Nucleotide excision repair pathway gene polymorphisms are linked to breast cancer risk in a Chinese population

The impact of XPC gene single nucleotide polymorphism rs2228001 on head and neck cancer patients' response to radiotherapy treatment

Background

Head and neck squamous carcinoma (HNSC) is the sixth most common neoplasm, with a 40-50% overall survival rate. HNSC standard treatment depends on tumor size, metastasis or human papillomavirus (HPV) status including surgery, chemotherapy, and radiotherapy. The last two may lead to defects in the tumor microenvironment and cancer cell biology as disorders in DNA damage repair systems. Here, we evaluate the correlation between single nucleotide polymorphism (SNP) rs2228001 in the XPC gene with the early and late adverse effects of radiotherapy, determine the distribution of the SNP and post-treatment follow-up in HNSC patients.

Materials and methods

Head and neck cancer tissues and clinical data were obtained from 79 patients. The SNP of the XPC gene (rs2228001) was evaluated with polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP). The chi-square test was used to determine the correlation between mutation and adverse effects occurrence.

Results/Conclusion

Single nucleotide polymorphism rs2228001 in the XPC gene is correlated with the early adverse effect of skin reaction and the late adverse effect of elevated C-reactive protein (CRP) levels in the HNSC patients.

DNA repair pathways in breast cancer: from mechanisms to clinical applications

BACKGROUND

Breast cancer (BC) is a complex disease with various subtypes and genetic alterations that impact DNA repair pathways. Understanding these pathways is essential for developing effective treatments and improving patient outcomes.

AREA COVERED

This study investigates the significance of DNA repair pathways in breast cancer, specifically focusing on various pathways such as nucleotide excision repair, base excision repair, mismatch repair, homologous recombination repair, non-homologous end joining, fanconi anemia pathway, translesion synthesis, direct repair, and DNA damage tolerance. The study also examines the role of these pathways in breast cancer resistance and explores their potential as targets for cancer treatment.

CONCLUSION

Recent advances in targeted therapies have shown promise in exploiting DNA repair pathways for BC treatment. However, much research is needed to improve the efficacy of these therapies and identify new targets. Additionally, personalized treatments that target specific DNA repair pathways based on tumor subtype or genetic profile are being developed. Advances in genomics and imaging technologies can potentially improve patient stratification and identify biomarkers of treatment response. However, many challenges remain, including toxicity, resistance, and the need for more personalized treatments. Continued research and development in this field could significantly improve BC treatment.

Combined GSTT1 Null, GSTM1 Null and XPD Lys/Lys Genetic Polymorphisms and Their Association with Increased Risk of Chronic Myeloid Leukemia

Purpose

Glutathione S-transferases (GSTT1 and GSTM1) are instrumental in detoxification process of activated carcinogens. Nucleotide excision repair is carried out by DNA helicase encoded by xeroderma pigmentosum group D (XPD) genes and aberrations in the XPD gene predisposes to increased risk of cancer. The present study aimed to investigate GSTT1, GSTM1 and XPD polymorphisms in newly diagnosed chronic myeloid leukemia (CML) patients and to examine the association of these polymorphisms with the risk of developing CML.

Patients and Methods

This case–control study was carried out from June 2019 to August 2021 involving 150 newly diagnosed patients with CML and an equal number of randomly selected age- and sex-matched healthy individuals. A multiplex-PCR assay was used to genotype GSTT1 null and GSTM1 null polymorphisms. XPD gene polymorphism was detected by PCR-RFLP using predesigned gene-specific primers.

Results

GSTT1 and GSTM1 null polymorphisms were detected in 42.7% and 61.3% of cases, respectively, compared to 18% and 35.3% for controls. The combination of both GST null polymorphisms revealed a significant association with CML. Frequencies of XPD Lys751Gln genotypes in cases were 62.7% heterozygous Lys/Gln, 24% homozygous Lys/Lys and 13.3% homozygous Gln/Gln, while in the controls were 74.7%, 20%, and 5.3%, respectively. Significant differences were also noted regarding the combination of GSTT1/GSTM1 null with XPD Lys/Lys, and GSTM1 null with XPD Lys/Lys.

Conclusion

In conclusion, GSTT1 null, GSTM1 null and XPD polymorphisms showed positive association with the risk of development of CML. Furthermore, age and gender did not exhibit any association with the studied polymorphisms, while CML phases were associated with GSTT1 null polymorphism.

