SNP Regulation of microRNA Expression and Subsequent Colon Cancer Risk

Introduction

MicroRNAs (miRNAs) regulate messenger RNAs (mRNAs) and as such have been implicated in a variety of diseases, including cancer. MiRNAs regulate mRNAs through binding of the miRNA 5’ seed sequence (~7–8 nucleotides) to the mRNA 3’ UTRs; polymorphisms in these regions have the potential to alter miRNA-mRNA target associations. SNPs in miRNA genes as well as miRNA-target genes have been proposed to influence cancer risk through altered miRNA expression levels.

Methods

MiRNA-SNPs and miRNA-target gene-SNPs were identified through the literature. We used SNPs from Genome-Wide Association Study (GWAS) data that were matched to individuals with miRNA expression data generated from an Agilent platform for colon tumor and non-tumor paired tissues. These samples were used to evaluate 327 miRNA-SNP pairs for associations between SNPs and miRNA expression levels as well as for SNP associations with colon cancer.

Results

Twenty-two miRNAs expressed in non-tumor tissue were significantly different by genotype and 21 SNPs were associated with altered tumor/non-tumor differential miRNA expression across genotypes. Two miRNAs were associated with SNP genotype for both non-tumor and tumor/non-tumor differential expression. Of the 41 miRNAs significantly associated with SNPs all but seven were significantly differentially expressed in colon tumor tissue. Two of the 41 SNPs significantly associated with miRNA expression levels were associated with colon cancer risk: rs8176318 (BRCA1), OR_AA 1.31 95% CI 1.01, 1.78, and rs8905 (PRKAR1A), OR_GG 2.31 95% CI 1.11, 4.77.

Conclusion

Of the 327 SNPs identified in the literature as being important because of their potential regulation of miRNA expression levels, 12.5% had statistically significantly associations with miRNA expression. However, only two of these SNPs were significantly associated with colon cancer.     

Polymorphisms in ERCC1 and XPF Genes and Risk of Gastric Cancer in an Eastern Chinese Population

Background

Inherited functional single nucleotide polymorphisms (SNPs) in DNA repair genes may alter DNA repair capacity and thus contribute to cancer risk.

Methods

Three ERCC1 functional SNPs (rs2298881C>A, rs3212986C>A and rs11615G>A) and two XPF/ERCC4 functional SNPs (rs2276466C>G and rs6498486A>C) were genotyped for 1125 gastric adenocarcinoma cases and 1196 cancer-free controls by Taqman assays. Odds ratios (OR) and 95% confidence intervals (CI) were used to estimate risk associations, and false-positive report probabilities (FPRP) were calculated for assessing significant findings.

Results

ERCC1 rs2298881C and rs11615A variant genotypes were associated with increased gastric cancer risk (adjusted OR = 1.33, 95% CI = 1.05–1.67 for rs2298881 AC/CC and adjusted OR = 1.23, 95% CI = 1.05–1.46 for rs11615 AG/AA, compared with their common genotype AA and GG, respectively). Patients with 2–3 ERCC1 risk genotypes had significant increased risk (adjusted OR = 1.56, 95% CI = 1.27–1.93), compared with those with 0–1 ERCC1 risk genotypes, and this risk was more significantly in subgroups of never drinkers, non-gastric cardia adenocarcinoma (NGCA) and clinical stage I+II. All these risks were not observed for XPF SNPs.

Conclusions

These findings suggest that functional ERCC1 SNPs may contribute to risk of gastric cancer. Larger and well-designed studies with different ethnic populations are needed to validate our findings.     

Polymorphisms of the DNA Methyltransferase 1 Associated with Reduced Risks of Helicobacter pylori Infection and Increased Risks of Gastric Atrophy

Introduction

DNA methyltransferase-1(DNMT1) is an important enzyme in determining genomic methylation patterns in mammalian cells. We investigated the associations between SNPs in the DNMT1 gene and risks of developing H. pylori seropositivity, gastric atrophy and gastric cancer in the Chinese population.

