Lack of association between the hOGG1 Ser326Cys polymorphism and breast cancer risk: evidence from 11 case-control studies

New perspectives in cancer biology from a study of canonical and non-canonical functions of base excision repair proteins with a focus on early steps

Alterations of DNA repair enzymes and consequential triggering of aberrant DNA damage response (DDR) pathways are thought to play a pivotal role in genomic instabilities associated with cancer development, and are further thought to be important predictive biomarkers for therapy using the synthetic lethality paradigm. However, novel unpredicted perspectives are emerging from the identification of several non-canonical roles of DNA repair enzymes, particularly in gene expression regulation, by different molecular mechanisms, such as (i) non-coding RNA regulation of tumour suppressors, (ii) epigenetic and transcriptional regulation of genes involved in genotoxic responses and (iii) paracrine effects of secreted DNA repair enzymes triggering the cell senescence phenotype. The base excision repair (BER) pathway, canonically involved in the repair of non-distorting DNA lesions generated by oxidative stress, ionising radiation, alkylation damage and spontaneous or enzymatic deamination of nucleotide bases, represents a paradigm for the multifaceted roles of complex DDR in human cells. This review will focus on what is known about the canonical and non-canonical functions of BER enzymes related to cancer development, highlighting novel opportunities to understand the biology of cancer and representing future perspectives for designing new anticancer strategies. We will specifically focus on APE1 as an example of a pleiotropic and multifunctional BER protein.

MTHFR, XRCC1 and OGG1 genetic polymorphisms in breast cancer: a case-control study in a population from North Sardinia

BACKGROUND

Despite conflicting results, considerable evidence suggests the association between single nucleotide polymorphisms in MTHFR, XRCC1 and OGG1 genes and, risk of developing breast cancer. Here a case-control study is reported, including 135 breat cancer patients and 112 healthy women, all representative of Northern Sardinian population.

METHODS

Polymerase chain reaction/restriction fragment length polymorphism method was used to determine the genotypes of five polymorphisms: MTHFR C677T (rs1801133) and A1298C (rs1801131), XRCC1 Arg194Trp (rs1799782) and Arg399Gln (rs25487) and OGG1 Ser326Cys (rs1052133). Allelic, genotypic and haplotype association analyses with disease risk and clinicopathological parameters were performed.

RESULTS

A nominally significant association with breast cancer risk was observed for MTHFR C677T polymorphism heterozygous genotype in the codominant model (OR: 0.57, 95% CI: 0.32-1.00, p = 0.049) and for Cys/Cys genotype of the OGG1 Ser326Cys polymorphism in the recessive model (OR: 0.23, 95% CI: 0.05-1.11, p = 0.0465). No significant differences were found at genotype-level for A1298C polymorphism of the MTHFR gene and Arg194Trp and Arg399Gln of the XRCC1 gene. Furthermore, the OGG1 and XRCC1 rs25487 polymorphisms were nominally associated with PgR, Her2 status and with sporadic breast cancer, respectively.

CONCLUSIONS

Based on genetic characteristics of individuals included in this study, results suggest that MTHFR CT and OGG1 Cys/Cys genotypes have a protective effect that may have an influence on breast cancer risk in a representative Northern Sardinian population.

Human 8-oxoguanine DNA glycosylase gene polymorphism (Ser326Cys) and cancer risk: updated meta-analysis

Genetic polymorphism of human 8-oxoguanine glycosylase 1 (hOGG1) has been reported to have a relationship with the risk of the development of various cancers. Many studies have described the influence of Ser326Cys polymorphism of the hOGG1 gene on cancer susceptibility. However, the results have remained inconclusive and controversial. Therefore, we performed a meta-analysis to more precisely determine the relationship between the hOGG1 polymorphism and the development of cancer.Electronic databases including PubMed, Embase, Google Scholar, and the Korean Studies Information Service System (KISS) were searched. The odds ratio (OR), 95% confidence interval (CI), and p value were calculated to assess the strength of the association with the risk of cancer using Comprehensive Meta-analysis software (Corporation, NJ, USA). The 127 studies including 38,757 cancer patients and 50,177 control subjects were analyzed for the meta-analysis.Our meta-analysis revealed that G allele of Ser326Cys polymorphism of the hOGG1 gene statistically increased the susceptibility of cancer (all population, OR = 1.092, 95% CI = 1.051-1.134, p < 0.001; in Asian, OR = 1.095, 95% CI = 1.048-1.145, p < 0.001; in Caucasian, OR = 1.097, 95% CI = 1.033-1.179, p = 0.002). Also, other genotype models showed significant association with cancer (p < 0.05, respectively).The present meta-analysis concluded that the G allele was associated with an increased risk of cancer. It suggested that the hOGG1 polymorphism may be a candidate marker of cancer.

