X-ray repair cross-complementing group 1 (XRCC1) genetic polymorphisms and risk of childhood acute lymphoblastic leukemia: a meta-analysis

The XRCC1 Arg194Trp polymorphism is significantly associated with lung adenocarcinoma: a case-control study in an Eastern European Caucasian group

DNA repair plays an important role in maintaining the integrity of the genome by repairing DNA damage induced by carcinogens. Certain genetic polymorphisms that occur in DNA-repair genes may affect the ability to repair DNA defects, and may represent a risk factor in carcinogenesis. The gene XRCC1 is involved in DNA repair. The purpose of our study was to investigate the association between XRCC1 Arg194Trp and Arg399Gln polymorphisms and the risk of lung cancer in a Romanian population. We recruited 222 healthy controls and 102 patients with lung cancer. Genotypes were determined by multiplex polymerase chain-reaction restriction fragment-length polymorphism. Statistical analysis (odds ratio, recessive model) revealed an increased risk for lung cancer for the homozygous 194Trp genotype (χ²=0.186, odds ratio 10.667, 95% confidence interval 1.309–86.933; P=0.007). Also, we found an association between the 194Trp allele and women with lung adenocarcinoma. In conclusion, the results of the study place the XRCC1 Arg194Trp polymorphism among independent risk factors for developing lung cancer.

Amerindian genetic ancestry and INDEL polymorphisms associated with susceptibility of childhood B-cell Leukemia in an admixed population from the Brazilian Amazon

Acute lymphoblastic leukemia (ALL) is a malignant tumor common in children. Studies of genetic susceptibility to cancer using biallelic insertion/deletion (INDEL) type polymorphisms associated with cancer development pathways may help to clarify etymology of ALL. In this study, we investigate the role of eight functional INDEL polymorphisms and influence of genetic ancestry to B-cell ALL susceptibility in children of Brazilian Amazon population, which has a high degree of inter-ethnic admixture. Ancestry analysis was estimated using a panel of 48 autosomal ancestry informative markers. 130 B-cell ALL patients and 125 healthy controls were included in this study. The odds ratios and 95% confidence intervals were adjusted for confounders. The results indicated an association between the investigated INDEL polymorphisms in CASP8 (rs3834129), CYP19A1 (rs11575899) e XRCC1 (rs3213239) genes in the development of B-cell ALL. The carriers of Insertion/Insertion (Ins/Ins) genotype of the polymorphism in CASP8 gene presented reduced chances of developing B-cell ALL (P=0.001; OR=0.353; 95% CI=0.192-0.651). The Deletion/Deletion (Del/Del) genotype of the polymorphism in CYP19A1 gene was associated to a lower chance of developing B-cell ALL (P=3.35×10-6; OR=0.121; 95% CI=0.050-0.295), while Del/Del genotype of the polymorphism in XRCC1 gene was associated to a higher chance of developing B-cell ALL (P=2.01×10-4; OR=6.559; 95% CI=2.433-17.681). We also found that Amerindian ancestry correlates with the risk of B-cell ALL. For each increase of 10% in the Amerindian ancestry results in 1.4-fold chances of developing B-cell ALL (OR=1.406; 95% IC=1.123-1.761), while each increase of 10% in the European ancestry presents a protection effect in the development of B-cell ALL (OR=0.666; 95% IC=0.536-0.827). The results suggest that genetic factors influence leukemogenesis and might be explored in the stratification of B-cell ALL risk in admixed populations.

