Helicobacter pylori-related host gene polymorphisms associated with susceptibility of gastric carcinogenesis: a two-stage case-control study in Chinese

Medium and large alleles of the PGC gene are risk factors for gastric cancer

BACKGROUND

A 100-bp insertion/deletion polymorphism in the pepsinogen C gene has been associated with the risk of gastric cancer (GC).

OBJECTIVE

We analyzed the relationships of the 100-bp insertion/deletion polymorphism with GC, atrophic gastritis (AG), and intestinal metaplasia (IM) in the Mexican general population (MGP).

METHODS

We studied the genomic DNA of subjects with GC n = 80, AG and IM n = 60, controls n = 110, and the MGP n = 97. PGC gene insertion/deletion polymorphism was identified by means of PCR, capillary electrophoresis and GeneScan software.

RESULTS

Different allele sizes of PGC polymorphism were observed in the studied groups, from 266 bp to 499 bp, which were grouped for the analysis as short alleles of 266-399 bp, medium alleles of 400-433 bp and large alleles of 434-499 bp. Carriers of one or two medium alleles, had an increased risk of GC, with OR of 1.99 (CI95% 1.08-3.67 p = 0.026) compared to homozygotes (no medium/no medium).

CONCLUSIONS

Previous studies have related PGC short alleles to risk for or protection against GC depending on the ethnic origin of the population. In our study, medium alleles were related to risk for GC. Further studies are required to establish the importance of this polymorphism in the origin of gastric neoplasia.

The mouse double minute 2 polymorphism is associated with both decreased p53 expression and poor clinicopathological outcomes of gastric cancer

This study aimed to determine the mouse double minute 2 (MDM2) SNP309 polymorphism and to evaluate MDM2 and p53 expression and the association of MDM2 positivity in gastric cancer and clinicopathological outcomes. A total of 400 patients with chronic gastritis, precancerous lesions, and gastric cancer were used to identify the MDM2 SNP309 polymorphism by using the Taq Man SNP Genotyping assay. Immunohistochemistry was performed to evaluate MDM2 and p53 expression. The associations of polymorphisms, protein expression, clinicopathological outcomes, and gastric cancer risk were calculated by multivariate Cox proportional hazards regression model analysis and expressed by odds ratios (ORs) and 95% confidence intervals (CIs). The MDM2 SNP309 G/G homozygous polymorphism was significantly associated with expressed MDM2 in gastric cancer (OR = 1.57, 95% CI = 1.39-2.03, P = 0.039). Moreover, in gastric cancer, p53 was significantly decreased compared to MDM2 (P = 0.007). However, MDM2 and p53 expression were not significantly different among genotypes, and the G/G genotype can result in the altered protein expression of p53 in gastric cancer. Clinicopathological outcome was significantly associated with MDM2 expression, including tumor location in the upper gastric region (OR = 1.48, 95% CI = 1.25-3.54, P = 0.037), undifferentiated type (OR = 2.47, 95% CI = 1.38-4.14, P = 0.016), presence of lymphatic invasion (OR = 1.96, 95% CI = 1.22-3.19, P = 0.014), and unresectable tumor (OR = 3.39, 95% CI = 1.61-4.94, P = 0.017). Our study indicated associations of the MDM2 SNP309 G/G homozygous polymorphism, MDM2 and p53 expression. Therefore, G/G-associated MDM2 revealed that P53 expression was decreased in gastric cancer and poor clinicopathological outcomes. Understanding the genetic polymorphisms and expression of MDM2 may help explain gastric cancer risk.

Single nucleotide polymorphisms of whole genes and atrophic gastritis susceptibility:a systematic review and meta-analysis

BACKGROUND

Atrophic gastritis (AG) is one of the important precancerous lesions of gastric cancer. Single nucleotide polymorphisms (SNPs) are closely related to AG susceptibility. However, the research conclusions on the predictive potential of SNPs are inconsistent. The study aims to retrospect the association between SNPs of whole genes and AG risk by meta-analysis.

MATERIALS AND METHODS

Up to April 29, 2020, a systematic literature search for the relationship of SNPs with AG susceptibility was performed utilizing PubMed, Web of Science and Chinese National Knowledge Infrastructure. The overall and stratified meta-analyses on extracted data were conducted by Stata11.2.

RESULTS

33 case-control studies were enrolled containing 9951 AG patients and 17,252 healthy controls, and 17 SNPs in 12 different genes were systematically reviewed. The results indicated that 12 genes could be categorized based on their functions, including immune response, cell proliferation and apoptosis, and DNA damage repair. For the SNPs in immune response-related genes, the C allele of TLR1 rs4833095 T/C increased AG risk to 1.21-fold and the recessive model of TLR4 rs11536878 in the TLR gene family decreased AG susceptibility to 0.48-fold. The variant alleles of IL-10 rs1800871 (OR = 1.21) and IL-8 rs4073 (OR = 1.22) in the IL gene family were positively associated with AG risk. PSCA rs2294008 enhanced AG risk in all genetic models. SNPs associated with AG susceptibility were mainly focused on immune response-related genes.

CONCLUSION

These SNPs related to immune response could influence on AG risk and have potential to be AG predictive biomarkers. It is worth noting that the number of studies for each SNPs were insufficient due to the limited published researches and updated meta-analysis needs to be performed based on extensive relevant studies for more reliable results.

TLR4 rs1927914 polymorphism contributes to serum TLR4 levels in patients with aortic aneurysm

Toll-like receptor 4 (TLR4) is a crucial regulator of inflammatory reactions and vascular remodeling. Elevated TLR4 expression has been proved to be correlated with an increased risk of aortic aneurysm (AA). This study aimed to explore the influence of TLR4 gene polymorphisms on TLR4 expression levels and its probable functional significance in AA disease. A total of 294 AA patients and 285 controls were enrolled in the study and serum TLR4 levels were detected by ELISA. All the participants were genotyped for two tag-SNPs in TLR4 (rs1927914 in the promoter region and rs11536889 in the 3'-untranslated region) using the KASP method. Relative luciferase activity was measured by the dual-luciferase reporter assay system. The rs1927914 TC, TC/CC genotypes and C allele showed associations with increased serum TLR4 levels in the total population and AA patients (all P<0.05). Further stratified analysis demonstrated that AA subjects with TC or TC/CC genotype of rs1927914 had significantly higher serum levels of TLR4 than those with TT genotype in male, age>60y, hypertension, diabetes, TAA type and size>5.0 cm subgroups (all P<0.05). In binary logistic analysis, rs1927914 TC genotype and dominant model presented significant associations with high TLR4 levels (OR = 1.579 and 1.431, P = 0.020 and 0.049, respectively) after adjusting age, hypertension and diabetes. However, rs11536889 polymorphism had no significant influence on serum TLR4 levels. Regarding rs1927914, luciferase activity of the C allele construct was significantly increased in comparison with the T allele construct (0.589 ± 0.004 vs. 0.340 ± 0.014, P<0.001). Our results provided evidence that rs1927914 polymorphism contributed to serum TLR4 levels, possibly by influencing promoter activity of TLR4, and could be a novel genetic factor in the formation of AA.

Associations between lncRNA-related polymorphisms and hepatocellular carcinoma risk: A two-stage case-control study

BACKGROUND AND AIM

Single-nucleotide polymorphisms (SNPs) in long non-coding RNAs (lncRNAs) are potential biomarkers for cancer risk, but their association with hepatocellular carcinoma (HCC) is unclear. We examined the association of lncRNA-related SNPs with HCC susceptibility and explored the optimal genetic models for SNPs.

METHODS

Five candidate SNPs linked with digestive tumors were first genotyped in a screening population of 700 HCC and 2800 control cases. The association between each SNP and HCC risk was estimated by multivariate logistic regression adjusted by sex and age and recorded as odds ratio (OR) with 95% confidence interval. Significant associations were further tested in a validation population with 1140 HCC and 5115 control cases. Finally, the most appropriate genetic models for HCC-associated SNPs were identified using pairwise allele differences; the overall gene effects of each SNP were further evaluated based on optimal genetic models.

