Genetic Variations in XRCC1 Gene in Sporadic Head and Neck Cancer (HNC) Patients

Machine learning-based ensemble approach in prediction of lung cancer predisposition using XRCC1 gene polymorphism

The employment of machine learning approaches has shown promising results in predicting cancer. In the current study, polymorphisms data of five single nucleotide polymorphisms (SNPs) of DNA repair gene XRCC1 (XRCC1 399, XRCC1 194, XRCC1 206, XRCC1 632, XRCC1 280) of the north Indian population along with four smoking status data is considered as an input to the proposed ensemble model to predict the risk of individual susceptibility to the lung cancer. The prediction accuracy of the proposed ensemble model for cancer predisposition was found to be 85%. The model performance is also evaluated using sensitivity, specificity, precision and the Gini index, which is found in the range of 0.83-0.87. The proposed model also outperformed in all evaluation parameters when compared with the individual Model (LM, SVM, RF, KNN and baseline neural net). Collectively, current results suggest the potential of the proposed ensemble model in predicting the risk of cancer based on XRCC1 SNPs data.Communicated by Ramaswamy H. Sarma.

Clinically significant findings of high-risk mutations in human SLC29A4 gene associated with diabetes mellitus type 2 in Pakistani population

This study conducted an in-depth analysis combining computational and experimental verifications of the deleterious missense mutations associated with the SLC29A4 protein. The functional annotation of the non-synonymous single nucleotide polymorphism (nsSNPs), followed by structure-function analysis, revealed 13 single nucleotide polymorphisms (SNP) as the most damaging. Among these, six mutants P429T/S, L144S, M108V, N86H, and V79E, were predicted as structurally and functionally damaging by protein stability analysis. Also, these variants are located at evolutionary conserved regions, either buried, contributing to the structural damage, or exposed, causing functional changes in the protein. These mutants were further taken for molecular docking studies. When verified via experimental analysis, the SNPs M108V (rs149798710), N86H (rs151039853), and V79E (rs17854505) showed an association with type 2 diabetes mellitus (T2DM). Minor allele frequency for rs149798710 (A > G) was 0.23 in controls, 0.29 in metformin responders, 0.37 in metformin non-responder, for rs151039853 (A > C) was 0.21 in controls, 0.28 in metformin responders, 0.36 in metformin non-responder and for rs17854505 (T > A) was 0.20 in controls, 0.25 in metformin responders, 0.37 in metformin non-responder. Hence, this study concludes that SLC29A4 M108V (rs149798710), N86H (rs151039853), and V79E (rs17854505) polymorphisms were associated with the increased risk of T2DM as well as with the increased risk towards the failure of metformin therapeutic response in T2DM patients of Pakistan. Communicated by Ramaswamy H. Sarma.

Genetic and expression deregulation of immunoregulatory genes in rheumatoid arthritis

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases globally, and is an important public health concern, associating with early death and systemic complications. Although key development in RA treatment has already been made still RA affected individuals face comorbidity and disability. Therefore, there is a need to discover new risk factors in helping early diagnosis and treatment of RA. The present study is designed to assess the variations of Vitamin D receptor (VDR) and interleukin -6 (IL-6) in RA patients. Polymorphisms of said genes were calculated in 300 RA patients and 300 controls, using Tetra-ARMS polymerase chain reaction. Secondly, expression levels of selected genes were checked using the quantitative PCR (qPCR) and obtained results were evaluated using a different statistical test. Logistic regression analysis showed that frequency of mutant allele of VDR gene polymorphisms (rs11168268, OR = 4.84; 95% CI = 2.94-7.97; p = 0.0001; rs2248098, OR = 1.65; 95% CI = 1.07-2.54; p = 0.02) and IL-6 gene polymorphisms (rs184229712, OR = 2.47; 95% CI = 1.56-3.92, p = 0.0001; rs36215814, OR = 2.14; 95% CI = 1.30-3.53; p = 0.002) was observed significantly higher in RA patients vs controls. Expression analysis showed the significant upregulation of IL-6 (p < 0.0001) and downregulation of VDR gene (p < 0.0001) in RA cases vs controls. ROC curve analysis showed that downregulation of IL-6 (AUC = 0.86, p < 0.001) and upregulation of VDR (AUC = 0.77, p < 0.001) was act as the good diagnostic marker for detection/diagnosis of arthritis. In conclusions, data from the present study showed the significant involvement of VDR and IL-6 gene variations in RA pathogenesis.