Genetic susceptibility in childhood acute leukaemias: a systematic review

Acute leukaemias (AL) correspond to 25-35% of all cancer cases in children. The aetiology is still sheltered, although several factors are implicated in causality of AL subtypes. Childhood acute leukaemias are associated with genetic syndromes (5%) and ionising radiation as risk factors. Somatic genomic alterations occur during fetal life and are initiating events to childhood leukaemia. Genetic susceptibility has been explored as a risk factor, since environmental exposure of the child to xenobiotics, direct or indirectly, can contribute to the accumulation of somatic mutations. Hence, a systematic review was conducted in order to understand the association between gene polymorphisms and childhood leukaemia risk. The search was performed in the electronic databases PubMed, Lilacs, and Scielo, selecting articles published between 1995 and 2013. This review included 90 case-control publications, which were classified into four groups: xenobiotic system (n = 50), DNA repair (n = 16), regulatory genes (n = 15), and genome wide association studies (GWAS) (n = 9). We observed that the most frequently investigated genes were: NQO1, GSTM1, GSTT1, GSTP1, CYP1A1, NAT2, CYP2D6, CYP2E1, MDR1 (ABCB1), XRCC1, ARID5B, and IKZF1. The collected evidence suggests that genetic polymorphisms in CYP2E1, GSTM1, NQO1, NAT2, MDR1, and XRCC1 are capable of modulating leukaemia risk, mainly when associated with environmental exposures, such as domestic pesticides and insecticides, smoking, trihalomethanes, alcohol consumption, and x-rays. More recently, genome wide association studies identified significant associations between genetic polymorphisms in ARID5B e IKZF1 and acute lymphoblastic leukaemia, but only a few studies have replicated these results until now. In conclusion, genetic susceptibility contributes to the risk of childhood leukaemia through the effects of gene-gene and gene-environment interactions.

X-ray repair cross-complementing group 1(XRCC1) genetic polymorphisms and thyroid carcinoma risk: a meta-analysis

A number of studies have been conducted to explore the association of XRCC1 polymorphisms with thyroid cancer risk, but the results have been inconsistent. Thus we performed the present meta-analysis to clarify this issue based on all of the evidence available to date. Relevant studies were retrieved by searching PubMed and statistical analysis conducted using Stata software. Nine studies were included in this meta-analysis (1,620 cases and 3,557 controls). There were 6 studies (932 cases and 2,270 controls) of the Arg194Trp polymorphism, 7 studies (1432 cases and 3356 controls) of the Arg280His polymorphism and 9 studies (1,620 cases and 3,557 controls) for the Arg399Gln polymorphism. No association of XRCC1 Arg194Trp, Arg280His and Arg399Gln polymorphism with thyroid cancer risk was observed in the overall analysis. However, subgroup analysis revealed: 1) an elevated risk in aa vs AA analysis (OR=2.03, 95%CI= 1.24-3.31) and recessive genetic model analysis (OR=1.93, 95%CI= 1.20-3.08) in the larger sample size trials for XRCC1 Arg194Trp polymorphism; 2) a decreased thyroid cancer risk on subgroup analysis based on ethnicity in Aa vs AA analysis (OR=0.84, 95%CI= 0.72-0.98) and in a dominant genetic model (OR=0.84, 95%CI= 0.72-0.97) in Caucasian populations for the XRCC1 Arg399Gln polymorphism; 3) a decreased thyroid cancer risk on subgroup analysis based on design type in Aa vs AA analysis (OR=0.72, 95% CI= 0.54-0.97) among the PCC trials for the Arg399Gln polymorphism. Our results suggest that the XRCC1 Arg399Gln polymorphism may be associated with decreased thyroid cancer risk among Caucasians and XRCC1 Arg194Trp may be associated with a tendency for increased thyroid cancer risk in the two larger sample size trials.

Focused screening of a panel of cancer-related genetic polymorphisms reveals new susceptibility loci for pediatric acute lymphoblastic leukemia

BACKGROUND

A genetic predisposition to acute lymphoblastic leukemia (ALL) in childhood is well established. Currently known risk loci, however, explain only one third of the estimated total risk related to common genetic variations.

PROCEDURE

We genotyped 1,421 polymorphisms in 407 candidate genes from the SNP500Cancer database (National Cancer Institute) using the Illumina Cancer SNP Panel. We investigated 78 cases (aged 0-19 years at diagnosis, and mixed ethnic background) of childhood B-precursor ALL and compared genotype data with those of 1,417 HapMap controls. To account for the ethnic diversity of the study population, structured association by genetically matching cases and controls using identity-by-state similarity was used. Case-control association analyses were performed using Cochran-Mantel-Haenszel tests, adjusted for the population substructure.

