Smoking related cancers and loci at chromosomes 15q25, 5p15, 6p22.1 and 6p21.33 in the Polish population

Genetic factors associated with the risk of smoking related cancers have until recently remained elusive. Since the publication of a genome-wide association study (GWAS) on lung cancer new genetic loci have been identified that appear to be associated with disease risk. In this replication study we genotyped 14 single nucleotide polymorphisms (SNPs) located at the 5p12.3-p15.33, 6p21.3-p22.1, 6q23-q27 and 15q25.1 loci in 874 lung, 450 bladder, 418 laryngeal cancer cases and cancer-free controls, matched by year of birth and sex to the cases. Our results revealed that loci in the chromosome region 15q25.1 (rs16969968[A], rs8034191[G]) and 5p15 (rs402710[T]) are associated with lung cancer risk in the Polish population (smoking status adjusted OR = 1.45, 1.35, 0.77; p ≤ 0.0001, 0.0005, 0.002; 95%CI 1.23-1.72, 1.14-1.59, 0.66-0.91 respectively). None of the other regions analyzed herein were implicated in the risk of lung, bladder or laryngeal cancer. This study supports previous findings on lung cancer but fails to show association of SNPs located in 15q25.1 and 5p15 region with other smoking related cancers like bladder and laryngeal cancer.     

Association of chromosome 8q24 variants with prostate cancer risk in the Siberian region of Russia and meta-analysis

Compelling evidence demonstrates chromosome 8q24 as a prostate cancer susceptibility locus. In present work we studied whether the common variants of 8q24 region, rs6983267 and rs1447295, were associated with the sporadic prostate cancer risk in the Russian population. Polymorphisms were genotyped in 393 case and 384 control Russian Caucasian men from Siberia region. The A allele of rs1447295 was significantly associated with the risk of prostate cancer (OR[CI 95%] = 1.74 [1.26-2.4], p = 7.8 x 10(-4)). A common G-A haplotype for rs6983267 - rs1447295 also showed an association with prostate cancer risk in Russian population (OR[CI 95%] = 2.03 [1.1 - 3.75], p = 0.02). We performed a meta-analysis combining our results with previous studies to evaluate the association between studied SNPs and prostate cancer risk. Meta-analysis has strongly supported the association for these SNPs (p < 10(-6)). Accordingly our study confirms the association between chromosome 8q24 and prostate cancer risk.     

Replication study of PLCE1 and C20orf54 polymorphism and risk of esophageal cancer in a Chinese population

Esophageal cancer is one of the most aggressive cancers in the world. Recent large-scale genome-wide association studies (GWAS) reported that functional genetic variations in the phospholipase C epsilon gene (PLCE1) were strongly associated with risk of esophageal squamous cell carcinoma (ESCC) and gastric cardia adenocarcinoma (GCA) in Chinese population. For C20orf54 rs13042395 genotype and risk of esophageal cancer, the results were inconsistent. We conducted a replication case-control study to evaluate the genetic effects of these two functional single nucleotide polymorphisms (SNPs) on the development of esophageal cancer. A total of 380 cases and 380 controls were recruited for this study. The genotypes were determined by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS). The variant alleles of the functional polymorphism, PLCE1 rs2274223 SNP was associated with the increased risk of esophageal cancer [adjusted odds ratio (OR) = 1.95, 95 % confidence interval (CI) = 1.05-3.59 for PLCE1 rs2274223 GG vs. AA]. However, there was no significant association between the C20orf54 rs13042395 genotype and esophageal cancer risk (adjusted OR = 0.99, 95 % CI = 0.63-1.57 for C20orf54 rs13042395 TT vs. CC). Stratified analyses indicated a significantly increased risk of esophageal cancer associated with the PLCE1 rs2274223 AG genotype was more evident among females, younger patients and never drinkers, compared with the PLCE1 rs2274223 AA genotypes. Stratified analyses also indicated a significantly increased risk of esophageal cancer associated with the PLCE1 rs2274223 GG genotype was more evident among never smokers and never drinkers compared with the PLCE1 rs2274223 AA genotypes. These findings indicated that functional polymorphisms PLCE1 rs2274223 might contribute to esophageal cancer susceptibility.     

