亚甲基四氢叶酸还原酶基因C677T多态与结直肠癌遗传易感性的相关性

目的:探讨亚甲基四氢叶酸还原酶基因(MTHFR)C677T多态与结直肠癌(CRC)遗传易感性的关系.方法:采用TaqMan方法检测CRC 449例与对照672例的MTHFR C677T的基因型分布及差异.以非条件Logistic回归法计算表示相对危险度的比值比(OR)及其95%可信区间(CI).OR值均经性别、年龄、吸烟、饮酒、体质量指数和一级亲属CRC家族史等因素校正.结果:CRC组677T等位基因频率显著低于对照组,其为CRC发生的保护因素(OR:0.70,95%CI:0.58-0.83,P<0.01).与CC纯合子相比,CT杂合子的CRC风险显著降低至0.73倍(95%CI:0.56-0.95,P<0.05),而TT纯合子的CRC风险进一步降至0.47倍(95%CI:0.33-0.68,P<0.01).在非饮酒人群中,C677T的CRC风险保护效应略有增强;而在饮酒人群中,CT和TT基因型携带者的CRC发病风险虽仍低于CC基因型携带者,但差异无统计学意义.在CRC人群中,荷大肿瘤(最大直径>4cm)者携带TT基因型的比例高于荷小肿瘤者(16.3% vs 8.3%,P<0.05);荷黏液腺癌者携带TT基因型的比例高于荷乳头状腺癌及管状腺癌者(22.2% vs 17.1%,10.3%,P=0.084).结论:MTHFR C677T降低CRC发病风险,饮酒可能削弱该多态的CRC风险保护效应.TT基因型可能与CRC肿瘤进展有关.     

Association of 8q24.21 loci with the risk of colorectal cancer: a systematic review and meta-analysis

Background and Aim: Recent genome‐wide association studies of colorectal cancer (CRC) have identified rs6983267 and trs10505477 polymorphisms as key loci in the 8q24 region to be associated with CRC. In the present study, we performed a meta‐analysis to determine whether these loci are risk factors for susceptibility to CRC. Methods: We meta‐analyzed the 22 included studies (47 003 cases and 45 754 controls) that evaluated the association of rs6983267 and trs10505477 with CRC under alternative genetic models. Results: A meta‐analysis of the pooled data showed allelic and genotypic association of the rs6983267 polymorphism with CRC risk in Asians, Europeans, and European‐Americans. A subanalysis of the US studies showed negative results in the studies with non‐identified ethnicity of the patients. A meta‐analysis of included studies of rs10505477 polymorphisms identified allelic and genotypic associations with CRC risk in the US patients. A further meta‐analysis of the US studies demonstrated positive results in the studies with non‐identified ethnicity of the samples. Conclusion: Our data suggested that the rs6983267 G > T polymorphism is a risk factor for CRC in Asians, Europeans, and Americans with European ancestry.     

A polymorphism of microRNA196a genome region was associated with decreased risk of glioma in Chinese population

MicroRNAs (miRNAs) are small non-coding RNAs that play important roles in regulation of eukaryotic gene expression. Aberrant expression and structural alternation of miRNAs are considered to participate in tumorigenesis and cancer development. Recently, different genotypes of miR-196a polymorphisms (SNP, rs11614913) were found to be associated with the survival of patients with lung cancer and increased risk of breast cancer. To further investigate whether this polymorphism may influence glioma risk or not, we examined the SNP allele frequency in Chinese population. Our data shows the genotype CC of miR-196a (rs11614913) polymorphism is associated with decreased risk of glioma in the Chinese population (OR = 0.74, 95% CI:0.56–0.98). Furthermore, a significant association was observed between this genotype and glioma risk in the subgroups of adult glioma (OR = 0.73, 95% CI:0.55–0.98), male glioma (OR = 0.69, 95% CI:0.48–0.99) and patients with glioblastoma (OR = 0.58, 95% CI:0.37–0.91). This was the first study investigating the association between the miR-196a rs11614913 and glioma risk. Compared with the results from previous studies in lung cancer and breast cancer, our data suggest a different genotype association in glioma. This may be related to the diversity on the tissue origin, tumor type, tumorigenesis, and developing process.     

