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Long non-coding RNAs (lncRNAs) serve as vital candidates to mediate cancer risk. Here, we aimed to identify the risk single-nucleotide polymorphisms (SNPs)-induced lncRNAs and to investigate their roles in gastric cancer (GC) development. Through integrating the differential expression analysis of lncRNAs in GC tissues and expression quantitative trait loci analysis in normal stomach tissues and GC tissues, as well as genetic association analysis based on GC genome-wide association studies and an independent validation study, we identified four lncRNA-related SNPs consistently associated with GC risk, including SNHG7 [odds ratio (OR) = 1.16, 95% confidence interval (CI): 1.09–1.23], NRAV (OR = 1.11, 95% CI: 1.05–1.17), LINC01082 (OR = 1.16, 95% CI: 1.08–1.22) and FENDRR (OR = 1.16, 95% CI: 1.07–1.25). We further found that a functional SNP rs6489786 at 12q24.31 increases binding of MEOX1 or MEOX2 at a distal enhancer and results in up-regulation of NRAV. The functional assays revealed that NRAV accelerates GC cell proliferation while inhibits GC cell apoptosis. Mechanistically, NRAV decreases the expression of key subunit genes through the electron transport chain, thereby driving the glucose metabolism reprogramming from aerobic respiration to glycolysis. These findings suggest that regulating lncRNA expression is a crucial mechanism for risk-associated variants in promoting GC development. [ABSTRACT FROM AUTHOR]

Background: Effective risk prediction models are lacking for personalized endoscopic screening of gastric cancer (GC). We aimed to develop, validate, and evaluate a questionnaire-based GC risk assessment tool for risk prediction and stratification in the Chinese population. Methods: In this three-stage multicenter study, we first selected eligible variables by Cox regression models and constructed a GC risk score (GCRS) based on regression coefficients in 416,343 subjects (aged 40–75 years) from the China Kadoorie Biobank (CKB, development cohort). In the same age range, we validated the GCRS effectiveness in 13,982 subjects from another independent Changzhou cohort (validation cohort) as well as in 5348 subjects from an endoscopy screening program in Yangzhou. Finally, we categorized participants into low (bottom 20%), intermediate (20–80%), and high risk (top 20%) groups by the GCRS distribution in the development cohort. Results: The GCRS using 11 questionnaire-based variables demonstrated a Harrell's C-index of 0.754 (95% CI, 0.745–0.762) and 0.736 (95% CI, 0.710–0.761) in the two cohorts, respectively. In the validation cohort, the 10-year risk was 0.34%, 1.05%, and 4.32% for individuals with a low (≤ 13.6), intermediate (13.7~30.6), and high (≥ 30.7) GCRS, respectively. In the endoscopic screening program, the detection rate of GC varied from 0.00% in low-GCRS individuals, 0.27% with intermediate GCRS, to 2.59% with high GCRS. A proportion of 81.6% of all GC cases was identified from the high-GCRS group, which represented 28.9% of all the screened participants. Conclusions: The GCRS can be an effective risk assessment tool for tailored endoscopic screening of GC in China. Risk Evaluation for Stomach Cancer by Yourself (RESCUE), an online tool was developed to aid the use of GCRS. [ABSTRACT FROM AUTHOR]

Dietary and genetic factors are considered to be associated with UGI cancer risk. However, examinations of the effect of healthy diet on UGI cancer risk and the extent to which healthy diet modifies the impact of genetic susceptibility on UGI cancer remains limited. Associations were analyzed through Cox regression of the UK Biobank data (n = 415,589). Healthy diet, based on "healthy diet score," was determined according to fruit, vegetables, grains, fish, and meat consumption. We compared adherence to healthy diet and the risk of UGI cancer. We also constructed a UGI polygenic risk score (UGI-PRS) to assess the combined effect of genetic risk and healthy diet. For the results high adherence to healthy diet reduced 24% UGI cancer risk (HR high-quality diet: 0.76 (0.62–0.93), p = 0.009). A combined effect of high genetic risk and unhealthy diet on UGI cancer risk was observed, with HR reaching 1.60 (1.20–2.13, p = 0.001). Among participants with high genetic risk, the absolute five-year incidence risk of UGI cancer was significantly reduced, from 0.16% to 0.10%, by having a healthy diet. In summary, healthy diet decreased UGI cancer risk, and individuals with high genetic risk can attenuate UGI cancer risk by adopting a healthy diet. [ABSTRACT FROM AUTHOR]