Genetic variant in TP63 on locus 3q28 is associated with risk of lung adenocarcinoma among never-smoking females in Asia

A recent genome-wide association study (GWAS) of subjects from Japan and South Korea reported a novel association between the TP63 locus on chromosome 3q28 and risk of lung adenocarcinoma (p = 7.3 × 10(-12)); however, this association did not achieve genome-wide significance (p ≤ 10(-7)) among never-smoking males or females. To determine if this association with lung cancer risk is independent of tobacco use, we genotyped the TP63 SNPs reported by the previous GWAS (rs10937405 and rs4488809) in 3,467 never-smoking female lung cancer cases and 3,787 never-smoking female controls from 10 studies conducted in Taiwan, Mainland China, South Korea, and Singapore. Genetic variation in rs10937405 was associated with risk of lung adenocarcinoma [n = 2,529 cases; p = 7.1 × 10(-8); allelic risk = 0.80, 95% confidence interval (CI) = 0.74-0.87]. There was also evidence of association with squamous cell carcinoma of the lung (n = 302 cases; p = 0.037; allelic risk = 0.82, 95% CI = 0.67-0.99). Our findings provide strong evidence that genetic variation in TP63 is associated with the risk of lung adenocarcinoma among Asian females in the absence of tobacco smoking.     

HapMap-based study of a region encompassing ERCC1 and ERCC2 related to lung cancer susceptibility in a Chinese population

DNA repair genes play a crucial role in carcinogenesis. The paper aims to explore if common variants in ERCC1 are involved in lung cancer susceptibility. A Chinese case-control study included 339 lung cancer cases and 358 controls using five haplotype-tagging SNPs (htSNPs) (rs3212980, rs3212964, rs3212961, rs11615 and rs2298881) from the HapMap database, capturing 95% of the common haplotypic diversity of ERCC1. A combined analysis of eleven htSNPs covering ERCC2 and ERCC1 was performed. No significant association between individual htSNPs and lung cancer susceptibility was observed. There were interactions between rs3212961 and rs2298881and smoking duration (P=0.03 and P=0.01, respectively). Thus, the variant alleles of rs3212961 [OR (95% CI)=1.81(1.03-3.17), P=0.04] and rs2298881 [OR (95% CI)=2.16(1.26-3.70), P=0.005] were associated with risk of lung cancer among long-term smokers (>20 years) but not among never smokers and short-term smokers. No significant associations with lung cancer susceptibility were observed for global or individual haplotypes defined by five htSNPs of ERCC1. A highly differential distribution of haplotypes based on eleven htSNPs covering ERCC2 and ERCC1 were found (global test P=4.3×10(-5)). After Bonferroni correction, haplotypeER2+1-1 [OR (95% CI)=3.63 (1.39-9.47), P=0.005, marginally] and haplotypeER2+1-8 [OR (95% CI)=4.46 (2.03-9.79), P=5.6×10(-5), strongly] were associated with increased risk of lung cancer. The diplotype analysis with haplotypeER2+1-8 was also statistically significant (P<0.001). Haplotype analysis of pathological subtypes revealed that htSNPs of both genes may mainly influence the risk of lung adenocarcinoma. Strong linkage disequilibrium exist in two regions encompassing ERCC2 and ERCC1. These data suggest that common genetic variations in ERCC1 may influence increased risk of smoking-related lung cancer and one of the causative effectors may locate around or within ERCC2.     

A Genome-wide Association Study of Lung Cancer Identifies a Region of Chromosome 5p15 Associated with Risk for Adenocarcinoma