Methods

The study consisted of 447 patients with gastric cancer; 111 patients with gastric atrophy; and 961 healthy controls. Five SNPs, rs10420321, rs16999593, rs8101866, rs8111085 and rs2288349 of the DNMT1 gene were genotyped. Anti-H.pylori IgG was detected by ELISA. Gastric atrophy was screened by the level of serum pepsinogen Ιand II and then confirmed by endoscopy and histopatholgical examinations.

Results

The age- and sex-adjusted OR of H. pylori seropositivity was 0.67 (95%CI: 0.51–0.87) for rs8111085 TC/CC genotypes, significantly lower than the TT genotype in healthy controls. The adjusted OR of H.pylori seropositivity was 0.68 (95%CI: 0.52–0.89) for rs10420321 AG/GG genotypes. In addition, patients carrying rs2228349 AA genotype have a significantly increased risk for H.pylori seropositivity (OR = 1.67; 95%CI: 1.02–2.75). Further haplotype analyses also showed that the ATTTG and ATCTA are significantly associated with increased risks in H.pylori infection compared to the GTCCG haplotype (OR = 1.38, 95%CI: 1.08–1.77; OR = 1.40, 95% CI: 1.09–1.80). The adjusted ORs of gastric atrophy were 1.66 (95%CI: 1.06–2.61) for rs10420321 GG genotype, and 1.67 (95%CI 1.06–2.63, P = 0.03) for rs8111085 CC genotype, but no association was found between SNPs in the DNMT1 gene and risk of developing gastric cancer.

Conclusions

Individuals with rs10420321 GG and rs8111085 CC genotype of the DNMT1 gene were associated with reduced risks for H.pylori infection. On the other hand, higher risks of gastric atrophy were found in the carriers with these two genotypes compared to other genotypes. Our results suggested that SNPs of DNMT1 could be used as genotypic markers for predicting genetic susceptibilities to H.pylori infection and risks in gastric atrophy.     

Innate Immunity and Non-Hodgkin’s Lymphoma (NHL) Related Genes in a Nested Case-Control Study for Gastric Cancer Risk

Objective

Genetic variants regulating the host immune system may contribute to the susceptibility for the development of gastric cancer. Little is known about the role of the innate immunity- and non-Hodgkin’s lymphoma (NHL)-related genes for gastric cancer risk. This nested case-control study was conducted to identify candidate genes for gastric cancer risk for future studies.

Methods

In the Discovery phase, 3,072 SNPs in 203 innate immunity- and 264 NHL-related genes using the Illumine GoldenGateTM OPA Panel were analyzed in 42 matched case-control sets selected from the Korean Multi-center Cancer Cohort (KMCC). Six significant SNPs in four innate immunity (DEFA6, DEFB1, JAK3, and ACAA1) and 11 SNPs in nine NHL-related genes (INSL3, CHMP7, BCL2L11, TNFRSF8, RAD50, CASP7, CHUK, CD79B, and CLDN9) with a permutated p-value <0.01 were re-genotyped in the Replication phase among 386 cases and 348 controls. Odds ratios (ORs) for gastric cancer risk were estimated adjusting for age, smoking status, and H. pylori and CagA sero-positivity. Summarized ORs in the total study population (428 cases and 390 controls) are presented using pooled- and meta-analyses.

Results

Four SNPs had no heterogeneity across the phases: in the meta-analysis, DEFA6 rs13275170 and DEFB1 rs2738169 had both a 1.3-fold increased odds ratio (OR) for gastric cancer (95% CIs = 1.1–1.6; and 1.1–1.5, respectively). INSL3 rs10421916 and rs11088680 had both a 0.8-fold decreased OR for gastric cancer (95% CIs = 0.7–0.97; and 0.7–0.9, respectively).

Conclusions

Our findings suggest that certain variants in the innate immunity and NHL-related genes affect the gastric cancer risk, perhaps by modulating infection-inflammation-immunity mechanisms that remain to be defined.     

Impact of VEGF-C Gene Polymorphisms and Environmental Factors on Oral Cancer Susceptibility in Taiwan

Background

Oral cancer, which is the fourth most common male cancer, is associated with environmental carcinogens in Taiwan. Vascular endothelial growth factor (VEGF)-C, an angiogenic/lymphangiogenic factor with high expression levels in tumor tissues, plays important roles in the development of several malignancies. This study was designed to examine associations of five VEGF-C gene polymorphisms with the susceptibility to and clinicopathological characteristics of oral squamous cell carcinoma.

