Polymorphisms in the XPC gene and gastric cancer susceptibility in a Southern Chinese population

A Significant Increasing Risk Association between Cigarette Smoking and XPA and XPC Genes Polymorphisms

Cigarette smoking (CS) is a major cause of various serious diseases due to tobacco chemicals. There is evidence suggesting that CS has been linked with the DNA damage repair system, as it can affect genomic stability, inducing genetic changes in the genes involved in the repair system, specifically the nucleotide excision repair (NER) pathway, affecting the function and/or regulation of these genes. Single nucleotide polymorphism (SNP), along with CS, can affect the work of the NER pathway and, therefore, could lead to different diseases. This study explored the association of four SNPs in both XPA and XPC genes with CS in the Saudi population. The Taq Man genotyping assay was used for 220 healthy non-smokers (control) and 201 healthy smokers to evaluate four SNPs in the XPA gene named rs10817938, rs1800975, rs3176751, and rs3176752 and four SNPs in the XPC gene called rs1870134, rs2228000, rs2228001, and rs2607775. In the XPA gene, SNP rs3176751 showed a high-risk association with CS-induced diseases with all clinical parameters, including CS duration, CS intensity, gender, and age of smokers. On the other hand, SNP rs1800975 showed a statistically significant low-risk association with all clinical parameters. In addition, rs10817938 showed a high-risk association only with long-term smokers and a low-risk association only with younger smokers. A low-risk association was found in SNP rs3176752 with older smokers. In the XPC gene, SNP rs2228001 showed a low-risk association only with female smokers. SNP rs2607775 revealed a statistically significant low-risk association with CS-induced diseases, concerning all parameters, except for male smokers. However, SNP rs2228000 and rs1870134 showed no association with CS. Overall, the study results demonstrated possible significant associations (effector/and protector) between CS and SNPs polymorphisms in DNA repair genes, such as XPA and XPC, except for rs2228000 and rs1870134 polymorphisms.

Whole Exome Sequencing of a Patient with a Milder Phenotype of Xeroderma Pigmentosum Group C

A 17-year-old female Korean patient (XP115KO) was previously diagnosed with Xeroderma pigmentosum group C (XPC) by Direct Sanger sequencing, which revealed a homozygous nonsense mutation in the XPC gene (rs121965088: c.1735C > T, p.Arg579Ter). While rs121965088 is associated with a poor prognosis, our patient presented with a milder phenotype. Hence, we conducted whole-exome sequencing in the patient and her family members to detect coexisting mutations that may have resulted in a milder phenotype of rs121965088 through genetic interaction. Materials and Methods: the whole-exome sequencing analysis of samples obtained from the patient and her family members (father, mother, and brother) was performed. To identify the underlying genetic cause of XPC, the extracted DNA was analyzed using Agilent's SureSelect XT Human All Exon v5. The functional effects of the resultant variants were predicted using the SNPinfo web server, and structural changes in the XPC protein using the 3D protein modeling program SWISS-MODEL. Results: Eight biallelic variants, homozygous in the patient and heterozygous in her parents, were detected. Four were found in the XPC gene: one nonsense variant (rs121965088: c.1735C > T, p.Arg579Ter) and three silent variants (rs2227998: c.2061G > A, p. Arg687Arg; rs2279017: c.2251-6A > C, intron; rs2607775: c.-27G > C, 5'UTR). The remaining four variants were found in non-XP genes, including one frameshift variant [rs72452004 of olfactory receptor family 2 subfamily T member 35 (OR2T35)], three missense variants [rs202089462 of ALF transcription elongation factor 3 (AFF3), rs138027161 of TCR gamma alternate reading frame protein (TARP), and rs3750575 of annexin A7 (ANXA7)]. Conclusions: potential candidates for genetic interactions with rs121965088 were found. The rs2279017 and rs2607775 of XPC involved mutations in the intron region, which affected RNA splicing and protein translation. The genetic variants of AFF3, TARP, and ANXA7 are all frameshift or missense mutations, inevitably disturbing the translation and function of the resultant proteins. Further research on their functions in DNA repair pathways may reveal undiscovered cellular relationships within xeroderma pigmentosum.