Interaction between dietary acrylamide intake and genetic variants for estrogen receptor-positive breast cancer risk

Purpose

The association between dietary acrylamide intake and estrogen receptor-positive (ER+) breast cancer risk in epidemiological studies is inconsistent. By analyzing gene-acrylamide interactions for ER+ breast cancer risk, we aimed to clarify the role of acrylamide intake in ER+ breast cancer etiology.

Methods

The prospective Netherlands Cohort Study on diet and cancer includes 62,573 women, aged 55–69 years. At baseline, a random subcohort of 2589 women was sampled from the total cohort for a case–cohort analysis approach. Dietary acrylamide intake of subcohort members (n = 1449) and ER+ breast cancer cases (n = 844) was assessed with a food frequency questionnaire. We genotyped single nucleotide polymorphisms (SNPs) in genes in acrylamide metabolism, sex steroid systems, oxidative stress and DNA repair. Multiplicative interaction between acrylamide intake and SNPs was assessed with Cox proportional hazards analysis, based on 20.3 years of follow-up.

Results

Unexpectedly, there was a statistically non-significant inverse association between acrylamide and ER+ breast cancer risk among all women but with no clear dose–response relationship, and no association among never smokers. Among the results for 57 SNPs and 2 gene deletions, rs1056827 in CYP1B1, rs2959008 and rs7173655 in CYP11A1, the GSTT1 gene deletion, and rs1052133 in hOGG1 showed a statistically significant interaction with acrylamide intake for ER+ breast cancer risk.

Conclusions

This study did not provide evidence for a positive association between acrylamide intake and ER+ breast cancer risk. If anything, acrylamide was associated with a decreased ER+ breast cancer risk. The interaction with SNPs in CYP1B1 and CYP11A1 suggests that acrylamide may influence ER+ breast cancer risk through sex hormone pathways.

Electronic supplementary material

The online version of this article (10.1007/s00394-018-1619-z) contains supplementary material, which is available to authorized users.

hOGG1 gene polymorphism and breast cancer risk: A systematic review and meta-analysis study

To address the effect of hGGO1 (rs1052133) gene polymorphism on the risk of breast cancer, a meta-analysis was performed. We pooled adjusted odds ratios (OR) as overall and three subgroups (menopausal status, ethnicity, and study setting). In overall analysis, we found a significant association when the model of inheritance was homozygote (pooled OR 1.14; 95% CI 1.01, 1.29). Subgroup analysis showed significant association for homozygote genetic models among postmenopause women (OR 1.23; 95% CI 1.01, 1.49) and Asian population (OR 1.17; 95% CI 1.01, 1.35). This study suggested that the carrier of Ser326Cys polymorphism of hOGG1, Cys/Cys vs Ser/Ser, are at higher risk for breast cancer, independent of other hormonal and environmental risk factors.

DNA repair genes polymorphisms and genetic susceptibility to Philadelphia-negative myeloproliferative neoplasms in a Portuguese population: The role of base excision repair genes polymorphisms

The role of base excision repair (BER) genes in Philadelphia-negative (PN)-myeloproliferative neoplasms (MPNs) susceptibility was evaluated by genotyping eight polymorphisms [apurinic/apyrimidinic endodeoxyribonuclease 1, mutY DNA glycosylase, earlier mutY homolog (E. coli) (MUTYH), 8-oxoguanine DNA glycosylase 1, poly (ADP-ribose) polymerase (PARP) 1, PARP4 and X-ray repair cross-complementing 1 (XRCC1)] in a case-control study involving 133 Caucasian Portuguese patients. The results did not reveal a correlation between individual BER polymorphisms and PN-MPNs when considered as a whole. However, stratification for essential thrombocythaemia revealed i) borderline effect/tendency to increased risk when carrying at least one variant allele for XRCC1_399 single-nucleotide polymorphism (SNP); ii) decreased risk for Janus kinase 2-positive patients carrying at least one variant allele for XRCC1_399 SNP; and iii) decreased risk in females carrying at least one variant allele for MUTYH SNP. Combination of alleles demonstrated an increased risk to PN-MPNs for one specific haplogroup. These findings may provide evidence for gene variants in susceptibility to MPNs. Indeed, common variants in DNA repair genes may hamper the capacity to repair DNA, thus increasing cancer susceptibility.

Lack of any Association between the Hogg1 Ser326Cys Polymorphism and Breast Cancer Risk: a Systematic Review And Meta-Analysis Of 18 Studies

Background:

The human 8-oxoguanine DNA glycosylase (hOGG1) gene may be linked with cancer susceptibility. The aim of this study was to quantitatively summarize any association between the hOGG1 Ser326Cys polymorphism and breast cancer (BC) risk.

Materials and Methods:

A comprehensive search of the PubMed, Embase, and ISI web of knowledge databases for papers published before 1 October 2016 was conducted. Summary odds ratios (ORs) with corresponding 95 % confidence intervals (95 %CIs) were estimated, with fixed-effects or random-effects models when appropriate, to assess any association.