Methodology/Principal Findings

Five single-nucleotide polymorphisms (SNPs) of VEGF-C were analyzed by a real-time polymerase chain reaction (PCR) in 470 male patients with oral cancer and 426 cancer-free controls. In this study, we found that the VEGF-C rs7664413 and rs2046463 polymorphisms were associated with oral-cancer susceptibility but not with any clinicopathological parameters. The GGACA or GACTG haplotype of five VEGF-C SNPs (rs3775194, rs11947611, rs1485766, rs7664413, and rs2046463) combined was also related to the risk of oral cancer. Among 611 male smokers, VEGF-C polymorphism carriers who also chewed betel quid were found to have a 14.5–24.2-fold risk of having oral cancer compared to the VEGF-C wild-type carrier who did not chew betel quid. Among 461 male betel-quid chewers, VEGF-C polymorphism carriers who also smoked had a 2.7–18.1-fold risk of having oral cancer compared to those who carried the wild type but did not smoke.

Conclusions

Our results suggest that the two SNPs of VEGF-C (rs7664413 and rs2046463) and either of two haplotypes of five SNPs combined have potential predictive significance in oral carcinogenesis. Gene-environmental interactions among VEGF-C polymorphisms, smoking, and betel-quid chewing might alter one''s susceptibility to oral cancer.     

TNF,IL6, and IL1B Polymorphisms Are Associated with Severe Influenza A (H1N1) Virus Infection in the Mexican Population

Background

Hypercytokinemia is the main immunopathological mechanism contributing to a more severe clinical course in influenza A (H1N1) virus infections. Most patients infected with the influenza A (H1N1) pdm09 virus had increased systemic levels of pro-inflammatory cytokines; including interleukin IL-6, IL-8, and tumor necrosis factor-alpha (TNF-α). We propose that single-nucleotide polymorphisms (SNPs) in the promoter regions of pro-inflammatory genes are associated with the severity of influenza A (H1N1) pdm09 virus infection.

Methods

145 patients with influenza A (H1N1) (pA/H1N1), 133 patients with influenza-like illness (ILI), and 360 asymptomatic healthy contacts (AHCs) were included. Eleven SNPs were genotyped in six genes (TNF, LT, IL1B, IL6, CCL1, and IL8) using real-time PCR; the ancestral genotype was used for comparison. Genotypes were correlated with 27 clinical severity variables. Ten cytokines (GM-CSF, TNF-α, IL-2, IL-1β, IL-6, IL-8, IFN-γ, IL-10, IL-5, and IL-4) were measured on a Luminex 100.

Results

The IL6 rs1818879 (GA) heterozygous genotype was associated with severe influenza A (H1N1) virus infection (odds ratio [OR] = 5.94, 95% confidence interval [CI] 3.05–11.56), and two IL1B SNPs, rs16944 AG and rs3136558 TC, were associated with a decreased risk of infection (OR = 0.52 and OR = 0.51, respectively). Genetic susceptibility was determined (pA/H1N1 vs. AHC): the LTA rs909253 TC heterozygous genotype conferred greater risk (OR = 1.9), and a similar association was observed with the IL1B rs3136558 CC genotype (OR = 1.89). Additionally, severely ill patients were compared with moderately ill patients. The TNF-238 GA genotype was associated with an increased risk of disease severity (OR = 16.06, p = 0.007). Compared with ILIs, patients with severe pA/H1N1 infections exhibited increased serum IL-5 (p <0.001) and IL-6 (p  =  0.007) levels.

Conclusions

The TNF gene was associated with disease severity, whereas IL1B and IL6 SNPs were associated with influenza A (H1N1) virus infection.     

Association of Ulcerative Colitis with FUT2 and FUT3 Polymorphisms in Patients from Southeast China

Objectives

Dysbiosis of intestinal microbiota has been implicated in ulcerative colitis (UC). Fucosyltransferase (FUT) 2 and FUT3 determine expression of histo-blood group antigens in the gut and may affect the intestinal microbiota. We investigated the association between FUT2 and FUT3 polymorphisms and UC in Chinese patients.