Background: Gastrointestinal (GI) cancer risk has been associated with metabolic syndrome (MetS), a surrogate indicator for unhealthy lifestyles, and a number of genetic loci, but the combined effect of MetS and genetic variants on GI cancer risk is uncertain. Methods: We included 430,036 participants with available MetS and genotype data from UK Biobank. During the follow‐up time, 5494 incident GI cancer cases, including esophageal cancer, gastric cancer, and colorectal cancer, were identified. We created a GI polygenic risk score (GI‐PRS) for overall GI cancer derived from three site‐specific cancer PRSs. Cox proportional hazards regression was used to estimate the associations of MetS and GI‐PRS with the risk of GI cancer. Results: MetS was significantly associated with 28% increment in GI cancer risk (hazard ratio [HR]MetS vs. non‐MetS: 1.28, 95% confidence interval [CI]: 1.21–1.35, p < 0.0001), whereas a high GI‐PRS (top quintile) was associated with 2.28‐fold increase in risk (HRhigh vs. low: 2.28, 95% CI: 2.09–2.49, p < 0.0001). Compared with participants without MetS and at low genetic risk (bottom quintile of GI‐PRS), those with MetS and at high genetic risk had 2.75‐fold increase in GI cancer risk (HR: 2.75, 95% CI: 2.43–3.12, p < 0.0001). Additionally, MetS in comparison with no MetS had 1.49‰, 2.75‰, and 3.37‰ absolute risk increases in 5 years among participants at low, intermediate (quintiles 2–4 of GI‐PRS) and high genetic risk, respectively, representing the number of subjects diagnosed as MetS causing a new GI cancer case in 5 years were 669, 364, and 296, respectively. Conclusions: Metabolic and genetic factors may jointly contribute to GI cancer risk and may serve as predictors by quantitative measurements to identify high‐risk populations of GI cancer for precise prevention. [ABSTRACT FROM AUTHOR]

Background and aims: Previous studies have reported the association between limited number of Helicobacterpylori (H. pylori) antigens and gastric cancer (GC) risk. The present study evaluated the association between serum antibodies against 15 different H. pylori proteins measured by using multiplex serology assay and GC risk. Methods: We searched PubMed databases, Embase, Web of Science, and Cochrane Library for relevant articles. A meta‐analysis was used to pool studies and to estimate odds ratios (ORs) with 95% confidence intervals (95%CIs) of different H. pylori antigens associated with GC risk. Heterogeneity was investigated using Cochran's Q test and I‐squared statistic. Results: Nine studies were identified, with a total of 3209 GC cases and 6964 controls. Five H. pylori virulence factors were significantly associated with non‐cardia GC risk at p‐value <0.0033 including: CagA (OR = 3.22, 95%CI: 2.10–4.94), HP0305 (OR = 1.72, 95%CI: 1.32–2.25), HyuA (OR = 1.42, 95%CI: 1.13–1.79), Omp (OR = 1.83, 95%CI: 1.30–2.58), and VacA (OR = 2.05, 95%CI: 1.67–2.52). However, none of the 15 antigens was associated with cardia GC risk. In subgroup analysis by ethnicity, we identified 7 antigens associated with the risk of non‐cardia GC among East Asian while only two antigens were identified in European population. Nevertheless, CagA and GroEL showed a stronger association in Caucasian (CagA OR = 5.83, 95%CI: 3.31–10.26; GroEL OR = 3.66, 95%CI: 1.58–8.50) compared with East Asian (CagA OR = 2.20, 95% CI: 1.85–2.61; GroEL OR = 1.47, 95%CI: 1.29–1.68). Conclusions: This study determined that H. pylori infection increases the risk of non‐cardia GC with differential effects by its virulence factors and with different patterns among East Asian and European populations. These results advance the understanding of the effect of H. pylori on GC. [ABSTRACT FROM AUTHOR]

Purpose: Glutathione peroxidase-7 (GPX7) is a newly discovered non-selenium-containing protein with glutathione peroxidase activity, which mainly protects the organism from oxidative damage and is very important for basic biology studies. This study aims to reveal the expression pattern of GPX7 and its prognosis potential from a pan-cancer perspective. Methods: Expression levels of GPX7 in human tumor tissues and normal tissues were evaluated using Human Protein Atlas (HPA), the Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx) and UALCAN databases. The prognostic potential of GPX7 for 33 TCGA tumors was evaluated by Kaplan–Meier analysis and Cox regression analysis. Subsequently, the Chinese Glioma Genome Atlas (CGGA) dataset was used to further verify the expression of GPX7 and its prognostic potential in glioma. We explored the correlation between GPX7 and immune infiltration, tumor mutational burden (TMB) and microsatellite instability (MSI). Furthermore, a nomogram lower-grade glioma (LGG) was constructed to verify the prognostic outcome of patients. Finally, the relationship between GPX7 and treatment regimens for LGG was also explored. Results: GPX7 was overexpressed in multiple tumors. Elevated expression of GPX7 was associated with poor prognosis of LGG patients (OS hazard ratio (HR) = 1.044, P < 0.0001; DFS HR = 1.035, P < 0.0001; PFS HR = 1.045, P < 0.0001). GPX7 was proved to be an independent prognostic factor of LGG through univariate and multivariate Cox analysis. The nomogram confirmed a better predictability (Concordance index (C-index): 0.845; 95% CI, 0.825– 0.865). GPX7 was positively correlated with TMB in LGG. GPX7 expression was negatively correlated with half-maximal inhibitory concentration (IC50) of temozolomide (TMZ) (spearman= − 0.59, P =1.3e-48). Conclusion: GPX7 was upregulated in multiple tumors, and it was a potential prognostic biomarker in LGG. High-expressed GPX7 can predict the sensitivity of TMZ in LGG patients. [ABSTRACT FROM AUTHOR]