RESULTS

Three candidate SNPs, rs7315438, rs6983267, and rs10795668, showed statistical connections with HCC risk in the discovery stage. Among these, rs7315438 remained steadily significant in the validation stage; rs7315438 and rs10795668 both reached statistical threshold in the combined analysis of both stages. SNP rs7315438 (TC vs TT/CC, OR = 1.410, P < 0.001) was associated with increased risk of HCC in a complete overdominant model, whereas rs10795668 (AG vs AA/GG, OR = 0.892, P = 0.035) exerted a protective effect on HCC risk in a complete overdominant model.

CONCLUSIONS

Long non-coding RNA-related SNPs rs7315438 and rs10795668 are potential biomarkers for HCC susceptibility, especially when evaluated based on their optimal genetic models.

Association of Toll-Like Receptor 4 Gene Polymorphisms with Acute Aortic Dissection in a Chinese Han Population

Background

Inflammation may be involved in the pathogenesis of acute aortic dissection (AAD). Toll-like receptor 4 (TLR4) is known to play a critical role in regulating the immune and inflammatory processes. To date, the relationship between genetic variation of TLR4 and AAD is far from clear. The purpose of our study was to illustrate the relevance of TLR4 polymorphisms with the susceptibility to AAD.

Methods

A total of 222 AAD patients and 222 controls were enrolled in this study. Frequency distributions of TLR4 polymorphisms (rs10759932 in the promoter and rs11536889 in the 3′-untranslated region) were determined by the KASP method. Clinical parameters were acquired from subjects' medical records, and serum TLR4 levels were collected from our previously published data.

Results

We found that rs10759932 polymorphism was associated with a reduced risk of AAD in the overall population (CC vs. TT: OR = 0.393, 95%CI = 0.164‐0.939, P = 0.036; recessive model: OR = 0.439, 95%CI = 0.196‐0.984, P = 0.045) and subgroup analyses stratified by sex. The GC genotype and dominant model of rs11536889 conferred a significantly higher risk of AAD compared with GG genotype in female subjects (GC vs. GG: OR = 3.382, 95%CI = 1.051‐10.885, P = 0.041; dominant model: OR = 3.043, 95%CI = 1.041‐8.900, P = 0.042). In addition, a significant interaction between the rs11536889 recessive model and dyslipidemia was observed for an increased risk of AAD (P_interaction = 0.038, OR = 15.229) after the adjustment for potential clinical covariates. We also used the false-positive report probability (FPRP) analysis to validate the significant results. Furthermore, rs11536889 polymorphism could affect the maximal aortic diameters of AAD (P = 0.037), while AAD patients carrying CC genotype of rs10759932 showed lower serum TLR4 levels than TT genotype carriers (P = 0.043).

Conclusions

Our findings provide evidence for the association between TLR4 polymorphisms and AAD susceptibility in a Chinese Han population, which may have some implications for understanding the role of TLR4 in the pathophysiology of AAD.

Polymorphisms in matricellular SPP1 and SPARC contribute to susceptibility to papillary thyroid cancer

There is a compelling need to identify novel genetic variants for papillary thyroid cancer (PTC) susceptibility. The Cancer Genome Atlas (TCGA) data showed associations between SPP1 and SPARC mRNA overexpression and aggressive behaviors of PTC, which prompted us to assess potential associations between genetic variants in these genes and PTC risk. Three highly linked SPARC loci (rs1054204, rs3210714, and rs3549) contributed to reduced PTC risk under a codominant model (odds ratio [OR], 0.79-0.80). Variant CAG alleles at these loci significantly enhanced SPARC transcription activation upon cotransfection with miR-29b and miR-495 when compared to the common alleles GGC (all P < 0.05). The three SPARC polymorphisms interacted with SPP1 rs4754, with elevated joint ORs of 2.43, 2.52, and 2.52, respectively. Additionally, interaction between SPP1 rs2358744 and SPARC rs2304052 was observed. Our study revealed associations between SPP1 and SPARC polymorphisms that, individually or in combination, are involved in PTC susceptibility.

TSHR rs2288496 associated with thyroid hormone and predict the occurrence of lymph node metastasis of papillary thyroid cancer

This study aimed to evaluate the association of potential functional tagging single nucleotide polymorphisms (tagSNPs) in BRAF and TSHR with papillary thyroid cancer (PTC). Two tagSNPs (rs6464149 and rs7810757) in BRAF and six tagSNPs (rs17630128, rs2075179, rs7144481, rs2371462, rs2268477, and rs2288496) in TSHR were genotyped in 300 cases of PTC and 252 healthy controls. There was no difference in the genotype frequencies of BRAF and TSHR between PTC patients and control subjects, suggesting no contribution of BRAF or TSHR polymorphisms to the susceptibility to PTC. We observed that a tagSNP located in the 3' untranslated region of TSHR, rs2288496, could affect the incidence of lymph node metastasis (LNM). The variant TC and TC + CC genotypes conferred an increased risk of LNM (for TC vs. TT: odds ratio (OR) = 2.01, 95% confidence interval (CI): 1.07-3.77; P= 0.030; for TC + CC vs. TT: OR = 1.87, 95% CI: 1.04-3.39, P= 0.038). Moreover, subjects carrying variant genotypes had higher TSH levels and lower thyroxine (T4) and Anti-TG levels compared with those in subjects carrying common genotypes. Our findings showed that PTC patients carrying the TSHR rs2288496 TC and CC variants were associated with higher TSH level and lower T4 and Anti-TG levels and were prone to developing LNM. To confirm these results, additional studies and functional experiments, especially in other ethnic populations, are needed.

PTPN11 hypomethylation is associated with gastric cancer progression

Protein tyrosine phosphatase non-receptor type 11 (PTPN11) encodes the tyrosine phosphatase SHP-2 that is overexpressed in gastric cancer (GC). In the present study, the association of PTPN11 methylation levels with the incidence of GC and its correlation with SHP-2 overexpression were investigated. The methylation levels of PTPN11 in tumor and adjacent normal tissues of 112 GC patients were assessed by quantitative methylation specific PCR (qMSP). The Cancer Genome Atlas (TCGA) public database was used to analyze the association between PTPN11 methylation and PTPN11 expression. Survival analyses were conducted in order to evaluate the prognostic value of PTPN11 methylation for GC. The results of the qMSP analysis indicated that the methylation levels of PTPN11 in GC tumor tissues were significantly decreased compared with those noted in the normal adjacent tissues (mean with standard deviation: 40.91±26.33 vs. 51.99±37.37, P=0.007). An inverse correlation between PTPN11 methylation levels and PTPN11 mRNA expression levels (P=4×10^-6, r=-0.237) was noted. Subgroup analyses indicated that the association of PTPN11 hypomethylation with the incidence of GC was specific to male subjects (P=0.015), heavy drinking patients (P=0.019), patients with poor tumor differentiation (P=0.010) and patients with tumor node and metastasis (TNM) stage III+IV (P=0.008). Kaplan-Meier analyses and log-rank test suggested that PTPN11 hypomethylation was not associated with GC patient overall survival (P=0.605) and recurrence (P=0.485), although it could predict the recurrence of GC patients up to and including 60 years (≤60, P=0.049). The results indicated that PTPN11 levels were hypomethylated in GC patients. TCGA data analysis suggested that PTPN11 hypomethylation could cause an upregulation in the transcription levels of PTPN11. Although, this may explain the pattern of SHP-2 overexpression in GC, additional studies are required to verify this hypothesis. The association of PTPN11 hypomethylation with GC incidence may be specific to male patients, heavy drinking patients, patients with poor tumor differentiation and patients with TNM stage of III+IV. PTPN11 hypomethylation can be considered a biomarker for the recurrence of GC patients with an age of 60 years or lower.

The interaction effects between TLR4 and MMP9 gene polymorphisms contribute to aortic aneurysm risk in a Chinese Han population

Background

A cross-talk between Toll-like receptor 4 (TLR4) and matrix metalloproteinase 9 (MMP9) plays a vital role in aortic pathophysiology. The objective of this study was to evaluate the interactions between TLR4 and MMP9 polymorphisms in the risk of aortic aneurysm (AA) and its subtypes.