Methods

We genotyped FUT2 (rs281377, rs1047781 and rs601338) and FUT3 (rs28362459, rs3745635 and rs3894326) in 485 UC patients and 580 healthy controls using SNaPshot. We also evaluated expression of Lewis a and b antigens in the sigmoid colon of 7 UC patients and 7 patients with benign colonic polyps.

Results

The frequencies of mutant allele (A) and genotype (GA+AA) in FUT3 (rs3745635) were higher in UC patients than controls (P = 0.016, 95%CI: 1.339–1.699; P = 0.038, 95%CI: 1.330–1.742, respectively). Stratified analyses revealed that the frequencies of mutant allele (G) and genotype (TG+GG) of FUT3 (rs28362459) were significantly lower in patients with extensive colitis than those with distal colitis (P<0.001, 95%CI: 0.503–0.742; P = 0.001, 95%CI: 0.567–0.786, respectively). Similar conclusions were drawn for the mutant allele (A) and genotype (GA+AA) of FUT3 (rs3745635) in patients with extensive colitis compared to those with distal colitis (P = 0.006, 95%CI: 0.553–0.845; P = 0.011, 95%CI: 0.621–0.900, respectively). Although expression of Lewis b antigen in the sigmoid colon did not differ between UC patients and controls, Lewis a antigen expression was higher in the cryptic epithelium of both inflammatory and non-inflammatory sigmoid colon of UC patients than controls (P = 0.028).

Conclusions

Our findings indicated that polymorphisms in FUT3 and its intestinal expression might be associated with UC pathogenesis.     

Genetic Variations in SMAD7 Are Associated with Colorectal Cancer Risk in the Colon Cancer Family Registry

Background

Recent genome-wide studies identified a risk locus for colorectal cancer at 18q21, which maps to the SMAD7 gene. Our objective was to confirm the association between SMAD7 SNPs and colorectal cancer risk in the multi-center Colon Cancer Family Registry.

Materials and Methods

23 tagging SNPs in the SMAD7 gene were genotyped among 1,592 population-based and 253 clinic-based families. The SNP-colorectal cancer associations were assessed in multivariable conditional logistic regression.

Results

Among the population-based families, both SNPs rs12953717 (odds ratio, 1.29; 95% confidence interval, 1.12–1.49), and rs11874392 (odds ratio, 0.80; 95% confidence interval, 0.70–0.92) were associated with risk of colorectal cancer. These associations were similar among the population- and the clinic-based families, though they were significant only among the former. Marginally significant differences in the SNP-colorectal cancer associations were observed by use of nonsteroidal anti-inflammatory drugs, cigarette smoking, body mass index, and history of polyps.

Conclusions

SMAD7 SNPs were associated with colorectal cancer risk in the Colon Cancer Family Registry. There was evidence suggesting that the association between rs12953717 and colorectal cancer risk may be modified by factors such as smoking and use of nonsteroidal anti-inflammatory drugs.     

Genetic Variation in DROSHA 3’UTR Regulated by hsa-miR-27b Is Associated with Bladder Cancer Risk

Purpose

miRNAs can regulate the biological processes, including differentiation, proliferation and apoptosis. DICER and DROSHA are two members of RNase III family, playing pivotal roles in the pathway of miRNAs biogenesis. In this study, we hypothesized that genetic variations of the DICER and DROSHA genes were associated with the bladder cancer risk.

Experimental Design

We performed a case-control study of 685 bladder cancer cases and 730 controls to investigate the association between the seven functional SNPs of DICER and DROSHA genes and bladder cancer risk. We then evaluated the functionality of the important SNPs.