Three genetic loci for lung cancer risk have been identified by genome-wide association studies (GWAS), but inherited susceptibility to specific histologic types of lung cancer is not well established. We conducted a GWAS of lung cancer and its major histologic types, genotyping 515,922 single-nucleotide polymorphisms (SNPs) in 5739 lung cancer cases and 5848 controls from one population-based case-control study and three cohort studies. Results were combined with summary data from ten additional studies, for a total of 13,300 cases and 19,666 controls of European descent. Four studies also provided histology data for replication, resulting in 3333 adenocarcinomas (AD), 2589 squamous cell carcinomas (SQ), and 1418 small cell carcinomas (SC). In analyses by histology, rs2736100 (TERT), on chromosome 5p15.33, was associated with risk of adenocarcinoma (odds ratio [OR] = 1.23, 95% confidence interval [CI] = 1.13–1.33, p = 3.02 × 10⁻⁷), but not with other histologic types (OR = 1.01, p = 0.84 and OR = 1.00, p = 0.93 for SQ and SC, respectively). This finding was confirmed in each replication study and overall meta-analysis (OR = 1.24, 95% CI = 1.17–1.31, p = 3.74 × 10⁻¹⁴ for AD; OR = 0.99, p = 0.69 and OR = 0.97, p = 0.48 for SQ and SC, respectively). Other previously reported association signals on 15q25 and 6p21 were also refined, but no additional loci reached genome-wide significance. In conclusion, a lung cancer GWAS identified a distinct hereditary contribution to adenocarcinoma.     

The XRCC1 399 glutamine allele is a risk factor for adenocarcinoma of the lung

Defects in the repair and maintenance of DNA increase risk for cancer. X-ray cross-complementing group 1 protein (XRCC1) is involved with the repair of DNA single-strand breaks. A nucleotide substitution of guanine to adenine leading to a non-conservative amino acid change was identified in the XRCC1 gene at codon 399 (Arg/Gln). This change is associated with higher levels of aflatoxin B1-adducts and glycophorin A somatic mutations. A case-control study was conducted to test the hypothesis that the 399Gln allele is positively associated with risk for adenocarcinoma of the lung. XRCC1 genotypes were assessed at codon 399 in 172 cases of lung adenocarcinoma and 143 cancer-free controls. Two ethnic populations were represented, non-Hispanic White and Hispanic. The distribution of XRCC1 genotypes differed between cases and controls. Among cases, 47.7% were Arg/Arg, 35.5% were Arg/Gln, and 16.9% were Gln/Gln. Among controls, XRCC1 allele frequencies were 45.5% for Arg/Arg, 44.8% for Arg/Gln, and 9.8% for Gln/Gln. Logistic regression analysis was used to assess the association between lung adenocarcinoma and the G/G genotype relative to the A/A or A/G genotypes. In non-Hispanic White participants, the lung cancer risk associated with the G/G genotype increased significantly after adjustment for age (OR=2.81; 95% CI, 1.2-7.9; P=0.03) and increased further after adjustment for smoking (OR=3.25; 95% CI, 1.2-10.7; P=0.03). Among all groups, a significant association was found between the G/G homozygote and lung cancer (OR=2.45; 95% CI, 1.1-5.8; P=0.03) after adjustment for age, ethnicity, and smoking. This study links a functional polymorphism in the critical repair gene XRCC1 to risk for adenocarcinoma of the lung.     

Large scale international replication and meta-analysis study confirms association of the 15q14 locus with myopia. The CREAM consortium

Myopia is a complex genetic disorder and a common cause of visual impairment among working age adults. Genome-wide association studies have identified susceptibility loci on chromosomes 15q14 and 15q25 in Caucasian populations of European ancestry. Here, we present a confirmation and meta-analysis study in which we assessed whether these two loci are also associated with myopia in other populations. The study population comprised 31 cohorts from the Consortium of Refractive Error and Myopia (CREAM) representing 4 different continents with 55,177 individuals; 42,845 Caucasians and 12,332 Asians. We performed a meta-analysis of 14 single nucleotide polymorphisms (SNPs) on 15q14 and 5 SNPs on 15q25 using linear regression analysis with spherical equivalent as a quantitative outcome, adjusted for age and sex. We calculated the odds ratio (OR) of myopia versus hyperopia for carriers of the top-SNP alleles using a fixed effects meta-analysis. At locus 15q14, all SNPs were significantly replicated, with the lowest P value 3.87?×?10(-12) for SNP rs634990 in Caucasians, and 9.65?×?10(-4) for rs8032019 in Asians. The overall meta-analysis provided P value 9.20?×?10(-23) for the top SNP rs634990. The risk of myopia versus hyperopia was OR 1.88 (95?% CI 1.64, 2.16, P?相似文献   