Results:

A total of 9,434 cases and 10,497 controls from 18 studies were included in this meta-analysis. When the eligible studies were pooled, there was no evidence found for a significant association between the hOGG1 Ser326Cys polymorphism and BC in in all genetic contrast models G vs. C (OR=1.19, 95% CI 0.92– 1.53), CG vs. CC (OR = 0.97, 95% CI 0.91-1.04, p = 0.46), GG vs. CC (OR = 1.11, 95% CI 0.91-1.35, p = 0.30), GG + CG vs. CC (OR = 0.98, 95% CI 0.92-1.05, p = 0.67), and GG vs. CG + CC (OR = 1.22, 95% CI 0.98-1.52, p = 0.07). According to subgroup analysis, we also did not find a significant association between the hOGG1 Ser326Cys polymorphism and BC risk in Asians and Caucasians considered separately.

Conclusions:

The current meta-analysis suggests that the hOGG1 Ser326Cys polymorphism is not significantly associated with BC risk.

Analysis of DNA Repair Genes Polymorphisms in Breast Cancer

Genetic polymorphisms in the DNA repair genes may be associated with increased cancer risk. The purpose of this study was to evaluate the association of the DNA repair genes polymorphisms with the risk of breast cancer development. The study included 200 breast cancer patients and 200 healthy controls. The following polymorphisms were studied: C/G (Ser326Cys, rs1052133) of the hOGG1, A/C (IVS5 + 33, rs3212961) of the ERCC1, A/C (Lys939Gln, rs2228001) of the XPC, C/T (Thr241Met, rs861539) of the XRCC3, G/T (Leu787Leu, rs1800392) of the WRN and G/T (Ser307Ser, rs1056503) of the XRCC4 gene. Presented study showed statistically significant increase in the breast cancer development risk of the G/G hOGG1 genotype (OR 8.13; 95 % CI, 4.37-15.14; p < 0.001) and for the G hOGG1 allele (OR 5.11; 95 % CI, 3.69-7.06; p < 0.001), as well as for the C/C ERCC1 genotype (OR 10.61; 95 % CI, 5.72-19.69; p < 0.001) and the C ERCC1 allele (OR 4.66; 95 % CI, 3.43-6.34; p < 0.001) in patients with breast cancer in comparison with healthy control group. We also observed positive association of the C/C XPC genotype (OR 3.80; 95 % CI, 2.27-6.38; p < 0.001) as well as the C XPC allele occurrence with an increased breast cancer development risk (OR 2.65; 95 % CI, 1.98-3.55; p < 0.001). Furthermore, we found an association of the G/T WRN gene polymorphism with increased risk of carcinoma. The hOGG1, ERCC1, XPC and WRN genes polymorphisms may be related to development of breast cancer.

Polymorphisms in DNA repair genes in gastrointestinal stromal tumours: susceptibility and correlation with tumour characteristics and clinical outcome

DNA repair pathways play an essential role in cancer susceptibility by maintaining genomic integrity. This led us to investigate the influence of polymorphisms in the genes coding repair pathway enzymes on gastrointestinal stromal tumours (GIST) susceptibility, tumour characteristics and clinical outcome. We investigated a panel of 20 polymorphisms in 11 genes in 81 cases and 147 controls. The XPD rs13181 wild-type allele and hOGG1 rs1052133 and XPF rs1800067 minor alleles were significantly associated with disease susceptibility. XPA rs1800975 and rs2808668 were associated with tumour size (P = 0.018), metastatic status at onset (P = 0.035) and mitotic index (P = 0.002). With regards to outcome treatment, the XPD rs50872 minor allele had a significant favourable impact on time to progression (TTP). Similarly, the XPC rs2228000 minor allele was correlated with a longer TTP (P = 0.03). On the contrary, the XPC rs2228001 and hOGG1 rs1052133 minor alleles were associated with a diminished TTP (P = 0.005 and P = 0.01, respectively). Regarding OS, we found the presence of at least one hOGG1 (rs1052133) minor allele that had a 60 % lower risk to die compared to the wild-type carriers (P = 0.04). Furthermore, the XRCC3 rs861539 variant allele is associated with a hazard of early death compared with the wild-type genotype (P = 0.04). To the best of our knowledge, this is the first study on polymorphisms in DNA repair genes, belonging to the different pathways, extensively evaluated in GIST patients. Through this multiple candidate gene approach, we report for the first time the significant associations between polymorphisms in DNA repair genes, susceptibility, clinical pathological features and clinical outcome in GIST.

