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

The Relationship Between the hOGG1 rs1052133 Polymorphism and the Occurrence of Nasopharyngeal Carcinoma: A Systematic Review and Meta-Analysis

Objectives: Exploring the relationship between the hOGG1 rs1052133 polymorphism and the occurrence of nasopharyngeal carcinoma (NPC). Methods: PubMed, Web of Science, Scopus, CNKI, Wanfangdata, and VIP were used to search for studies and the NOS evaluation scale was used to evaluate the quality. All studies were grouped according to different genotypes. The Cochrane's Q test and I2 test were used for heterogeneity evaluations. If heterogeneity was small, the fixed effects model was used, and conversely, the random effects model was used. Publication bias was also detected. P < .05 in all results indicated statistically significant. Results: We ultimately included 6 studies with 2021 NPC patients in the study group and 2375 healthy populations in the control group. After meta-analysis, it was found that the total OR value of the "Ser/Cys (CG) vs Ser/Ser (CC)" group was 1.00 (95% CI: 0.85-1.18) and the "Cys/Cys (GG) vs Ser/Ser (CC)" group was 1.06 (95% CI: 0.87-1.28). These results were not statistically significant (P > .05). Furthermore, the integrated total OR values of each group were not statistically significant with or without the smoking history, even in other genotype models (Allele, Dominant, Recessive, and Additive) (P > .05). Conclusion: There is no clear correlation between the hOGG1 rs1052133 polymorphism and the occurrence of NPC, even with or without the smoking history.

The Relationship Between GSTT1, GSTM1, GSTO1, GSTP1 and MTHFR Gene Polymorphisms and DNA Damage of BRCA1 and BRCA2 Genes in Arsenic-Exposed Workers

OBJECTIVE

To investigate the associations between genetic polymorphisms of GSTT1, GSTM1, GSTO1, GSTP1 and MTHFR genes and the DNA damage levels of BRCA1 and BRCA2 genes.

METHODS

Peripheral blood samples were used to measure DNA damage levels and genetic polymorphisms, and urine samples were collected to analyze arsenic metabolites in 79 arsenic-exposed workers and 24 non-arsenic-exposed workers.

RESULTS

The BRCA1 and BRCA2 damage levels in exposure group were significantly higher than that in control group. Significant associations were detected between GSTT1 and GSTO1 polymorphisms and DNA damage levels of BRCA1 and BRCA2 genes in subjects (P < 0.05).

CONCLUSIONS

Our findings suggest that the DNA damage levels of BRCA1 and BRCA2 genes may modulate by genetic variations of GSTT1 and GSTO1 when individuals are exposed to carcinogens, such as arsenic.

Association of hOGG1 Ser326Cys, ITGA2 C807T, TNF-A -308G>A and XPD Lys751Gln polymorphisms with the survival of Malaysian NPC patients

Background

Nasopharyngeal carcinoma is a rare form of cancer across the world except in certain areas such as Southern China, Hong Kong and Malaysia. NPC is considered a relatively radiosensitive tumor and patients diagnosed at early stages tend to survive longer compared to those with advanced disease. Given that early symptoms of NPC are non-specific and that the nasopharynx is relatively inaccessible, less invasive screening methods such as biomarker screening might be the key to improve NPC survival and management. A number of genes with their respective polymorphisms have been shown in past studies to be associated with survival of various cancers. hOGG1 and XPD genes encode for a DNA glycosylase and a DNA helicase respectively; both are proteins that are involved in DNA repair. ITGA2 is the alpha subunit of the transmembrane receptor integrin and is mainly responsible for cell-cell and cell-extracellular matrix interaction. TNF-α is a cytokine that is released by immune cells during inflammation.

Methods

Restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) was used to genotype all the aforementioned gene polymorphisms. Kaplan-Meier survival function, log-rank test and Cox regression were used to investigate the effect of gene polymorphisms on the all-cause survival of NPC.