Results

We found that rs10719T>C polymorphism located in 3’ untranslated region (UTR) of DROSHA gene was associated with the increased risk of bladder cancer. Stratified analysis suggested that rs10719TC/CC genotype can increase risk of bladder cancer among male patients (Adjusted OR = 1.34, 95% CI = 1.05-1.70, P = 0.018), and ever smokers (1.56, 1.14-2.14, 0.006), compared with TT genotype. Furthermore, DROSHA rs10719T>C polymorphism was predicted to regulate the binding activity of hsa-miR-27a/b. Luciferase reported gene assay confirmed that rs10719 T to G substitution disrupted the binding site for hsa-miR-27b, resulting the increased levels of DROSHA protein.

Conclusions

Taken together, these findings suggested that DROSHA rs10719T>C polymorphism may be associated with bladder cancer risk in a Chinese population, and hsa-miR-27b can influence the expression of DROSHA protein by binding with 3’UTR.     

Genetic Polymorphisms of miR-146a and miR-27a,H. pylori Infection,and Risk of Gastric Lesions in a Chinese Population

Background

MicroRNAs (miRNAs) have been implicated in various human diseases. Single nucleotide polymorphisms (SNPs) in inflammation-related miRNA may play an important role in Helicobacter pylori (H. pylori)-induced gastric lesions. To evaluate the associations between miRNA SNPs, H. pylori and gastric lesions, a population-based study was conducted in Linqu County, China.

Methodology/Principal Findings

Based on serum miRNA array conducted in this population, two SNP loci (miR-146a rs2910164: G>C and miR-27a rs895819: T>C) were determined by polymerase chain reaction-restriction fragment length polymorphism in 2,380 participants with diverse gastric lesions. Using participants with superficial gastritis and mild chronic atrophic gastritis as the reference group, we found that rs2910164 CC carriers had a significantly increased risk of intestinal metaplasia [adjusted odds ratio (OR), 1.42; 95% confidence interval (CI), 1.03–1.97] and dysplasia (OR, 1.54; 95% CI, 1.05–2.25) compared to GG carriers, whereas no significant association was observed for rs895819. Stratified analysis by H. pylori infection indicated that rs2910164 C allele was associated with an increased risk of intestinal metaplasia and dysplasia only among individuals infected with H. pylori (CC vs. GG: OR, 1.53; 95% CI, 1.12–2.08, P for trend = 0.004). Participants who simultaneously carried variant alleles and H. pylori infection were more likely to develop intestinal metaplasia and dysplasia, although the interaction between genetic variants and H. pylori infection was not significant (P for interaction = 0.35 for rs2910164 and 0.92 for rs895819).

Conclusions/Significance

These findings suggest that miR-146a rs2910164 polymorphism may contribute to the evolution of H. pylori-associated gastric lesions in this high-risk population.     

Endothelial Nitric Oxide Synthase G894T Polymorphism Associates with Disease Severity in Puumala Hantavirus Infection

Introduction

Hantavirus infections are characterized by both activation and dysfunction of the endothelial cells. The underlying mechanisms of the disease pathogenesis are not fully understood. Here we tested the hypothesis whether the polymorphisms of endothelial nitric oxide synthase, eNOS G894T, and inducible nitric oxide synthase, iNOS G2087A, are associated with the severity of acute Puumala hantavirus (PUUV) infection.

Patients and Methods

Hospitalized patients (n = 172) with serologically verified PUUV infection were examined. Clinical and laboratory variables reflecting disease severity were determined. The polymorphisms of eNOS G894T (Glu298Asp, rs1799983) and iNOS G2087A (Ser608Leu, rs2297518) were genotyped.

Results

The rare eNOS G894T genotype was associated with the severity of acute kidney injury (AKI). The non-carriers of G-allele (TT-homozygotes) had higher maximum level of serum creatinine than the carriers of G-allele (GT-heterozygotes and GG-homozygotes; median 326, range 102–1041 vs. median 175, range 51–1499 μmol/l; p = 0.018, respectively). The length of hospital stay was longer in the non-carriers of G-allele than in G-allele carriers (median 8, range 3–14 vs. median 6, range 2–15 days; p = 0.032). The rare A-allele carriers (i.e. AA-homozygotes and GA-heterozygotes) of iNOS G2087A had lower minimum systolic and diastolic blood pressure than the non-carriers of A-allele (median 110, range 74–170 vs.116, range 86–162 mmHg, p = 0.019, and median 68, range 40–90 vs. 72, range 48–100 mmHg; p = 0.003, respectively).