Polymorphisms in base excision repair genes: Breast cancer risk and individual radiosensitivity

Breast cancer (BC) is the most common cancer among women worldwide. The aetiology and carcinogenesis of BC are not clearly defined, although genetic, hormonal, lifestyle and environmental risk factors have been established. The most common treatment for BC includes breast-conserving surgery followed by a standard radiotherapy (RT) regimen. However, radiation hypersensitivity and the occurrence of RT-induced toxicity in normal tissue may affect patients’ treatment. The role of DNA repair in cancer has been extensively investigated, and an impaired DNA damage response may increase the risk of BC and individual radiosensitivity. Single nucleotide polymorphisms (SNPs) in DNA repair genes may alter protein function and modulate DNA repair efficiency, influencing the development of various cancers, including BC. SNPs in DNA repair genes have also been studied as potential predictive factors for the risk of RT-induced side effects. Here, we review the literature on the association between SNPs in base excision repair (BER) genes and BC risk. We focused on X-ray repair cross complementing group 1 (XRCC1), which plays a key role in BER, and on 8-oxoguanine DNA glycosylase 1, apurinic/apyrimidinic endonuclease 1 and poly (ADP-ribose) polymerase-1, which encode three important BER enzymes that interact with XRCC1. Although no association between SNPs and radiation toxicity has been validated thus far, we also report published studies on XRCC1 SNPs and variants in other BER genes and RT-induced side effects in BC patients, emphasising that large well-designed studies are needed to determine the genetic components of individual radiosensitivity.

Oxidative stress in susceptibility to breast cancer: study in Spanish population

Background

Alterations in the redox balance are involved in the origin, promotion and progression of cancer. Inter-individual differences in the oxidative stress regulation can explain a part of the variability in cancer susceptibility.

The aim of this study was to evaluate if polymorphisms in genes codifying for the different systems involved in oxidative stress levels can have a role in susceptibility to breast cancer.

Methods

We have analyzed 76 single base polymorphisms located in 27 genes involved in oxidative stress regulation by SNPlex technology. First, we have tested all the selected SNPs in 493 breast cancer patients and 683 controls and we have replicated the significant results in a second independent set of samples (430 patients and 803 controls). Gene-gene interactions were performed by the multifactor dimensionality reduction approach.

Results

Six polymorphisms rs1052133 (OGG1), rs406113 and rs974334 (GPX6), rs2284659 (SOD3), rs4135225 (TXN) and rs207454 (XDH) were significant in the global analysis. The gene-gene interactions demonstrated a significant four-variant interaction among rs406113 (GPX6), rs974334 (GPX6), rs105213 (OGG1) and rs2284659 (SOD3) (p-value = 0.0008) with high-risk genotype combination showing increased risk for breast cancer (OR = 1.75 [95% CI; 1.26-2.44]).

Conclusions

The results of this study indicate that different genotypes in genes of the oxidant/antioxidant pathway could affect the susceptibility to breast cancer. Furthermore, our study highlighted the importance of the analysis of the epistatic interactions to define with more accuracy the influence of genetic variants in susceptibility to breast cancer.

Single nucleotide polymorphisms of DNA base-excision repair genes (APE1, OGG1 and XRCC1) associated with breast cancer risk in a Chinese population

Altered DNA repair capacity can result in increased susceptibility to cancer. The base excision repair (BER) pathway effectively removes DNA damage caused by ionizing radiation and reactive oxidative species (ROS). In the current study, we analyzed the possible relation of polymorphisms in BER genes, including 8-oxoguanine DNA glycosylase (OGG1), apurinic/apyrimidinic endonuclease 1 (APE1), and X-ray repair cross-complementing group 1 protein (XRCC1), with breast cancer risk in Chinese Han women. This case-control study examined 194 patients with breast cancer and 245 cancer-free hospitalized control subjects. Single nucleotide polymorphisms (SNPs) of OGG1 (Ser326Cys), XRCC1 (Arg399Gln), and APE1 (Asp148Glu and -141T/G) were genotyped and analyzed for their association with breast cancer risk using multivariate logistic regression models. We found that XRCC1 Arg399Gln was significantly associated with an increased risk of breast cancer. Similarly, the XRCC1 Gln allele was significantly associated with an elevated risk in postmenopausal women and women with a high BMI (≥ 24 kg/m2). The OGG1 Cys allele provided a significant protective effect against developing cancer in women with a low BMI (< 24 kg/m2). When analyzing the combined effects of these alleles on the risk of breast cancer, we found that individuals with ≥ 2 adverse genotypes (XRCC1 399Gln, APE1 148Asp, and OGG1 326Ser) were at a 2.18-fold increased risk of breast cancer (P = 0.027). In conclusion, our data indicate that Chinese women with the 399Gln allele of XRCC1 have an increased risk of breast cancer, and the combined effects of polymorphisms of BER genes may contribute to tumorigenesis.