Influence of Arg399Gln, Arg280His and Arg194Trp XRCC1 gene polymorphisms of Base Excision Repair pathway on the level of 8-oxo-guanine and risk of head and neck cancer in the Polish population

BACKGROUND

Reduced efficiency of DNA repair systems has long been a suspected factor in increasing the risk of cancer.

OBJECTIVE

In this work we investigate influence of three selected polymorphisms of DNA repair gene XRCC1 and level of oxidative damage (measured as level of 8-oxo-guanine) on modulation of the risk of HNSCC.

METHODS

In group of 359 patients with HNSCC (diagnosed with OSCC) the occurrence of polymorphic variants in Arg399Gln, Arg280His and Arg194Trp of XRCC1 were studied with TaqMan technique. In addition we determined level of 8-oxo-guanine with ELISA.

RESULTS

Arg399Gln polymorphism and Arg194Trp polymorphism of XRCC1 gene increases the risk of HNSCC. The coexistence of Arg399Gln and Arg194Trp simultaneously enhances this effect. At the same time, their coexistence with His280His raises the risk to a level higher than in the absence of such coexistence, although the His280His itself is not associated with an increased risk of HNSCC. Patients have higher levels of 8-oxo-guanine than control group, and His280His is polymorphism with highest mean value of 8-oxoG level among studied.

CONCLUSION

Patients with HNSCC not only have an increased level of 8-oxoguanine and the Arg399Gln and Arg/Trp of XRCC1 modulate risk of cancer, but there is also a relationship between these two phenomena, and it can be explained using intragenic combinations revealing that a high level of 8-oxoG could be a potential mechanism behind the modulation of HNSCC risk by the polymorphisms studied.

Relationship of single nucleotide polymorphisms and haplotype interaction of mitochondrial unfolded protein response pathway genes with head and neck cancer

Aim: In this study, we evaluated the effect of selected polymorphisms of mitochondrial unfolded protein response (UPR^mt) pathway in 500 head and neck cancer (HNC) patients and 500 healthy controls from Pakistan. Materials & methods: The experiments were conducted using tetra-ARMS PCR followed by DNA sequencing. Results: Multivariate analysis showed that AA genotype of rs3782116 showed fivefold, GG genotype of rs6598072 approximately twofold and CC genotype of rs4946936 and TT genotype of rs12212067 showed twofold increased risk of HNC. Furthermore, haplotype analysis showed that certain haplotypes of UPR^mt pathway single nucleotide polymorphisms have significant association with increased HNC risk. Conclusion: These results show that genetic aberrations in UPR^mt pathway genes have association with increased HNC risk and can be an indicator of advance clinical outcome especially invasion and metastasis.

Screening and identification of potential target genes in head and neck cancer using bioinformatics analysis