Conclusions

Patients with the TT-homozygous genotype of eNOS G894T had more severe PUUV-induced AKI than the other genotypes. The eNOS G894T polymorphism may play role in the endothelial dysfunction observed during acute PUUV infection.     

A MAP3k1 SNP Predicts Survival of Gastric Cancer in a Chinese Population

Objectives

Genome-wide association studies (GWAS) have demonstrated that the single nucleotide polymorphism (SNP) MAP3K1 rs889312 is a genetic susceptibility marker significantly associated with a risk of hormone-related tumors such as breast cancer. Considering steroid hormone-mediated signaling pathways have an important role in the progression of gastric cancer, we hypothesized that MAP3K1 rs889312 may be associated with survival outcomes in gastric cancer. The purpose of this study was to test this hypothesis.

Methods

We genotyped MAP3K1 rs889312 using TaqMan in 884 gastric cancer patients who received subtotal or total gastrectomy. Kaplan-Meier survival analysis and Cox proportional hazard regression were used to analyze the association between MAP3K1 rs889312 genotypes and survival outcomes of gastric cancer.

Results

Our findings reveal that the rs889312 heterozygous AC genotype was significantly associated with an increased rate of mortality among patients with diffuse-type gastric cancer (log-rank P = 0.028 for AC versus AA/CC, hazard ratio [HR] = 1.32, 95% confidence interval [CI] = 1.03–1.69), compared to those carrying the homozygous variant genotypes (AA/CC). Additionally, univariate and multivariate Cox regression analysis demonstrate that rs889312 polymorphism was an independent risk factor for poor survival in these patients.

Conclusions

In conclusion, we demonstrate that MAP3K1 rs889312 is closely correlated with outcome among diffuse-type gastric cancer. This raises the possibility for rs889312 polymorphisms to be used as an independent indicator for predicting the prognosis of diffuse-type gastric cancer within the Chinese population.     

Association between Single Nucleotide Polymorphisms in the ADD3 Gene and Susceptibility to Biliary Atresia

Background and Objectives

Based on the results of previous studies, the ADD3 gene, located in the 10q24.2 region, may be a susceptibility gene of biliary atresia (BA). In this study, two single nucleotide polymorphisms (SNPs) in the ADD3 gene, rs17095355 C/T and rs10509906 G/C, were selected to investigate whether there is an association between these SNPs and susceptibility to BA in a Chinese population.

Methods

A total of 752 Han Chinese (134 BA cases and 618 ethnically matched healthy controls) were included in the present study. The ADD3 gene polymorphisms were genotyped using a TaqMan genotyping assay.

Results

Positive associations were found for the SNP rs17095355 in the codominant model; specifically, the frequencies of the CT and TT genotypes and the T allele were higher in the cases than the controls, demonstrating a significant risk for BA (odds ratio [OR] = 1.62, 95% confidence interval [CI] = 1.02–2.58; OR = 2.89, 95% CI = 1.72–4.86; and OR = 1.75, 95% CI = 1.34–2.29, respectively). Regarding rs10509906, the per-C-allele conferred an OR of 0.70 (95% CI = 0.49–1.00) under the additive model. A greater risk of BA was associated with the T_a-G_b (a for rs17095355 and b for rs10509906) haplotype (OR = 1.82, 95% CI = 1.27–2.61) compared with the C_a-C_b haplotype.

Conclusion

This study suggests that the ADD3 gene plays an important role in BA pathogenesis and reveals a significant association between two SNPs, rs17095355 and rs10509906, and BA.     

Association Analysis between the Polymorphisms of HSD11B1 and H6PD and Risk of Polycystic Ovary Syndrome in Chinese Population

Objectives

To evaluate whether single nucleotide polymorphisms of HSD11B1 (rs846908) and H6PD (rs6688832 and rs17368528) are associated with polycystic ovary syndrome (PCOS) in Chinese population.