The hOGG1 Ser326Cys polymorphism contributes to digestive system cancer susceptibility: evidence from 48 case-control studies

The Ser326Cys polymorphism in the human 8-oxogunaine DNA glycosylase (hOGG1) gene had been implicated in cancer susceptibility. Studies investigating the associations between the Ser326Cys polymorphism and digestion cancer susceptibility showed conflicting results. Therefore, a meta-analysis was performed to derive a more precise estimation of the relationship. We conducted a meta-analysis of 48 studies that included 12,073 cancer cases and 19,557 case-free controls. We assessed the strength of the association using odds ratios (ORs) with 95% confidence intervals (CIs). In our analysis, the hOGG1 Ser326Cys polymorphism was significantly associated with the risk of digestive system cancers (Cys/Cys vs. Ser/Ser: OR = 1.17, 95% CI = 1.00-1.35, P < 0.001; Cys/Cys vs. Cys/Ser + Ser/Ser: OR = 1.14, 95% CI = 1.00-1.29, P < 0.001). In subgroup analyses by cancer types, we found that the hOGG1 Ser326Cys polymorphism may increase hepatocellular cancer and colorectal cancer risks, but decrease the risk of oral cancer. These findings supported that hOGG1 Ser326Cys polymorphism may contribute to the susceptibility of digestive cancers.

Polymorphism of DNA repair genes OGG1, XRCC1, XPD and ERCC6 in bladder cancer in Belarus

CONTEXT

The study of DNA base and nucleotide excision repair gene polymorphisms in bladder cancer seems to have a predictive value because of the evident relationship between the DNA damage response induced by environmental mutagens and cancer predisposition.

OBJECTIVE

The objective was to determine OGG1 Ser326Cys, XRCC1 Arg399Gln, XPD Asp312Asn, and ERCC6 Met1097Val polymorphisms in bladder cancer patients as compared to controls.

METHODS

Both groups were predominantly represented by Belarusians and Eastern Slavs. DNA samples from 336 patients and 370 controls were genotyped using a PCR-RFLP method.

RESULTS

The genotype distributions were in agreement with the Hardy-Weinberg equilibrium. The minor allele frequencies in the control population were in the range of those in Caucasians in contrast to Asians. The OGG1 326 Ser/Cys and XPD 312 Asp/Asn heterozygous genotypes were inversely associated with cancer risk (OR [95% CI] = 0.69 [0.50-0.95] and 1.35 [1.0-1.82], respectively). The contrasting effects of these genotypes were potentiated due to their interactions with smoking habit or age.

CONCLUSIONS

Among four DNA repair gene polymorphisms, the OGG1 326 Ser/Cys and XPD 312 Asp/Asn heterozygous genotypes might be recognized as potential genetic markers modifying susceptibility to bladder cancer in Belarus.

Ethnic background and genetic variation in the evaluation of cancer risk: a systematic review

The clinical use of genetic variation in the evaluation of cancer risk is expanding, and thus understanding how determinants of cancer susceptibility identified in one population can be applied to another is of growing importance. However there is considerable debate on the relevance of ethnic background in clinical genetics, reflecting both the significance and complexity of genetic heritage. We address this via a systematic review of reported associations with cancer risk for 82 markers in 68 studies across six different cancer types, comparing association results between ethnic groups and examining linkage disequilibrium between risk alleles and nearby genetic loci. We find that the relevance of ethnic background depends on the question. If asked whether the association of variants with disease risk is conserved across ethnic boundaries, we find that the answer is yes, the majority of markers show insignificant variability in association with cancer risk across ethnic groups. However if the question is whether a significant association between a variant and cancer risk is likely to reproduce, the answer is no, most markers do not validate in an ethnic group other than the discovery cohort's ancestry. This lack of reproducibility is not attributable to studies being inadequately populated due to low allele frequency in other ethnic groups. Instead, differences in local genomic structure between ethnic groups are associated with the strength of association with cancer risk and therefore confound interpretation of the implied physiologic association tracked by the disease allele. This suggest that a biological association for cancer risk alleles may be broadly consistent across ethnic boundaries, but reproduction of a clinical study in another ethnic group is uncommon, in part due to confounding genomic architecture. As clinical studies are increasingly performed globally this has important implications for how cancer risk stratifiers should be studied and employed.

Association between OGG1 Ser326Cys and APEX1 Asp148Glu polymorphisms and breast cancer risk: a meta-analysis

BACKGROUND

The base excision repair (BER) pathway removes DNA damage caused by ionizing radiation, reactive oxidative species and methylating agents. OGG1 and APE1 are two important genes in the BER pathway. Many epidemiological studies have evaluated the association between polymorphisms in the two BER genes (OGG1 Ser326Cys and APE1 Asp148Glu) and breast cancer risk. However, the results are inconsistent.

METHODS

We searched the electronic databases including PubMed, Embase and Cochrane library for all eligible studies for the period up to February 2014. Data were extracted by two independent authors and pooled odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were used to assess the strength of the association.