Background and Aim: Helicobacter pylori (H. pylori) infection rates have been changing with different populations and geographic areas. We systematically evaluated the longitudinal trends in H. pylori prevalence in China over the past decades. Methods: We performed a systematic review of literature reporting the prevalence of H. pylori infection in mainland China from 1990 to 2019 in the PubMed and China National Knowledge Infrastructure databases. We conducted a meta‐analysis of qualified studies using a random effects model to estimate the pooled prevalence with a 95% confidence interval (95%CI). Results: A total of 412 eligible studies with 1 377 349 subjects were included. The pooled H. pylori prevalence was 44.2% (95%CI: 43.0–45.5%) in mainland China, with an estimated 589 million individuals infected with H. pylori. The prevalence was relatively high in the Northwest (51.8%, 95%CI: 47.5–56.1%), East (47.7%, 95%CI: 45.4–50.0%), and Southwest China (46.6%, 95%CI: 42.1–51.1%). The prevalence significantly decreased from 58.3% (95%CI: 50.7–65.5%) in the period 1983–1994 to 40.0% (95%CI: 38.2–41.8%) in the period 2015–2019. The prevalence increased with age, ranging from 28.0% (95%CI: 23.9–32.5%) in children and adolescents to 46.1% (95%CI: 44.5–47.6%) in adults. Conclusion: Although the burden of H. pylori infections is still huge in China, the infection rate has been decreasing over the past decades. Targeted H. pylori eradication strategies may be considered in areas or populations with a high incidence of gastric cancer. [ABSTRACT FROM AUTHOR]

Genome‐wide association studies (GWAS) have identified multiple gastric cancer risk loci and several protein‐coding susceptibility genes. However, the role of long‐noncoding RNAs (lncRNAs) transcribed from these risk loci in gastric cancer development and progression remains to be explored. Here, we functionally characterize a lncRNA, lncPSCA, as a novel tumor suppressor whose expression is fine‐regulated by a gastric cancer risk‐associated genetic variant. The rs2978980 T > G change in an intronic enhancer of lncPSCA interrupts binding of transcription factor RORA, which down‐regulates lncPSCA expression in an allele‐specific manner. LncPSCA interacts with DDX5 and promotes DDX5 degradation through ubiquitination. Increased expression of lncPSCA results in low levels of DDX5, less RNA polymerase II (Pol II) binding with DDX5 in the nucleus, thus activating transcription of multiple p53 signaling genes by Pol II. These findings highlight the importance of functionally annotating lncRNAs in GWAS risk loci and the great potential of modulating lncRNAs as innovative cancer therapy. Synopsis: The long non‐coding RNA lncPSCA is a tumor suppressor encoded at the 8q24.3 gastric cancer risk locus. LncPSCA promotes DDX5 degradation, reduces RNA polymerase II interactions with DDX5, and activates transcription of multiple p53 signaling genes. LncRNA lncPSCA is a novel tumor suppressor at the 8q24.3 gastric cancer risk locus.The rs2978980 risk polymorphism interrupts RORA binding to a lncPSCA enhancer and down‐regulates its expression in an allele‐specific manner.LncPSCA interacts with DDX5 and promotes DDX5 degradation via ubiquitination. [ABSTRACT FROM AUTHOR]