Genetic variations in nucleotide excision repair pathway genes and hepatoblastoma susceptibility

The etiology of hepatoblastoma is largely unknown due to the rarity of this disease. Nucleotide excision repair (NER), a versatile system in repairing DNA damage, is highly implicated in carcinogenesis. However, it remains unclear whether single nucleotide polymorphisms (SNPs) of genes in the NER pathway are related to hepatoblastoma risk. A total of 313 Chinese children diagnosed with hepatoblastoma and 1446 controls were recruited from seven hospitals across China. TaqMan assay was adopted to genotype 19 SNPs in NER pathway genes including ERCC1, XPA, XPC, XPD, XPF and XPG. Of them, only two SNPs in XPC gene predisposed to hepatoblastoma risk. The XPC rs2607775 polymorphism significantly contributed to hepatoblastoma risk (dominant model: adjusted OR = 1.44, 95% CI = 1.01-2.05, P = .046). However, XPC rs1870134 conferred a significantly decreased risk of hepatoblastoma in recessive model (adjusted OR = 0.50, 95% CI = 0.26-0.98, P = .042). Stratified analysis revealed that rs2607775 CG/GG genotype, rs1870134 CC genotype and four to five risk genotypes were associated with the risk of hepatoblastoma under certain subgroups. The significant relationships were confirmed by haplotype analyses and false-positive report probability analyses. In addition, expression quantitative trait locus analysis suggested that rs2607775 G increased expression of XPC mRNA. Collectively, our discover a promising candidate XPC gene as a biomarker for the risk of hepatoblastoma.

The correlation between polymorphisms in the XPC gene and glioma susceptibility in a Chinese pediatric population

BACKGROUND

A previous study revealed that single nucleotide polymorphisms (SNPs) in coding genes play a key role in tumorigenesis, genetic disorders, and drug resistance. Xeroderma pigmentosum group C (XPC) protein is a key DNA damage recognition factor that is required for maintaining the genomic stability. However, the correlation between XPC polymorphisms and glioma susceptibility is still unclear. Hence, this study aimed to investigate the correlation between XPC polymorphisms and pediatric glioma susceptibility.

METHODS

A total of 399 participants (171 glioma patients and 228 controls) were enrolled to evaluate the correlation between XPC polymorphism and pediatric glioma susceptibility. The count data of two groups was analyzed by chi-squared (χ²) test. Moreover, logistic regression was used to assess the strength of XPC polymorphisms associated with glioma susceptibility.

RESULTS

We identified that XPC rs1870134 G>C reduced pediatric glioma susceptibility. Compared to participants with rs1870134 GG/GC genotypes, those with rs1870134 CC genotype had a significantly lower risk for glioma [adjusted odds ratio (AOR) =0.10, 95% confidence interval (CI): 0.01 to 0.78, P=0.028]. Patients with 4-5 genotypes have higher risk of glioma than those with 0-3 genotypes (AOR =1.59, 95% CI: 1.04 to 2.43, P=0.031). The stratified analysis showed that the risky effects of rs2228000 CT/TT genotypes and rs2229090 GC/CC genotypes were more predominant among children aged ≥60 months, astrocytic tumors, and clinical stage I.

CONCLUSIONS

We found for the first time that XPC polymorphisms had a statistically significant correlation with pediatric glioma susceptibility in a Chinese population. The XPC rs2228000 CT/TT and rs2229090 GC/CC genotypes could both increase the risk of pediatric glioma in subgroups with females, astrocytic tumors, and clinical stage I. The XPC polymorphism has potential to be a useful adjunct method to screen pediatric glioma.

