BACKGROUND: Long noncoding RNAs (lncRNAs) play a crucial role in tumorigenesis. However, the value of lncRNAs in the diagnosis of gastric cancer remains unknown. To identify whether lncRNA‐AA174084 is a potential marker for the early diagnosis of gastric cancer (GC), the authors investigated its levels in tissues, blood, and gastric juices from patients with various stage of gastric tumorigenesis.METHODS: Total RNA in 860 specimens from patients and healthy controls was extracted. Levels of AA174084 in 134 paired GC tissues, 127 gastric mucosal tissues, 335 plasma samples, and 130 gastric juice samples at each stage of gastric tumorigenesis were measured using real‐time reverse transcriptase‐polymerase chain reaction analysis. The potential association between AA174084 levels and patients' clinicopathologic features were analyzed. A receiver operating characteristic (ROC) curve was constructed for differentiating GC patients from controls.RESULTS: Expression levels of AA174084 were down‐regulated significantly in 95 of 134 GC tissues (71%) compared with the levels in paired, adjacent, normal tissues (P < .001). AA174084 levels had significant, negative correlations with age (P = .031), Borrmann type (P = .016), and perineural invasion (P = .032). Plasma AA174084 levels in patients with GC dropped markedly on day 15 after surgery compared with preoperative levels (P < .001) and were associated with invasion (P = .049) and lymphatic metastasis (P = .042). AA174084 levels in gastric juice from patients with GC were significantly higher than the levels in normal mucosa or in patients with minimal gastritis, gastric ulcers, and atrophic gastritis (P < .001). The area under ROC was up to 0.848 (P < .001).CONCLUSIONS: AA174084 may have potential as marker for the early diagnosis of GC. Cancer 2014;120:3320–3328. © 2014 American Cancer Society.

LncRNA-RMRP promotes carcinogenesis by acting as a miR-206 sponge and is used as a novel biomarker for gastric cancer

Colorectal cancer (CRC) is one of the most common digestive malignancies in the world. EDNRB is a new candidate tumor suppressor gene which is often down-regulated or even silenced by promoter hypermethylation in various human cancers. However, the function of EDNRB gene in CRC remains unknown. In this study, we examined the expression and DNA methylation of EDNRB in CRC tissues. A total of 42 paired CRC and adjacent normal tissue samples were used to determine mRNA levels and DNA methylation status of EDNRB gene by qRT-PCR and methylation-specific PCR (MSP), respectively. Our study showed that EDNRB promoter hypermethylation was more frequently in CRC tissues than in the normal tissues (92.86 versus 59.52, p = 0.001). Consequently, significantly lower level of EDNRB mRNA was found in CRC tumor samples than in normal samples (0.31 ± 0.91 versus 0.70 ± 1.18, p = 0.032). Our results suggested that EDNRB promoter hypermethylation might downregulate its gene expression in CRC, and thus played an important role in the development of CRC. The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/7420980471113303

Aberrant DNA methylation can be a potential genetic mechanism in non-small cell lung cancer (NSCLC). However, inconsistent findings existed among the recent association studies between cigarette smoking and gene methylation in lung cancer. The purpose of our meta-analysis was to evaluate the role of gene methylation in the smoking behavior of NSCLC patients. A total of 116 genes were obtained from 97 eligible publications in the current meta-analyses. Our results showed that 7 hypermethylated genes (including CDKN2A, RASSF1, MGMT, RARB, DAPK, WIF1 and FHIT) were significantly associated with the smoking behavior in NSCLC patients. The further population-based subgroup meta-analyses showed that the CDKN2A hypermethylation was significantly associated with cigarette smoking in Japanese, Chinese and Americans. In contrast, a significant association of RARB hypermethylation and smoking behavior was only detected in Chinese but not in Japanese. The genes with altered DNA methylation were likely to be potentially useful biomarkers in the early diagnosis of NSCLC.