Functional assays to determine the significance of two common XPC 3'UTR variants found in bladder cancer patients

Lack of association between XPC Lys939Gln polymorphism and prostate cancer risk: an updated meta-analysis based on 3039 cases and 3253 controls

Several studies have evaluated the relationship between xeroderma pigmentosum complementation group C (XPC) variants and prostate cancer (PCa) risk. However, the results remain inconclusive. The objective of this study was to identify the role of XPC Lys939Gln variant on PCa occurrence. Relevant case-control studies published between 2000 and 2014 were retrieved in electronic databases. The pooled odds ratio (ORs) and 95% confidence interval (CI) were employed to calculate the strength of association. Finally, a total of eight articles including 3039 PCa patients and 3203 healthy controls were screened out. Our results found that the frequency of C allele was a little higher in PCa cases than that in control, but it was not associated with the increased risk of PCa (C vs. A: OR=1.05, 95% CI=0.98-1.13, P=0.19). This insignificant association was also observed in other genetic models (P>0.05). In subgroup analysis by ethnicity, no significant relationship was found in any study-population (Asian, Caucasian and African) as well. In conclusions, our results indicated that XPC Lys939Gln polymorphism was not associated with PCa susceptibility. Further large well-designed epidemiologic studies with gene-gene and gene-environment interaction should be included and considered.

Comprehensive analyses of DNA repair pathways, smoking and bladder cancer risk in Los Angeles and Shanghai

Tobacco smoking is a bladder cancer risk factor and a source of carcinogens that induce DNA damage to urothelial cells. Using data and samples from 988 cases and 1,004 controls enrolled in the Los Angeles County Bladder Cancer Study and the Shanghai Bladder Cancer Study, we investigated associations between bladder cancer risk and 632 tagSNPs that comprehensively capture genetic variation in 28 DNA repair genes from four DNA repair pathways: base excision repair (BER), nucleotide excision repair (NER), non-homologous end-joining (NHEJ) and homologous recombination repair (HHR). Odds ratios (ORs) and 95% confidence intervals (CIs) for each tagSNP were corrected for multiple testing for all SNPs within each gene using pACT and for genes within each pathway and across pathways with Bonferroni. Gene and pathway summary estimates were obtained using ARTP. We observed an association between bladder cancer and POLB rs7832529 (BER) (pACT = 0.003; ppathway = 0.021) among all, and SNPs in XPC (NER) and OGG1 (BER) among Chinese men and women, respectively. The NER pathway showed an overall association with risk among Chinese males (ARTP NER p = 0.034). The XRCC6 SNP rs2284082 (NHEJ), also in LD with SREBF2, showed an interaction with smoking (smoking status interaction pgene = 0.001, ppathway = 0.008, poverall = 0.034). Our findings support a role in bladder carcinogenesis for regions that map close to or within BER (POLB, OGG1) and NER genes (XPC). A SNP that tags both the XRCC6 and SREBF2 genes strongly modifies the association between bladder cancer risk and smoking.

The impact of single-nucleotide polymorphisms (SNPs) in OGG1 and XPC on the age at onset of Huntington disease

The age at onset of Huntington disease (HD) shows a strong, negative correlation with the number of CAG repeats within the huntingtin (HTT) gene. However, this does not account for all the inter-individual variability seen among patients. In order to assess whether single-nucleotide polymorphisms (SNPs) in the OGG1 and XPC genes, both implicated in responses to oxidative stress, are associated with the age of onset of HD, 9 SNPs have been genotyped in 299 individuals with HD and 582 controls. After correction for multiple testing, two OGG1/XPC haplotypes were found to be associated with younger age at onset independently of the number of CAG repeats within the HTT gene. Both haplotypes contain XPC coding variants that would be expected to impact on protein function and/or variants in the 3'UTR that could result in altered protein levels via allele-specific mIR binding. One haplotype also contains the OGG1-326Cys (rs1052133) allele that has been associated with a lower 8-oxoG repair activity and is particularly sensitive to the cellular redox status. These results highlight the potential role of oxidative stress in determining the age at onset of HD.