Results

NPC cases carrying T/T genotype of ITGA2 C807T have poorer all-cause survival compared to those with C/C genotypes, with an adjusted HR of 2.06 (95% CI = 1.14–3.72) in individual model. The 5-year survival rate of C/C carriers was 55% compared to those with C/T and T/T where the survival rates were 50% and 43%, respectively.

Conclusion

The finding from the present study showed that ITGA2 C807T polymorphism could be potentially useful as a prognostic biomarker for NPC. However, the prognostic value of ITGA2 C807T polymorphism has to be validated by well-designed further studies with larger patient numbers.

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.

Polymorphisms in BER genes and risk of breast cancer: evidences from 69 studies with 33760 cases and 33252 controls

Recently, numerous studies have reported an association between single nucleotide polymorphisms in base-excision repair genes and the risk of developing breast cancer, however there is no consensus. The aim of this meta-analysis was to review and quantitatively assess the relationship between single nucleotide polymorphisms in base-excision repair genes and breast cancer risk. The results suggested that a mutation of T to G in rs1760944 may lead to a higher risk of developing breast cancer in the Mongoloid population, and G to A of rs25487 significantly reduced the risk of breast cancer in Mongoloid and Caucasoid populations. In contrast to the CC and CG genotypes, the GG genotype of rs1052133 located on theOGG1 gene appeared to be a protective factor against developing breast cancer in both Mongoloid and Caucasoid populations. There was no evidence to suggest that rs25489, rs1799782, rs1130409, rs1805414 and rs1136410 were associated with breast cancer risk. In conclusion, this study provides evidence to support the theory that DNA repair genes are associated with breast cancer risk, providing information to further understand breast cancer etiology. and The potential biological pathways linking DNA repair, ethnic background, environment and breast cancer require further investigation.

Haplotype CGC from XPD, hOGG1 and ITGA2 polymorphisms increases the risk of nasopharyngeal carcinoma in Malaysia

BACKGROUND

8-oxoG, a common DNA lesion resulting from reactive oxygen species (ROS), has been shown to be associated with cancer initiation. hOGG1 DNA glycosylase is the primary enzyme responsible for excision of 8-oxoG through base excision repair (BER). Integrins are members of a family of cell surface receptors that mediate the cell-cell and extracellular matrix (ECM) interactions. Integrins are involved in almost every aspect of carcinogenesis, from cell differentiation, cell proliferation, metastasis to angiogenesis. Loss of ITGA2 expression was associated with enhanced tumor intravasation and metastasis of breast and colon cancer. XPD gene encodes DNA helicase enzyme that is involved in nucleotide excision repair (NER). It is shown in previous research that XPD homozygous wildtype Lys/Lys genotype was associated with higher odds of NPC.

METHODS

We conducted a 1 to N case-control study involving 300 nasopharyngeal carcinoma (NPC) cases and 533 controls matched by age, gender and ethnicity to investigate the effect of hOGG1 Ser326Cys, ITGA2 C807T and XPD Lys751Gln polymorphisms on NPC risk. Linkage disequilibrium and haplotype analysis were conducted to explore the association of allele combinations with NPC risk. Restriction fragment length polymorphism (RFLP-PCR) was used for DNA genotyping.

RESULTS

No significant association was observed between hOGG1 Ser326Cys and ITGA2 C807T polymorphisms with NPC risk after adjustment for age, gender, ethnicity, cigarette smoking, alcohol and salted fish consumption. Lys/Lys genotype of XPD Lys751Gln polymorphism was associated with increased NPC risk (OR = 1.60, 95% CI = 1.06-2.43). Subjects with history of smoking (OR = 1.81, 95% CI = 1.26-2.60), and salted fish consumption before age of 10 (OR = 1.77, 95% CI = 1.30-2.42) were observed to have increased odds of NPC. The odds of developing NPC of CGC haplotype was significantly higher compared to reference AGC haplotype (OR = 2.20, 95% CI = 1.06-4.58).

CONCLUSION

The allele combination of CGC from hOGG1, ITGA2 and XPD polymorphisms was significantly associated with increased odds of NPC.

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.

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.