Genome-wide association studies (GWAS) have identified several susceptibility loci for gastric cancer (GC), but the majority of identified single-nucleotide polymorphisms (SNPs) fall within the non-coding region and are likely to exert their biological function by modulating gene expression. To systematically estimate expression-associated SNPs (eSNPs) that confer genetic predisposition to GC, we evaluated the associations of 314,203 stomach tissue-specific eSNPs with GC risk in three GWAS datasets (2,631 cases and 4,373 controls). Subsequently, we conducted a gene-based analysis to calculate the cumulative effect of eSNPs through sequence kernel association combined test and Sherlock integrative analysis. At the SNP-level, we identified two novel variants (rs836545 at 7p22.1 and rs1892252 at 6p22.2) associated with GC risk. The risk allele carriers of rs836545-T and rs1892252-G exhibited higher expression levels of DAGLB (P = 3.70 × 10–18) and BTN3A2 (P = 3.20 × 10–5), respectively. Gene-based analyses identified DAGLB and FBXO43 as novel susceptibility genes for GC. DAGLB and FBXO43 were significantly overexpressed in GC tissues than in their adjacent tissues (P = 5.59 × 10–7 and P = 3.90 × 10–6, respectively), and high expression level of these two genes was associated with an unfavorable prognosis of GC patients (P = 1.30 × 10–7 and P = 7.60 × 10–3, respectively). Co-expression genes with these two novel genes in normal stomach tissues were significantly enriched in several cancer-related pathways, including P53, MAPK and TGF-beta pathways. In summary, our findings confirm the importance of eSNPs in dissecting the genetic basis of GC, and the identified eSNPs and relevant genes will provide new insight into the genetic and biological basis for the mechanism of GC development. [ABSTRACT FROM AUTHOR]

Background: The association of Helicobacter pylori (H. pylori) babA2 gene with gastric cancer (GC) was reported by several studies, but results were inconsistent. This meta-analysis was performed to investigate the relationship between H. pylori babA2 gene and GC risk.Methods: Case-control studies involving the association between H. pylori babA2 gene and GC risk were systematically identified from PubMed databases. A meta-analysis was used to pool studies and to estimate odds ratios (ORs) with 95% confidence intervals (CIs) of H. pylori babA2 gene associated with GC risk.Results: Twenty studies were identified with a total of 1289 GC cases and 1081 controls. H. pylori babA2 gene was associated with an increased risk of GC by 2.05 fold (95% CI, 1.30-3.24, P = 0.002). In subgroup analysis, we found that H. pylori babA2 gene was significantly associated with GC risk in Asian population (OR = 2.63, 95% CI: 1.36-5.09 P = 0.004) but not in South American population (OR = 1.35, 95% CI: 0.69-2.64, P = 0.379).Conclusions: This meta-analysis indicates that H. pylori babA2 gene may be associated with increased risk of GC, especially in Asian population. [ABSTRACT FROM AUTHOR]

Background: The association of ABO blood groups with gastric cancer risk was proposed decades ago, but the results have been inconsistent.Methods: We used two single nucleotide polymorphisms to determine ABO genotype in 4932 gastric cancer cases and 6158 controls of Chinese descent, and evaluated the associations of ABO blood groups and genotypes with risk of gastric cancer using multivariable logistic regression models. We also systematically reviewed published literature and performed a meta-analysis of all relevant studies.Results: In the case-control study, compared with blood group O, both blood group A and AB were associated with increased gastric cancer risk (for group A, odds ratio (OR) = 1.13, 95% confidence interval (CI): 1.02-1.24; for group AB, OR = 1.18, 95% CI: 1.02-1.36, respectively). Analyses of ABO genotypes revealed associations of AO and AB with risk of gastric cancer compared with OO genotype. Consistent with the case-control study, meta-analysis of 40 studies including 33,613 cases and 2,431,327 controls demonstrated that blood group A (OR = 1.19, 95% CI: 1.13-1.25) and AB (OR = 1.09, 95% CI: 1.03-1.16) were associated with increased risk of gastric cancer.Conclusions: Our analyses validated the association of blood group A with risk of gastric cancer, and suggested that blood group AB was also associated with gastric cancer risk. Functional investigations are warranted to elucidate the exact mechanism of ABO blood groups in gastric carcinogenesis. [ABSTRACT FROM AUTHOR]

Background: Gastric cancer (GC) is one of the high-incidence and high-mortality cancers all over the world. Though genome-wide association studies (GWASs) have found some genetic loci related to GC, they could only explain a small fraction of the potential pathogenesis for GC.Methods: We used multi-marker analysis of genomic annotation (MAGMA) to analyze pathways from four public pathway databases based on Chinese GWAS data including 2631 GC cases and 4373 controls. The differential expressions of selected genes in certain pathways were assessed on the basis of The Cancer Genome Atlas database. Immunohistochemistry was also conducted on 55 GC and paired normal tissues of Chinese patients to localize the expression of genes and further validate the differential expression.Results: We identified three pathways including chemokine signaling pathway, potassium ion import pathway, and interleukin-7 (IL7) pathway, all of which were associated with GC risk. NMI in IL7 pathway and RAC1 in chemokine signaling pathway might be two new candidate genes involved in GC pathogenesis. Additionally, NMI and RAC1 were overexpressed in GC tissues than normal tissues.Conclusion: Immune and inflammatory associated processes and potassium transporting might participate in the development of GC. Besides, NMI and RAC1 might represent two new key genes related to GC. Our findings might give new insight into the biological mechanism and immunotherapy for GC. [ABSTRACT FROM AUTHOR]