RESULTS

Common variations rs6966 (3' UTR of PPP1R13L, chr 19q13.32, P = 4.55 × 10(-9)) and rs414580 (intron 2 of MSR1, chr 8p22, P = 6.09 × 10(-8)) were significantly associated with ALL. These SNPs remained significant after adjustment for multiple testing. The SNP rs6966 tags a haplotype block which includes SNPs in PPP1R13L and ERCC2 genes, which are related to DNA repair and cell survival. rs6966 and rs414580 conferred allelic odds ratios of 3.74 (95% confidence interval [CI] 2.31-6.04) and 3.93 (95% CI 2.31-6.69), respectively.

CONCLUSIONS

These findings reveal two independent novel susceptibility loci for childhood ALL.

Association between the XRCC1 Arg194Trp polymorphism and risk of cancer: evidence from 201 case-control studies

The Arg194Trp polymorphism in the X-ray cross-complementing group 1 (XRCC1) had been implicated in cancer susceptibility. The previous published data on the association between XRCC1 Arg194Trp polymorphism and cancer risk remained controversial. Hence, we performed a meta-analysis to investigate the association between cancer susceptibility and XRCC1 Arg194Trp (59,227 cases and 81,587 controls from 201 studies) polymorphism in different inheritance models. We used odds ratios with 95 % confidence intervals to assess the strength of the association. Overall, significantly increased cancer risk was found (recessive model: (odds ration [OR] = 1.18, 95% confidence interval [CI] = 1.09-1.27; homozygous model: OR = 1.21, 95% CI = 1.10-1.33; additive model: OR = 1.05, 95% CI = 1.01-1.09) when all eligible studies were pooled into the meta-analysis. In further stratified and sensitivity analyses, significantly increased glioma risk was found among Asians, significantly decreased lung cancer risk was found among Caucasians, and significant increased breast cancer risk was found among hospital-based studies. In summary, this meta-analysis suggests that Arg194Trp polymorphism may be associated with increased breast cancer risk, Arg194Trp polymorphism is associated with increased glioma risk among Asians, and Arg194Trp polymorphism is associated with decreased lung cancer risk among Caucasians. In addition, our work also points out the importance of new studies for Arg194Trp association in some cancer types, such as gastric, pancreatic, prostate, and nasopharyngeal cancers, where at least some of the covariates responsible for heterogeneity could be controlled, to obtain a more conclusive understanding about the function of the XRCC1 Arg194Trp polymorphism in cancer development (I (2) > 75%).

XRCC1 gene polymorphisms and the risk of differentiated thyroid carcinoma (DTC): a meta-analysis of case-control studies

Background

Previous studies investigating the association between X-ray repair cross-complementing group 1 (XRCC1) polymorphisms and thyroid cancer risk have yielded inconsistent results. This meta-analysis was performed to derive a more precise estimation of the relationship between three XRCC1 polymorphisms and thyroid cancer risk.

Methods/Principal Findings

PubMed and EMBASE database were systematically searched to identify relevant studies. 10 publications were selected for this meta-analysis, including 11 studies for Arg399Gln polymorphism (1726 cases and 3774 controls), 7 studies for Arg194Trp polymorphism (1037 cases and 2487 controls) and 8 studies for Arg280His polymorphism (1432 cases and 3356 controls). The results in total population did not show any significant association between these three polymorphisms and the risk of DTC for all genetic models. However, when stratified by ethnicity, the results showed that Arg280His polymorphism was associated with an increased risk of DTC among Caucasians (Arg/His vs. Arg/Arg: OR = 1.45, 95% CI = 1.09–1.93; dominant model: OR = 1.43, 95% CI = 1.08–1.89; additive model: OR = 1.38, 95% CI = 1.05–1.80), whereas individuals carrying Arg/His genotype have a significantly reduced risk of DTC among Asians (Arg/His vs. Arg/Arg: OR = 0.71, 95% CI = 0.51–0.98). We also detected that 399Gln variant allele carriers might presented an overall decreased risk of DTC in mixed population. Furthermore, subgroup analyses by histological subtype revealed that Arg194Trp polymorphism was significantly associated with reduced risk for papillary thyroid carcinoma (PTC) (dominant model: OR = 0.71, 95% CI = 0.50–0.99).