Peroxisome proliferator-activated receptor-γ 34C>G polymorphism and colorectal cancer risk: A meta-analysis

AIM: To investigate the association between peroxisome proliferator-activated receptor-γ (PPAR-γ ) gene polymorphism 34 C>G and colorectal cancer (CRC),a meta-analysis review was performed in this report.METHODS: A systematic literature search and selection of eligible relevant studies were carried out.Nine independent studies with a total number of 4533 cases and 6483 controls were included in the meta-analysis on the association between polymorphism 34 C>G and CRC.RESULTS: There was no evidence for the as...     

血管内皮生长因子-460C/T基因多态性与非贲门胃癌的关系

目的探讨VEGF-460C/T基因多态性与非贲门胃癌的关系。方法研究人群为胃癌(包括胃体癌及胃窦癌)患者159例,对照组为非溃疡性消化不良患者162例。应用聚合酶链反应和限制性片段长度多态性(PCR-RFLP)技术对VEGF-460C/T基因位点多态性进行基因分型,比较病例组与对照组基因型分布及其与临床病理特征的关系。结果 VEGF-460位点CC、CT和TT基因型在病例组中的频率分别为3.2%、35.2%、61.6%,在对照组中的频率分别为8.0%、48.2%、43.8%,基因型在两组分布显著不同(χ2=11.454,P=0.003)。TT纯合子在胃癌组分布较对照组明显增高,TT型患胃癌风险是CC型的3.58倍[OR=0.279,95%可信区间(CI):0.095～0.817],是CT型的1.9倍[OR=0.52,95%CI:0.329～0.824]。进一步分析表明携带T等位基因患胃癌的相对危险度是携带C等位基因的1.8倍[OR=0.55,95%CI:0.387～0.792]。基因型分布与临床分期和病理分级未见显著性差异。结论 VEGF-460C/T基因多态性T等位基因可作为胃癌易感性的预测指标,但不能作为预后预测指标。     

硒蛋白S基因G-254A位点多态性与食管癌发病风险的关联性

目的探讨内蒙古汉族人群硒蛋白(Sel)S基因G-254A位点多态性与食管癌发病风险的相关性。方法采用四引物扩增阻碍突变体系聚合酶链式反应检测124例内蒙古汉族食管癌患者和132例健康对照者的基因型和等位基因频率,并进行测序验证,分析两组SelS基因G-254A位点基因型和等位基因频率分布的差异,同时对食管癌发病风险进行分层分析和多因素Logistic回归分析。结果吸烟、饮酒和基因突变是食管癌发病的主要危险因素(OR分别为1.782、1.594、2.286,均P<0.1);SelS基因G-254A位点CT、CC、TT基因型和C、T等位基因频率在两组间存在统计学差异(均P<0.05)。内蒙古汉族人群中携带T等位基因的CT和(或)TT基因型者患食管癌的风险高于CC基因型者(OR=2.005,95%CI:1.36~2.591),携带T等位基因且吸烟的个体患食管癌的风险增加,是CC基因型的2.611倍(OR=2.611,95%CI:1.410~4.835)。结论吸烟、饮酒和基因突变是食管癌发病的主要危险因素,吸烟与SelS基因突变可交互作用增加食管癌发病风险。     

环氧化酶-2基因启动子区多态性与结直肠癌的易感性

目的:探讨环氧化酶-2(cyclooxygenase-2,COX-2)基因启动子区的-1195(G/A,rs689466)及3’非翻译区的8473(T/C,rs5275)2个位点的基因多态性与结直肠癌(colorectal cancer,CRC)发病风险的相关性.方法:采用病例-对照研究,利用聚合酶链式反应和限制性片段长度多态性(polymerase chain reaction-restrictive fragment length polymorphism,PCR-RFLP)分析方法,对343例CRC患者和340例健康人的COX-2基因的2个位点的多态性进行检测,采用SPSS11.0软件包统计分析各位点的基因型分布和等位基因频率.结果:COX-2-8473位点多态性的各基因型频率在病例组及对照组中分布均无显著差异(P>0.05),但COX-2-1195位点多态性的基因型频率在二组中分布有显著性差异(P<0.001),结果显示CRC患者COX-2-1195AG基因型在病例组的频率较对照组显著增高(校正后OR=2.23;95%CI:1.50-3.32),AA基因型在病例组中的频率亦较对照组高(校正后OR=2.46;95%CI:1.51-4.02),A等位基因携带者在病例组中的频率高于对照组(校正后OR=2.27;95%CI:1.55-3.34).各基因型分布在结肠癌及直肠癌中的分布无显著性差异(P>0.05).COX-2-1195A等位基因与淋巴结转移及TNM分期有显著相关性.结论:COX-2-1195位点AG/AA基因型是CRC的风险因素,且与CRC的淋巴结转移及TNM分期相关.     