Methods

KASP method was used to detect polymorphisms of TLR4 (rs11536889 and rs1927914) and MMP9 (rs17576) in 472 AA patients and 498 controls. According to location and size, AA patients were further classified into abdominal AA (AAA), thoracic AA (TAA), and large AA (>5.0 cm), small AA(≤5.0 cm), respectively.

Results

The significant interaction effect of TLR4rs1927914 with MMP9rs17576 polymorphisms was observed for the risk of TAA (P_interaction = 0.038, OR = 6.186) and large AA (P_interaction = 0.044, OR = 5.892). There were epistatic effects between TLR4rs1927914 and MMP9rs17576 polymorphisms on the risk of overall AA, AAA, TAA and large AA when they were present together. Moreover, the cumulative effects of the pairwise interaction TLR4rs1927914-MMP9rs17576 were associated with an increased risk of overall AA (P_trend = 0.032) and AAA (P_trend = 0.031).

Conclusions

The novel interaction between TLR4rs1927914 and MMP9rs17576 polymorphisms could increase the risk of AA disease or its subtypes by exerting epistatic and cumulative effects.

Electronic supplementary material

The online version of this article (10.1186/s12872-019-1049-8) contains supplementary material, which is available to authorized users.

TLR4 and MMP2 polymorphisms and their associations with cardiovascular risk factors in susceptibility to aortic aneurysmal diseases

Background: Toll-like receptor 4 (TLR4) and matrix metalloproteinase 2 (MMP2) play important roles in aortic pathophysiology. We aimed to evaluate the contribution of TLR4 and MMP2 polymorphisms individually and complex interactions between gene and risk factors in susceptibility to aortic aneurysm (AA) and its subtypes. Methods: KASP method was adopted to detect TLR4rs11536889, rs1927914 and MMP2rs2285053 polymorphisms in 498 controls and 472 AA patients, including 212 abdominal AA (AAA) and 216 thoracic AA (TAA). Results: In the overall analysis, MMP2rs2285053 TC genotype was correlated with TAA risk (P = 0.047, OR = 1.487). Stratified analysis revealed an increased AA risk in males with TLR4rs1927914 TC genotype, while MMP2rs2285053 TC conferred an elevated AA risk in the subjects ≤60 years, and its TC genotype and dominant model were associated with TAA in the subjects ≤60 year. The interaction between TLR4rs1927914 and MMP2rs2285053 was associated with AAA risk (P _interaction = 0.028, OR = 2.913). Furthermore, significant interaction between TLR4rs11536889 and dyslipidemia was observed for TAA risk, while TLR4rs1927914 could interact with hypertension and diabetes to increase the risk of AA or its subtypes. Two-way interaction effect of TLR4rs1927914 and MMP2rs2285053 was enhanced by diabetes or dyslipidemia. Conclusion: TLR4 and MMP2 polymorphisms and their complex interactions with cardiovascular risk factors contributed to aortic aneurysmal diseases.

SNP interactions of PGC with its neighbor lncRNAs enhance the susceptibility to gastric cancer/atrophic gastritis and influence the expression of involved molecules

Multidimensional interactions of multiple factors are more important in promoting cancer initiation. Gene-gene interactions between protein-coding genes have been paid great attention, while rare studies refer to the interactions between encoding and noncoding genes. Our research group previously found encoding gene PGC polymorphisms could affect the susceptibility to atrophic gastritis (AG) and gastric cancer (GC). Interestingly, several SNPs in long noncoding RNA (lncRNA) genes, just adjacent to PGC, were found to be associated with AG risk and GC prognosis afterward. This study aims to explore the SNP interactions between PGC and its neighbor lncRNAs on the risk of AG and GC. Genotyping for seven PGC SNPs and seven lncRNA SNPs was conducted using Sequenom MassARRAY platform in a total of 2228 northern Chinese subjects, including 536 GC cases, 810 AG cases, and 882 controls. We found 15 pairwise PGC-lncRNAs SNPs had interactions: Five pairs were associated with AG risk, and ten pairs were associated with GC risk. Moreover, two GC-related interactions PGC rs6939861 with lnc-C6orf-132-1 rs7749023 and rs7747696 survived the Bonferroni correction (P_correction  = 0.049 and 0.007, respectively). Several combinations showed obvious epistasis and cumulative effects on disease risk. Some three-way interactions of SNPs with smoking and drinking could also be observed. Besides, a few interacting SNPs showed correlations with the expression levels of PGC protein and related lncRNAs in serum. Our study would provide research clues for further screening combination biomarkers uniting both protein-coding and noncoding genes with the potential in prediction of the susceptibility to GC and its precursor.

Association of IL10 gene promoter polymorphisms with risks of gastric cancer and atrophic gastritis

OBJECTIVE

To investigate the association between polymorphisms of the interleukin 10 ( IL10) gene and risk of gastric cancer (GC) and atrophic gastritis (AG).

METHODS

This study enrolled patients with GC, patients with AG and healthy control subjects. Demographic data were collected and the IL10 gene -1082A/G, -819C/T and -592A/C polymorphisms were genotyped. An enzyme-linked immunosorbent assay was performed to detect Helicobacter pylori infection.

RESULTS

The study enrolled 556 participants including 208 in the GC group, 116 in the AG group and 232 controls (CON group). In a recessive model of the IL10-819C/T polymorphism, a significantly decreased risk of GC was found compared with AG and non-cancer subjects, respectively (AG→GC: odds ratio OR 0.41; non-cancer→GC: OR 0.57). The CC genotype demonstrated a significantly increased risk of AG compared with CON. Similar significant results were detected in males and H. pylori-negative subgroups. The ACC haplotype was associated with a decreased risk of GC compared with AG. The ATC haplotype was associated with a decreased risk of AG compared with the CON group, but it was associated with an increased risk of GC compared with AG.

CONCLUSION

The IL10 gene promoter -819C/T (rs1800871) polymorphism was associated with the risk of GC and AG in a Chinese population.

MUC1 and MUC5AC Acting on Helicobacter pylori-Related Deficiency and Solid Syndrome of Spleen and Stomach

To investigate the relationship of MUC1, MUC5AC, and the syndrome of spleen and stomach, 109 subjects (34 peptic ulcer (PU), 62 chronic gastritis (CG), and 13 healthy volunteers (CON)) were included. All the subjects included were surveyed with questionnaire to classify them into damp-heat syndrome of spleen and stomach (DHSS), spleen-qi deficiency syndrome (SQD), and CON, examined by gastric endoscope, and biopsied. Rapid urease and methylene blue staining (MBS) were performed on every subject to diagnose for Helicobacter pylori (Hp) infection, and both were defined as Hp-positive. Hematoxylin and eosin (HE) staining was performed on every specimen to explore the histomorphology, inflammatory degree, and inflammatory activity of different groups; then Elivision™ plus kit was used to test the expression of MUC1 and MUC5AC. All the results of digital images were reviewed by two experts blindly. The inflammatory degree with Hp infection was higher than those uninfected or CON, but no significant difference was found between DHSS and SQD. And the expressions of MUC5AC with positive Hp was higher than those with negative Hp or CON regardless of the deficiency and solid syndrome of spleen-stomach but not for MUC1. We speculate that the deficiency and solid syndrome of spleen-stomach is a condition like Tai Ji symbol of dynamic equilibrium, showing the higher expression of MUC5AC but no change of MUC1 in the circumstance of Hp infection.