Association of DNA repair gene XPC Ala499Val (rs2228000 C>T) and Lys939Gln (rs2228001 A>C) polymorphisms with the risk of chronic myeloid leukemia: A case-control study in a South Indian population

BACKGROUND

Xeroderma pigmentosum complementation group C (XPC), a DNA repair protein, plays an important role in the maintenance of genomic integrity and is essential for the nucleotide excision repair pathway. Polymorphisms in the XPC gene may alter DNA repair leading to genetic instability and oncogenesis. The present study aimed to assess the relationship between the XPC Ala499Val (rs2228000 C>T) and Lys939Gln (rs2228001 A>C) non-synonymous polymorphisms and susceptibility to chronic myeloid leukemia (CML) pathogenesis, disease progression and the response to targeted therapeutic regimen, imatinib mesylate.

METHODS

This case-control study included 212 cases and 212 controls, and the genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism assays.

RESULTS

Our results showed significant association of variant CT (odds ratio = 1.92, 95% confidence interval = 1.21-3.06, p = 0.003) and TT (odds ratio = 2.84, 95% confidence interval = 1.22-6.71, p = 0.007) genotypes in patients with the XPC Ala499Val polymorphism and CML risk. In addition, these genotypes were associated with CML progression to advanced phases (p = 0.006), splenomegaly (p = 0.017) and abnormal lactate dehydrogenase levels (p = 0.03). XPC Lys939Gln was found to correlate with a poor response to therapy, showing borderline significant association with minor cytogenetic response (p = 0.08) and a poor molecular response (p = 0.06). Significant association of the Ala499Val and Lys939Gln polymorphisms with prognosis was observed (Hasford high risk, p = 0.031 and p = 0.019, respectively). Haplotype analysis showed a strong correlation of variant TC haplotype with poor therapy responses (minor cytogenetic response, p = 0.019; poor molecular response, p < 0.0001).

CONCLUSIONS

In conclusion, our results suggest that XPC Ala499Val is a high-penetrance CML susceptibility polymorphism. Both polymorphisms studied are considered as genetic markers with respect to assessing disease progression, therapy response and prognosis in CML patients.

Comprehensive assessment of the association between XPC rs2228000 and cancer susceptibility based on 26835 cancer cases and 37069 controls

Objectives In the present study, we examined available articles from online databases to comprehensively investigate the effect of the XPC (xeroderma pigmentosum complementation group C) rs2228000 polymorphism on the risk of different types of clinical cancer.

Methods We conducted a group of overall and subgroup pooling analyses after retrieving the data from four databases (updated till September 2019). The P-value of association, OR (odds ratios), and 95% CI (confidence interval) were calculated.

Results We selected a total of 71 eligible studies with 26835 cancer cases and 37069 controls from the 1186 retrieved articles. There is an enhanced susceptibility for bladder cancer cases under T vs. C [P=0.004; OR (95% CI) = 1.25 (1.07, 1.45)], TT vs. CC [P=0.001; 1.68 (1.25, 2.26)], CT+TT vs. CC [P=0.016; 1.26 (1.04, 1.53)], and TT vs. CC+ CT [P=0.001; 1.49 (1.18, 1.90)] compared with negative controls. Additionally, there is an increased risk of breast cancer under T vs. C, TT vs. CC and TT vs. CC+ CT (P<0.05, OR > 1). Nevertheless, there is a decreased risk of gastric cancer cases in China under T vs. C [P=0.020; 0.92 (0.85, 0.99)], CT vs. CC [P=0.001, 0.83 (0.73, 0.93)], and CT+TT vs. CC [P=0.003, 0.84 (0.76, 0.94)].

Conclusions The TT genotype of XPC rs2228000 may be linked to an increased risk of bladder and breast cancer, whereas the CT genotype is likely to be associated with reduced susceptibility to gastric cancer in the Chinese population.