Polymorphisms in base-excision repair and nucleotide-excision repair genes in relation to lung cancer risk

Polymorphisms in DNA repair genes may be associated with differences in DNA repair capacity, thereby influencing the individual susceptibility to smoking-related cancer. We investigated the association of 10 base-excision and nucleotide-excision repair gene polymorphisms (XRCC1 -77 T/C, Arg194Trp, Arg280His and Arg399Gln; APE1 Asp148Glu; OGG1 Ser326Cys; XPA -4 G/A; XPC PAT; XPD Asp312Asn and Lys751Gln) with lung cancer risk in Caucasians. Genotypes were determined by PCR-RFLP and PCR-single base extension assays in 110 lung cancer patients and 110 age- and sex-matched controls, and the results were analyzed using logistic regression adjusted for relevant covariates. A significant association between the APE1 Asp148Glu polymorphism and lung cancer risk was found, with adjusted odds ratios (OR) of 3.38 (p=0.001) for the Asp/Glu genotype and 2.39 (p=0.038) for the Glu/Glu genotype. Gene-smoking interaction analyses revealed a statistically significant interaction between cumulative cigarette smoking and the XRCC1 Arg399Gln and XPD Lys751Gln polymorphisms: these polymorphisms were significantly associated with lung cancer in nonsmokers and light smokers (<25 PY; OR=4.92, p=0.021 for XRCC1 399 Gln/Gln; OR=3.62, p=0.049 for XPD 751 Gln/Gln), but not in heavy smokers (> or =25 PY; OR=0.68, p=0.566 for XRCC1 399 Gln/Gln; OR=0.46, p=0.295 for XPD 751 Gln/Gln). Both the XRCC1 Arg194Trp and Arg280His as well as the OGG1 Ser326Cys heterozygous genotypes were associated with a significantly reduced risk for lung cancer (OR=0.32, p=0.024; OR=0.25, p=0.028; OR=0.51, p=0.033, respectively). No associations with lung cancer risk were found for the XRCC1 -77 T/C, the XPA -4 G/A and the XPC PAT polymorphisms. In conclusion, the APE1 Asp148Glu polymorphism is highly predictive for lung cancer, and cumulative cigarette smoking modifies the associations between the XRCC1 Arg399Gln and the XPD Lys751Gln polymorphisms and lung cancer risk.     

Chromosome 15q25 (CHRNA3-CHRNB4) Variation Indirectly Impacts Lung Cancer Risk in Chinese Males

Introduction

Recently, genome-wide association studies (GWAS) in Caucasian populations have identified an association between single nucleotide polymorphisms (SNPs) in the CHRNA5-A3-B4 nicotinic acetylcholine receptor subunit gene cluster on chromosome 15q25, lung cancer risk and smoking behaviors. However, these SNPs are rare in Asians, and there is currently no consensus on whether SNPs in CHRNA5-A3-B4 have a direct or indirect carcinogenic effect through smoking behaviors on lung cancer risk. Though some studies confirmed rs6495308 polymorphisms to be associated with smoking behaviors and lung cancer, no research was conducted in China. Using a case-control study, we decided to investigate the associations between CHRNA3 rs6495308, CHRNB4 rs11072768, smoking behaviors and lung cancer risk, as well as explore whether the two SNPs have a direct or indirect carcinogenic effect on lung cancer.

Methods

A total of 1025 males were interviewed using a structured questionnaire (204 male lung cancer patients and 821 healthy men) to acquire socio-demographic status and smoking behaviors. Venous blood samples were collected to measure rs6495308 and rs11072768 gene polymorphisms. All subjects were divided into 3 groups: non-smokers, light smokers (1–15 cigarettes per day) and heavy smokers (>15 cigarettes per day).

Results

Compared to wild genotype, rs6495308 and rs11072768 variant genotypes reported smoking more cigarettes per day and a higher pack-years of smoking (P<0.05). More importantly, among smokers, both rs6495308 CT/TT and rs11072768 GT/GG had a higher risk of lung cancer compared to wild genotype without adjusting for potential confounding factors (OR = 1.36, 95%CI = 1.09–1.95; OR = 1.11, 95%CI = 1.07–1.58 respectively). Furthermore, heavy smokers with rs6495308 or rs11072768 variant genotypes have a positive interactive effect on lung cancer after adjustment for potential confounding factors (OR = 1.13, 95%CI = 1.01–3.09; OR = 1.09, 95%CI = 1.01–3.41 respectively). However, No significant associations were found between lung cancer risk and both rs6495308 and rs11072768 genotypes among non-smokers and smokers after adjusting for age, occupation, and education.

