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BackgroundStudies have shown inconsistent associations of nitrite and nitrate intake with the risk of gastric cancer or its associated mortality. We performed a meta-analysis of observational studies to evaluate the correlation of nitrite and nitrate intake with the risk of gastric cancer.Material/MethodsWe searched for studies reporting effect estimates and 95% confidence intervals (CIs) of gastric cancer in PubMed, EMBASE, and the Cochrane Library through November 2018. The summary results of the included studies were pooled using a random-effects model.ResultsEighteen case-control and 6 prospective cohort studies recruiting 800 321 participants were included in this study. The summary results indicated that the highest (odds ratio [OR], 1.27; 95%CI, 1.03–1.55; P=0.022) or moderate (OR: 1.12; 95%CI, 1.01–1.26; P=0.037) nitrite intake were associated with a higher risk of gastric cancer. However, we noted that high (OR, 0.81; 95%CI, 0.68–0.97; P=0.021) or moderate (OR, 0.86; 95%CI, 0.75–0.99; P=0.036) nitrate intakes were associated with a reduced risk of gastric cancer. These associations differed when stratified by publication year, study design, country, the percentage of male participants, assessment of exposure, adjusted model, and study quality.ConclusionsHigh or moderate nitrite intake was associated with higher risk of gastric cancer, whereas high or moderate nitrate intake was correlated with lower risk of gastric cancer.

BackgroundThe identification of susceptibility genes for specific types of cancer can provide necessary information for the complete characterization of cancer syndromes. Eight single nucleotide polymorphisms (SNPs), rs465498, rs17728461, rs4488809, rs753955, rs13361707, rs9841504, rs2274223, and rs13042395, were reported by genome wide association studies (GWASs) to be closely related to the susceptibility of lung cancer (LC), gastric cancer (GC) or esophageal cancer (EC) in Han population from northern or southern China. However, Chinese Han people from different geographic areas may have different genetic backgrounds. This study aims to assess the genetic associations of the eight SNPs mentioned above with three cancers risk in a Han population from northwest China.MethodsA total of 186 cancer-free controls and 436 cases with non-small cell lung cancer (NSCLC) (159 cases), non-cardia GC (167 cases) or EC (110 cases) were enrolled in this study. Chi-square test and polytomous logistic regression analyses were used to estimate the association between eight cancer-related SNPs and three cancers in a Han Chinese population from northwest China. The logistic regression results were adjusted for confounding factors and Benjamini and Hochberg False Discovery Rate (FDR) method was used to adjust the multiple hypothesis tests. Association analyses by cigarette smoking or alcohol drinking status were analyzed by crossover analyses.ResultsOne of the eight SNPs, rs17728461 was associated with NSCLC susceptibility (in a heterozygous model, OR = 0.44, 95% CI = 0.27–0.72, p = 0.001). Two SNPs, rs753955 and rs13042395, were associated with the risk of non-cardia GC in different genetic models (p < 0.05). No SNPs were associated with EC. The crossover analyses showed that the rs13042395 CT genotype, combined with cigarette smoking or alcohol drinking, could further increase the risk for non-cardia GC (p < 0.05).ConclusionsThese results indicated that rs17728461 may be specifically associated with the risk of NSCLC. rs753955 and rs13042395 were specifically associated with susceptibility to non-cardia GC in Ningxia Han Chinese. Susceptibility-associated polymorphisms in the northwestern Han Chinese were not very consistent with those in the northern Han Chinese or southern Han Chinese. The validation of these findings with a functional evaluation and a larger population is still required.

Elucidation of the mechanisms underlying multidrug resistance (MDR) is required to ensure the efficacy of chemotherapy against gastric cancer (GC). To investigate this issue, here we identified that microRNA‐765 (miRNA‐765) is up‐regulated both in MDR GC cell lines and in specimens from patients who are not responding to chemotherapy. In addition, down‐regulation of miRNA‐765 increased the sensitivity of GC cells to anticancer drugs, whereas its overexpression had the opposite effect. Moreover, miRNA‐765 suppressed drug‐induced apoptosis and positively regulated the expression of MDR‐related genes. Finally, we showed that the basic leucine zipper ATF‐like transcription factor 2, a tumor suppressor gene, is the functional target of miRNA‐765. In summary, these results suggest that miRNA‐765 may promote MDR via basic leucine zipper ATF‐like transcription factor 2 in GC cells.

Our study demonstrated genome-wide DNA methylation variations between primary B cells and corresponding LCLs, which might yield new insight on the methylation mechanism of EBV-induced immortalization.