A33512C and Intronic Poly(AT) Insertion/Deletion (PAT-/+) Polymorphisms of the XPC Gene and Their Association With the Risk of Breast Cancer

BACKGROUND

Several lines of evidence suggest that A33512C and intronic poly(AT) insertion/deletion (PAT-/+) polymorphisms of the XPC gene is associated with various types of malignancy. This case-control study aimed to determine the possible association between A33512C and PAT-/+ polymorphisms of the XPC gene and breast cancer (BC).

PATIENTS AND METHODS

A total of 200 women diagnosed with BC as cases and 200 ethnically matched healthy controls were genotyped for A33512C and PAT-/+ polymorphisms of the XPC gene by PCR-restriction fragment length polymorphism and PCR methods, respectively. The possible association between XPC A33512C and PAT-/+ polymorphisms with the risk of BC were also analyzed.

RESULTS

PAT-/+ polymorphism of the XPC gene was significantly associated with increased risk of BC (P < .05), whereas there was no association between XPC A33512C polymorphism and BC (P > .05). The frequency of the XPC PAT+ allele in BC patients was significantly higher than those in healthy controls (odds ratio, 0.561; 95% confidence interval, 0.403-0.779; P < .05). The combined genotypes AC/PAT+/+ and CC/PAT+/+ were significantly associated with increased risk of BC.

CONCLUSION

The prevalence of XPC PAT+ allele was significantly higher in patients with high-tumor-stage disease compared to healthy controls. Overall, the significantly higher frequency of the PAT+ allele in the BC group compared to the control group may suggest an etiologic link between the presence of the PAT+ allele and the risk of BC.

Association between the miRNA-149 rs2292832 T>C polymorphism and Kawasaki disease susceptibility in a southern Chinese population

Background

Kawasaki disease (KD), which is characterized by vasculitis, is prone to occur in patients under 5 years of age, has an ambiguous etiology, and displays coronary artery lesions as the chief complication. Previous studies have linked miRNA‐149 to cancers, and rs2292832 T>C is related to allergic diseases and inflammatory bowel disease, which both show immune system disorders and coronary artery disease. Therefore, we performed a study concentrating on the association between the miRNA‐149 rs2292832 T>C polymorphism and KD susceptibility.

Methods

The subjects enrolled were 532 children with KD and 623 controls. We used TaqMan real‐time PCR to obtain the genotypes of the rs2292832 T>C polymorphism.

Results

Ultimately, no significant association was found between the miRNA‐149 rs2292832 T>C polymorphism and KD susceptibility, even in stratification analysis.

Conclusion

Our results indicated that in southern Chinese patients, the miRNA‐149 rs2292832 T>C polymorphism did not affect KD susceptibility, which needs to be further confirmed.

LIG3 gene polymorphisms and risk of gastric cancer in a Southern Chinese population

DNA ligase III (LIG3) has been implicated in the etiology of cancer. However, few studies have accessed the association of LIG3 single nucleotide polymorphisms (SNPs) with gastric cancer risk, especially in Chinese population. The current study was undertaken to investigate contribution of LIG3 gene polymorphisms to gastric cancer risk. We first applied TaqMan assay to genotype three LIG3 gene SNPs (rs1052536 C > T, rs3744356 C > T, rs4796030 A > C) in 1142 patients with gastric cancer and 1173 healthy controls. And then, we adopted unconditional multivariate logistic regression analysis to estimate the association between LIG3 SNP genotypes and gastric cancer risk. In all, no positive association was found between the three LIG3 SNPs and gastric cancer risk in single locus analysis or combined risk genotypes analysis. However, compared with participants with rs4796030 AA genotype, participants with the AC/CC had a decreased risk of developing tumors from cardia at an adjusted OR of 0.68 (95% CI = 0.48-0.96, P = 0.026). In addition, we found that participants harboring 2-3 risk genotypes were at a significantly increased risk of developing tumor from cardia (adjusted OR = 1.63, 95% CI = 1.16-2.28, P = 0.005). These results suggest that genetic variations in LIG3 gene may play a weak role in modifying the risk of gastric cancer. Future functional studies should be performed to elucidate the biological role of LIG3 polymorphisms in gastric cancer carcinogenesis.