Conclusion

This study confirmed both rs6495308 and rs11072768 gene polymorphisms association with smoking behaviors and had an indirect link between gene polymorphisms and lung cancer risk.     

MicroRNA Related Polymorphisms and Breast Cancer Risk

Genetic variations, such as single nucleotide polymorphisms (SNPs) in microRNAs (miRNA) or in the miRNA binding sites may affect the miRNA dependent gene expression regulation, which has been implicated in various cancers, including breast cancer, and may alter individual susceptibility to cancer. We investigated associations between miRNA related SNPs and breast cancer risk. First we evaluated 2,196 SNPs in a case-control study combining nine genome wide association studies (GWAS). Second, we further investigated 42 SNPs with suggestive evidence for association using 41,785 cases and 41,880 controls from 41 studies included in the Breast Cancer Association Consortium (BCAC). Combining the GWAS and BCAC data within a meta-analysis, we estimated main effects on breast cancer risk as well as risks for estrogen receptor (ER) and age defined subgroups. Five miRNA binding site SNPs associated significantly with breast cancer risk: rs1045494 (odds ratio (OR) 0.92; 95% confidence interval (CI): 0.88–0.96), rs1052532 (OR 0.97; 95% CI: 0.95–0.99), rs10719 (OR 0.97; 95% CI: 0.94–0.99), rs4687554 (OR 0.97; 95% CI: 0.95–0.99, and rs3134615 (OR 1.03; 95% CI: 1.01–1.05) located in the 3′ UTR of CASP8, HDDC3, DROSHA, MUSTN1, and MYCL1, respectively. DROSHA belongs to miRNA machinery genes and has a central role in initial miRNA processing. The remaining genes are involved in different molecular functions, including apoptosis and gene expression regulation. Further studies are warranted to elucidate whether the miRNA binding site SNPs are the causative variants for the observed risk effects.     

ERAP1 genetic variations associated with HLA-B27 interaction and disease severity of syndesmophytes formation in Taiwanese ankylosing spondylitis

IntroductionAnkylosing spondylitis (AS) is a familial, heritable disease specified by syndesmophyte formation leading to an ankylosed spine. Endoplasmic reticulum aminopeptidase 1 (ERAP1) genetic variations have been widely proved to be associated with AS in several ethnic populations. The aim of this study was to investigate whether ERAP1 single nucleotide polymorphisms (SNPs) are associated with AS susceptibility and disease severity in Taiwanese.MethodsFour ERAP1 SNPs (rs27037, rs27980, rs27044 and rs30187) were genotyped in 797 Taiwanese AS patients and 1,150 healthy controls. Distributions of genotype and alleles were compared between AS patients and healthy controls, and among AS patients stratified by clinical parameters.ResultsThe SNP rs27037T allele appeared to be a risk factor for AS susceptibility (P = 5.5 × 10^-5, OR 1.30, 95% CI: 1.15 to 1.48; GT+TT vs. GG P = 9.3 × 10^-5, OR 1.49, 95% CI: 1.22 to 1.82). In addition, the coding SNP (cSNP) rs27044G allele (P = 1.5 × 10^-4, OR 1.28, 95% CI: 1.13 to 1.46; CG+GG vs. CC, P = 1.7 × 10^-3, OR 1.44, 95% CI: 1.15 to 1.81) and the cSNP rs30187T allele (P = 1.7 × 10^-3, OR 1.23, 95% CI: 1.08 to 1.40; CT+TT vs. CC P = 6.1 × 10^-3, OR 1.38, 95% CI: 1.10 to 1.74) were predisposing factors for AS. Notably, the rs27044G allele carriers (CG+GG vs. CC, P = 0.015, OR 1.59, 95% CI: 1.33 to 2.30) and rs30187T allele carriers (CT+TT vs. CC, P = 0.011, OR 1.63, 95% CI: 1.12 to 2.38) were susceptible to syndesmophyte formation in AS patients. Furthermore, two cSNPs (rs27044 and rs30187) strongly associated with HLA-B27 positivity in AS patients. Finally, the ERAP1 SNP haplotype TCG (rs27037T/rs27980C/rs27044G) is a major risk factor for AS (adjusted P <0.00001, OR 1.38, 95% CI: 1.12 to 1.58) in Taiwanese.ConclusionsThis study provides the first evidence of ERAP1 SNPs involving syndesmophyte formation. The interactions between ERAP1 SNPs and HLA-B27 play critical roles in pMHC I pathway processing contributing to the pathogenesis of AS in multiple populations.     