Potential biomarker panels in overall breast cancer management: advancements by multilevel diagnostics

Breast cancer (BC) prevalence has reached an epidemic scale with half a million deaths annually. Current deficits in BC management include predictive and preventive approaches, optimized screening programs, individualized patient profiling, highly sensitive detection technologies for more precise diagnostics and therapy monitoring, individualized prediction and effective treatment of BC metastatic disease. To advance BC management, paradigm shift from delayed to predictive, preventive and personalized medical services is essential. Corresponding step forwards requires innovative multilevel diagnostics procuring specific panels of validated biomarkers. Here, we discuss current instrumental advancements including genomics, proteomics, epigenetics, miRNA, metabolomics, circulating tumor cells and cancer stem cells with a focus on biomarker discovery and multilevel diagnostic panels. A list of the recommended biomarker candidates is provided.

XRCC1 and OGG1 Gene Polymorphisms and Breast Cancer: A Systematic Review of Literature

Context:

Known polymorphisms of DNA repair genes can be associated with the risk of many types of cancer. There is no consensus regarding association between XRCC1 and OGG1 with breast cancer (BC).

Objectives:

The aim of this study is to collect relevant published studies systematically.

Data Sources:

Sixty-two publications were identified through searching PubMed, PubMed Central, ISI web of knowledge, and reference list of related articles.

Study Selection:

We performed a systematic review according MOOSE guideline criteria. All longitudinal cohort and case-control studies investigating association of any type and grade of breast cancer with XRCC1 and OGG1 gene and their polymorphisms were eligible for initial inclusion.

Data Extraction:

Two authors screened titles and abstracts and extracted all needed information from eligible studies. Four research methodological components causing bias for the association between gene polymorphisms and breast cancer risk, including source of controls sampling, population ethnicity, sample size of studies and menopausal status of cases and controls was used for assessment of quality of studies

Results:

A total of 14,793 breast cancer cases and 15,409 controls were included in assessment of XRCC1 Arg194Trp. Four studies showed significant association and one study showed protective effect of XRCC1 Arg194Trp and BC. A total of 7,716 cases and 7,370 controls were included for XRCC1 Arg280His. Only one study showed significant association of XRCC1 Arg280His and breast cancer (OR = 1.82 (1.06 - 3.15). A total of 27,167 cases and 31,998 controls were included to estimate association between XRCC1 Arg399Gln polymorphism and breast cancer. Seven studies showed significant association and one showed protective effect of XRCC1 Arg399Gln and BC. A total of 9,417 cases and 11,087 controls were included for OGG1 Ser326Cys. Among studies focused on OGG1 Ser326Cys, none showed significant association with breast cancer.

Conclusions:

Systematic search of major databases identify many studies addressing the relationship between BC and susceptible alleles in the base excision repair genes and the fact that there are many variations in the magnitude of association depending on inheritance model and the population of the study.

hOGG1 gene polymorphisms and susceptibility to polycystic ovary syndrome

Oxidative stress generates 8-hydroxy-2'-deoxyguanine (8-oxodG), which can structurally modify DNA. Glycosylase hOGG1 can remove the mutagenic lesion 8-oxodG from DNA. The aim of the present study was to determine whether polymorphisms in hOGG1 were associated with the risk of polycystic ovary syndrome (PCOS). One common single-nucleotide polymorphism (Ser326Cys) in exon 7 and four rare polymorphisms (c.-18G>T, c.-23A>G, c.-45G>A and c. -53G>C) were screened in the 5' untranslated region of the hOGG1 gene. No such distributional differences were observed between the PCOS patients and controls either in the genotype frequency or in the allele frequency. There were no differences in the clinical variables among the different genotypes in all the variants, except that the follicle-stimulating hormone level was elevated in the GC genotype of c. -53G>C in PCOS patients (P=0.002). These results suggest that the polymorphisms in hOGG1 may not be an independent risk factor for PCOS.

hOGG1 C1245G gene polymorphism associated with prostate cancer: a meta-analysis

BACKGROUND

Prostate cancer (Pca) is one of the most frequently encountered multifactorial malignant diseases worldwide. The human oxoguanine glycosylase 1 (hOGG1) C1245G polymorphism (rs1052133) has been found to be associated with Pca. However, the conclusions have been controversial.