Associations of mRNA expression of DNA repair genes and genetic polymorphisms with cancer risk: a bioinformatics analysis and meta-analysis

A systematical bioinformatics and meta-analysis were carried out to establish our understanding of possible relationships between DNA repair genes and the development of cancer. The bioinformatics analysis confirmed that lower XPA and XPC levels and higher XPD, XPF, and WRN levels were observed in 19 types of cancer, and subsequently results indicated that elevated XPA and XPC had a better impact on overall survival, however, higher XPD, XPF, and WRN showed worse influence on cancer prognosis. The meta-analysis included 58 eligible studies demonstrated that harboring XPA rs10817938, XPD rs238406 increased overall cancer risk, however, XPA rs2808668 SNP in overall cancer analysis and XPF rs3136038 in the digestive system remarkably reduced the cancer risk. Moreover, no correlation was investigated for XPC rs1870134, WRN rs1346044 and rs1801195. These suggest that the DNA repair gene was associated with carcinogenesis, and contribute to the prognosis, and the critical SNPs further involved in affecting cancer risk.

TP53 rs1042522 C>G polymorphism and Wilms tumor susceptibility in Chinese children: a four-center case-control study

Wilms tumor is the most common renal malignancy that occurs in children. TP53 gene is considered as a tumor-suppressing gene through controlling cell growth. TP53 gene rs1042522 C>G (Arg72Pro) polymorphism is widely investigated in various types of cancers. However, it is not established if TP53 rs1042522 C>G polymorphism is a candidate variant for Wilms tumor risk. The aim of the study was to determine whether TP53 rs1042522 C>G polymorphism is responsible for the risk of Wilms tumor in Chinese children. All subjects (355 cases and 1070 controls) from four centers of China were genotyped for rs1042522 C>G polymorphism. The effect of rs1042522 C>G polymorphism on Wilms tumor prevalence was analyzed using logistic regression models. We failed to detect a significant relationship between rs1042522 C>G polymorphism and Wilms tumor risk. Further stratification analysis also could not detect a significant relationship. We conclude that TP53 rs1042522 C>G polymorphism might not have enough impact on the risk of Wilms tumor. More validation study with larger sample size will be required to better define the role of TP53 rs1042522 C>G polymorphism in Wilms tumor risk.

Polymorphisms in ERCC5 rs17655 and ERCC1 rs735482 Genes Associated with the Survival of Male Patients with Postoperative Oral Squamous Cell Carcinoma Treated with Adjuvant Concurrent Chemoradiotherapy

The nucleotide excision repair (NER) pathway plays a major role in the repair of DNA damaged by exogenous agents, such as chemotherapeutic and radiotherapeutic agents. Thus, we investigated the association between key potentially functional single nucleotide polymorphisms (SNPs) in the NER pathway and clinical outcomes in oral squamous cell carcinoma (OSCC) patients treated with concurrent chemoradiotherapy (CCRT). Thirteen SNPs in five key NER genes were genotyped in 319 male OSCC patients using iPLEX MassARRAY. Cox proportional hazards models and Kaplan–Meier survival curves were used to estimate the risk of death or recurrence. Carriers of the XPC rs2228000 TT genotype showed a borderline significant increased risk of poor overall survival under the recessive model (hazard ratio (HR) = 1.81, 95% confidence interval (CI) = 0.99–3.29). The CC genotypes of ERCC5 rs17655 (HR = 1.54, 95% CI = 1.03–2.29) and ERCC1 rs735482 (HR = 1.65, 95% CI = 1.06–2.58) were associated with an increased risk of worse disease-free survival under the recessive model. In addition, participants carrying both the CC genotypes of ERCC5 rs17655 and ERCC1 rs735482 exhibited an enhanced susceptibility for recurrence (HR = 2.60, 95% CI = 1.11–6.09). However, no statistically significant interaction was observed between them. Our findings reveal that the ERCC5 rs17655 CC and ERCC1 rs735482 CC genotypes were associated with an increased risk of recurrence in male patients with OSCC treated with CCRT. Therefore, CCRT may not be beneficial, and alternative treatments are required for such patients.