人染色体8p11(CHRNB3-CHRNA6)区域基因多态性与中国汉族人群肺癌易感性的相关性

为探讨人染色体8p11(CHRNB3-CHRNA6)区域基因多态性与中国汉族人群肺癌遗传易感性之间的关系,文章采用病例-对照研究,对784例肺癌患者和782例性别、年龄、籍贯频数与之相匹配的健康对照中该区域6个标签SNP位点进行基因分型,并统计分析其基因型频率分布与肺癌易感性的关系,以及吸烟在其中的影响。结果发现rs16891561位点TT基因型在60岁以上人群(校正OR=0.42,95%CI=0.20-0.88;P=0.022)、女性人群(校正OR=0.34,95%CI=0.13-0.87;P=0.025)、非吸烟人群中(校正OR=0.32,95%CI=0.13-0.79;P=0.013)对肺癌发生具有保护效应;rs4236926位点TT基因型在60岁以上人群(校正OR=0.48,95%CI=0.23-0.99;P=0.048)、非吸烟人群(校正OR=0.32,95%CI=0.13-0.80;P=0.014)中对肺癌发生具有保护效应,这两种保护效应主要是与腺癌相关。对这两个位点进行累积效应分析发现,含有3~4个变异等位基因型的非吸烟者罹患肺癌的风险显著降低(校正OR=0.29,95%CI=0.11-0.71;P=0.007),并且,含有3~4个变异等位基因型的个体累计吸烟量("包-年"平均数=13.2)与其他个体相比显著降低。由此可见人染色体8p11(CHRNB3-CHRNA6)区域基因多态性与中国汉族人群肺癌易感性和吸烟行为相关。     

Associations of Genetic Variants in the PSCA,MUC1 and PLCE1 Genes with Stomach Cancer Susceptibility in a Chinese Population

BackgroundSeveral genetic variants including PSCA rs2294008 C>T and rs2976392 G>A, MUC1 rs4072037 T>C, and PLCE1 rs2274223 A>G have shown significant association with stomach cancer risk in the previous genome-wide association studies (GWASs).MethodsTo evaluate associations of these SNPs in the Han Chinese, an independent hospital based case-control study was performed by genotyping these four polymorphisms in a total of 692 stomach cancer cases and 774 healthy controls acquired by using frequency matching for age and gender. False-positive report probability (FPRP) analysis was also performed to validate all statistically significant findings.ResultsIn the current study, significant association with stomach cancer susceptibility was observed for all the four polymorphisms of interest. Specifically, a significant increased stomach cancer risk was associated with PSCA rs2294008 (CT vs. CC: adjusted OR = 1.37, 95% CI = 1.07–1.74, and CT/TT vs.CC: adjusted OR = 1.30, 95% CI = 1.03–1.63), PSCA rs2976392 (AG vs. GG: adjusted OR = 1.30, 95% CI = 1.02–1.65, and AG/AA vs. GG: adjusted OR = 1.26, 95% CI = 1.00–1.59), or PLCE1 rs2274223 (AG vs. AA: adjusted OR = 1.48, 95% CI = 1.15–1.90, and AG/GG vs. AA: adjusted OR = 1.45, 95% CI = 1.14–1.84), respectively. In contrast, MUC1 rs4072037 was shown to decrease the cancer risk (CT vs. TT: adjusted OR = 0.77, 95% CI = 0.60–0.98). Patients with more than one risk genotypes had significant increased risk to develop stomach cancer (adjusted OR = 1.30, 95% CI = 1.03–1.64), when compared with those having 0–1 risk genotypes. Stratified analysis indicated that the increased risk was more pronounced in younger subjects, men, ever smokers, smokers with pack years ≤ 27, patients with high BMI, or non-cardia stomach cancer.ConclusionsThis study substantiated the associations between four previous reported genetic variants and stomach cancer susceptibility in an independent Han Chinese population. Further studies with larger sample size and different ethnicities are warranted to validate our findings.     