SNP-SNP interactions of three new pri-miRNAs with the target gene PGC and multidimensional analysis of H. pylori in the gastric cancer/atrophic gastritis risk in a Chinese population

Gastric cancer (GC) is a multistep complex disease involving multiple genes, and gene–gene interactions have a greater effect than a single gene in determining cancer susceptibility. This study aimed to explore the interaction of the let-7e rs8111742, miR-365b rs121224, and miR-4795 rs1002765 single nucleotide polymorphisms (SNPs) with SNPs of the predicted target gene PGC and Helicobacter pylori status in GC and atrophic gastritis (AG) risk. Three miRNA SNPs and seven PGC SNPs were detected in 2448 cases using the Sequenom MassArray platform. Two pairwise combinations of miRNA and PGC SNPs were associated with increased AG risk (let-7e rs8111742 – PGC rs6458238 and miR-4795 rs1002765 – PGC rs9471643). Singly, miR-365b rs121224 and PGC rs6912200 had no effect individually but in combination they demonstrated an epistatic interaction associated with AG risk. Similarly, let-7e rs8111742 and miR-4795 rs1002765 SNPs interacted with H. pylori infection to increase GC risk (rs8111742: P_interaction = 0.024; rs1002765: P_interaction = 0.031, respectively). A three-dimensional interaction analysis found miR-4795 rs1002765, PGC rs9471643, and H. pylori infection positively interacted to increase AG risk (P_{interaction =} 0.027). Also, let-7e rs8111742, PGC rs6458238, and H. pylori infection positively interacted to increase GC risk (P_{interaction =} 0.036). Furthermore, both of these three-dimensional interactions had a dosage–effect correspondence (P_trend < 0.001) and were verified by MDR. In conclusion, the miRNAs SNPs (let-7e rs8111742 and miR-4795 rs1002765) might have more superior efficiency when combined with PGC SNPs and/or H. pylori for GC or AG risk than a single SNP on its own.

Promoter methylation of RNF180 is associated with H.pylori infection and serves as a marker for gastric cancer and atrophic gastritis

Promoter methylation (PM) of RING-finger protein (RNF) 180 affects gastric cancer (GC) prognosis, but its association with risk of GC or atrophic gastritis (AG) is unclear. We investigated relationships between RNF180 PM and GC or AG, and the effects of Helicobactor pylori (H.pylori) infection on RNF180 PM. This study included 513 subjects (159 with GC, 186 with AG, and 168 healthy controls [CON]) for RNF180 PM analysis, and another 55 GC patients for RNF180 gene expression analysis. Methylation was quantified using average methylation rates (AMR), methylated CpG site counts (MSC) and hypermethylated CpG site counts (HSC). RNF180 promoter AMR and MSC increased with disease severity. Optimal cut-offs were GC + AG: AMR > 0.153, MSC > 4 or HSC > 1; GC: AMR > 0.316, MSC > 15 and HSC > 6. Hypermethylation at 5 CpG sites differed significantly between GC/AG and CON groups, and was more common in GC patients than AG and CON groups for 2 other CpG sites. The expression of RNF180 mRNA levels in tumor were significantly lower than those in non-tumor, with the same as in hypermethylation than hypomethylation group. H.pylori infection increased methylation in normal tissue or mild gastritis, and increased hypermethylation risk at 3 CpG sites in AG. In conclusion, higher AMR, MSC and HSC levels could identify AG + GC or GC. Some RNF180 promoter CpG sites could identify precancerous or early-stage GC. H.pylori affects RNF180 PM in normal tissue or mild gastritis, and increases hypermethylation in 3 CpG sites in AG.

Associations between RET tagSNPs and their haplotypes and susceptibility, clinical severity, and thyroid function in patients with differentiated thyroid cancer

BACKGROUND

It is unclear whether common genetic variants of the RET proto-oncogene contribute to disease susceptibility, clinical severity, and thyroid function in differentiated thyroid cancer (DTC).

METHODS

A total of 300 DTC patients and 252 healthy controls were enrolled in this study. Seven RET tagging single nucleotide polymorphisms were genotyped using the KASPar platform.

RESULTS

Subgroup analysis showed that concomitant thyroid benign diseases were less likely to occur in DTC subjects with the rs1799939 AG or AG plus AA genotypes (odds ratio (OR) = 1.93 and 1.88, P = 0.009 and 0.011, respectively). A rare haplotype, CGGATAA, was associated statistically with a reduced risk of DTC (OR = 0.18, P = 0.001). Concerning the aggressive features of DTC, higher level of N stage was more likely to occur in subjects carrying the wild-type genotypes at rs1800860 site (for dominant model: OR = 0.48, P = 0.008). Another rare haplotype, CAAGCGT, conferred increased risk for the occurrence of distant metastasis (OR = 7.57, P = 0.009). Notably, higher thyroid stimulating hormone levels and lower parathyroid hormone levels were found in patients with rs2075912, rs2565200, and rs2742240 heterozygotes and rare homozygotes; similar results were observed between PTH levels and rs1800858.

CONCLUSION

This study provided useful information on RET variants that should be subjected to further study.

Single nucleotide polymorphisms and cancer susceptibility

A large number of genes associated with various cancer types contain single nucleotide polymorphisms (SNPs). SNPs are located in gene promoters, exons, introns as well as 5'- and 3'- untranslated regions (UTRs) and affect gene expression by different mechanisms. These mechanisms depend on the role of the genetic elements in which the individual SNPs are located. Moreover, alterations in epigenetic regulation due to gene polymorphisms add to the complexity underlying cancer susceptibility related to SNPs. In this systematic review, we discuss the various genetic and epigenetic mechanisms involved in determining cancer susceptibility related to various SNPs located in different genetic elements. We also discuss the diagnostic potential of these SNPs and the focus for future studies.

Comprehensive assessment of association between TLR4 gene polymorphisms and cancer risk: a systematic meta-analysis

Previous studies have explored the association between toll-like receptor 4 (TLR4) polymorphisms and risk of various cancers, but the results remained controversial. To obtain an assessment of the effect of TLR4 polymorphisms (rs4986790, rs4986791 and rs11536889) on cancer risk, fifty-five articles (containing 20107 cases and 28244 controls) were recruited for meta-analysis. Our result indicated that two Single Nucleotide Polymorphisms (SNP) in TLR4 were associated with decreased cancer risk for rs4986791: OR = 0.764, 95% CI: 0.652-0.894, P = 0.001 in allele model; OR = 0.769, 95%CI: 0.650-0.909, P = 0.002 in recessive model; OR = 0.505, 95% CI: 0.352-0.726, P = 0.000 in dominant model; for 11536889: OR = 0.927, 95% CI: 0.872–0.984, P = 0.013 in allele model; OR = 0.926, 95% CI: 0.862–0.944,P = 0.034 in recessive model. In terms of subgroup analyses sorted by ethnicity, only polymorphism of rs4986791 had a significant influence on decrease of cancer risk among both Caucasian and Asian populations. The findings suggested that TLR4 polymorphisms may serve as a genetic risk factor for cancers.

SPP1 rs4754 and its epistatic interactions with SPARC polymorphisms in gastric cancer susceptibility

The matricellular glycoprotein products of the SPP1 and SPARC genes play critical roles in many aggressive tumor phenotypes including gastric cancer. We sought to test whether the polymorphisms of these two genes, individually or jointly, influence gastric cancer susceptibility. Nine potentially functional, tagging single nucleotide polymorphisms (tagSNPs) of SPP1 and SPARC were selected and detected using the Kompetitive Allele Specific PCR method in 301 gastric cancer cases and 1441 healthy control subjects. We found that the genotype frequencies of SPP1 rs4754 in gastric cancer were significantly different from those in controls. The rs4754 TT genotype conferred an increased risk of gastric cancer, with unadjusted and adjusted ORs ranging from 1.75 to 1.95 (all P<0.05). The assessment of the effect modifications of sex and age on the genetic effects also confirmed the statistically significant association of the rs4754 TT genotype with increased gastric cancer risk. Epistatic interactions were found between SPP1 rs4754 and SPARC rs1054204, rs3210714 and rs3549 (all P values for interaction<0.05). During the assessment of the epistatic effects between pairs of interacting factors, increased gastric cancer risk was observed in the combined presence of the SPP1 rs4754 TT genotype and the common genotypes of interacting SPARC SNPs, with ORs ranging from 3.94 to 4.41. When the genetic influence of SPP1 rs4754 TT was excluded, the genetic effects of the SPARC rs1054204, rs3210714 and rs3549 common genotypes on gastric cancer susceptibility switched from being risky to beneficial. These data reveal an association between the SPP1 rs4754 polymorphism and altered risk of gastric cancer and highlight an important role of the epistatic effects of SPP rs4754 with SPARC polymorphisms in gastric carcinogenesis. Additional functional experiments and independent large-scale studies, especially in other ethnic populations, are needed to confirm our results.