Materials and Methods

A case-control study was implemented to investigate the association between HSD11B1 and H6PD polymorphisms and PCOS. Patients with PCOS (n = 335) and controls (n = 354) were recruited in this study. Genetic variants of HSD11B1 (rs846908) and H6PD (rs6688832 and rs17368528) were analyzed by TaqMan method.

Results

We found a significantly 0.79-fold lower risk of G allele of rs6688832 in control group compared with the patients with PCOS (adjusted OR, 0.79; 95%CI = 0.63–0.99; P = 0.040). Additionally, significant difference in the levels of follicle stimulating hormone (FSH) was observed between AA and AG genotype in rs6688832. The rs6688832 AG genotype was associated with lower level of FSH (P = 0.039) and higher risk of hyperandrogenism (P = 0.016) in patients with PCOS. When all subjects were divided into different subgroups according to age and body mass index (BMI), we found that the frequency of G allele of rs6688832 was significantly higher in controls than that in PCOS patients in the subgroup of BMI > 23 (adjusted OR, 0.70; 95% CI = 0.50–0.98; P = 0.037).

Conclusions

Our findings showed a statistical association between H6PD rs6688832 and PCOS risk in Chinese population. The G allele of rs6688832 in H6PD might exert potential genetic protective role against the development of PCOS, especially in overweight women. PCOS patients with AG genotype of rs6688832 might confer risk to the phenotype of hyperandrogenemia of PCOS.     

Variance of the SGK1 gene is associated with insulin secretion in different European populations: results from the TUEF, EUGENE2, and METSIM studies

Hypothesis

Serum- and Glucocorticoid-inducible Kinase 1 (SGK1) is involved in the regulation of insulin secretion and may represent a candidate gene for the development of type 2 diabetes mellitus in humans.

Methods

Three independent European populations were analyzed for the association of SGK1 gene (SGK) variations and insulin secretion traits. The German TUEF project provided the screening population (N = 725), and four tagging SNPs (rs1763527, rs1743966, rs1057293, rs9402571) were investigated. EUGENE2 (N = 827) served as a replication cohort for the detected associations. Finally, the detected associations were validated in the METSIM study, providing 3798 non-diabetic and 659 diabetic (type 2) individuals.

Results

Carriers of the minor G allele in rs9402571 had significantly higher C-peptide levels in the 2 h OGTT (+10.8%, p = 0.04; dominant model) and higher AUC_C-Peptide/AUC_Glc ratios (+7.5%, p = 0.04) compared to homozygous wild type TT carriers in the screening population. As interaction analysis for BMI×rs9402571 was significant (p = 0.04) for the endpoint insulin secretion, we stratified the TUEF cohort for BMI, using a cut off point of BMI = 25. The effect on insulin secretion only remained significant in lean TUEF participants (BMI≤25). This finding was replicated in lean EUGENE2 rs9402571 minor allele carriers, who had a significantly higher AUC_Ins/AUC_Glc (TT: 226±7, XG: 246±9; p = 0.019). Accordingly, the METSIM trial revealed a lower prevalence of type 2 diabetes (OR: 0.85; 95%CI: 0.71–1.01; p = 0.065, dominant model) in rs9402571 minor allele carriers.

Conclusions

The rs9402571 SGK genotype associates with increased insulin secretion in lean non-diabetic TUEF/EUGENE2 participants and with lower diabetes prevalence in METSIM. Our study in three independent European populations supports the conclusion that SGK variability affects diabetes risk.     

Positive Association between APOA5 rs662799 Polymorphism and Coronary Heart Disease: A Case-Control Study and Meta-Analysis

Objective

Apolipoprotein A5 (APOA5) is associated with plasma triglyceride (TG) levels, a risk factor for coronary heart disease (CHD). This study explored the association between CHD and the APOA5 rs662799 polymorphism.

Methods

We collected 1,521 samples (783 CHD patients and 738 controls) for this case-control study. Meta-analysis was performed using Review Manager Software and Stata Software.