RESULTS

A total of 17 studies including 9,040 cases and 10,042 controls were available for OGG1 Ser326Cys polymorphism and 7 studies containing 2,979 cases and 3,111 controls were included for APE1 Asp148Glu polymorphism. With respect to OGG1 Ser326Cys polymorphism, we did not find a significant association with breast cancer risk when all eligible studies were pooled into the meta-analysis. However, in subgroup analyses by ethnicity and menopausal status, statistical significant increased breast cancer risk was found in Asian populations (Cys/Cys vs. Ser/Ser: OR=1.157, 95% CI 1.013-1.321, P=0.011; Cys/Cys vs. Ser/Cys+Ser/Ser: OR=1.113, 95% CI 1.009-1.227, P=0.014) and postmenopausal patients (Cys/Cys vs. Ser/Cys+Ser/Ser: OR=1.162, 95% CI 1.003-1.346, P=0.024). In subgroup analysis according to quality score, source of control, and HWE in controls, no any significant association was detected. With respect to APE1 Asp148Glu polymorphism, no significant association with breast cancer risk was demonstrated in the overall and stratified analyses.

CONCLUSIONS

The present meta-analysis suggests that the OGG1 Ser326Cys polymorphism may be a risk factor for breast cancer in Asians and postmenopausal patients. Further large and well-designed studies are needed to confirm this association.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1156934297124915.

Single nucleotide polymorphisms (SNPs) of ERCC2, hOGG1, and XRCC1 DNA repair genes and the risk of triple-negative breast cancer in Polish women

Triple-negative breast cancer (TNBC) refers to about 15–20 % of all breast cancer cases. It is characterized by worse clinical outcome, poor prognosis, and absence of prognostic indicators. Several polymorphisms in the nucleotide excision repair (NER) and base excision repair (BER) gene have been extensively studied in association with various human cancers. The aim of this study was to evaluate the role of the hOGG1-Ser326Cys (rs13181), XRCC1-Arg194Trp (rs1799782), and ERCC2-Lys751Gln (rs13181) gene polymorphisms with clinical parameters and the risk for development of triple-negative breast cancer. Our research included 70 patients with TNBC and 70 healthy controls. Gene polymorphisms were genotyped by the PCR-RFLP (restriction fragment length polymorphism) method. The genotype distributions were contrasted by the chi-square test, and the significance of the polymorphism was assessed by multiple logistic regression producing odds ratios (ORs) and 95 % confidence intervals (CIs). In the present work, a relationship was identified between ERCC2-Lys751Gln polymorphism and the incidence of triple-negative breast cancer. An association was observed between triple-negative breast carcinoma occurrence and the presence of Gln/Gln genotype (OR = 5.71 (2.12–5.43), p = 0.0007). A tendency for an increased risk of TNBC was detected with the occurrence of 751Gln allele of ERCC2 polymorphism. No significant associations between Ser326Cys and Arg194Trp genotype and TNBC were observed. We suggest that the Lys751Gln polymorphism of the ERCC2 gene may be risk factors for triple-negative breast cancer development in Polish women.

Genetic polymorphism in hOGG1 is associated with triple-negative breast cancer risk in Chinese Han women

8-hydroxy-2'-deoxyguanine (8-OHdG), a typical product of oxidative stress-induced DNA damage, can cause a G-T transversion during DNA replication if it is not removed. Human 8-oxoguanine glycosylase 1 (hOGG1), a key DNA repair gene, recognizes and excises 8-OHdG from damaged DNA accurately; however, a c.977C>G (Ser326Cys) polymorphism in hOGG1 can inhibit the gene's ability to remove 8-OHdG. The aim of present study was to investigate the association between the c.977C>G polymorphism in hOGG1 and the risk of breast cancer in Chinese Han women. We used high-resolution melting and sequencing to analyze the genotypes of 630 patients with sporadic breast cancer patients and 777 healthy controls. We also performed risk-stratified subgroup analyses to determine the association between the c.977C>G polymorphism and other characteristics of breast cancer subgroups. Breast cancer patients and healthy controls did not have significantly different of c.977C/G genotypes (odds ratio [OR] = 1.10, 95% confidence interval [CI] = 0.82-1.49, p = 0.57) and c.977G/G genotypes (OR = 1.34, 95% CI = 0.97-1.84, p = 0.09). However, the c.977G/G genotype was especially prevalent in breast cancer patients who were younger than 55 years (OR = 1.58, 95% CI = 1.05-2.39, p = 0.04), were premenopausal status (OR = 1.87, 95% CI = 1.14-3.06, p = 0.02), had triple-negative disease (OR = 2.14, 95% CI = 1.06-4.29, p = 0.04), or p53-positive disease (OR = 1.56, 95% CI = 1.14-2.12, p = 0.005). These findings suggest that the c.977C>G polymorphism in hOGG1 is associated with an increased risk of breast cancer in Chinese Han women who are younger than 55 years, premenopausal, triple-negative, or p53-positive subgroups.