MUC1 rs4072037 polymorphism is associated with decreased risk of gastric cancer: a meta-analysis

BACKGROUND

Several studies have recently investigated the association between mucin 1 (MUC1) rs4072037 polymorphism and gastric cancer (GC) risk, but with conflicting results. The aim of this meta-analysis was to evaluate the association between MUC1 rs4072037 polymorphism and GC risk.

METHODS

A comprehensive database search of PubMed, Elsevier, Embase and China National Knowledge Infrastructure (CNKI) databases was performed to identify relevant studies. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of any association.

RESULTS

A total of 12 papers containing 18 studies were included in this meta-analysis, involving 12,373 cases and 15,008 controls. Our data suggested that rs4072037 polymorphism was associated with a decreased risk of GC. Stratification analyses of ethnicity indicated that rs4072037 decreased the risk of GC among white populations, but no significant relationship was observed among Asian populations. No significant associations were observed in subgroups of Lauren classification (intestinal or diffuse) and anatomical classification (cardia or non-cardia).

CONCLUSIONS

In conclusion, this meta-analysis suggested that rs4245739 polymorphism in the MUC1 gene may play a pivotal role in the pathogenesis of GC, especially for white populations.

A global burden of gastric cancer: the major impact of China

Gastric cancer (GC) is a highly aggressive cancer and a major cause of cancer-related deaths worldwide. Approximately half of the world's GC cases and deaths occur in china. GC presents challenges in early diagnosis and effective therapy due to a lack of understanding of the underlying molecular biology. The primary goals of this review are to outline current GC research in china and describe future trends in this field. Areas covered: This review mainly focuses on a series of GC-related advances China has achieved. Considerable progress has been made in understanding the role of H. pylori in GC by a series of population-based studies in well-established high-risk areas; A few germline and somatic alterations have been identified by 'omics' studies; Studies on the mechanisms of malignant phenotypes have helped us to form an in-depth understanding of GC and advance drug discovery. Moreover, identification of potential biomarkers and targeted therapies have facilitated the diagnosis and treatment of GC. However, many challenges remain. Expert commentary: To combat GC, sufficient funding is important. More attention should be paid on early diagnosis and the discovery of novel efficient biomarkers and the development of biomarker-based or targeted therapeutics in GC.

Pepsinogen C expression, regulation and its relationship with cancer

Pepsinogen C (PGC) belongs to the aspartic protease family and is secreted by gastric chief cells. PGC could be activated to pepsin C and digests polypeptides and amino acids, but as a zymogen PGC’s functions is unclear. In normal physiological conditions, PGC is initially detected in the late embryonic stage and is mainly expressed in gastric mucosa. The in situ expression of PGC in gastric mucosa is decreased considerably in the process of superficial gastritis → atrophic gastritis → gastric cancer (GC), proving that PGC is a comparatively ideal negative marker of GC. Serum PGC, and PGA levels and the PGA/PGC ratio have satisfactory sensitivity, specificity and price–quality ratio for predicting high GC risk. Ectopic PGC expression is significantly increased in prostate cancer, breast cancer, ovary cancer and endometrial cancer. In those sex-related cancers high level PGC expression indicates better prognosis and longer survival. The regulation of PGC expression involves genetic and epigenetic alteration of the encoding PGC gene, hormones modulation and interactions between PGC with other transcription factors and protein kinases. More and more research evidence hinted that PGC has strong correlation with cancer. In the systematic review, we respectively elaborate the structure, potential physiological functions, expression characteristics and regulation of PGC, and especially focus on the relationship between PGC expression and cancer to highlight the role of PGC in the tumorigenesis and its application value in clinical practice.

Promoter Polymorphism of Toll-Like Receptor 4 is Associated with a Decreased Risk of Coronary Artery Disease: A Case-Control Study in the Chinese Han Population

Background

Coronary artery disease (CAD) is considered a chronic inflammatory disease of the blood vessels. Toll-like receptor 4 (TLR4) is a transmembrane receptor involved in inflammatory reactions. The aim of this study was to determine the association between polymorphisms in the promoter region and 3′-untranslated region (3′-UTR) of TLR4, and the associated CAD risk.

Material/Methods

This study enrolled 424 participants with CAD and 424 controls without CAD. The polymorphisms in the promoter region and 3′-UTR of TLR4 were identified from the HapMap database, including rs10116253, rs10983755, and rs11536889. Genomic DNA was extracted from peripheral blood. Polymerase chain reaction-restriction fragment length polymorphism was performed to identify genotype polymorphisms. Relative luciferase activity was measured using the dual-luciferase reporter assay system.

Results

TLR4 rs10116253 in the promoter region was associated with CAD risk. The variant (CC+TC) genotypes of rs10116253 were associated with a decreased CAD risk (OR 95% CI 0.73 (0.54–0.98), p=0.034). In the stratification analyses, the variant (CC+TC) genotypes of rs10116253 were observed to have a relationship with decreased CAD risk in the male subgroup (OR: 95% CI 0.68 (0.48–0.98), p=0.041). Moreover, the variant CC and (CC+TC) genotypes of rs10116253 were correlated with a decreased CAD risk in participants younger than 60-year-old (TC: OR (95% CI 0.62 (0.39–0.98), p=0.042; TC+CC: OR 95% CI 0.63 (0.41–0.98), p=0.039). Regarding rs10116253, the luciferase activity of the mutant C allele construct was lower than that of the wild T allele construct (5.215±0.009 vs. 5.304±0.041; p=0.087).

Conclusions

The results provided evidence of an association between the TLR4 rs10116253 in the promoter region and a reduced risk of CAD.

Association of nucleotide excision repair pathway gene polymorphisms with gastric cancer and atrophic gastritis risks

Polymorphisms of NER genes could change NER ability, thereby altering individual susceptibility to GC. We systematically analyzed 39 SNPs of 8 key genes of NER pathway in 2686 subjects including 898 gastric cancer (GC), 851 atrophic gastritis (AG) and 937 controls (CON) in northern Chinese. SNP genotyping were performed using Sequenom MassARRAY platform. The results demonstrated that DDB2 rs830083 GG genotype was significantly associated with increased GC risk compared with wildtype CC (OR=2.32, P = 6.62 × 10⁻⁹); XPC rs2607775 CG genotype conferred a 1.73 increased odds of GC risk than non-cancer subjects compared with wild-type CC (OR=1.73, P= 3.04 × 10⁻⁴). The combined detection of these two polymorphisms demonstrated even higher GC risk (OR=3.05). Haplotype analysis suggested that DDB2 rs2029298-rs326222-rs3781619-rs830083 GTAG haplotype was significantly associated with disease risk in each step of CON→AG→GC development (AG vs. CON: OR=2.88, P= 7.51 × 10⁻⁷; GC vs. AG: OR=2.90, P=5.68 × 10⁻¹⁵; GC vs. CON: OR=8.42, P=2.22 × 10⁻¹⁵); DDB2 GTAC haplotype was associated with reduced risk of GC compared with CON (OR=0.63, P= 8.31 × 10⁻¹²). XPC rs1870134-rs2228000- rs2228001-rs2470352-rs2607775 GCAAG haplotype conferred increased risk of GC compared with AG (OR=1.88, P= 6.98 × 10⁻⁴). XPA rs2808668 and drinking, DDB2 rs326222, rs3781619, rs830083 and smoking demonstrated significant interactions in AG; XPC rs2607775 had significant interaction with smoking in GC. In conclusion, NER pathway polymorphisms especially in “damage incision” step were significantly associated with GC risk and had interactions with environment factors. The detection of NER pathway polymorphisms such as DDB2 and XPC might be applied in the prediction of GC risk and personalized prevention in the future.