N-Acetyltransferase 2 genetic polymorphisms and risk of colorectal cancer

AIM:To investigate the possible association between meat intake,cigarette smoking and N-acetyltransferase 2 (NAT2) genetic polymorphisms on colorectal cancer (CRC) risk.METHODS:Patients with CRC were matched for gender and age to healthy controls.Meat intake and cigarette smoking were assessed using a specific frequency questionnaire.DNA was extracted from peripheral blood and the genotypes of the polymorphism were assessed by polymerase chain reaction-restriction fragment length polymorphism.Five NAT2 alle...     

Association between genetic variants in pre-miRNA and colorectal cancer risk in a Chinese population

Introduction

Single-nucleotide polymorphisms (SNPs) in pre-miRNAs may alter microRNA expression levels or processing and then contribute to the susceptibility of cancer development. We hypothesized that SNPs in pre-miRNAs may be associated with the risk of colorectal cancer (CRC).

Materials and methods

We genotyped four common polymorphisms (i.e., rs11614913, rs3746444, rs2910164, and rs2292832) in pre-miRNAs of 353 CRC patients and 540 healthy controls to investigate the association between the SNPs and the risk of CRC using polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) assay.

Results

The rs11614913 CT, TT genotypes, and T allele were associated with an increased risk of CRC compared with the CC genotype and C allele (CT vs. CC: OR = 7.34, 95 % CI 3.76–14.34; TT vs. CC: OR = 13.66, 95 % CI 6.76–27.6; T vs. C: OR = 1.99, 95 % CI 1.63–2.42, respectively). Interestingly, using the rs2910164 GG genotype as a reference, the rs2910164 GC genotype was associated with an increased risk of CRC (OR = 1.49, 95 % CI 1.02–2.18), whereas the rs2910164 CC genotype was associated with a decreased risk of CRC (OR = 0.58, 95 % CI 0.37–0.93). When compared with the rs2910164G allele, rs2910164 C allele was associated with a reduced risk of CRC (OR = 0.80, 95 % CI 0.66–0.97, p = 0.02).

Conclusion

These findings suggest that rs11614913 and rs2910164 polymorphisms may be associated with the etiology of CRC.     

Risk modification of colorectal cancer susceptibility by interleukin-8 -251T>A polymorphism in Malaysians

AIM: To investigate the allele and genotype frequencies and associated risk of interleukin (IL)-8 -251T>A polymorphism on colorectal cancer (CRC) susceptibility risk.METHODS: Peripheral blood samples of 255 normal controls and 255 clinically and histopathologically confirmed CRC patients were genotyped for IL-8 -251T>A polymorphism employing allele-specific polymerase chain reaction. The relative association of variant allele and genotypes with CRC susceptibility risk was determined by calculating the odds ratios (ORs). Corresponding χ² tests on the CRC patients and controls were carried out and 95% confidence intervals (CIs) were determined using Fisher’s exact test. The allele frequencies and its risk association were calculated using FAMHAP, haplotype association analysis software.RESULTS: On comparing the frequencies of genotypes of patients and controls, the homozygous variant AA was significantly higher in CRC patients (P = 0.002) compared to controls. Investigation on the association of the polymorphic genotypes with CRC susceptibility risk, showed that the homozygous variant IL-8 -251AA had a significantly increased risk with OR 3.600 (95% CI: 1.550-8.481, P = 0.001). In the case of allele frequencies, variant allele A of IL-8 -251 showed a significantly increased risk of CRC predisposition with OR 1.32 (95% CI: 1.03-1.69, P = 0.003).CONCLUSION: Variant allele and genotype of IL-8 (-251T>A) was significantly associated with CRC susceptibility risk and could be considered as a high-risk variant for CRC predisposition.     