Polymorphisms in base excision repair genes and thyroid cancer risk

Thyroid cancer (TC) is the most frequent endocrine malignancy, accounting however for only 1-2% of all human cancers, and the best-established risk factor for TC is radiation exposure, particularly during childhood. Since the BER pathway seems to play an important role in the repair of DNA damage induced by IR and other genotoxicants, we carried out a hospital-based case-control study in order to evaluate the potential modifying role of 6 BER polymorphisms on the individual susceptibility to non-familial TC in 109 TC patients receiving iodine-131, and 217 controls matched for age (± 2 years), gender and ethnicity. Our results do not reveal a significant involvement of XRCC1 Arg194Trp and Arg399Gln, OGG1 Ser326Cys, APEX1 Asp148Glu, MUTYH Gln335His and PARP1 Val762Ala polymorphisms on the individual susceptibility towards TC, mostly in agreement with the limited available evidence. By histological stratification analysis, we observed that the association between the presence of heterozygosity in the MUTYH Gln335His polymorphism and TC risk almost reached significance for the papillary subtype of TC. This was the first time that the putative association between this polymorphism and TC susceptibility was evaluated. However, since the sample size was modest, the possibility of a type I error should not be excluded and this result should, therefore, be interpreted with caution. More in depth studies involving larger populations should be pursued in order to further clarify the potential usefulness of the MUTYH Gln335His genotype as a predictive biomarker of susceptibility to TC and the role of the remaining BER polymorphisms on TC susceptibility.

Base excision repair and cancer

Base excision repair is the system used from bacteria to man to remove the tens of thousands of endogenous DNA damages produced daily in each human cell. Base excision repair is required for normal mammalian development and defects have been associated with neurological disorders and cancer. In this paper we provide an overview of short patch base excision repair in humans and summarize current knowledge of defects in base excision repair in mouse models and functional studies on short patch base excision repair germ line polymorphisms and their relationship to cancer. The biallelic germ line mutations that result in MUTYH-associated colon cancer are also discussed.

Lack of association between hOGG1 Ser326Cys polymorphism and the risk of bladder cancer: a meta-analysis

OBJECTIVE

In some but not all studies, hOGG1 Ser326Cys polymorphism has been reported to contribute to the risk of bladder cancer. To determine whether there is a significant association of hOGG1 Ser326Cys polymorphism with the susceptibility for bladder cancer, we performed a comprehensive meta-analysis.

METHODS

The electronic PubMed, Medline and Springer databases were searched for publications on the association between hOGG1 Ser326Cys polymorphism and bladder cancer through to May 20, 2011. Seven case-control studies were identified, including 2,474 cases and 2,408 controls. From these identified publications, crude odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to estimate the strength of association using fixed- or random-effects models. Two investigators each extracted data and conducted the analysis independently.

RESULTS

Overall, no significant associations were found between hOGG1 Ser326Cys polymorphism and bladder cancer in codominant models (GG vs. CC: OR 1.11, 95% CI 0.74-1.66, p = 0.63; GC vs. CC: OR 1.07, 95% CI 0.80-1.41, p = 0.65). Similarly, no significant associations with bladder cancer were observed in the recessive model (GG vs. GC+CC: OR 1.05, 95% CI 0.65-1.70, p = 0.85), dominant model (GG+GC vs. CC: OR 1.07, 95% CI 0.87-1.32, p = 0.53) and allele model (G vs. C: OR 1.06, 95% CI 0.90-1.26, p = 0.49). In the stratified analyses by ethnicity, control sources, pathology, Hardy-Weinberg equilibrium, significant associations were still not observed.

CONCLUSIONS

The overall current literature on hOGG1 Ser326Cys polymorphism and the risk of bladder cancer suggests no statistically significant association between the two. Additional primary studies may be necessary to provide evidence of any significant association between this specific polymorphism and bladder cancer.

The effect of hOGG1 Ser326Cys polymorphism on cancer risk: evidence from a meta-analysis

Background

Human oxoguanine glycosylase 1 (hOGG1) in base excision repair (BER) pathway plays a vital role in DNA repair. Numerous epidemiological studies have evaluated the association between hOGG1 Ser326Cys polymorphism and the risk of cancer. However, the results of these studies on the association remain conflicting. To derive a more precise estimation of the association, we conducted a meta-analysis.

Methodology/Principal Findings

A comprehensive search was conducted to identify the eligible studies of hOGG1 Ser326Cys polymorphism and cancer risk. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. We found that the hOGG1 Ser326Cys polymorphism was significantly associated with overall cancer risk (Cys/Cys vs. Ser/Ser: OR = 1.19, 95%CI = 1.09–1.30, P<0.001; Cys/Cys vs. Cys/Ser+Ser/Ser: OR = 1.16, 95%CI = 1.08–1.26, P<0.001). Moreover, in subgroup analyses by cancer types, the stronger significant association between hOGG1 Ser326Cys polymorphism and lung cancer risk was found (Cys/Cys vs. Ser/Ser: OR = 1.29, 95%CI = 1.16–1.44, P<0.001; Cys/Cys vs. Cys/Ser+Ser/Ser: OR = 1.22, 95%CI = 1.12–1.33, P<0.001). The significant effects of hOGG1 Ser326Cys polymorphism on colorectal, breast, bladder, prostate, esophageal, and gastric cancer were not detected. In addition, in subgroup analyses by ethnicities, we found that the hOGG1 Ser326Cys polymorphism was associated with overall cancer risk in Asians (Cys/Cys vs. Ser/Ser: OR = 1.21, 95%CI = 1.10–1.33, P<0.001).