From inflammation to gastric cancer: Role of Helicobacter pylori

Gastric cancer is a multifactorial disease and a leading cause of mortality and the risk factors for this include environmental factors and factors that influence host-pathogen interaction and complex interplay between these factors. Gastric adenocarcinomas are of two types, namely intestinal and diffuse type, and Helicobacter pylori (H. pylori) infection has been suspected of being causally linked to the initiation of chronic active gastritis, which leads to adenocarcinoma of the intestinal type. Even though most individuals with H. pylori infection do not show any clinical symptoms, long-term infection leads to inflammation of gastric epithelium and approximately 10% of infected patients develop peptic ulcers and 1–3% of patients develop gastric adenocarcinoma. Among the several mechanisms involved in tumorigenesis, CagA and peptidoglycan of H. pylori, which enter the infected gastric epithelial cells play an important role by triggering oncogenic pathways. Inflammation induced by H. pylori in gastric epithelium, which involves the cyclooxygenase-2/prostaglandin E2 pathway and IL-1β, is also an important factor that triggers chronic active gastritis and adenocarcinoma. H. pylori infection induced oxidative stress and dysregulated E-cadherin/β-catenin/p120 interactions and function also play a critical role in tumorigenesis. Environmental and dietary factors, in particular salt intake, are known to modify the pathogenesis induced by H. pylori. Gastric cancer induced by H. pylori appears to involve several mechanisms, making this mode of tumorigenesis a highly complicated process. Nevertheless, there are many events in this tumorigenesis that remain to be clarified and investigated.

SNP interactions of Helicobacter pylori-related host genes PGC, PTPN11, IL1B, and TLR4 in susceptibility to gastric carcinogenesis

A series of host genes that respond to Helicobacter pylori (H. pylori) infection are involved in the process of gastric carcinogenesis. This study sought to examine interactions among polymorphisms of H. pylori-related genes PGC, PTPN11, TLR4, and IL1B and assess whether their interaction effects were modified by H. pylori infection. Thirteen polymorphisms of the aforementioned genes were genotyped by the Sequenom MassARRAY platform in 714 gastric cancer patients, 907 atrophic gastritis cases and 1276 healthy control subjects. When we considered the host genetic effects alone, gene–gene interactions consistently decreased the risks of gastric cancer and/or atrophic gastritis, including three two-way interactions: PGC rs6912200-PTPN11 rs12229892, PGC rs4711690-IL1B rs1143623 and PTPN11 rs12229892-IL1B rs1143623 and a three-way interaction: PGC rs4711690-PGC rs6912200-PTPN11 rs12229892. When the effect modification of H. pylori infection was evaluated, the cumulative effects of the aforementioned three-way interaction on atrophic gastritis susceptibility switched from being beneficial to being risky by the status of H. pylori infection. These data showed that SNP interactions among H. pylori-related genes PGC, PTPN11, and IL1B, are associated with susceptibility to gastric carcinogenesis. Moreover, we provided important hints of an effect modification by H. pylori infection on the cumulative effect of PGC and PTPN11 polymorphisms. Functional experiments and further independent large-scale studies especially in other ethnic populations are still needed to confirm our results.

Interaction between Helicobacter pylori and host genetic variants in gastric carcinogenesis

Helicobacter pylori (H. pylori) is the definite carcinogen of gastric cancer. H. pylori infection induces chronic inflammation, causes DNA damage and aberrant methylation of genes and these pathways are involved in H. pylori-related gastric carcinogenesis. Polymorphisms of the genes involved in these pathways could alter susceptibility to gastric cancer. In this mini review, we focused on the role of polymorphisms in these genes on the susceptibility to gastric cancer, with a particular emphasis on their possible interactions with H. pylori infection. We found that many studies on this theme did not simultaneously report H. pylori infection and the interactions remained inconclusive.

SNP-SNP Interaction between TLR4 and MyD88 in Susceptibility to Coronary Artery Disease in the Chinese Han Population

The toll-like receptor 4 (TLR4)-myeloid differentiation factor 88 (MyD88)-dependent signaling pathway plays a role in the initiation and progression of coronary artery disease (CAD). We investigated SNP-SNP interactions between the TLR4 and MyD88 genes in CAD susceptibility and assessed whether the effects of such interactions were modified by confounding risk factors (hyperglycemia, hyperlipidemia and Helicobacter pylori (H. pylori) infection). Participants with CAD (n = 424) and controls (n = 424) without CAD were enrolled. Polymerase chain restriction-restriction fragment length polymorphism was performed on genomic DNA to detect polymorphisms in TLR4 (rs10116253, rs10983755, and rs11536889) and MyD88 (rs7744). H. pylori infections were evaluated by enzyme-linked immunosorbent assays, and the cardiovascular risk factors for each subject were evaluated clinically. The significant interaction between TLR4 rs11536889 and MyD88 rs7744 was associated with an increased CAD risk (p value for interaction = 0.024). In conditions of hyperglycemia, the interaction effect was strengthened between TLR4 rs11536889 and MyD88 rs7744 (p value for interaction = 0.004). In hyperlipidemic participants, the interaction strength was also enhanced for TLR4 rs11536889 and MyD88 rs7744 (p value for interaction = 0.006). Thus, the novel interaction between TLR4 rs11536889 and MyD88 rs7744 was related with an increased risk of CAD, that could be strengthened by the presence of hyperglycemia or hyperlipidemia.

Helicobacter pylori Infection Synergistic with IL-1β Gene Polymorphisms Potentially Contributes to the Carcinogenesis of Gastric Cancer

Helicobacter pylori (H. pylori) infection is the most common chronic bacterial infection in the world and the etiological agent for most gastric cancer (GC). Interleukin-1β (IL-1β) is a potent proinflammatory cytokine, and its deregulation is closely associated with the tumorigenesis of several cancers. Recent studies have revealed that the IL-1β-31 and -511T alleles are closely associated with gastric carcinogenesis due to their roles in the induction of gastric precancerous lesions and hypochlorhydria. Furthermore, H. pylori infection has a synergistic effect on the development of GC with IL-1β gene polymorphisms, and the highest prevalence of severe gastric abnormalities are found in patients with both host and bacterial high-risk genotypes (cagA(+)/vacAs1(+)/IL-1β-511T). Therefore, these recent advances demonstrate that H. pylori synergistic with IL-1β gene polymorphisms contribute to the gastric carcinogenesis by their involvement in precancerous gastric lesions and low gastric acid secretion.

New and Unexpected Biological Functions for the Src-Homology 2 Domain-Containing Phosphatase SHP-2 in the Gastrointestinal Tract

SHP-2 is a tyrosine phosphatase expressed in most embryonic and adult tissues. SHP-2 regulates many cellular functions including growth, differentiation, migration, and survival. Genetic and biochemical evidence show that SHP-2 is required for rat sarcoma viral oncogene/extracellular signal-regulated kinases mitogen-activated protein kinase pathway activation by most tyrosine kinase receptors, as well as by G-protein-coupled and cytokine receptors. In addition, SHP-2 can regulate the Janus kinase/signal transducers and activators of transcription, nuclear factor-κB, phosphatidyl-inositol 3-kinase/Akt, RhoA, Hippo, and Wnt/β-catenin signaling pathways. Emerging evidence has shown that SHP-2 dysfunction represents a key factor in the pathogenesis of gastrointestinal diseases, in particular in chronic inflammation and cancer. Variations within the gene locus encoding SHP-2 have been associated with increased susceptibility to develop ulcerative colitis and gastric atrophy. Furthermore, mice with conditional deletion of SHP-2 in intestinal epithelial cells rapidly develop severe colitis. Similarly, hepatocyte-specific deletion of SHP-2 induces hepatic inflammation, resulting in regenerative hyperplasia and development of tumors in aged mice. However, the SHP-2 gene initially was suggested to be a proto-oncogene because activating mutations of this gene were found in pediatric leukemias and certain forms of liver and colon cancers. Moreover, SHP-2 expression is up-regulated in gastric and hepatocellular cancers. Notably, SHP-2 functions downstream of cytotoxin-associated antigen A (CagA), the major virulence factor of Helicobacter pylori, and is associated with increased risks of gastric cancer. Further compounding this complexity, most recent findings suggest that SHP-2 also coordinates carbohydrate, lipid, and bile acid synthesis in the liver and pancreas. This review aims to summarize current knowledge and recent data regarding the biological functions of SHP-2 in the gastrointestinal tract.