Conclusions

This meta-analysis suggests that Arg280His polymorphism might contribute to the susceptibility of DTC among Caucasians, whereas it might provide protective effects in Asians against the risk of DTC. Additionally, our results support the protective role of Arg194Trp polymorphism in developing PTC, and show evidence of an association between Arg399Gln polymorphism and decreased risk of DTC in mixed population.

Quantitative assessment of the associations between XRCC1 polymorphisms and bladder cancer risk

Background

The XRCC1 polymorphisms have been implicated in bladder cancer risk, but individually published studies show inconsistent results. The aim of our study was to clarify the effects of XRCC1 variants on bladder cancer risk.

Methods

A systematic literature search up to September 13, 2012 was carried out in PubMed, EMBASE and Wanfang databases, and the references of retrieved articles were screened. Crude odds ratios with 95% confidence intervals were used to assess the associations between XRCC1 Arg194Trp and Arg399Gln polymorphisms and bladder cancer risk. Heterogeneity and publication bias were also evaluated.

Results

A total of 14 and 18 studies were eligible for meta-analyses of Arg194Trp and Arg399Gln, respectively. Regrouping was adopted in accordance with the most probable appropriate genetic models. No obvious heterogeneity between studies was found. For overall bladder cancer, the pooled odds ratios for Arg194Trp and Arg399Gln were 1.69 (95% confidence interval: 1.25 to 2.28; P = 0.001) and 1.10 (95% confidence interval: 1.03 to 1.19; P = 0.008), respectively. After excluding the studies that were not in Hardy–Weinberg equilibrium, the estimated pooled odds ratio still did not change at all.

Conclusions

The meta-analysis results suggest that XRCC1 Arg194Trp and Arg399Gln polymorphisms may be associated with elevated bladder cancer risk.

Association between the XRCC1 polymorphisms and glioma risk: a meta-analysis of case-control studies

Background

X-ray repair cross-complementing group 1 (XRCC1) is one of the DNA repair genes encoding a scaffolding protein that participate in base excision repair (BER) pathway. However, studies on the association between polymorphisms in this gene and glioma have yielded conflicting results. This meta-analysis was performed to derive a more precise estimation between XRCC1 polymorphisms (Arg399Gln, Arg194Trp, and Arg280His) and glioma risk.

Methods

Data were collected from several electronic databases, with the last search up to November 28, 2012. Meta-analysis was performed by critically reviewing 9 studies for Arg399Gln polymorphism (3146 cases and 4296 controls), 4 studies for Arg194Trp polymorphism (2557 cases and 4347 controls), and 4 studies for Arg280His polymorphism (1936 cases and 2895 controls). All of the statistical analyses were performed using the software programs STATA (version 11.0).

Results

The combined results showed that Arg399Gln polymorphism was significantly associated with glioma risk (Gln/Gln versus Arg/Arg: OR = 1.52, 95% CI = 1.03–2.23; recessive model: OR = 1.32, 95% CI = 1.01–1.73; additive model: OR = 1.21, 95% CI = 1.00–1.47), whereas Arg194Trp/Arg280His polymorphisms were all not significantly associated with glioma risk. As for ethnicity, Arg399Gln polymorphism was associated with increased risk of glioma among Asians (Gln/Gln versus Arg/Arg: OR = 1.78, 95% CI = 1.29–2.47; Arg/Gln versus Arg/Arg: OR = 1.28, 95% CI = 1.05–1.56; recessive model: OR = 1.59, 95% CI = 1.16–2.17; dominant model: OR = 1.36, 95% CI = 1.13–1.65; additive model: OR = 1.32, 95% CI = 1.15–1.52), but not among Caucasians. Stratified analyses by histological subtype indicated that the Gln allele of Arg399Gln polymorphism showed borderline association with the risk of glioblastoma among Caucasians. However, no evidence was observed in subgroup analyses for Arg194Trp/Arg280His polymorphisms.