Conclusions

This meta-analysis showed that hOGG1 326Cys allele might be a low-penetrant risk factor for lung cancer.

Genome-based prediction of breast cancer risk in the general population: a modeling study based on meta-analyses of genetic associations

BACKGROUND

Genome-wide association studies identified novel breast cancer susceptibility variants that could be used to predict breast cancer in asymptomatic women. This review and modeling study aimed to investigate the current and potential predictive performance of genetic risk models.

METHODS

Genotypes and disease status were simulated for a population of 10,000 women. Genetic risk models were constructed from polymorphisms from meta-analysis including, in separate scenarios, all polymorphisms or statistically significant polymorphisms only. We additionally investigated the magnitude of the odds ratios (OR) for 1 to 100 hypothetical polymorphisms that would be needed to achieve similar discriminative accuracy as available prediction models [modeled range of area under the receiver operating characteristic curve (AUC) 0.70-0.80].

RESULTS

Of the 96 polymorphisms that had been investigated in meta-analyses, 41 showed significant associations. AUC was 0.68 for the genetic risk model based on all 96 polymorphisms and 0.67 for the 41 significant polymorphisms. Addition of 50 additional variants, each with risk allele frequencies of 0.30, requires per-allele ORs of 1.2 to increase this AUC to 0.70, 1.3 to increase AUC to 0.75, and 1.5 to increase AUC to 0.80. To achieve AUC of 0.80, even 100 additional variants would need per-allele ORs of 1.3 to 1.7, depending on risk allele frequencies.

CONCLUSION

The predictive ability of genetic risk models in breast cancer has the potential to become comparable to that of current breast cancer risk models.

IMPACT

Risk prediction based on low susceptibility variants becomes a realistic tool in prevention of nonfamilial breast cancer.

hOGG1 Ser326Cys polymorphism and renal cell carcinoma risk in a Chinese population

Oxidative DNA damage caused by reactive oxygen species plays an important role in cancer development. Human 8-oxoguanine DNA glycosylase (hOGG1) is involved in base excision repair of 8-oxoguanine from damaged DNA. We hypothesized that variants in the hOGG1 gene are associated with risk of renal cell carcinoma (RCC). In a hospital-based case-control study of 572 RCC patients and 575 cancer-free controls frequency matched by age and sex, we genotyped the functional polymorphism Ser326Cys (rs1052133) and assessed its associations with risk of RCC in a Chinese population. We found that individuals with the Cys allele were associated with an increased risk of RCC (odds ratio [OR] = 1.40, 95% confidence interval [CI] = 1.02-1.90), compared with those with the Ser/Ser genotype, particularly among subgroups of body mass index >24 kg/m(2) (OR = 1.75, 95% CI = 1.12-2.73) and non-smokers (OR = 1.60, 95% CI = 1.07-2.38). Further, the polymorphism was associated with risk of developing localized stage and well-differentiated RCC. Our results suggested that the polymorphism is involved in the etiology of RCC and thus may be a marker for genetic susceptibility to RCC.

Two functional variations in 5'-UTR of hoGG1 gene associated with the risk of breast cancer in Chinese

8-Hydroxy-2'-deoxyguanine (8-OHdG) is produced by the oxidative stress-induced damage in DNA, which could pair with adenine (A) during DNA replication, leading to G-T transversion mutations. Glycosylase hOGG1 can recognize and excise oxidized guanines from duplex DNA. This work aims to investigate the relationship between the functional variations in 5-untranslated region (5'-UTR) of hOGG1 gene and the risk of breast cancer. Genotypes were analyzed in 518 sporadic breast cancer patients and 777 health controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression. Risk-stratified subgroup analysis was performed to reveal the associations between the detected variations and the risk of characteristic breast cancer. In addition, immunohistochemistry was carried out to assess the functional effect of these variations on hOGG1gene expression. Five variations in 5'-UTR of hOGG1 gene are found in this study. Three of them, c.-18G>T, c.-23A>G, and c.-53G>C, are known single nucleotide polymorphisms, the other two, c.-45G>A and c.-63G>C, are rare variations. The frequency of c.-18G/T and c.-53G/C was significantly higher in breast cancer patients than those in healthy controls (P = 0.03, OR 2.01, 95% CI 1.04-3.90; and P = 0.01, OR 2.43, 95% CI 1.17-5.04, respectively). Both variations were especially prevalent in premenopausal status, and in the triple (estrogen receptor, progesterone receptor, and human epidermal growth factor Receptor 2) negative subgroups, respectively. Moreover, the variation of c.-18G>T could cause a reduced expression of hOGG1 gene.