METHODS

Based on the PubMed, Embase, HuGENet and Chinese National Knowledge Infrastructure (CNKI) databases, this meta-analysis was conducted with 4 models. Eleven qualified studies were included.

RESULTS

Although no positive relation was discovered in the pooled analysis, significant associations between rs1052133 and Pca were found in the Asian population (recessive: odds ratio [OR] = 1.580, 95% confidence interval [95% CI], 1.189-2.098; GG vs. GC: OR = 1.504, 95% CI, 1.114-2.030; GG vs. CC: OR = 1.677, 95% CI, 1.201-2.342; allele analysis: OR = 1.249, 95% CI, 1.077-1.449), whites (dominant: OR = 2.138, 95% CI, 1.483-3.083; recessive: OR = 3.143, 95% CI, 1.171-8.437; GG vs. CC: OR = 3.992, 95% CI, 1.891-8.431; allele analysis: OR = 1.947, 95% CI, 1.467-2.586) and mixed populations (recessive: OR = 0.636, 95% CI, 0.484-0.834; GG vs. GC: OR = 0.654, 95% CI, 0.492-0.871; GG vs. CC: OR = 0.624, 95% CI, 0.473-0.823; allele analysis: OR = 0.857, 95% CI, 0.771-0.954). After excluding studies deviating from the Hardy-Weinberg equilibrium, a significant association was also found in the same ethnic groups. In addition, a new positive relation was identified in the "other country" subgroup (with China, South Korea and Australia included) (dominant: OR = 1.622, 95% CI, 1.163-2.261; recessive: OR = 1.773, 95% CI, 1.308-2.404; GG vs. GC: OR = 1.614, 95% CI, 1.169-2.230; GG vs. CC: OR = 2.108, 95% CI, 1.456-3.051; allele analysis: OR = 1.494, 95% CI, 1.235-1.808) and among the Chinese-Korean population.

CONCLUSIONS

In conclusion, we suggest that the hOGG1 C1245G polymorphism might be potentially associated with Pca risk in different ethnicities and countries, especially among Asians. Further studies are needed to confirm these relations.

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.

Contribution of personalized Cyclin D1 genotype to triple negative breast cancer risk

Aim: Cell cycle regulator cyclin D1 (CCND1) is a pivotal regulator for G1/S phase transition, playing a critical part in initiation of carcinogenesis. Triple negative breast cancer comprises a very heterogeneous group of cancer cells, but little is known about what is wrong in the genome of these patients. This study investigated contribution of CCND1 genotype to individual triple negative breast cancer susceptibility. Materials: In all, 2464 native Taiwan subjects consist of 1232 breast cancer cases and 1232 controls were enrolled in a hospital-based, case-control study. CCND1 A870G (rs9344) genotyping was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Risk-stratified analyses correlated genotype and age-related characteristics of breast cancer subgroups. Results: No significant difference was found between patient and control groups in distribution of genotypic and allelic frequencies in CCND1 genotype, yet CCND1 A870G (rs9344) GG genotype was far less prevalent in breast cancer patients younger than 55 years (OR=0.62, 95%CI=0.43-0.89, P=0.0362), with first menarche earlier than 12.2 years (OR=0.61, 95% CI=0.42-0.87, P=0.0241), with menopause earlier than 49.0 years (OR=0.57, 95%CI=0.39-0.82, P=0.0093), or showing triple-negative breast cancer (OR=0.28, 95%CI=0.13-0.62, P=0.0006). Such valuable findings suggest CCND1 A870G (rs9344) as a predictive marker for triple negative breast cancer in Taiwanese women; the authors sincerely hope these help us fight the toughest subtype in clinical management.

