Dinucleotide polymorphism of p73 gene is associated with a reduced risk of lung cancer in a Chinese population

p73, a structural and functional homologue of p53, shares some p53-like tumor suppressor activity but also possesses oncogenic activity. Therefore, p73 plays an important role in modulating cell-cycle control and apoptosis. A potentially functional dinucleotide polymorphism, G4C14-to-A4T14, has been identified in the 5' untranslated region (UTR) of exon 2 of the p73 gene, which may theoretically form a stem-loop structure and affect gene expression. To test the hypothesis that these 2 common variants play a role in lung cancer susceptibility, we conducted a case-control study of 425 lung cancer patients and 588 cancer-free controls frequency-matched to the cases on age and sex in a Chinese population. The results showed that these 2 polymorphisms were in complete linkage disequilibrium and the frequencies of variant p73 AT haplotype (A4T14) were less common in the cases (0.225) than in the controls (0.287) (p = 0.0018), suggesting that this AT haplotype was protective against lung cancer. Compared to the p73 GC/GC homozygotes, both the AT/AT variant homozygotes and GC/AT heterozygotes were associated with a significantly decreased risk (adjusted OR: 0.45, 95% CI: 0.26-0.80 and OR: 0.70, 95% CI: 0.53-0.92, respectively). These results suggest that this p73 dinucleotide polymorphism may have a role in lung cancer susceptibility in our study population. Further studies are needed to elucidate potential functional relevance of the p73 AT variant allele.     

Single nucleotide polymorphisms in DNA repair genes and basal cell carcinoma of skin

In addition to environmental exposures like UV radiation and, in some cases, arsenic contamination of drinking water, genetic factors may also influence the individual susceptibility to basal cell carcinoma of skin (BCC). In the present study, 529 cases diagnosed with BCC and 533 controls from Hungary, Romania and Slovakia were genotyped for one polymorphism in each of seven DNA repair genes. The variant allele for T241M (C>T) polymorphism in the XRCC3 gene was associated with a decreased cancer risk [odds ratio (OR), 0.73; 95% confidence interval (CI), 0.61-0.88; P = 0.0007, multiple testing corrected P = 0.004]. The risk of multiple BCC was significantly lower among variant allele carriers than in non-carriers (P = 0.04). Men homozygous for the C-allele for E185Q (G>C) polymorphism in the NBS1 gene showed an increased BCC risk (OR, 2.19; 95% CI, 1.23-3.91), but not women (OR, 0.84; 95% CI, 0.49-1.47). In men, the age and nationality adjusted OR for the genotype CC (XRCC3)/CC (NBS1) was 8.79 (95% CI, 2.10-36.8), compared with the genotype TT (XRCC3)/GG (NBS1). The data from this study show overall risk modulation of BCC by variant allele for T241M polymorphism in XRCC3 and gender-specific effect by E185Q polymorphism in NBS1.     

A novel polymorphism in human cytosine DNA-methyltransferase-3B promoter is associated with an increased risk of lung cancer

DNA repair is central to genomic integrity. Reduced expression of several nucleotide excision repair genes has been demonstrated to be associated with increased risk of lung cancer. Because methylation of gene promoters is one of the major regulatory mechanisms of gene expression and most nucleotide excision repair gene promoters have not been fully characterized, we hypothesized that genetic variants of the genes that are responsible for regulating genomic methylation are associated with increased risk of lung cancer. Recently, we identified a C-->T transition at a novel promoter region of cytosine DNA-methyltransferase-3B (DNMT3B) and found that this polymorphic transition significantly increases the promoter activity. In this hospital-based case-control study of 319 patients with incident lung cancer and 340 healthy controls frequency matched on age (+/-5 years), sex, ethnicity, and smoking status, we genotyped subjects for this DNMT3B promoter polymorphism to determine the association between this genetic variant and risk of lung cancer. Compared with CC homozygotes, CT heterozygotes had a >2-fold increased risk of lung cancer [adjusted odds ratio (OR), 2.13; 95% confidence interval (CI), 1.47-3.08] and TT homozygotes an OR of 1.42 (95% CI, 0.91-2.21). The combined variant genotype (CT + TT) was associated with a nearly 2-fold increased risk (adjusted OR, 1.88; 95% CI, 1.32-2.66). These results suggest that this novel variant of DNMT3B is associated with increased risk of lung cancer and may contribute to identifying individuals genetically susceptible to tobacco-induced cancers. Additional studies on the underlying molecular mechanism of this polymorphism are warranted.     