An inverse association of Helicobacter pylori infection with oral squamous cell carcinoma

BACKGROUND

Few studies have focused on the relationship between Helicobacter pylori (H. pylori) infection and oral diseases. In this study, we explored the correlation between H. pylori infection and oral squamous cell carcinoma (OSCC).

METHODS

A total of 68 patients with OSCC and 104 age- and sex- matched healthy control subjects were retrospectively enrolled in this study. The H. pylori immunoglobin (Ig) G antibodies in serum were detected by enzyme-linked immunosorbent assay (ELISA) method to assess the status of H. pylori infection of our study sample. Polymerase chain reaction (PCR) was also employed using H. pylori genus-specific 16S rRNA primers in fasting blood, and OSCC specimens were analyzed by histochemical stain of each enrolled subject. The strength of correlation between H. pylori and the development of OSCC was estimated by Spearman's correlation coefficient.

RESULTS

According to the three methods for detecting prevalence of H. pylori infection in the patients with OSCC, it was statistically lower than that in the healthy controls (35.3% vs. 54.8%, P = 0.012). An inverse correlation was observed between H. pylori infection and OSCC development (Spearman's correlation coefficient = -0.191, P = 0.012). In stratification analysis, we also found a statistical association between H. pylori infection and OSCC in the subpopulation with age ≥ 60 years (P = 0.037).

CONCLUSION

Our findings suggested that H. pylori infection may be negatively related to OSCC. A reverse association of H. pylori infection with OSCC risk in the subpopulation with age ≥ 60 years was also found.

Polymorphic rs9471643 and rs6458238 upregulate PGC transcription and protein expression in overdominant or dominant models

The pepsinogen C (PGC) gene encodes a major differentiation biomarker for gastric mucosa and has two single nucleotide polymorphisms, rs9471643 G>C and rs6458238 G>A, within its 5' upstream region that are involved in gastric carcinogenesis. However, in what genetic models the two polymorphisms modulate disease risk and how they relate to gastric carcinogenesis needs further study. We fitted the most appropriate genetic models to the PGC polymorphisms and validated their robustness; then with knowledge of the genetic model, we investigated the influence of functional variant alleles or genotypes on gene expression in vitro and in vivo. We confirmed that rs9471643 CG genotype was stably associated with reduced gastric cancer risk in complete overdominant model. This favorable CG genotype was also associated with reduced atrophic gastritis risk in subjects carrying rs6458238 AG/AA genotype. The G>C transition at rs9471643 enhanced promoter activity and transcription factor binding ability, and the CG genotype was consistently associated with elevated levels of PGC mRNA, in situ protein and serum protein in complete overdominant model based-analyses. Additionally, rs6458238 AG/AA genotype was associated with reduced atrophic gastritis risk in dominant model. Its favorable A allele was related to higher promoter activity and lower transcription factor binding ability, and the AG/AA genotype showed association with elevated levels of serum PGC protein in dominant model based-analyses. Our results suggest that rs9471643 CG and rs6458238 AG/AA genotypes have important roles in up-regulating PGC expression, which may partially explain why individuals with these favorable genotypes have decreased risks of getting gastric cancer.

Lack of association of common polymorphisms in MUC1 gene with H. pylori infection and non-cardia gastric cancer risk in a Chinese population

Several lines of evidence support the notion that MUC1 is often aberrantly expressed in gastric cancer, and it is a ligand for Helicobacter pylori. Genetic variation in MUC1 gene may confer susceptibility to H. pylori infection and gastric cancer. We assessed the association of common polymorphisms in MUC1 gene with H. pylori infection and non-cardia gastric cancer using an LD-based tag SNP approach in north-western Chinese Han population. A total of four SNPs were successfully genotyped among 288 patients with non-cardia gastric cancer and 281 age- and sex-matched controls. None of the tested SNPs was associated with H. pylori infection. SNP rs9426886 was associated with a decreased risk of non-cardia gastric cancer, but lost significance after adjustment for multiple testing. Overall, our data indicated that common genetic variations in MUC1 gene might not make a major contribution to the risk of H. pylori infection and non-cardia gastric cancer in our studied population.

PGC TagSNP and its interaction with H. pylori and relation with gene expression in susceptibility to gastric carcinogenesis

Background

Pepsinogen C (PGC) plays an important role in sustaining the cellular differentiation during the process of gastric carcinogenesis. This study aimed to assess the role of PGC tagSNPs and their interactions with Helicobacter pylori (H. pylori) in the development of gastric cancer and its precursor, atrophic gastritis.

Methods

Four PGC tagSNPs (rs6941539, rs6912200, rs3789210 and rs6939861) were genotyped by Sequenom MassARRAY platform in a total of 2311 subjects consisting of 642 gastric cancer, 774 atrophic gastritis, and 895 healthy control subjects. The mRNA and protein expression levels of PGC in gastric tissues and in serum were respectively measured by quantitative reverse transcriptase–polymerase chain reaction (qRT-PCR), immunohistochemistry, and Eenzyme-linked immunoabsorbent assay (ELISA).

Results

We found associations between PGC rs3789210 CG/GG genotypes and reduced gastric cancer risk and between PGC rs6939861 A variant allele and increased risks of both gastric cancer and atrophic gastritis. As for the haplotypes of PGC rs6941539-rs6912200-rs3789210-rs6939861 loci, the TTCA and TTGG haplotypes were respectively associated with increased and reduced risks of both gastric cancer and atrophic gastritis; additionally, the CTCA haplotype was associated with increased atrophic gastritis risk. Very interestingly, rs6912200 CT/TT genotypes had a positive interaction with H. pylori, synergistically elevating the gastric cancer risk. Moreover, healthy subjects who carried rs6912200 CT, TT and CT/TT variant genotypes had lower histological and serum expression levels of PGC protein.

Conclusions

Our findings highlight an important role of PGC rs3789210 and rs6939861 in altering susceptibility to atrophic gastritis and/or gastric cancer. Moreover, people who carry rs6912200 variant genotypes exhibit higher gastric cancer risk in case of getting H. pylori infection, which strongly suggest a necessity of preventing and/or eliminating H. pylori infection in those individuals.

Molecular oncology testing in resource-limited settings

Cancer prevalence and mortality are high in developing nations, where resources for cancer control are inadequate. Nearly one-quarter of cancers in resource-limited nations are infection related, and molecular assays can capitalize on this relationship by detecting pertinent pathogen genomes and human gene variants to identify those at highest risk for progression to cancer, to classify lesions, to predict effective therapy, and to monitor tumor burden over time. Prime examples are human papillomavirus in cervical neoplasia, Helicobacter pylori and Epstein-Barr virus in gastric adenocarcinoma and lymphoma, and hepatitis B or C virus in hepatocellular cancer. Research is underway to engineer devices that overcome social, economic, and technical barriers limiting effective laboratory support. Additional challenges include an educated workforce, infrastructure for quality metrics and record keeping, and funds to sustain molecular test services. The combination of well-designed interfaces, novel and robust electrochemical technology, and telemedicine tools will promote adoption by frontline providers. Fast turnaround is crucial for surmounting loss to follow-up, although increased use of cell phones, even in rural areas, enhances options for patient education and engagement. Links to a broadband network facilitate consultation and centralized storage of medical data. Molecular technology shows promise to address gaps in health care through rapid, user-friendly, and cost-effective devices reflecting clinical priorities in resource-poor areas.