Head and neck cancer (HNC) is the sixth most common cancer worldwide. Recent studies on the pathogenesis of HNC have identified some biochemical associations of this disease, but the molecular mechanisms are not clear. To explore the genetic alterations in head and neck tumors, to identify new high-specificity and high-sensitivity tumor markers, and to investigate potentially effective therapeutic targets, in silico methods were used to study HNC. The GSE58911 microarray dataset was downloaded from the Gene Expression Omnibus online database to identify potential target genes in the carcinogenesis and progression of HNC. Differentially expressed genes (DEGs) were identified and functional enrichment analysis was performed. In addition, a protein-protein interaction network was also constructed, and gene analysis was undertaken using Search Tool for the Retrieval of Interacting Genes and Cytoscape. A total of 648 differentially expressed genes were identified. Kyoto Encyclopedia of Genes and Genomes pathway and Gene Ontology functional enrichment analysis of DEGs included muscle system process, extracellular matrix organization, actin binding, structural molecule activity, structural constituent of muscle, extracellular region part, ECM-receptor interaction, amoebiasis, focal adhesion, drug metabolism-cytochrome P450, and chemical carcinogenesis. There were 26 hub genes identified and biological process analysis revealed that these genes were mainly enriched in extracellular matrix organization, serine-type endopeptidase activity, extracellular matrix, and complement and coagulation cascades. Survival analysis revealed that interleukin (IL)-8 (C-X-C motif chemokine ligand 8), IL1B, and serpin family A member 1 may be involved in the carcinogenesis of HNC. In summary, the DEGs and hub genes identified in the present study may increase understanding of the molecular mechanisms of development of HNC and provide potential target genes for clinical diagnosis and targeted therapy.

Association of nineteen polymorphisms from seven DNA repair genes and the risk for bladder cancer in Gansu province of China

Background

Balance of DNA damage and proper repair plays an important role in progression of bladder cancer. Here we aimed to assess the associations of nineteen polymorphisms from seven DNA repair–associated genes (PRAP1, OGG1, APEX1, MUTYH, XRCC1, XRCC2 and XRCC3) with bladder cancer and their interactions in the disease in a Han Chinese population.

Methodology/Principal Findings

A chip-based TaqMan genotyping for the candidate genes was performed on 227 bladder cancer patients and 260 healthy controls. APEX1 rs3136817, MUTYH rs3219493, three SNPs (rs3213356, rs25487 and rs1799782) in XRCC1, and three SNPs (rs1799794, rs861531 and rs861530) in XRCC3 showed significant associations with the risk of bladder cancer. In haplotype analysis, elevated risks of bladder cancer were observed in those with either haplotype GT (OR = 1.56, P = 0.003) of APEX1, or GGGTC (OR = 2.05, P = 0.002) of XRCC1, whereas decreased risks were in individuals with either GCGCC (OR = 0.40, P = 0.001), or GCGTT (OR = 0.60, = 0.005) of XRCC1, or CCC (OR = 0.65, P = 0.004) of MUTYH, or TTTAT (OR = 0.36, P = 0.009) of XRCC3. Interaction analysis showed that the two-loci model (rs1799794 and rs861530) was the best with the maximal testing accuracy of 0.701, and the maximal 100% cross-validation consistency (P = 0.001).

Conclusions

Polymorphisms and haplotypes of DNA repair genes are associated with the risk of bladder cancer, and of which the SNPs (rs1799794 and rs861530) in XRCC3 gene might be two major loci in relation to the susceptibility to bladder cancer in a northwest Chinese population.

Haplotype analysis of XRCC2 gene polymorphisms and association with increased risk of head and neck cancer

We aimed to investigate the effect of hotspot variations of XRCC2 gene on the risk of head and neck cancer (HNC) in 400 patients and 400 controls. Five polymorphisms of XRCC2 gene G4234C (rs3218384), G4088T (rs3218373), G3063A (rs2040639), R188H (rs3218536) and rs7802034 were analyzed using Allele- specific polymerase chain reaction (ARMS-PCR) followed by sequence analysis. For rs3218373, the GG genotype indicated a statistically significant 3-fold increased risk of HNC (P < 0.001) after multivariate adjustment. For rs7802034, the GG genotype suggested statistically significant 2-fold increased risk of HNC (P < 0.001). For SNP of rs3218536, the AA genotype indicated a significant 3-fold increased risk of HNC (P < 0.001). Additionally, haplotype analysis revealed that TACAG, TGGAG, TACGG and TAGGA haplotypes of XRCC2 polymorphisms are associated with HNC risk. Two SNPs in XRCC2 (rs2040639 and rs3218384) were found increased in strong linkage disequilibrium. Furthermore, joint effect model showed 20 fold (OR = 19.89; 95% CI = 2.65–149.36, P = 0.003) increased HNC risk in patients carrying four homozygous risk alleles of selected polymorphisms. These results show that allele distributions and genotypes of XRCC2 SNPs are significantly associated with increased HNC risk and could be a genetic adjuster for the said disease.