Nucleotide excision repair polymorphisms may modify ionizing radiation-related breast cancer risk in US radiologic technologists

Exposure to ionizing radiation has been consistently associated with increased risk of female breast cancer. Although the majority of DNA damage caused by ionizing radiation is corrected by the base-excision repair pathway, certain types of multiple-base damage can only be repaired through the nucleotide excision repair pathway. In a nested case-control study of breast cancer in US radiologic technologists exposed to low levels of ionizing radiation (858 cases, 1,083 controls), we examined whether risk of breast cancer conferred by radiation was modified by nucleotide excision gene polymorphisms ERCC2 (XPD) rs13181, ERCC4 (XPF) rs1800067 and rs1800124, ERCC5 (XPG) rs1047769 and rs17655; and ERCC6 rs2228526. Of the 6 ERCC variants examined, only ERCC5 rs17655 showed a borderline main effect association with breast cancer risk (OR(GC) = 1.1, OR(CC) = 1.3; p-trend = 0.08), with some indication that individuals carrying the C allele variant were more susceptible to the effects of occupational radiation (EOR/Gy(GG) = 1.0, 95% CI = <0, 6.0; EOR/Gy(GC/CC) = 5.9, 95% CI = 0.9, 14.4; p(het) = 0.10). ERCC2 rs13181, although not associated with breast cancer risk overall, statistically significantly modified the effect of occupational radiation dose on risk of breast cancer (EOR/Gy(AA) = 9.1, 95% CI = 2.1-21.3; EOR/Gy(AC/CC) = 0.6, 95% CI = <0, 4.6; p(het) = 0.01). These results suggest that common variants in nucleotide excision repair genes may modify the association between occupational radiation exposure and breast cancer risk.     

Polymorphisms in nucleotide excision repair genes, polycyclic aromatic hydrocarbon-DNA adducts, and breast cancer risk.

Genes involved in the nucleotide excision repair (NER) pathway, which removes bulky DNA adducts, are potential low-penetrance cancer susceptibility genes. We recently reported an association between detectable polycyclic aromatic hydrocarbon (PAH)-DNA adducts and breast cancer risk. Using a population-based breast cancer case-control study on Long Island, New York, we examined whether polymorphisms in NER genes modified the association between PAH-DNA adducts and breast cancer risk. We examined polymorphisms in ERCC1 (3'-untranslated region 8092C/A), XPA (5'-untranslated region -4G/A), XPD (Asp(312)Asn in exon 10), XPF (Arg(415)Gln in exon 8), and XPG (Asp(1104)His in exon 15) in 1,053 breast cancer cases and 1,102 population-based controls. The presence of at least one variant allele in XPD was associated with a 25% increase in the odds ratio [OR, 1.25; 95% confidence interval (95% CI), 1.04-1.50] for breast cancer. The increase associated with homozygosity of the variant alleles for XPD and ERCC1 was stronger among those with detectable PAH-DNA adduct levels (OR, 1.83; 95% CI, 1.22-2.76 and OR, 1.92; 95% CI, 1.14-3.25 for detectable versus nondetectable adducts and homozygous wild-type genotype for XPD and ERCC1, respectively). We found no association between XPA, XPF, and XPG genotypes, PAH-DNA adducts, and breast cancer risk. When we combined genotypes for these NER pathway genes, there was a significant trend for increasing breast cancer risk with increasing number of putative high-risk alleles. Overall, this study suggests that the risk of breast cancer may be elevated among women with polymorphisms in NER pathway genes and detectable PAH-DNA adducts.     

The DNA Repair Gene ERCC6 rs1917799 Polymorphism is Associated with Gastric Cancer Risk in Chinese