Results

Significant differences were observed between CHD cases and controls at the level of both genotype (χ² = 8.964, df = 2, P = 0.011) and allele (χ² = 9.180, df = 1, P = 0.002, OR = 1.275, 95% CI = 1.089–1.492). A breakdown analysis by gender showed a significant association of APOA5 rs662799 with CHD in males (χ² = 7.770, df = 1, P = 0.005; OR = 1.331, 95% CI = 1.088–1.628). An additional meta-analysis using 21378 cases and 28428 controls established that rs662799 is significantly associated with CHD (P < 0.00001).

Conclusion

Both our case-control study and meta-analysis confirm a significant association between APOA5 rs662799 and CHD. In addition, our results suggest a male-specific association between the APOA5 rs662799 polymorphism and CHD.     

Oncogenic CagA promotes gastric cancer risk via activating ERK signaling pathways: a nested case-control study

Background

CagA cellular interaction via activation of the ERK signaling pathway may be a starting point in the development of gastric cancer. This study aimed to evaluate whether genes involved in ERK downstream signaling pathways activated by CagA are susceptible genetic markers for gastric cancer.

Methods

In the discovery phase, a total of 580 SNPs within +/−5 kbp of 30 candidate genes were genotyped to examine an association with gastric cancer risk in the Korean Multi-center Cancer Cohort (100 incident gastric cancer case-control sets). The most significant SNPs (raw or permutated p value<0.02) identified in the discovery analysis were re-evaluated in the extension phase using unconditional logistic regression model (400 gastric cancer case-control sets). Combined analyses including pooled- and meta-analysis were conducted to summarize all the results.

Results

24 SNPs in eight genes (ERK, Dock180, C3G, Rap1, Src, CrkL, Mek and Crk) were significantly associated with gastric cancer risk in the individual SNP analyses in the discovery phase (p<0.05). In the extension analyses, ERK rs5999749, Dock180 rs4635002 and C3G rs7853122 showed marginally significant gene-dose effects for gastric cancer. Consistently, final combined analysis presented the SNPs as significantly associated with gastric cancer risk (OR = 1.56, [95% CI: 1.19–2.06], OR = 0.61, [95% CI: 0.43–0.87], OR = 0.59, [95% CI: 0.54–0.76], respectively).

Conclusions

Our findings suggest that ERK rs5999749, Dock180 rs4635002 and C3G rs7853122 are genetic determinants in gastric carcinogenesis.     

Ghrelin Gene Variants Influence on Metabolic Syndrome Components in Aged Spanish Population

Background

The role of genetic variations within the ghrelin gene on cardiometabolic profile and nutritional status is still not clear in humans, particularly in elderly people.

Objectives

We investigated six SNPs of the ghrelin gene and their relationship with metabolic syndrome (MS) components.

Subjects and Methods

824 subjects (413 men/411 women, age 77.31±5.04) participating in the Mataró aging study (n = 310) and the Hortega study (n = 514) were analyzed. Anthropometric variables, ghrelin, lipids, glucose and blood pressure levels were measured, and distribution of SNPs -994CT (rs26312), -604GA (rs27647), -501AC (rs26802), R51Q (rs34911341), M72L (rs696217) and L90G (rs4684677) of the ghrelin gene evaluated. Genotypes were determined by multiplex PCR and SNaPshot minisequencing. MS (IDF criteria) was found in 54.9%.

Results

No association between any of the SNPs and levels of total fasting circulating ghrelin levels was found. C/A-A/A genotype of M72L was associated with increased risk of central obesity according to IDF criteria, while G/A-G/G genotypes of -604GA with reduced risk. A/A genotype of -501AC polymorphism was associated to decreased BMI. In relation to lipid profile, the same genotypes of -604GA were associated with increased total cholesterol and LDL-cholesterol and -501AC with reduced triglycerides. There were no associations with systolic or diastolic blood pressure levels or with hypertension, glucose levels or diabetes and ghrelin polymorphisms. However, G/G genotype of -604GA was associated with glucose >100 mg/dL. Haplotype analysis showed that only one haplotype is associated with increased risk of waist circumference and central obesity. The analysis of subjects by gender showed an important and different association of these polymorphisms regarding MS parameters.

Conclusion

Ghrelin gene variants -604GA, -501AC and M72L are associated with certain components of MS, in particular to BMI and lipid profile in elderly Spanish subjects.