CYP1A1 and GSTP1 gene variations in breast cancer: a systematic review and case-control study

In first part of this study, a systematic review was designed to explore the involvement of CYP1A1 and GSTP1 genes in breast cancerogenesis. Based on systematic review, we designed a study to screen CYP1A1 and GSTP1 genes for mutation and their possible association with breast carcinogenesis. A total of 400 individuals were collected and analyzed by PCR-SSCP. After sequence analysis of coding region of CYP1A1 we identified eleven mutations in different exons of respective gene. Among these eleven mutations, ~3 folds increased breast cancer risk was found associated with Asp82Glu mutation (OR 2.99; 95% CI 1.26-7.09), with Ser83Thr mutation (OR 2.99; 95% CI 1.26-7.09) and with Glu86Ala mutation (OR 3.18; 95% CI 1.27-7.93) in cancer patients compared to controls. Furthermore, ~4 folds increase in breast cancer risk was found associated with Asp347Glu, Phe398Tyr and 5178delT mutations (OR 3.92; 95% CI 1.35-11.3) in patients compared to controls. The sequence analysis of GSTP1 resulted in identification of total five mutations. Among these five mutations, ~3 folds increase in breast cancer risk was observed associated with 1860G>A mutation, with 1861-1876delCAGCCCTCTGGAGTGG mutation (OR 2.70; 95% CI 1.10-6.62) and with 1861C>A mutation (OR 2.97; 95% CI 1.01-8.45) in cancer patients compared to controls. Furthermore, ~5 folds increase in breast cancer risk was associated with 1883G>T mutation (OR 4.75; 95% CI 1.46-15.3) and ~6 folds increase in breast cancer risk was found associated with Iso105Val mutation (OR 6.43; 95% CI 1.41-29.3) in cancer patients compared to controls. Our finding, based on systematic review and experimental data suggest that the polymorphic CYP1A1 and GSTP1 genes may contribute to risk of developing breast cancer.

Association and multiple interaction analysis among five XRCC1 polymorphic variants in modulating lung cancer risk in North Indian population

XRCC1 is a scaffold protein that provides for interaction of DNA polymerase, DNA ligase and damaged DNA. Genotyping was done for the five non-synonymous and synonymous variants of XRCC1 i.e. XRCC1, Arg¹⁹⁴Trp, Pro²⁰⁶Pro, Arg²⁸⁰His, Arg³⁹⁹Gln, Gln⁶³²Gln. Logistic regression analysis was used to analyze the association of XRCC1 with lung cancer, followed by data mining analysis which included both Multi-dimensionality reduction (MDR) and Classification and Regression tree (CART) analysis so as to find possible interaction between SNPs on XRCC1 gene. Statistical analysis revealed XRCC1 Gln⁶³²Gln (OR=2.67, p=<0.001) depicted an overall high risk towards lung cancer. Histological subdivision revealed carriers of mutant genotype in case of XRCC1 Arg³⁹⁹Gln imposed a protective effect towards SQCC subtype. Likewise, mutant genotype in XRCC1 Pro²⁰⁶Pro implied a protective effect for SCLC subtype (OR=0.29, p=0.0017) on the contrary XRCC1 Gln⁶³²Gln showed a high risk in SQCC diseased group (OR=4.16, p=<0.0001). Combination of XRCC1 Gln⁶³²Gln with other SNPs revealed XRCC1 Gln⁶³²Gln with Arg¹⁹⁴Trp (OR=2.10, p=0.03) and Pro²⁰⁶Pro (OR=5.6, p<0.0004) increased an overall risk towards lung cancer. Haplotype analysis illustrated haplotype block 11 (CGAGG) carrying minor allele for XRCC1 206 was associated with the highest risk towards lung cancer on the contrary block 4 (CAGAG) carrying mutant allele for XRCC1 399 significantly decreased the risk. Multi-dimensionality reduction (MDR) results showed the three factor model comprising XRCC1 206, 632, 280 as the best model (CVC=10, prediction error=0.34). Further Classification and Regression tree (CART) analysis revealed terminal node 1 carrying mutant of XRCC1 632 and wild type of XRCC1 280 represented the highest risk group. Our results demonstrated high order interaction between SNPs of XRCC1 gene. This study depicted a positive association of XRCC1 Gln⁶³²Gln towards lung cancer, however XRCC1 Arg³⁹⁹Gln, Arg¹⁹⁴Trp showed an overall no effect or protective effect.