Objective: Excision repair cross-complementing group 6 (ERCC6) is a major component of the nucleotideexcision repair pathway that plays an important role in maintaining genomic stability and integrity. Severalrecent studies suggested a link of ERCC6 polymorphisms with susceptibility to various cancers. However, therelation of ERCC6 polymorphism with gastric cancer (GC) risk remains elusive. In this sex- and age- matchedcase-control study including 402 GC cases and 804 cancer-free controls, we aimed to investigate the associationbetween a potentially functional polymorphism (rs1917799 T>G) in the ERCC6 regulatory region and GC risk.Methods: The genotypes of rs1917799 were determined by Sequenom MassARRAY platform and the status ofHelicobacter pylori infection was detected by enzyme-linked immunosorbent assay. Odd ratios (ORs) and 95%confidential interval (CI) were calculated by logistic regression analysis. Results: Compared with the commonTT genotype, the ERCC6 rs1917799 GG genotype was associated with increased GC risk (adjusted OR=1.46,95%CI: 1.03-2.08, P=0.035). When compared with (GT+TT) genotypes, the GG genotype also demonstrateda statistical association with increased GC risk (adjusted OR=1.38, 95%CI: 1.01-1.89, P=0.044). This was alsoobserved for the male subpopulation (GG vs. TT: adjusted OR=1.71, 95%CI: 1.12-2.62, P=0.013; G allele vs.T allele: adjusted OR=1.32, 95%CI: 1.07-1.62, P=0.009). Genetic effects on increased GC risk tended to beenhanced by H. pylori infection, smoking and drinking, but their interaction effects on GC risk did not reachstatistical significance. Conclusions: ERCC6 rs1917799 GG genotype might be associated with increased GCrisk in Chinese, especially in males.     

Genetic Association between the XPG Asp1104His Polymorphism and Head and Neck Cancer Susceptibility: Evidence Based on a Meta-Analysis

Background: Previous studies evaluating the association between the xeroderma pigmentosum group G(XPG) Asp1104His polymorphism and head and neck cancer susceptibility have proven controversial. Thismeta-analysis of the literature was performed to obtain a more precise estimation of the relationship. Materialsand Methods: We systematically searched PubMed, Embase and Web of Science with a time limit of Dec 18,2014. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of any association.Results: We performed a meta-analysis of eight published case-control studies, including 3,621 cases and 5,475controls. Overall, no significant association was found between the XPG Asp1104His polymorphism and head andneck cancer susceptibility under all genetic models. In the subgroup analysis by ethnicity, the XPG Asp1104Hispolymorphism had statistically significant association with elevated head and neck cancer risk under CC vs GG(OR=1.24, 95% CI=1.00~1.54) and the recessive model (OR=1.22, 95%CI=1.01~1.46) in Asian populations. Asimilar result was found under CC vs GG (OR =1.22, 95%CI =1.01~1.47) in the population based subgroup bysource of control. When performed by tumor site, the XPG Asp1104His polymorphism had statistically significantassociation with elevated laryngeal cancer under all genetic models (CC vs GG: OR=1.59, 95% CI=1.16~2.19; GCvs GG: OR=1.38, 95%CI=1.10~1.72; dominant model: OR=1.42, 95% CI=1.15~1.74; recessive model: OR=1.36,95% CI=1.02~1.81). Conclusions: This meta-analysis suggested that the XPG Asp1104His polymorphism is arisk factor for head and neck cancer susceptibility, especially for laryngeal cancer and in Asian populations.     

p73 G4C14-to-A4T14 polymorphism and risk of lung cancer

Genetic variants in genes controlling cellular processes such as cell cycle, DNA repair, and apoptosis may modulate lung cancer risk. p73 has some p53-like activity and plays an important role in modulating these processes. The noncoding region of exon 2 of the p73 gene has two polymorphisms that are in complete linkage disequilibrium with one another, which may alter translation efficiency of the p73 protein. To test the hypothesis that this p73 polymorphism plays a role in the etiology of lung cancer, we conducted a hospital-based case-control study of 1054 patients newly diagnosed with lung cancer and 1139 cancer-free controls and evaluated the association between the p73 variant AT allele and risk of lung cancer. Cancer-free controls were frequency matched to the cases by age (+/-5 years), sex, and smoking status, and all subjects were non-Hispanic whites. The variant AT allele and genotypes were more common among the cases than among the controls (P = 0.0007 and P < 0.001, respectively). Compared with the GC/GC genotype, the variant GC/AT and AT/AT genotypes were associated with a statistically significantly increased risk for lung cancer [adjusted odds ratio (OR) = 1.32, 95% confidence interval (CI), 1.10-1.59 and OR = 1.54, 95% CI, 1.05-2.26, respectively] in an allele dose-effect relationship (trend test: P < 0.001). The risk associated with the AT allele (GC/AT+AT/AT) was more pronounced in younger (相似文献   