Conclusions

Our meta-analysis suggested that Arg399Gln polymorphism was associated with increased risk of glioma among Asians and borderline increased risk for glioblastoma among Caucasians, whereas Arg194Trp/Arg280His polymorphisms might have no influence on the susceptibility of glioma in different ethnicities.

Association of XRCC1 gene polymorphisms with chronic myeloid leukemia in the population of Andhra Pradesh, India

Chronic myeloid leukemia (CML), a clonal myeloproliferative disorder, is characterized primarily by the presence of chimeric BCR-ABL oncogene, and its progression from chronic to blast phase is associated with the accumulation of additional molecular and chromosomal abnormalities. The molecular mechanisms underlying this genetic instability are poorly understood. The activity of BCR-ABL is known to be associated with the increased production of intracellular reactive oxygen species and spontaneous DNA damage, which when effected by impaired/inaccurate DNA repair systems result in increased susceptibility to CML progression. Using case-control study design, we explored possible association of the repair gene, XRCC1, particularly the codons 399, 280, and 194 polymorphisms screened through PCR-RFLP, with the CML in the sample of 350 cases (206 male and 144 female) and 350 controls from Hyderabad, the capital city of state of the Andhra Pradesh, India. The patient group constituted 301 early chronic phase cases followed by 28 accelerated and 21 blast phase cases. The median age of the patients was 42 years (range, 9-70 years). The genotype distribution revealed significant association of codons 399 (χ(2) = 11.904, degree of freedom (d.f.) = 2; P = 0.002) and 194 (χ(2) = 8.091, d.f. = 2, P = 0.017) with CML, not 280 (P = 0.29). Although these polymorphisms are known to affect the function of XRCC1, the nature and extent of their genetic association with CML does not indicate their direct role in its development. The results seem to suggest that XRCC1 gene might have an important role in CML progression but not in its causation.

Polymorphisms of DNA repair gene XRCC1 and hepatocellular carcinoma risk among East Asians: a meta-analysis

Association studies on the X-ray repair cross-complementing group 1 (XRCC1) polymorphisms (Arg194Trp, Arg280His, and Arg399Gln) in hepatocellular carcinoma (HCC) have shown conflicting results. The aim of this study was to quantitatively summarize the evidence for such a relationship. Published literatures from PubMed, Embase, CNKI, and Chinese Biomedicine Database were retrieved. Pooled odds ratio (OR) with 95 % confidence interval (CI) was calculated using fixed- or random-effects model. Thirteen studies including 3,011 HCC cases and 3,619 controls were included in the meta-analysis of the association between XRCC1 Arg399Gln polymorphism and HCC risk. The results indicated that Arg399Gln polymorphism was significantly associated with risk of HCC in a codominant model (Gln/Gln vs. Arg/Arg, OR = 1.32, 95 % CI = 1.08-1.61; Arg/Gln vs. Arg/Arg, OR = 1.41, 95 % CI = 1.12-1.80) and a dominant model (Gln/Gln + Arg/Gln vs. Arg/Arg, OR = 1.39, 95 % CI = 1.15-1.69), but not in a recessive model (Gln/Gln vs. Arg/Gln + Arg/Arg, OR = 1.13, 95 % CI = 0.95-1.35). Limiting the analysis to the studies within Hardy-Weinberg equilibrium, the results were persistent and robust. When stratifying for region and source of controls, persistent results were observed in any subgroup. No evidence of association of Arg194Trp (980 HCC cases and 966 controls) and Arg280His (1,200 HCC cases and 1,236 controls) with HCC risk was found. No publication bias was found in the present study. The results from the present meta-analysis indicated that the Arg399Gln polymorphisms of XRCC1 may be a genetic susceptibility for HCC in the East Asian population. Further, large and well-designed studies are needed to confirm this conclusion.