DNA repair genes XRCC1 and ERCC1 polymorphisms and the risk of sporadic breast cancer in Han women in the Gansu Province of China

AIMS

Polymorphisms in DNA damage repair genes may affect DNA repair capacity and modulate breast cancer susceptibility. In this study, we aimed to analyze two polymorphisms for each of the DNA repair genes X-ray repair cross-complementing group 1 (XRCC1) rs25487 and rs1799782 and excision repair cross-complementing group 1 (ERCC1) rs3212964 and rs11615, to evaluate their associations with the risk of sporadic breast cancer in Han women in the Gansu Province of China.

METHODS

Genotypes were determined by a polymerase chain reaction-based approach for 101 patients with breast cancer and in 101 disease-free controls.

RESULTS

We found that individuals with the AA genotype at XRCC1 rs25487 had a significantly increased risk of breast cancer compared with GG genotype (p<0.001, odds ratio [OR]=6.39, 95% confidence interval [CI]: 2.18-18.65). The dominant model showed that the combined rs25487 genotypes (AA+AG) increased the disease risk (p<0.001, OR=3.17, 95% CI: 1.76-5.72). However, no statistical associations were found between rs1799782 in XRCC1, or rs3212964 and rs11615 in ERCC1 and the risk of disease. In haplotype analysis, the GC haplotype in XRCC1 conferred an increased risk (p<0.001) with a 4.78-fold increase for each copy (95% CI: 2.52-8.72). Significant associations were also shown between the single nucleotide polymorphisms (SNPs) and the status of estrogen receptor (ER), progesterone receptor (PR), and HER-2.

CONCLUSIONS

The results suggest that the XRCC1 rs25487 polymorphism may increase the risk of breast cancer.

Worldwide Distribution of Four SNPs in X-Ray and Repair and Cross-Complementing Group 1 (XRCC1)

PURPOSE

X-ray repair cross-complementing group 1 (XRCC1) repairs single-strand breaks in DNA. Several reports have shown the association of single nucleotide polymorphisms (SNPs) (Arg194Trp, Pro206Pro, Arg280His, Arg399Gln) in XRCC1 to diseases. Limited population data are available regarding SNPs in XRCC1, especially in African populations. In this study, genotype distributions of four SNPs in worldwide populations were examined and compared with those reported previously.

MATERIALS AND METHODS

Four SNPs (Arg194Trp, Pro206Pro, Arg280His, Arg399Gln) in XRCC1 from genomic DNA samples of 10 populations were evaluated by using polymerase chain reaction followed by restriction fragment length polymorphism analysis.

RESULTS

The frequency of the minor allele corresponding to the Trp allele of XRCC1Arg194Trp was higher in Asian populations than in African and Caucasian populations. As for XRCC1Pro206Pro, Africans showed higher minor allele frequencies than did Asian populations, except for Tamils and Sinhalese. XRCC1 Arg280His frequencies were similar among Africans and Caucasians but differed among Asian populations. Similarly, lower mutant XRCC1 Arg399Gln frequencies were observed in Africans.

CONCLUSIONS

This study is the first to show the existence of a certain genetic heterogeneity in the worldwide distribution of four SNPs in XRCC1.

Haplotype analysis of the XRCC1 gene and laryngeal cancer

OBJECTIVE

Several polymorphisms in DNA repair genes have been extensively studied in association with various human cancers, including laryngeal cancer. The present study aimed to investigate the association between polymorphisms of the XRCC1 gene and laryngeal cancer in a Chinese population.

