Helicobacter pylori infection and esophageal cancer risk:An updated meta-analysis

AIM:To clarify the association between Helicobacter pylori(H.pylori)infection and the risk of esophageal carcinoma through a meta-analysis of published data.METHODS:Studies which reported the association between H.pylori infection and esophageal cancer published up to June 2013 were included.The odds ratios(ORs)and corresponding 95%CIs of H.pyloriinfection on esophageal cancer with respect to health control groups were evaluated.Data were extracted independently by two investigators and discrepancies were resolved by discussion with a third investigator.The statistical software,STATA(version 12.0),was applied to investigate heterogeneity among individual studies and to summarize the studies.A meta-analysis was performed using a fixed-effect or random-effect method,depending on the absence or presence of significant heterogeneity.RESULTS:No significant association between H.pylori infection and esophageal squamous cell carcinoma(ESCC)risk was found in the pooled overall population(OR=0.97,95%CI:0.76-1.24).However,significant associations between H.pylori infection and ESCC risk were found in Eastern subjects(OR=0.66,95%CI:0.43-0.89).Similarly,cytotoxin-associated gene-A(CagA)positive strains of infection may decrease the risk of ESCC in Eastern subjects(OR=0.77,95%CI:0.65-0.92),however,these associations were not statistically significant in Western subjects(OR=1.26,95%CI:0.97-1.63).For esophageal adenocarcinoma(EAC)the summary OR for H.pylori infection and CagA positive strains of infection were 0.59(95%CI:0.51-0.68)and 0.56(95%CI:0.45-0.70),respectively.CONCLUSION:H.pylori infection is associated with a decreased risk of ESCC in Eastern populations and a decreased risk of EAC in the overall population.

Long non-coding RNAs as key regulators of cancer metastasis

The recent advances in functional genomics have discovered that a large number of long non-coding RNAs(lncRNAs)are pervasively transcribed from the human genome.Increasing evidence further indicates that lncRNAs are important for gene expression during cell differentiation and development through various mechanisms such as nuclear organization,post-transcription regulation,alternative splicing,and epigenetic regulation.Thus,aberrant expression of lncRNAs can cause abnormality in those cellular functions and lead to various pathological conditions.One of such fatal consequences is cancer metastasis which is responsible for more than 90%of cancer-related deaths.A good understanding of how lncRNAs regulate different genetic and epigenetic changes during different stages of cancer metastasis is important not only for general cancer biology but also for identification of novel biomarkers and therapeutic targets for treatment of metastatic cancer.A significant progress has been made regarding the role of lncRNAs in cancer for past several years.In this study,we first discuss general functions of lncRNAs and then highlight recent findings of how lncRNAs impact cancer metastasis,and finally we provide our perspectives on clinical implications of lncRNAs.