Polymorphisms in the XPG gene and risk of gastric cancer in Chinese populations

DNA repair genes play an important role in maintaining stability and integrity of genomic DNA. Polymorphisms in nucleotide excision repair genes may cause variations in DNA repair capacity phenotype and thus contribute to cancer risk. In this case-control study of 1,125 gastric cancer cases and 1,196 cancer-free controls, we investigated the association between three functional single nucleotide polymorphisms (SNPs, rs2296147T > C, rs2094258C > T and rs873601G > A) in the xeroderma pigmentosum group G (XPG) gene and gastric cancer risk. We used the Taqman assays to genotype these three SNPs and logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs). We found that only the rs873601A variant genotypes were associated with a significant higher risk for gastric adenocarcinoma (adjusted OR = 1.30, 95% CI = 1.03-1.64 for AA vs. GG and adjusted OR = 1.23, 95% CI = 1.01-1.49 for AA vs. GG/AG). Stratification analysis indicated that this risk was more pronounced in subgroups of older age (>59 years), males, ever-smokers, and patients with NGCA. All these were not found for the other two SNPs (rs2296147T > C and rs2094258C > T). We then performed expression analysis using gastric cancer adjacent normal tissues from 141 patients and found that the A variant allele was associated with non-significantly reduced expression of XPG mRNA (P(trend) = 0.107). Further analysis using mRNA expression data from the HapMap suggested that the A allele was associated with significantly reduced expression of XPG mRNA in normal cell lines for 45 Chinese (P(trend) = 0.003) as well as for 261 subjects with different ethnicities (P(trend) = 0.001). These support the hypothesis that functional XPG variants may contribute to the risk of gastric cancer. Larger studies with different ethnic populations are warranted to validate our findings.     

Are SNP-Smoking Association Studies Needed in Controls? DNA Repair Gene Polymorphisms and Smoking Intensity

Variations in tobacco-related cancers, incidence and prevalence reflect differences in tobacco consumption in addition to genetic factors. Besides, genes related to lung cancer risk could be related to smoking behavior. Polymorphisms altering DNA repair capacity may lead to synergistic effects with tobacco carcinogen-induced lung cancer risk. Common problems in genetic association studies, such as presence of gene-by-environment (G x E) correlation in the population, may reduce the validity of these designs. The main purpose of this study was to evaluate the independence assumption for selected SNPs and smoking behaviour in a cohort of 320 healthy Spanish smokers. We found an association between the wild type alleles of XRCC3 Thr241Met or KLC3 Lys751Gln and greater smoking intensity (OR = 12.98, 95% CI = 2.86–58.82 and OR=16.90, 95% CI=2.09-142.8; respectively). Although preliminary, the results of our study provide evidence that genetic variations in DNA-repair genes may influence both smoking habits and the development of lung cancer. Population-specific G x E studies should be carried out when genetic and environmental factors interact to cause the disease.     

Significant association of SNP rs2106261 in the ZFHX3 gene with atrial fibrillation in a Chinese Han GeneID population