Polymorphisms in DNA repair and metabolic genes in bladder cancer

We investigated the association of urinary bladder cancer with genetic polymorphisms in the xeroderma pigmentosum complementation group C (XPC), group D (XPD) and group G (XPG), X-ray repair cross-complementing group 1 (XRCC1) and group 3 (XRCC3), Nijmegen breakage syndrome 1 (NBS1), cyclin D1, methylene-tetrahydrofolate reductase (MTHFR), NAD(P)H dehydrogenase quinone 1 (NQO1), H-ras and glutathione S-transferase theta 1 (GSTT1) genes. Bladder cancer patients from the different hospitals in Stockholm County Council area and matching controls were genotyped for different polymorphisms. The frequency of the variant allele for A/C polymorphism in exon 15 of the XPC gene was significantly higher in the bladder cancer cases than in the controls (OR 1.49, 95% CI 1.16-1.92, P = 0.001). The variant allele homozygote genotype for the T/C polymorphism in exon 1 of the H-ras gene was associated with a decreased risk for bladder cancer (OR 0.12, 95% CI 0.02-0.67, P = 0.006). The variant allele genotypes for the single nucleotide polymorphisms (SNPs) in DNA repair genes, XPG and NBS1, showed a marginal association with the occurrence of bladder cancer (OR 0.38, 95% CI 0.15-0.94, P = 0.03 and OR 1.64, 95% CI 0.92-2.90, P = 0.09, respectively). We also report a positive correlation between the null homozygote of GSTT1 with the risk of bladder cancer (OR 2.54, 95% CI 1.32-4.98, P = 0.003). For other polymorphisms included in this study, NBS1 Glu185Gln, XPD Lys751Gln, XPG Asp1104His, XRCC1 Arg399Gln, XRCC3 Thr241Met, cyclin D1 Pro242Pro, MTHFR Ala222Val and Glu429Ala, NQO1 Arg139Trp and Pro187Ser, no significant differences for genotype distributions and allele frequencies between the bladder cancer cases and the controls were observed in the present study.     

A common polymorphism in the 3'UTR of cyclooxygenase 2/prostaglandin synthase 2 gene and risk of lung cancer in a Chinese population

Cyclooxygenases (COXs) are key enzymes that convert arachidonic acid to prostaglandins. Overexpression of COX-2, one of the COX isozymes, has been shown to be an early event in lung carcinogenesis and may play an important role in lung cancer development. A common single nucleotide polymorphism, T8473C, located within a potential functional region in the 3'UTR of COX-2 gene was identified and we hypothesized that this COX-2 variant is associated with lung cancer risk. To test this hypothesis, we genotyped this variant in a case-control study of 322 histologically-confirmed lung cancer patients and 323 age and sex frequency-matched cancer-free controls in a Chinese population. The results showed that the frequencies of variant genotypes 8473CT/CC were significantly less common in the cases (27.3%) than in the controls (35.3%) (P=0.034), suggesting that the 8473C allele was protective against lung cancer. Multivariate logistic regression analyses revealed that the COX-2 variant genotypes (8473CT/CC) were associated with a significantly decreased risk of lung cancer compared with the 8473TT wild-type homozygotes (OR=0.64, 95% CI=0.45-0.92). When we defined the reference group as non-smokers having the 8473CT/CC variant genotypes, the smokers with the 8473TT wild-type genotype had the greatest risk (adjusted OR=5.28, 95% CI=3.10-9.00). These findings indicate that the COX-2 T8473C polymorphism may contribute to lung cancer susceptibility in the Chinese population. Further larger molecular epidemiological studies are warranted to confirm these findings.     

DNA repair gene XPC genotypes/haplotypes and risk of lung cancer in a Chinese population