Genetic variants in nucleotide excision repair pathway predict survival of esophageal squamous cell cancer patients receiving platinum-based chemotherapy

The benefits of platinum-based chemotherapy (PBC) on survival of esophageal squamous cell carcinoma (ESCC) patients are inexplicit due to the varied therapeutic effects. Nucleotide excision repair (NER) pathway plays a vital role in removing platinum-DNA adducts in tumor cells and hence may modulate the therapeutic effect and survival outcome. The present study assessed the associations of 26 potentially functional regulatory single nucleotide polymorphisms (rSNPs) in nine core NER genes with disease-free survival (DFS) and overall survival (OS) in 339 ESCC patients. We found that ERCC2 rs2097215 T and rs3916788 A, ERCC5 rs3759497 A and XPC rs3731054 C alleles were associated with unfavorable DFS. Patients carrying high-risk allele group (HRG, 5-8 risk alleles) had a significantly shorter DFS, compared with those carrying low-risk alleles (LRG, 0-4 risk alleles) [adjusted hazards ratio (HR_adj ) = 1.64, 95%CI = 1.23-2.19, P_adj < 0.001]. Three of these SNPs (ie, ERCC2 rs2097215 T and rs3916788 A and ERCC5 rs3759497 A) were also significantly associated with a poorer OS (HRG vs LRG: HR_adj  = 1.75, 95%CI = 1.23-2.47, P_adj  = 0.002). The expression quantitative trait loci (eQTL) analysis revealed significant genotype-expression correlations for ERCC5 rs3759497 and ERCC2 2097215 and rs3916788, which suggest regulatory roles of these SNPs. It appears that these NER variants may independently or jointly exert an impact on survival outcome of Chinese ESCC patients undergoing adjuvant platinum-based therapy. Large studies are warranted to validate these findings.

Genetic variants in the nucleotide excision repair pathway genes and gastric cancer susceptibility in a southern Chinese population

BACKGROUND

Potentially functional polymorphisms can modulate protein activities and host's DNA repair capacity, thereby influencing cancer susceptibility. The association of the polymorphisms in the nucleotide excision repair core pathway genes and gastric cancer susceptibility remains largely unknown.

METHODS

Here, we systematically analyzed the associations between nine polymorphisms in four key genes (XPA, ERCC1, ERCC2, and ERCC4) in the nucleotide excision repair pathway and gastric cancer risk in a Chinese population including 1142 patients and 1173 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the risk associations.

RESULTS

We observed that ERCC1 rs2298881 CA variant genotype was associated with an increased gastric cancer risk (CA vs. CC: adjusted OR [AOR]=1.33, 95% CI=1.09-1.62; dominant model: AOR=1.32, 95% CI=1.10-1.60). However, ERCC1 rs3212986 AA variant genotype was identified as a protective factor for gastric cancer (AA vs. CC: AOR=0.73, 95% CI=0.54-0.98; recessive model: AOR=0.72, 95% CI=0.54-0.96). Genotype-based mRNA expression analysis further indicated that the rs2298881 A allele was associated with decreased ERCC1 mRNA expression.

CONCLUSION

In all, these results indicated that the ERCC1 polymorphisms may affect the risk of gastric cancer in the Chinese Han population.