CCL22 16C/A Genetic Variation is not Associated with Breast Carcinoma in Southern Iranian Population

Background: CCL22/MDC is a CC chemokine with a critical role in regulation of the immune balance in physiological condition. CCL22/CCR-4 ligation has been documented to participate in the migration of regulatory T (Treg) cells and Th2 lymphocytes to the site of breast tumors; circumstances that are known to be associated with poor prognosis. Objective: To investigate the association of a single nucleotide polymorphism (SNP) in CCL22 gene; 16C/A (rs4359426; Asp2Ala), with susceptibility to breast cancer in a sample of Iranian population. Methods: 161 patients with pathologically confirmed breast carcinoma (mean age 49.3 ± 11.5 yrs) and 178 agematched healthy women (mean age: 49.3 ± 12.9 yrs) were studied. CCL22 genotypes were investigated by the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method. Data was verified by direct automated sequencing. Arlequin analysis showed no deviation from Hardy-Weinberg equilibrium. Results: The most frequent genotype in both patient and control groups was wild type CC genotype with frequency of 146 out of 161 (90.7%) among patients and 153 out of 178 (86.0%) in control group (p=0.24). The frequency of CA genotype was 15 (9.3%) and 23 (12.9%) in patients and controls, respectively (p=0.38). No AA genotype was observed among patients but this genotype was observed with the frequency of 2 out of 178 (1.1%) in control subjects. The minor allele frequency (MAF) was 0.07 in the population. Conclusion: No correlation was found between the investigated genotypes and clinicopathological characteristics of the patients. Conclusively, results of this investigation do not support the association of 16C/A SNP (rs4359426; Asp2Ala) in CCL22 gene with susceptibility to, and progression of, breast cancer in Iranian population.     

Association between transforming growth factor-β1 polymorphisms and hepatocellular cancer risk: A meta-analysis

Aim: The association between transforming growth factor‐β1 (TGF‐β1) gene polymorphisms and hepatocellular cancer (HCC) risk has been widely reported, but results were somewhat controversial. To derive a more precise estimation of the relationship between TGF‐β1 polymorphisms and HCC risk, we conducted a meta‐analysis of all available studies relating the C‐509T and/or T869C polymorphisms of the TGF‐β1 gene to the risk of developing HCC. Methods: Two investigators independently searched the MEDLINE, PubMed, Web of Science, Embase, CNKI (China National Knowledge Infrastructure) and CBM (Chinese Biomedical Literature database) for the period up to August 2011. Result: A total of nine case‐control articles were identified. Five studies with 1825 cases and 2869 controls for C‐509T polymorphism, and six studies with 536 cases and 1496 controls for T869C polymorphism were included. In the overall analysis, no significant association between the polymorphisms and risk of HCC was observed. Stratified analysis showed that significant association between C‐509T polymorphism and HCC was present only in controls with liver disease (T vs. C: odds ratio [OR] = 0.769, 95% confidence interval [CI] = 0.661–0.895; TT vs. CC: OR = 0.570, 95% CI = 0.412–0.788; TT/TC vs. CC: OR = 0.668, 95% CI = 0.523–0.854; TT vs. TC/CC: OR = 0.717, 95% CI = 0.550–0.934), but not in healthy controls. With respect to T869C polymorphism, only a decreased risk was found in recessive models in controls with liver disease. Conclusions: This meta‐analysis supports that the TGF‐β1 C‐509T polymorphism may act in a protecting role in HCC susceptibility in populations with related liver disease.     

XPC Lys939Gln polymorphism,smoking and risk of sporadic colorectal cancer among Malaysians

AIM: To investigate the risk association of xeroderma pigmentosum group C (XPC ) Lys939Gln polymorphism alone and in combination with cigarette smoking on colorectal cancer (CRC) predisposition. METHODS: Peripheral blood samples of 510 study subjects (255 CRC patients, 255 controls)were collected. DNA was extracted and genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism. The association between polymorphic genotype and CRC predisposition was determined using the OR and 95%CI. RESULTS: The frequency of the homozygous variant (Gln/Gln) genotype was significantly higher in cases compared with controls (16.0% vs 10.2%, P = 0.049). The Gln/Gln genotype of XPC showed a significantly higher association with the risk of CRC (OR = 1.884; 95%CI: 1.082-3.277; P = 0.025). In the case of allele frequencies, variant allele C was associated with a significantly increased risk of CRC (OR = 1.375; 95%CI: 1.050-1.802; P = 0.020). Moreover, the risk was markedly higher for those who were carriers of the Gln/Gln variant genotype and were also cigarette smokers (OR = 3.409; 95%CI: 1.061-10.949; P = 0.032). CONCLUSION: The XPC Gln/Gln genotype alone and in combination with smoking increases the risk of CRC among Malaysians.     