DNA repair is central to normal cellular functions, and polymorphisms of DNA repair genes may cause variation in DNA repair capacity in the general population. Newly identified polymorphisms of xeroderma pigmentosum group C (XPC), one of the nucleotide excision repair genes, were shown to contribute to genetic susceptibility to cancer. In this study, we hypothesized that 2 exonic variants C499T and A939C and their haplotypes in XPC are associated with lung cancer risk. To test this hypothesis, we performed a case-control study of 320 histologically confirmed lung cancer patients and 322 age and sex frequency-matched cancer-free controls in a Chinese population. Multivariate logistic regression analyses revealed that the risks [adjusted odds ratios (ORs) and 95% confidence intervals (CIs)] associated with the XPC variant genotypes were 1.57 (95% CI = 1.13-2.19) for 499CT/TT and 1.21 (95% CI = 0.87-1.69) for 939AC/CC compared with the 499CC and 939AA wild-type homozygotes, respectively. Individuals with both putative risk genotypes (499CT/TT and 939AC/CC) had a greater risk of lung cancer (adjusted OR = 2.37; 95% CI = 1.33-4.21) compared with individuals with both wild-type genotypes (499CC and 939AA). When we performed the haplotype analysis and assumed the XPC 499T and 939C as risk alleles, the adjusted ORs increased as the number of variants in the haplotype genotypes increased (p(trend) < 0.001). In the stratified analysis, the greatest risk was found in smokers having the combined variant genotypes (adjusted OR = 7.36; 95% CI = 3.19-17.00) compared with nonsmokers having both wild-type genotypes and in smokers with 2 or 3 haplotype variants (adjusted OR = 7.27; 95% CI = 3.37-15.68) compared with nonsmokers having 0 haplotype variant. These findings indicate that XPC exonic variants may contribute to the risk of lung cancer in the Chinese population, and these variant genotypes may modulate the risk of lung cancer associated with smoking.     

Polymorphism of the p73 gene in relation to colorectal cancer risk and survival

The results regarding a GC/AT polymorphism in the p73 gene in relation to cancer risk are inconsistent, and the significance of loss of heterozygosity (LOH) of the gene is unclear. In the present study, we investigated whether this polymorphism was related to the risk of colorectal cancer, and whether there were relationships between the polymorphism and LOH, protein expression or clinicopathological variables. 179 patients with colorectal cancer and 260 healthy controls were genotyped for the polymorphism by PCR-restriction fragment length polymorphism (RFLP). Fifty informative cases were examined for LOH in tumours. Immunohistochemistry was performed on distant (n = 42) and adjacent normal mucosa (n = 33), primary tumour (n = 6 9) and lymph node metastasis (n = 12). The frequencies of the genotypes were 63% for wild-type (GC/GC), 30% for heterozygotes (GC/AT) and 7% for variants (AT/AT) in patients, and 62, 36 and 2% in controls, respectively. The frequencies of the genotypes in the patients and controls were significantly different (P = 0.02). The patients carrying the AT allele had a better prognosis than those with the GC/GC genotype (OR = 0.42, 95% CI = 1.15-5.02, P = 0.02). No LOH was observed at the p73 locus. Expression of p73 protein was increased from normal mucosa to primary tumours (P = 0.02), but was not significantly changed between primary tumours and metastases (P = 1.0). In conclusion, the AT/AT homozygotes may have a greater risk of developing colorectal cancer, while the patients who carried the AT allele had a better prognosis.     

Genetic polymorphisms of the XPG and XPD nucleotide excision repair genes in sarcoma patients

There are more than 50 subtypes of soft tissue sarcomas, among which 30% are associated with specific genetic alterations, including translocations. Several studies have reported associations between cancer risk and polymorphisms of DNA repair genes from the nucleotide excision repair (NER) pathway. NER involves more than 20 proteins whose inactivation leads to xeroderma pigmentosum (XP) or cockayne syndrome (CS), among which XPD, a helicase allowing DNA strand excision by the endonuclease XPG. DNA from 93 patients with synovial sarcomas, myxoid liposarcomas, dermatofibrosarcomas protuberans (DFSP), malignant fibrous histiocytomas and leiomyosarcomas were genotyped for both XPD Lys751Gln and XPG Asp1104His polymorphisms. Departure from Hardy-Weinberg was highly significant for the XPG polymorphism with an excess of heterozygotes in synovial sarcomas (p = 1.5 x 10(-5)), myxoid liposarcomas (p = 1.5 x 10(-4)) and to a lesser extent in DFSP (p = 0.028). In the case of XPD, a significant deviation was observed in synovial sarcomas (p = 3 x 10(-6)) and DFSP (p = 0.0014). When tumors were pooled according to their genetic alterations, the proportion of carriers of the variant XPG allele was significantly increased in sarcomas with specific translocations as compared to sarcomas with complex genetics (p < 10(-9)). No difference was found for XPD. Genotyping of the tumor samples in synovial sarcomas and myxoid liposarcomas revealed frequent loss of heterozygosity for XPG, mostly due to the loss of the frequent allele. For XPD, both alleles were lost with a similar frequency. Our results raise the potential implication of the XPG Asp1104His polymorphism in the occurrence of chromosomal translocations associated with specific subtypes of sarcomas.     