METHODS

Five polymorphisms of the XRCC1 gene (rs3213403, rs1799778, rs1001581, rs3213282, and rs3810378) were genotyped by TaqMan in 234 patients with larynx cancer and 230 age- and sex-matched controls without cancer.

RESULTS

The rs3213403, rs1799778, and rs3213282 polymorphisms of XRCC1 were associated with larynx cancer. Haplotype analysis indicated that CCA (odds ratio [OR], 5.707; 95% confidence interval [CI], 3.277-9.938; p<0.001), TGG (OR, 4.344; 95% CI, 2.804-6.732; p<0.001), ACA (OR, 1.615; 95% CI, 1.159-2.250; p=0.004), and GCG (OR, 1.702; 95% CI, 1.164-2.489; p=0.005) were associated with an increased risk for larynx cancer, respectively. However, TGA (OR, 0.518; 95% CI, 0.398-0.673; p<0.001) and ACC (OR, 0.314; 95% CI, 0.215-0.457; p<0.001) were associated with a decreased risk for larynx cancer.

CONCLUSIONS

The results indicated that XRCC1 genetic polymorphisms were associated with larynx cancer in a Chinese population.

Deregulation of base excision repair gene expression and enhanced proliferation in head and neck squamous cell carcinoma

Defects in the DNA damage repair pathway contribute to cancer. The major pathway for oxidative DNA damage repair is base excision repair (BER). Although BER pathway genes (OGG1, APEX1 and XRCC1) have been investigated in a number of cancers, our knowledge on the prognostic significance of these genes and their role in head and neck squamous cell carcinoma is limited. Protein levels of OGG1, APEX1 and XRCC1 and a proliferation marker, Ki-67, were examined by immunohistochemical analysis, in a cohort of 50 HNSCC patients. Significant downregulation of OGG1 (p<0.04) and XRCC1 (p<0.05) was observed in poorly differentiated HNSCC compared to mod-well-differentiated cases. Significant upregulation of APEX1 (p<0.05) and Ki-67 (p<0.05) was observed in poorly differentiated HNSCC compared to mod-well-differentiated cases. Significant correlation was observed between XRCC1 and OGG1 (r=0.33, p<0.02). Inverse correlations were observed between OGG1 and Ki-67 (r=-0.377, p<0.005), between APEX1 and XRCC1 (r=-0.435, p<0.002) and between OGG1 and APEX1 (r=-0.34, p<0.02) in HNSCC. To confirm our observations, we examined BER pathway genes and a proliferation marker, Ki-67, expression at the mRNA level on 50 head and neck squamous cell carcinoma (HNSCC) and 50 normal control samples by quantitative real-time polymerase chain reaction. Significant downregulation was observed in case of OGG1 (p<0.04) and XRCC1 (p<0.02), while significant upregulation was observed in case of APEX1 (p<0.01) and Ki-67 (p<0.03) in HNSCC tissue samples compared to controls. Our data suggested that deregulation of base excision repair pathway genes, such as OGG1, APEX1 and XRCC1, combined with overexpression of Ki-67, a marker for excessive proliferation, may contribute to progression of HNSCC in Pakistani population.

Harnessing massively parallel sequencing in personalized head and neck oncology

Advances in the management of patients with head and neck squamous cell carcinoma (HNSCC) have not significantly changed the prognosis of this tumor over the past five decades. Molecular heterogeneity of HNSCC and its association with HPV, in addition to the increase in the number of cancers arising in traditionally low-risk patients, are among some of the obstacles to the successful management of this group of tumors. Massively parallel sequencing, otherwise known as next-generation sequencing (NGS), is rapidly changing conventional patient management by providing detailed information about each patient's genome and transcriptome. Despite major advances in technology and a significant reduction in the cost of sequencing, NGS remains mainly limited to research facilities. In addition, there are only a few published studies that have utilized this technology in HNSCC. This paper aims to report briefly on current commercially available NGS platforms and discuss their clinical applications, ethical considerations, and utilization in personalized patient care, particularly as this relates to head and neck cancer.

