development, proliferation, differentiation and apoptosis. Altered ncRNA expression is associated with gastric cancer occurrence, invasion, and metastasis. Moreover, aberrant expression of microRNAs (miRNAs) is significantly related to gastric cancer tumor stage, size, differentiation and metastasis. MiRNAs interrupt cellular signaling pathways, inhibit the activity of tumor suppressor genes, and affect the cell cycle in gastric cancer cells. Some miRNAs, including miR-21, miR-106a and miR-421, could be potential markers for the diagnosis of gastric cancer. Long non-coding RNAs (lncRNAs), a new research hotspot among cancer-associated ncRNAs, play important roles in epigenetic, transcriptional and post-transcriptional regulation. Several gastric cancer-associated lncRNAs, such as CCAT1, GACAT1, H19, and SUMO1P3, have been explored. In addition, Piwi-interacting RNAs, another type of small ncRNA that is recognized by gastroenterologists, are involved in gastric carcinogenesis, and piR-651/823 represents an efficient diagnostic biomarker of gastric cancer that can be detected in the blood and gastric juice. Small interfering RNAs also function in post-transcriptional regulation in gastric cancer and might be useful in gastric cancer treatment.

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