The MDM2 SNP309T>G Polymorphism Increases Bladder Cancer Risk among Caucasians: a Meta-analysis

Published studies have evaluated associations between the MDM2 SNP309T>G polymorphism and bladder cancer susceptibility. However, these generated inconsistent results. The aim of the present investigation was to quantify the strength of association between MDM2 SNP309T>G polymorphism and bladder cancer risk by conducting a meta-analysis. We searched PubMed and Embase for related studies that had been published in English before April 1, 2014 and associations were assessed by summarizing the odds ratios (ORs) with thecorresponding 95% confidence intervals (CIs). Five case-control studies with a total of 972 cases and 1,012 controls were finally identified to be eligible for the meta-analysis. Overall, the results indicated that there was no significant association between the MDM2 SNP309T>G polymorphism and bladder cancer risk (for the allele model G vs. T: OR=1.08, 95% CI 0.85-1.36, p=0.54; for the co-dominant model GG vs. TT: OR=1.20, 95% CI 0.74-1.93, p=0.46; for the dominant model GG+GT vs. TT: OR=0.98, 95% CI 0.80-1.20, p=0.83; for the recessive model GG vs. GT+TT: OR=1.20, 95% CI 0.83-1.74, p=0.33). However, on subgroup analysis by ethnicity, significant associations were found in Caucasians in three models (for the allele model G vs. T: OR=1.41, 95% CI 1.10-1.81, p=0.006; for the co-dominant model GG vs. TT: OR=2.16, 95% CI 1.28-3.63, p=0.004; for therecessive model GG vs. GT+TT: OR=2.06, 95% CI 1.31-3.22, p=0.002). In summary, the present meta-analysis provides evidence that the genotype for the MDM2 SNP309T>G polymorphism may be associated with genetic susceptibility to bladder cancer among Caucasians.     

Risk Modulation of Oral Pre Cancer and Cancer with Polymorphisms in XPD and XPG Genes in North Indian Population

Background: Environmental carcinogens cause DNA damages which if not repaired properly, may increase therisk of cancer. The Xerodermapigmentosum group D (XPD) and group G (XPG) genes are essential genes for DNArepair and alteration in DNA repair causes cancer. The present study aimed to evaluate the relationship between XPDand XPG polymorphisms and risk of oral pre cancer and cancer. Methods: Present study genotyped 302 samples oforal diseases and 300 controls for XPD (A/C) and XPG (G/C) polymorphisms with PCR-RFLP method. Results: Ourresult showed that compared to AA genotype frequency of AC and CC genotype for XPD(A/C) polymorphism weresignificantly lower among cases than in control and are associated with decreased risk of oral diseases (OR= 0.621and 0.603 respectively). In contrast with reference to GG genotype the frequency of CC genotype of XPG (G/C) wassignificantly higher in case than in control population (p value=0.004) and found to increase the risk of oral diseases(OR= 2.077). Particularly C allele for XPD A/C polymorphism was found to be associated with decreased risk of Lichenplanus and increased risk of ( OR = 0.470 and 1.541 respectively) oral cancer. While C allele of XPG G/C polymorphismsignificantly increased the risk of Oral Submucous Fibrosis and Leukoplakia (OR= 1.879 and 1.837 respectively) butnot of Lichen planus and oral cancer. In combined genotype analysis from the aforesaid polymorphisms presence of Callele for XPD (A/C) polymorphisms were found to decrease the risk of oral diseases. However, the same C allele wasobserved to increase the chance of having high stage disease (OR= 5.71) with nodal involvement (OR= 6.78) once thecancer been initiated. Conclusion: This work shows association of XPD (A/C), XPG (G/C) polymorphisms with thedevelopment of pre oral cancer as well as oral cancer and its clinical courses.     

Polymorphisms in XPD exons 10 and 23 and bladder cancer risk.