Association between CYP1A1 Ile462Val variation and acute leukemia risk: meta-analyses including 2164 cases and 4160 controls

BACKGROUND

Previously, CYP1A1 Ile462Val polymorphism has been indicated to be a risk factor for several malignancies. Increasing reports have focused on the association of CYP1A1 Ile462Val polymorphisms with susceptibility to acute leukemia and have generated controversial results. The goal of the present study was to derive a more precise estimation of the relationship.

METHODS

Relevant literature has been rigorously searched and screened. Eligible studies were identified for the period up to Apr 2012. Meta-analyses evaluating the association of CYP1A1 Ile462Val variation with acute leukemia were carried out. Subgroup analyses on ethnicity, clinical types and source of controls were further performed.

RESULTS

A total of thirteen publications including fourteen case-control studies with 2164 cases and 4160 controls were selected for analysis. The overall data indicated a significant association of CYP1A1 Ile462Val polymorphism with acute leukemia risk (Val/Val vs Ile/Ile OR = 1.49; 95% CI = 1.11-1.98; dominant model: OR = 1.26; 95% CI = 1.05-1.51; recessive model: OR = 1.38; 95% CI = 1.04-1.83). In subgroup analysis on ethnicity, increased risk was shown among mixed ethnicities (Val/Val vs Ile/Ile: OR = 2.36; 95% CI = 1.46-3.82; dominant model: OR = 1.37; 95% CI = 1.01-1.86; recessive model: OR = 2.20; 95% CI = 1.37-3.53) but not Asians or Caucasians. In subgroup analysis on clinical types, increased risk was observed in the acute lymphocytic leukemia (ALL) subgroup (Val/Val vs Ile/Ile: OR = 2.06; 95% CI = 1.42-3.01; recessive model: OR = 1.91; 95% CI = 1.32-2.76) but not in the acute myeloid leukemia (AML) subgroup.

CONCLUSION

The results of the present study suggest that CYP1A1 Ile462Val polymorphism might be a low-penetrant risk factor for acute leukemia. Subgroup analyses suggest that homozygous Val/Val alleles might modify the susceptibility to ALL.

CYP1A1 MspI polymorphism and acute myeloid leukemia risk: meta-analyses based on 5018 subjects

Background

Evidence indicates that CYP1A1 MspI polymorphism might be a possible risk factor for several malignancies. A growing body of literature has been devoted to the association of CYP1A1 MspI polymorphism with acute myeloid leukemia (AML). However, the results remain conflicting. The aim of the present study was to derive a more precise estimation of the relationship.

Methods

Meta-analyses assessing the association of CYP1A1 MspI variation with AML were conducted and subgroup analyses on ethnicity and age groups were further performed. Eligible studies were identified for the period up to May 2012.

Results

A total of ten case–control studies including 1330 cases and 3688 controls were selected for analysis. The overall data failed to indicate a significant association of CYP1A1 MspI polymorphism with AML risk (C vs T: OR = 1.13; 95%CI = 0.87-1.48; CC vs TT: OR = 1.72; 95%CI = 0.99-3.01; CC + TC vs TT: OR = 1.16; 95%CI = 0.86-1.55). In subgroup analysis stratified by ethnicity, significant AML risk was shown among Asians (CC + TC vs TT: OR = 1.33; 95%CI = 1.09-1.62) but not Caucasians or mixed races. In subgroup analysis regarding age groups, no associations were observed in either the childhood AML or the adult AML subgroups.

Conclusion

The results of the present study suggested that CYP1A1 MspI polymorphism might be a risk factor for AML among Asians. Further investigations are needed to confirm the conclusions.