Atrial fibrillation (AF) is the most common cardiac rhythm disorder at the clinical setting and accounts for up to 15% of all strokes. Recent genome-wide association studies (GWAS) identified two single nucleotide polymorphisms (SNPs), rs2106261 and rs7193343 in ZFHX3 (zinc finger homeobox 3 gene) and rs13376333 in KCNN3 (encoding a potassium intermediate/small conductance calcium-activated channel, subfamily N, member 3) that showed significant association with AF in multiple populations of European ancestry. Here, we studied a Chinese Han, GeneID cohort consisting of 650 AF patients and 1,447 non-AF controls to test whether the GWAS findings on ZFHX3/KCNN3 and AF can be expanded to a different ethnic population. No significant association was detected for rs7193343 in ZFHX3 and rs13376333 in KCNN3. However, significant association was identified between rs2106261 in ZFHX3 and AF in the GeneID population for both allelic frequencies (P=0.001 after adjusting for covariates of age, gender, hypertension, coronary artery disease, and diabetes mellitus; OR=1.32), and genotypic frequencies assuming either an additive or recessive model (OR=1.29, P=0.001 and OR=1.77, P =0.00018, respectively). When only lone AF cases were analyzed, the association remained significant (OR=1.50, P=0.001 for allelic association; OR=1.45, P=0.001 for an additive model; OR=2.24, P=0.000043 for a recessive model). Our results indicate that rs2106261 in ZFHX3 confers a significant risk of AF in a Chinese Han population. The study expands the association between ZFHX3 and AF to a non-European ancestry population and provides the first evidence of a cross-race susceptibility of the 16q22 AF locus.     

A common genetic variant of 5p15.33 is associated with risk for prostate cancer in the Chinese population

Recent evidence has suggested that single-nucleotide polymorphisms (SNPs) located at 5p15.33 contribute to susceptibilities for several cancer types, including prostate cancer. To determine whether SNP rs402710 in this region plays a role in prostate cancer, we analyzed these associations in a Chinese population; 251 prostate cancer patients and 273 control subjects were included in this case-control study. Genotypes were determined by PCR-RFLP. We found that subjects carrying the CC homozygote had a decreased risk for prostrate cancer compared to those carrying TT/TC genotypes (odds ratio (OR) = 0.69, 95% confidence interval (CI) = 0.48-0.98, P = 0.038). Compared with the TT homozygote, subjects carrying the CC homozygote also had a decreased risk for prostate cancer (OR = 0.71, 95%CI = 0.51-0.99, P = 0.043). We conclude that rs402710 polymorphisms in the 5p15.33 region are associated with prostate cancer risk in the Chinese population. Further investigations with large cohorts and done worldwide are warranted to determine whether our findings are detected in other populations.     

Characterization of SNPs Associated with Prostate Cancer in Men of Ashkenazic Descent from the Set of GWAS Identified SNPs: Impact of Cancer Family History and Cumulative SNP Risk Prediction

Background

Genome-wide association studies (GWAS) have identified multiple SNPs associated with prostate cancer (PrCa). Population isolates may have different sets of risk alleles for PrCa constituting unique population and individual risk profiles.

Methods

To test this hypothesis, associations between 31 GWAS SNPs of PrCa were examined among 979 PrCa cases and 1,251 controls of Ashkenazic descent using logistic regression. We also investigated risks by age at diagnosis, pathological features of PrCa, and family history of cancer. Moreover, we examined associations between cumulative number of risk alleles and PrCa and assessed the utility of risk alleles in PrCa risk prediction by comparing the area under the curve (AUC) for different logistic models.

Results

Of the 31 genotyped SNPs, 8 were associated with PrCa at p≤0.002 (corrected p-value threshold) with odds ratios (ORs) ranging from 1.22 to 1.42 per risk allele. Four SNPs were associated with aggressive PrCa, while three other SNPs showed potential interactions for PrCa by family history of PrCa (rs8102476; 19q13), lung cancer (rs17021918; 4q22), and breast cancer (rs10896449; 11q13). Men in the highest vs. lowest quartile of cumulative number of risk alleles had ORs of 3.70 (95% CI 2.76–4.97); 3.76 (95% CI 2.57–5.50), and 5.20 (95% CI 2.94–9.19) for overall PrCa, aggressive cancer and younger age at diagnosis, respectively. The addition of cumulative risk alleles to the model containing age at diagnosis and family history of PrCa yielded a slightly higher AUC (0.69 vs. 0.64).

Conclusion

These data define a set of risk alleles associated with PrCa in men of Ashkenazic descent and indicate possible genetic differences for PrCa between populations of European and Ashkenazic ancestry. Use of genetic markers might provide an opportunity to identify men at highest risk for younger age of onset PrCa; however, their clinical utility in identifying men at highest risk for aggressive cancer remains limited.