INTRODUCTION: The nucleotide excision repair gene, xeroderma pigmentosum complementation group D (XPD), has been hypothesized to have a role in cancer risk, but results from prior molecular epidemiologic studies and genotype-phenotype analyses are conflicting. MATERIALS AND METHODS: We examined the frequency of the XPD Asp312Asn polymorphism in exon 10 and the XPD Lys751Gln polymorphism in exon 23 in 505 incident bladder cancer cases and 486 healthy controls. RESULTS: Overall, the XPD exon 10 and 23 genotypes were not associated with bladder cancer risk, after adjusting for age, sex, ethnicity, and smoking status. A gender-specific role was evident that showed an increased risk for women, but not for men, associated with the variant genotypes for both exons. For example, when the exon 23 variant allele genotypes were combined (Lys/Gln + Gln/Gln), there was an increased bladder cancer risk in women [odds ratio (OR), 1.69; 95% confidence interval (95% CI), 1.12-2.58] but not in men (OR, 0.99; 95% CI, 0.79-1.24; P(interaction) = 0.041; OR, 1.62; 95% CI, 1.02-2.58). There was also a gene-smoking interaction that showed the variant alleles for either exon or the combination of both increase the risk of bladder cancer for light and heavy smokers. For exon 23 (P(interaction) = 0.057; OR, 1.21; 95% CI, 0.99-1.47), heavy smokers (> or = 20 pack-years) who carried the exon 23 variant allele genotypes had an OR of 4.13 (95% CI, 2.53-6.73), whereas heavy smokers with the wild-type genotypes were at lower risk (OR, 3.55; 95% CI, 2.19-5.75). Moderate smokers (1-19 pack-years) with the variant allele genotypes had an OR of 1.54 (95% CI, 0.94-2.53), whereas moderate smokers with the wild-type genotypes had an OR of 1.12 (95% CI, 0.63-1.98). CONCLUSIONS: Although we did not observe main effects associated with the XPD genotypes, these results do suggest the variant allele genotypes were associated with increased bladder cancer risk in women and smokers with statistically significant interactions in the exon 23 polymorphism. Although there is biological plausibility, these novel findings for gender and smoking should be interpreted with caution upon confirmation in larger studies.     

An intron splice acceptor polymorphism in hMSH2 and risk of leukemia after treatment with chemotherapeutic alkylating agents.

PURPOSE: We sought to determine whether the -6 exon 13 T>C polymorphism in the DNA mismatch repair gene hMSH2 modulates susceptibility to acute myeloid leukemia after therapy and particularly after O(6)-guanine alkylating chemotherapy. We also determined the extent of microsatellite instability (MSI) in therapy-related acute myeloid leukemia (t-AML) as a marker of dysfunctional DNA mismatch repair. Experimental Design: Using a novel restriction fragment length polymorphism, verified by direct sequencing, we have genotyped 91 t-AML cases, 420 de novo acute myeloid leukemia cases, and 837 controls for the hMSH2 -6 exon 13 polymorphism. MSI was evaluated in presentation bone marrow from 34 cases using the mononucleotide microsatellite markers BAT16, BAT25, and BAT26. RESULTS: Distribution of the hMSH2 -6 exon 13 polymorphism was not significantly different between de novo acute myeloid leukemia cases and controls, with heterozygotes and homozygotes for the variant (C) allele representing 12.2 and 1.6%, respectively, of the control population. However, the variant (C) hMSH2 allele was significantly overrepresented in t-AML cases that had previously been treated with O(6)-guanine alkylating agents, including cyclophosphamide and procarbazine, compared with controls (odds ratio, 4.02; 95% confidence interval, 1.40-11.37). Thirteen of 34 (38%) t-AML cases were MSI positive, and 2 of these 13 cases were homozygous for the variant (C) allele, a frequency substantially higher than in the control population. CONCLUSIONS: Association of the hMSH2 -6 exon 13 variant (C) allele with leukemia after O(6)-guanine alkylating agents implicates this allele in conferring a nondisabling DNA mismatch repair defect with concomitant moderate alkylation tolerance, which predisposes to the development of t-AML via the induction of DNA mismatch repair-disabling mutations and high-grade MSI. Homozygosity for the hMSH2 variant in 2 of 13 MSI-positive t-AML cases provides some support for this model.     

Involvement of p53 R72P polymorphism in the association of MDM2-SNP309 with breast cancer