HSD17B12 gene rs11037575 C>T polymorphism confers neuroblastoma susceptibility in a Southern Chinese population

A previous genome-wide association study (GWAS) identified four genetic polymorphisms (rs1027702 near DUSP12, rs10055201 in IL31RA, rs2619046 in DDX4, and rs11037575 in HSD17B12 gene) that were associated with neuroblastoma susceptibility, especially for low-risk subjects. The aim of this study was to examine the association between these four polymorphisms and neuroblastoma susceptibility in a Southern Chinese population composed of 256 cases and 531 controls. Overall, among all the polymorphisms, single-locus analysis only revealed significant association between the HSD17B12 rs11037575 C>T polymorphism and neuroblastoma susceptibility (CT vs CC: adjusted odds ratio [OR] =0.71, 95% confidence interval [CI] =0.51-0.97, P=0.030). Moreover, stratified analysis indicated that the rs11037575 T allele was associated with decreased neuroblastoma risk among the children aged 0-18 months (adjusted OR =0.60, 95% CI =0.37-0.97, P=0.036); regarding the tumor site, this polymorphism protected against tumor in the mediastinum (adjusted OR =0.59, 95% CI =0.37-0.94, P=0.025). When risk genotypes were combined, we found that girls with two to four risk genotypes were at a significantly increased risk of neuroblastoma (adjusted OR =1.65, 95% CI =1.03-2.64, P=0.039). In terms of clinical stages, individuals with two to four risk genotypes had a tendency toward the development of stage III/IV diseases (adjusted OR =1.69, 95% CI =1.12-2.54, P=0.012). In conclusion, we verified that the HSD17B12 rs11037575 T allele might negatively associate with neuroblastoma risk. These findings need further validation by prospective studies with larger sample size and different ethnicities.

Association between genetic variants in the XPG gene and gastric cancer risk in a Southern Chinese population

Xeroderma pigmentosum group G (XPG) recognizes and excises DNA damage on the 3' side during the DNA repair process. Previous studies indicated that XPG gene polymorphisms may associate with gastric cancer susceptibility, but results were inconsistent. We evaluated the association of five potentially functional XPG polymorphisms (rs2094258 C>T, rs751402 C>T, rs2296147 T>C, rs1047768 T>C, and rs873601 G>A) with gastric cancer susceptibility in 1142 gastric cancer cases and 1173 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression models. Overall, no significant association was detected between any of selected polymorphism and gastric cancer risk. However, we found that individuals carrying 3-4 risk genotypes were at significantly higher risk of gastric cancer than those with 0-2 risk genotypes (OR=1.32, 95% CI=1.04-1.68, P=0.021). The stratification analysis revealed that the cumulative effect of risk genotypes (3-4 vs. 0-2) on gastric cancer were more prominent among subgroups older than 58 years and men. In conclusion, our results indicated that none of the selected XPG polymorphism could significantly alter gastric cancer susceptibility alone. These polymorphisms might collectively confer increased gastric cancer susceptibility. These findings would be strengthened by larger prospective multicenter studies involving different ethnic populations.

Lack of Associations between XPC Gene Polymorphisms and Neuroblastoma Susceptibility in a Chinese Population

Neuroblastoma is one of the most malignant solid tumors in infants and young children. No more than 40% of neuroblastoma patients can survive for longer than five years after it has been diagnosed. XPC protein is a pivotal factor that recognizes DNA damage and starts up the nucleotide excision repair (NER) in mammalian cells. This makes up the first group to defend against the cancer. Previous studies have identified that XPC gene polymorphisms were associated with various types of cancer. However, the associations between XPC gene polymorphisms and neuroblastoma risk have not yet been studied. We investigated the associations between three XPC gene polymorphisms (rs2228001 A>C, rs2228000 C>T, and rs2229090 G>C) and neuroblastoma risk with 256 neuroblastoma patients and 531 healthy controls in a Chinese Han population. Odds ratios and 95% confidence intervals were used to access the association between these three polymorphisms and neuroblastoma risk. No significant association was detected between these three polymorphisms and neuroblastoma risk in the overall analysis as well as in the stratification analysis. These results suggest that none of these three polymorphisms may be associated with the risk of neuroblastoma in the Chinese Han population.