Combined genetic and nutritional risk models of triple negative breast cancer

Triple negative breast cancer (TNBC) presents clinical challenges due to unknown etiology, lack of treatment targets, and poor prognosis. We examined combined genetic and nutritional risk models of TNBC in 354 breast cancer cases. We evaluated 18 DNA-repair nonsynonymous single nucleotide polymorphisms (nsSNPs) and dietary/nutritional intakes. Multivariate Adaptive Regression Splines models were used to select nutrients of interest and define cut-off values for logistic regression models. Our results suggest that TNBC was associated with 6 DNA-repair nsSNPs, ERCC4 R415Q (rs1800067), MSH3 R940Q (rs184967), MSH6 G39E (rs1042821), POLD1 R119H (rs1726801), XRCC1 R194W (rs1799782), and XPC A499V (rs2228000) and/or deficiencies in 3 micronutrients (zinc, folate, and β-carotene). Combined analyses of these 6 nsSNPs and 3 micronutrients showed significant association with TNBC: odds ratios = 2.77 (95% confidence interval = 1.01-7.64) and 10.89 (95% confidence interval = 3.50-33.89) for 2 and at least 3 risk factors, respectively. To the best of our knowledge, this is the first study to suggest that multiple genetic and nutritional factors are associated with TNBC, particularly in combination. Our findings, if validated in larger studies, will have important clinical implication that dietary modulations and/or micronutrient supplementations may prevent or reverse TNBC phenotype, so tumors can be treated with less toxic therapeutic strategies, particularly in genetically susceptible women.

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.

The significance of the alteration of 8-OHdG in serous ovarian carcinoma

Background

Oxidative damage and DNA repair dysfunction are associated with carcinogenesis. 8-OHdG is one of the major oxidative DNA adducts. Present work aims to investigate whether the expression of 8-OHdG and its key repair gene hOGG1 play distinctive role in two types of serous ovarian cancer.

Materials and methods

8-OHdG level in DNA from tumor and matched tumor-adjacent normal tissue in 48 high-grade papillary serous carcinomas (HG-SOC), 24 low-grade papillary serous carcinomas (LG-SOC), 20 serous cystadenomas, and 16 non-tumor control ovaries was tested. The Cox proportional hazards model and the log-rank test were used to assess the associations between the 8-OHdG level in two types of serous cancer and patients’ survival. Real-time polymerase chain reaction and protein immunoblot were employed to detect hOGG1 mRNA and protein levels in tumor and adjacent normal tissues. Immunohistochemistry was used to determine the expression of hOGG1 and p53.

Results

There was no difference of average 8-OHdG/10⁶dG DNA level either between HG-SOC (27.8 ± 8.9), LG-SOC (25.2 ± 7.4) and benign serous cystadenoma (26.5 ± 7.7, p = 0.35); or between the tumor-adjacent normal tissue of HG-SOC (18.8 ± 5.2), LG-SOC (21.4 ± 6.5), benign serous cystadenoma (20.5 ± 9.1) and non-tumor ovary (21.6 ± 4.9, p = 0.62). The 8-OHdG/10⁶dG level was significantly higher in tumor comparing to that in matched normal tissue adjacent to carcinoma in HG-SOC (1.52 ± 0.52, p = 0.02), but not in LG-SOC or benign serous cystadenoma. Increased level of 8-OHdG in tumor DNA was an independent factor of overall survival in serous ovarian carcinoma upon multivariate analysis (p < 0.01). Increased level of 8-OHdG in tumor DNA indicates poorer overall and progression-free survival durations than counterparts (47.3 vs 105.7 months and 13.5 vs 45.3 months, respectively). Protein levels of hOGG1 were remarkably decreased in HG-SOC (p < 0.01), but not in LG-SOC and serous cystadenoma compared with the tissue adjacent to carcinoma. A positive result on p53 immunostaining was associated with lower hOGG1 expression in HG-SOC (p = 0.04).

Conclusion

Increased 8-OHdG level and decreased expression of hOGG1 in tumor were found in HG-SOC but not LG-SOC. Increased 8-OHdG level in tumor DNA was significantly associated with poorer overall survival and progression-free survival in serous ovarian carcinoma.