Functional short tandem repeat polymorphism of PTPN11 and susceptibility to hepatocellular carcinoma in Chinese populations

Background

PTPN11, which encodes tyrosine phosphatase Shp2, is a critical gene mediating cellular responses to hormones and cytokines. Loss of Shp2 promotes hepatocellular carcinoma (HCC), suggesting that PTPN11 functions as a tumor suppressor in HCC tumorgenesis. The aim of this study was to evaluate the effects of the short tandem repeat (STR) polymorphism (rs199618935) within 3'UTR of PTPN11 on HCC susceptibility in Chinese populations.

Methodology/Principal Findings

We analyzed the associations in 400 patients from Jiangsu province of China, validating the findings in an additional 305 patients from Shanghai of China. Unconditional logistic regression was used to analyze the association between rs199618935 and HCC risk. Additional biochemical investigations and in-silico studies were used to evaluate the possible functional significance of this polymorphism. Logistic regression analysis showed that compared with individuals carrying shorter alleles (11 and 12 repeats), those subjects who carry longer alleles (13 and 14 repeats) had a significantly decreased risk of HCC [adjusted odds ratio (OR)  = 0.63, 95% confidence interval (CI)  = 0.53–0.76, P = 2.00×10⁻⁷], with the risk decreased even further in those carrying allele 15 and 16 (adjusted OR = 0.46, 95% CI = 0.34–0.62, P = 1.00×10⁻⁷). Biochemical investigations showed that longer alleles of rs199618935 conferred higher PTPN11 expression in vivo and in vitro. The altered luciferase activities in reporter gene system suggested that STR regulation of PTPN11 expression could be a transcriptional event. Finally, in-silico prediction revealed that different alleles of rs199618935 could alter the local structure of PTPN11 mRNA.

Conclusions/Significance

Taken together, our findings suggested that the STR polymorphism within PTPN11 contributes to hepatocarcinogenesis, possibly by affecting PTPN11 expression through a structure-dependent mechanism. The replication of our studies and further functional studies are needed to validate our findings.

Effect of the -2081G/A polymorphism of the TLR4 gene and its interaction with Helicobacter pylori infection on the risk of gastric cancer in Chinese individuals

AIMS

Toll-like receptor 4 (TLR4) plays an important role in gastric carcinoma. Using a case-control study, we analyzed the genotypic distribution of TLR4 rs10983755 (-2081G/A) and rs11536878 in a Chinese population and investigated the effect of their interactions with Helicobacter pylori infection on susceptibility to gastric cancer (GC) and atrophic gastritis (AG).

METHODS

In this study, 409 and 581 cases of GC and AG, respectively, were selected for analyses along with an equal number of matched controls. The TLR4 polymorphisms were genotyped using Sequenom MassARRAY. Serum levels of anti-H. pylori IgG were determined by enzyme-linked immunosorbent assay.

RESULTS

The TLR4-2081G/A polymorphism was negatively associated with GC (AG+AA vs. GG: odds ratio [OR]=0.70, 95% confidence interval [CI]=0.53-0.93, p=0.012). A decreased risk of GC was observed in H. pylori negative and TLR4-2081(AG+AA) genotype subjects [H. pylori(-)/AG+AA vs. H. pylori(+)/GG: OR=0.16, 95% CI=0.09-0.27, p<0.001]. The rs11536878 polymorphism was not associated with GC or AG.

CONCLUSIONS

The TLR4-2081G/A polymorphism seems to affect the risk of gastric carcinogenesis and may to some degree play a protective role against H. pylori infection.

The interaction effects of pri-let-7a-1 rs10739971 with PGC and ERCC6 gene polymorphisms in gastric cancer and atrophic gastritis

Background

The aim of this study was to investigate the interaction effects of pri-let-7a-1 rs10739971 with pepsinogen C (PGC) and excision repair cross complementing group 6 (ERCC6) gene polymorphisms and its association with the risks of gastric cancer and atrophic gastritis. We hoped to identify miRNA polymorphism or a combination of several polymorphisms that could serve as biomarkers for predicting the risk of gastric cancer and its precancerous diseases.

Methods

Sequenom MassARRAY platform method was used to detect polymorphisms of pri-let-7a-1 rs10739971 G→A, PGC rs4711690 C→G, PGC rs6458238 G→A, PGC rs9471643 G→C, and ERCC6 rs1917799 in 471 gastric cancer patients, 645 atrophic gastritis patients and 717 controls.

Results

An interaction effect of pri-let-7a-1 rs10739971 polymorphism with ERCC6 rs1917799 polymorphism was observed for the risk of gastric cancer (P_interaction = 0.026); and interaction effects of pri-let-7a-1 rs10739971 polymorphism with PGC rs6458238 polymorphism (P_interaction = 0.012) and PGC rs9471643 polymorphism (P_interaction = 0.039) were observed for the risk of atrophic gastritis.

Conclusion

The combination of pri-let-7a-1 rs10739971 polymorphism and ERCC6 and PGC polymorphisms could provide a greater prediction potential than a single polymorphism on its own. Large-scale studies and molecular mechanism research are needed to confirm our findings.

Host genetic factors respond to pathogenic step-specific virulence factors of Helicobacter pylori in gastric carcinogenesis

The interindividual differences in risk of Helicobacter pylori (H. pylori)-associated gastric cancer involve significant heterogeneities of both host genetics and H. pylori strains. Several recent studies proposed a distinct sequence for H. pylori exerting its virulence in the host stomach: (i) adhering to and colonizing the surface of gastric epithelial cells, (ii) evading and attenuating the host defense, and (iii) invading and damaging the gastric mucosa. This review focuses on several key issues that still need to be clarified, such as which virulence factors of H. pylori are involved in the three pathogenic steps, which host genes respond to the step-specific virulence factors, and whether and/or how the corresponding host genetic variations influence the risk of gastric carcinogenesis. Urease, BabA and SabA in the adhesion-step, PGN and LPS in the immune evasion-step, and CagA, VacA and Tipα in the mucosal damage-step were documented to play an important role in step-specific pathogenicity of H. pylori infection. There is evidence further supporting a role of potentially functional polymorphisms of host genes directly responding to these pathogenic step-specific virulence factors in the susceptibility of gastric carcinogenesis, especially for urease-interacting HLA class II genes, BabA-interacting MUC1, PGN-interacting NOD1, LPS-interacting TLR4, and CagA-interacting PTPN11 and CDH1. With the continuous improvement of understanding the genetic profile of H. pylori-associated gastric carcinogenesis, a person at increased risk for gastric cancer may benefit from several aspects of efforts: (i) prevent H. pylori infection with a vaccine targeting certain step-specific virulence factor; (ii) eradicate H. pylori infection by blocking step-specific psychopathological characteristics of virulence factors; and (iii) adjust host physiological function to resist the carcinogenic role of step-specific virulence factors or interrupt the cellular signal transduction of the interplay between H. pylori and host in each pathogenic step, especially for the subjects with precancerous lesions in the stomach.

Polymorphisms of the TLR4 gene and risk of gastric cancer

OBJECTIVE

Toll-like receptor 4 (TLR4) is an important lipo-polysaccharide (LPS) receptor in gastric epithelial cell signaling transduction and plays critical roles in the development and progression of gastric cancer (GC). We investigated the effects of TLR4 gene polymorphisms and gene-environmental interactions on the risk of GC in Northeastern China.

METHODS

We genotyped two single-nucleotide polymorphisms (SNPs) in TLR4 (rs10116253 and rs1927911) in 217 GC patients and 294 cancer-free controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Odds ratio (OR) and 95% confidence intervals (CIs) were estimated by unconditional logistic-regression models.

RESULTS

Individuals carrying CC genotype of rs10116253 and TT genotype of rs1927911 had a significantly decreased risk of GC (adjusted OR=0.33, 95% CI 0.18-0.60, P<0.001 and adjusted OR=0.37, 95% CI 0.21-0.67, P=0.001 respectively), compared with TT genotype of rs10116253 and CC genotype of rs1927911. In addition, the SNP effects were additive to the effects of some known environmental factors without any interaction between them in the susceptibility to GC.

CONCLUSION

Our data suggested that TLR4 gene polymorphisms may be associated with a decreased risk of GC in Chinese population. And these SNPs and their combined effects with environmental factors may be associated with the risk of GC.