RAD51C--a new human cancer susceptibility gene for sporadic squamous cell carcinoma of the head and neck (HNSCC)

INTRODUCTION

Head and neck squamous cell carcinomas (HNSSCs) are one of the leading causes of cancer-associated death worldwide. Although certain behavioral risk factors are well recognized as tumor promoting, there is very little known about the presence of predisposing germline mutations in HNSCC patients.

METHODS

In this study, we analyzed 121 individuals with HNSCCs collected at our institution for germline alterations in the newly identified cancer susceptibility gene RAD51C.

RESULTS

Sequencing of all exons and the adjacent introns revealed five distinct heterozygous sequence deviations in RAD51C in seven patients (5.8%). A female patient without any other risk factors carried a germline mutation that disrupted the canonical splice acceptor site of exon 5 (c.706-2A>G).

CONCLUSIONS

As there are only a few publications in the literature identifying germline mutations in head and neck cancer patients, our results provide the first indication that paralogs of RAD51, recently described as mutated in breast and ovarian cancer patients, might also be candidates for genetic risk factors in sporadic squamous cell carcinomas of the head and neck.

Association of XRCC1 genetic polymorphism (Arg399Gln) with laryngeal cancer: a meta-analysis based on 4,031 subjects

Several case-control studies on the relation between XRCC1 gene Arg399Gln polymorphism and laryngeal cancer do not have similar conclusions. To further evaluate the relation between the XRCC1 gene Arg399Gln polymorphism and laryngeal cancer, we selected seven case-control studies related to the XRCC1 gene Arg399Gln polymorphism and laryngeal cancer by searching MEDLINE, EMBase, Chinese Biomedical Literature Database, Chinese CNKI, and Wanfang database. We utilized Q test and I (2) test to test the heterogeneity between each study. The fixed effects model was utilized to calculate the odds ratio (OR) and 95 % confidence interval. The present study included 1,654 patients with laryngeal cancer and 2,377 cancer-free control subjects. By meta-analysis, we did not find any association of XRCC1 gene Arg399Gln polymorphism with laryngeal cancer (OR = 1.13, 95 % CI 0.81-1.58, P = 0.47). Therefore, we concluded that XRCC1 gene Arg399Gln polymorphism was not associated with laryngeal cancer.

DNA repair gene XRCC1 polymorphisms and head and neck cancer risk: an updated meta-analysis including 16344 subjects

BACKGROUND

DNA repair gene X-ray repair cross complementing group 1 (XRCC1) plays an important role in the maintenance of the genomic integrity and protection of cells from DNA damage. Sequence variation in XRCC1 gene may alter head and neck cancer (HNC) susceptibility. However, these results are inconclusive. To derive a more precise estimation of the relationship between XRCC1 polymorphism and HNC risk, we undertook a meta-analysis involving 16,344 subjects.

METHODS

A search of the literature by PubMed, Embase, Web of Science and China National Knowledge Infrastructure was performed to identify studies based on the predetermined inclusion criteria. The odds ratio (OR) with 95% confidence interval (CI) was combined using a random-effects model or a fixed-effects model.

RESULTS

Twenty-nine studies consisting of 6,719 cases and 9,627 controls were identified and analyzed. Overall, no evidence of significant association was observed between XRCC1 Arg194Trp, XRCC1 Arg280His, XRCC1 Arg399Gln genotypes and the risk of HNC in any genetic models. Subgroup analyses according to ethnicity, tumor site, publication year, genotyping method also detected no significant association in any subgroup, except that oral cancer was associated with Arg194Trp variant in recessive model. Furthermore, no significant effect of these polymorphisms interacted with smoking on HNC risk was detected but Arg194Trp homozygous variant.

CONCLUSION

In conclusion, this meta-analysis suggests that the XRCC1 Arg194Trp, Arg280His and Arg399Gln polymorphism may not involve in HNC susceptibility. Further studies about gene-gene and gene-environment interactions in different populations are required.