The allelic variant MDM2-SNP309 (T>G) has been suggested to influence cancer development, but the clinical correlation between the risk allele and breast cancer remains controversial. The genetic background and the ethnicity of selected subgroups may influence the power of these risk genotypes. In this study, we investigated whether MDM2-SNP309 is associated with p53 R72P genetic polymorphism for the risk of breast cancer development in Asian Taiwanese, which has not been well-studied in this regard. Two hundred and fifty-five patients and 324 cancer-free controls were included, and we found that the MDM2-SNP309 TG and GG genotypes displayed marginally increased risks of breast cancer (GG vs. TT: OR = 1.7, 95% CI = 0.93 to 3.09; TG + TT vs. TT: OR = 1.57, 95% CI = 0.98 to 2.56). The breast cancer risk associated with MDM2-SNP309 was enhanced after stratification for the homozygous GG genotype at p53 codon 72 representing the Arg form of this genotype (GG vs. TT: OR = 3.7, 95% CI = 1.144 to 12.02; TG + GG vs. TT: OR = 2.7, 95% CI = 1.027 to 6.895). Also, the median age at diagnosis of patients with MDM2-SNP309 GG increased from 4 years earlier to 9 years earlier than TT patients after stratification for the GG genotype at p53 codon 72. Moreover, the G-allele of MDM2-SNP309 exhibited a stronger capacity than the T-allele to drive the full-length P2 promoter of the MDM2 gene in several human cell lines, suggesting that the association between MDM2-SNP309 and breast cancer is likely multifactorial rather than due to inconsistent gene expression in different cancer sources.     

The 765G>C Polymorphism in the Cyclooxygenase-2 Gene and Gastric Cancer Risk: an Update by Meta-analysis

Background: The 765G>C polymorphism in cyclooxygenase-2 (COX-2) gene has been extensively investigatedfor association with gastric cancer (GC). However, the results of different studies have been inconsistent. The aimof this study is to comprehensively evaluate the genetic risk of -765G>C polymorphism in the COX-2 gene forGC. Materials and Methods: We searched Pubmed, Embase, Medline, CNKI database, Wanfang database, Weipudatabase, and Chinese Biomedical database, covering all publications (last search been performed on Jan 10,2014). Statistical analyses were performed using Revman 5.2 and STATA 10.0 software. Results: A total of 1,874cases and 3,005 controls in 10 case-control studies were included in this meta-analysis. The results indicated thatthe variant C allele carriers (GC+CC) had a 69% increased risk of GC when compared with the homozygote GG(odds ratio (OR)=1.69, 95% confidence interval (CI), 1.10-2.61 for GC+CC vs GG). In the subgroup analysis byethnicity, significant elevated risks were associated with C allele carriers in Asians (OR=1.75, 95%CI=1.40-2.18,and p<0.00001) and in Indians (OR=8.38, 95%CI=4.34-16.16, and p<0.00001) but not in Caucasians (OR=1.07,95%CI=0.81-1.42, and p=0.62) or in Dutch (OR=0.53, 95%CI= 0.33-0.87, and p= 0.01).In the subgroup analysisby Helicobacter pylori (H. pylori) status, a significantly increased risk was identified among H. pylori (+) (OR=3.58,95%CI=2.33-3.50, and p<0.00001) and H. pylori (-) (OR=2.32, 95%CI=1.46-3.69, and p=0.0004). Conclusions:This meta-analysis suggested that the -765G>C polymorphism in the COX-2 gene could be a risk factor for GCin Asians and Indians.     

Role of DNA Repair-related Gene Polymorphisms in Susceptibility to Risk of Prostate Cancer

Aim: We assessed the association between genetic variants of XPG, XPA, XPD, CSB, XPC and CCNH inthe nucleotide excision repair (NER) pathway and risk of prostate cancer. Methods: We genotyped the XPG,XPA, XPD, CSB, XPC and CCNH polymorphisms by a 384-well plate format on the MassARRAY® platform.Multivariate logistical regression analysis was used to assess the associations between the six gene polymorphismsand risk of prostate cancer. Results: Individuals carrying the XPG rs229614 TT (OR=2.01, 95%CI=1.35-3.27)genotype and T allele (OR=1.73, 95%CI=1.37-2.57) were moderately significantly associated with a higher riskof prostate cancer. Subjects with XPD rs13181 G allele had a marginally increased risk of prostate cancer, withadjusted OR(95%CI) of 1.53 (1.04-2.37). Moreover, individuals carrying with CSB rs2228526 GG genotype(OR=2.05, 95% CI=1.23-3.52) and G allele (OR=1.56, 95%CI=1.17-2.05) were associated with a higher increasedrisk of prostate cancer. The combination genotype of XPG rs2296147 T and CSB rs2228526 G allele hadaccumulative effect on the risk of this cancer, with an OR (95% CI) of 2.23(1.37-3.59). Conclusions: Our studyindicates that XPG rs2296147 and CSB rs2228526 polymorphisms are significantly associated with increasedrisk of prostate cancer, and that combination of XPG rs2296147 T allele and CSB rs2228526 G allele is stronglyassociated with an increased risk.