Estimation of gastric cancer burden attributable to Helicobacter pylori infection in Asia.

BACKGROUND: Helicobacter pylori causes large burden of gastric cancer (GC) in Asia. We aimed to comprehensively quantify the burden of GC attributable to H. pylori infection in Asia. METHODS: We searched related articles from January 1998 to December 2020 to obtain the prevalence and relative risks (or odds ratio) of GC associated with H. pylori in Asia. The burden of GC attributable to H. pylori infection was quantified by Population Attributable Fraction (PAF) and Disability-adjusted life-years (DALYs). RESULTS: We quantified the burden of GC attributable to H. pylori infection with 415.6 thousand DALYs and 38.03% PAF through the five included Asian countries in 2019. The study found that the burden had obvious regional differences. The DALYs ranged from 298.9 thousand in China to 1.9 thousand in Malaysia, and the PAFs were between 58.00% in Japan and 30.89% in China. The average prevalence of H. pylori in the included general population was estimated to be 56.29%. CONCLUSIONS: Helicobacter pylori poses a huge disease burden of GC to the population, and its eradication should receive attention, especially in the countries with high incidence of and mortality due to GC.

Variant of SNPs at lncRNA NEAT1 contributes to gastric cancer susceptibility in Chinese Han population.

BACKGROUND: The long noncoding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) has been implicated in many tumors risk including gastric cancer. However, the association of single nucleotide polymorphisms (SNPs) at NEAT1 with gastric cancer risk has not been studied. The aim of this study was to investigate the association between SNPs in NEAT1 and gastric cancer susceptibility. METHODS: In this study, four SNPs in lncRNA NEAT1 were selected for genotyping in 484 gastric cancer patients and 484 controls in Chinese Han population. Quantitative real-time PCR (qRT-PCR) was conducted to evaluate the potential function of rs3825071. Attributable risk percentage (ARP) and population attributable risk percentage (PARP) were used to assess the epidemiological effect. RESULTS: In the dominant model (GG), the genotypes AG + AA of rs3825071 and rs7943779 were associated with an increased risk of gastric cancer (OR = 1.72, 95%CI = 1.27-2.32 and OR = 1.63, 95%CI = 1.19-2.22). Individuals harboring ≥ 3 risk alleles have higher risk of gastric cancer (OR = 1.88, 95% CI = 1.26-2.80, P = 0.002). ARP and PARP associated with gastric cancer were 42.53% and 10.88% for rs3825071, and were 33.78% and 6.26% for rs7943779, respectively. Furthermore, compared with the genotype GG of rs3825071, the genotypes AG and AA had higher expression of NEAT1. CONCLUSIONS: We found that the genetic variations in NEAT1 were significantly associated with risk of gastric cancer. The G > A variant of rs3825071 may confer gastric cancer susceptibility by changed biological effects to increase the expression of NEAT1.

Genetic variant of cyclooxygenase-2 in gastric cancer: More inflammation and susceptibility.

Gastric cancer accounts for the majority cancer-related deaths worldwide. Although various methods have considerably improved the screening, diagnosis, and treatment of gastric cancer, its incidence is still high in Asia, and the 5-year survival rate of advanced gastric cancer patients is only 10%-20%. Therefore, more effective drugs and better screening strategies are needed for reducing the incidence and mortality of gastric cancer. Cyclooxygenase-2 (COX-2) is considered to be the key inducible enzyme in prostaglandins (PGs) synthesis, which is involved in multiple pathways in the inflammatory response. For example, inflammatory cytokines stimulate innate immune responses via Toll-like receptors and nuclear factor-kappa B to induce COX-2/PGE2 pathway. In these processes, the production of an inflammatory microenvironment promotes the occurrence of gastric cancer. Epidemiological studies have also indicated that non-steroidal anti-inflammatory drugs can reduce the risk of malignant tumors of the digestive system by blocking the effect of COX-2. However, clinical use of COX-2 inhibitors to prevent or treat gastric cancer may be limited because of potential side effects, especially in the cardiovascular system. Given these side effects and low treatment efficacy, new therapeutic approaches and early screening strategies are urgently needed. Some studies have shown that genetic variation in COX-2 also play an important role in carcinogenesis. However, the genetic variation analysis in these studies is incomplete and isolated, pointing out only a few single nucleotide polymorphisms (SNPs) and the risk of gastric cancer, and no comprehensive study covering the whole gene region has been carried out. In addition, copy number variation (CNV) is not mentioned. In this review, we summarize the SNPs in the whole COX-2 gene sequence, including exons, introns, and both the 5' and 3' untranslated regions. Results suggest that COX-2 does not increase its expression through the CNV and the SNPs in COX-2 may serve as the potential marker to establish risk stratification in the general population. This review synthesizes emerging insights of COX-2 as a biomarker in multiple studies, summarizes the association between whole COX-2 sequence variation and susceptibility to gastric cancer, and discusses the future prospect of therapeutic intervention, which will be helpful for early screening and further research to find new approaches to gastric cancer treatment.

Which Individuals with Positive Family History of Gastric Cancer Urgently Need Intensive Screening and Eradication of Helicobacter Pylori? A Systematic Review and Meta-Analysis.

Background: Family history may inform individuals that they are at risk of gastric cancer (GC). However, it is too extensive to conduct intensive screening strategies for all individuals with family history of GC instead of average-risk screening. To establish more precise prevention strategies, accurate risk estimates are necessary for individuals with family history of GC. Methods: We searched PubMed, EMBASE and Cochrane for all relevant studies from their inception to May 21, 2020, for cohort and case-control studies investigating the association between family history of GC and its risk. Relative risk (RR) and 95% confidence interval (CI) were pooled from studies using random-effects or fixed effects. Results: The RR of GC was 2.08 (95% CI=1.86-2.34) in individuals with family history of GC according to twenty-nine case-control studies and 1.83 (95%CI=1.67-2.01) from six cohort studies. The increased risk was higher in individuals with sibling history of GC than those with parental history of GC (RR=3.18, 95% CI=2.12-4.79 vs. RR=1.66, 95% CI=1.46-1.89, P=0.021). For individuals with 2 or more first-degree relatives (FDRs) with GC, the RR was 2.81(95% CI=1.89-3.99). Subjects with both family history and Helicobacter pylori (H. pylori) infection confer a higher risk of GC (RR = 4.03, 95%CI=2.46-6.59). Conclusion: The RR of GC among FDRs is lower than in previous studies. However, the risk of GC is markedly increased in individuals having a sibling with GC, more than 2 FDRs with GC. Intensified screening and eradication therapy for H. pylori could be considered for these individuals.