The methylenetetrahydrofolate reductase (MTHFR) gene in colorectal cancer: role in tumor development and significance of allelic loss in tumor progression

Background and Aim: Folate deficiency predisposes to sporadic colorectal cancer (CRC). Methylenetetrahydrofolate reductase (MTHFR) is a critical folate-metabolising enzyme and a polymorphism at position 677 (C677T), is associated with reduced enzyme activity. We investigated whether this functional polymorphism modulates the risk of developing CRC. Methods: This was a retrospective case-control study, 136 unselected cases of sporadic CRC and 848 normal population controls were genotyped for the MTHFR C677T polymorphism. Tumor tissue was genotyped to assess loss of heterozygosity (LOH). Results: MTHFR CT heterozygotes had a significantly increased risk of developing CRC (53.7% of CRC cases vs 38.4% of controls), odds ratio 1.86 (95% CI 1.3–2.7, p<0.005). No increased cancer risk was observed in TT homozygotes. The MTHFR ‘T’ allele frequency was significantly higher in the cancer group (0.3713) as compared to controls (0.2900, p<0.008). LOH at the MTHFR locus was observed in 18% of informative cancers, with exclusive loss of the variant ‘T’ allele, in all cases. Conclusion: In this study of a homogenous northern European population, MTHFR CT heterozygotes had an almost two-fold increased risk of developing sporadic CRC. The exclusive pattern of MTHFR allele loss in cases of LOH, suggest that functional MTHFR activity within a tumor might play an important role in the survival and progression of a colonic neoplasm.     

Evaluation of SNPs in miR-196-a2, miR-27a and miR-146a as risk factors of colorectal cancer

AIM: To investigate whether selected single nucleotide polymorphisms (SNPs) in miR-196a2, miR-27a and miR-146a genes are associated with sporadic colorectal cancer (CRC).METHODS: In order to investigate the effect of these SNPs in CRC, we performed a case-control study of 197 cases of sporadic CRC and 212 cancer-free controls originating from the Central-European Caucasian population using TaqMan Real-Time polymerase chain reaction and allelic discrimination analysis.RESULTS: The genotype and allele frequencies of SNPs were compared between the cases and the controls. None of the performed analysis showed any statistically significant results.CONCLUSION: Our data suggest a lack of association between rs11614913, rs895819 and rs2910164 and colorectal cancer risk in the Central-European Caucasian population, a population with an extremely high incidence of sporadic colorectal cancer.     

Reprimo 824 G>C and p53R2 4696 C>G single nucleotide polymorphisms and colorectal cancer: a case–control disease association study

Background Improved survival from colorectal cancer (CRC) may result from screening for inherited genetic risk factors. Reprimo and p53R2 are p53-inducible genes involved in cell cycle surveillance and DNA repair. Single nucleotide polymorphisms (SNPs) of these genes have been discovered, but their effects on the genes' function and association with CRC is not known. Methods Ninety healthy controls, 52 diverticular disease controls and 96 CRC cases were genotyped. DNA was extracted from buccal brush biopsies. Genotyping was performed by polymerase chain reaction (PCR) or polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) methods. Tests for Hardy–Weinberg equilibrium and allelic- and genotype-disease association were performed online using the Finetti program. Results All three populations were in Hardy–Weinberg equilibrium with respect to p53R2 4696C>G SNP, and no CRC associations were demonstrated with this SNP. The healthy and CRC populations were in Hardy–Weinberg equilibrium with respect to the Reprimo 824G>C SNP, but the diverticular disease population was not (P = 0.03). No CRC were demonstrated with Reprimo 824G>C. Conclusion No association between p53R2 4696C>G and Reprimo 824G>C with CRC was shown by this study. An association between the Reprimo 824G>C heterozygote and diverticular disease may exist on the basis of deviation from Hardy–Weinberg equilibrium.