CometChip enables parallel analysis of multiple DNA repair activities

DNA damage can be cytotoxic and mutagenic, and it is directly linked to aging, cancer, and other diseases. To counteract the deleterious effects of DNA damage, cells have evolved highly conserved DNA repair pathways. Many commonly used DNA repair assays are relatively low throughput and are limited to analysis of one protein or one pathway. Here, we have explored the capacity of the CometChip platform for parallel analysis of multiple DNA repair activities. Taking advantage of the versatility of the traditional comet assay and leveraging micropatterning techniques, the CometChip platform offers increased throughput and sensitivity compared to the traditional comet assay. By exposing cells to DNA damaging agents that create substrates of Base Excision Repair, Nucleotide Excision Repair, and Non-Homologous End Joining, we show that the CometChip is an effective method for assessing repair deficiencies in all three pathways. With these applications of the CometChip platform, we expand the utility of the comet assay for precise, high-throughput, parallel analysis of multiple DNA repair activities.

XPF -673C>T variation is associated with the susceptibility to breast cancer

PURPOSE

XPF variations might decrease the DNA repair capacity and further contribute to cancer development. This study aimed to investigate the association of XPF polymorphisms with risk of developing breast cancer.

METHODS

TCGA, the Human Protein Atlas and Kaplan-Meier plotter were used to analyze the expression of XPF in breast cancer tissues and its effect on the survival of breast cancer patients. The expression of XPF in breast cancer tissues was detected by qRT-PCR. This case-control study included 467 breast cancer patients and 467 healthy controls. The genotype of genetic variation was detected by polymerase chain reaction restriction fragment length polymorphism. Odds ratios and 95 % confidence intervals were calculated. Correlations between XPF variation and clinicopathological parameters were assessed through Kendall's Tau-b test. The relationship between XPF gene function variation and XPF gene expression was analyzed by GTEx.

RESULTS

The expression of XPF in breast cancer tissues is higher than that in normal tissues. Breast cancer patients with high XPF expression have a higher relapse free survival rate (HR = 0.88, 95 % CI = 0.80-0.97), but have no effect on the overall survival rate (logrank P = 0.28). XPF -673C > T variant can reduce the risk of breast cancer patients (OR = 0.35, 95 %CI = 0.20-0.63 for codominant mode; OR = 0.66, 95 %CI = 0.51-0.85 for dominant model; OR = 0.40, 95 %CI = 0.23-0.70 for recessive model). The XPF 11985 GG genotype reduced the risk of early breast cancer (OR = 0.49, 95 %CI = 0.24-0.97), but not the risk of advanced breast cancer (OR = 1.20, 95 % CI = 0.58-2.48). XPF 11985A > G variant can also reduce the risk of ERBB2 expression in patients (OR = 0.50, 95 %CI = 0.27-0.94). There is no correlation between XPF -673C > T/XPF11985A > G variants and ER and PR. XPF -673C > T variant can reduce XPF expression (P < 0.05).

CONCLUSIONS

Genetic variations of XPF gene may affect its expression and the risk of breast cancer in the Chinese population.

Association between NER pathway gene polymorphisms and neuroblastoma risk in an eastern Chinese population

Neuroblastoma is a common childhood malignancy. Nucleotide excision repair (NER) polymorphisms have been shown to influence cancer susceptibility by modifying DNA repair efficiency. To investigate the association of NER gene polymorphisms with neuroblastoma risk, we constructed a three-center case-control study. A total of 19 candidate single-nucleotide polymorphisms (SNPs) in NER genes were analyzed. Odds ratios (ORs) and 95% confidential intervals (CIs) were calculated to evaluate the associations. We identified five independent SNPs that were significantly associated with neuroblastoma risk, including XPA rs1800975 (dominant model: adjusted OR = 0.73, 95% CI = 0.55-0.98, p = 0.033), XPA rs3176752 (recessive model: adjusted OR = 2.78, 95% CI = 1.12-6.91, p = 0.028), XPD rs3810366 (dominant: adjusted OR = 1.44, 95% CI = 1.05-1.97, p = 0.022; recessive: adjusted OR = 1.58, 95% CI = 1.18-2.11, p = 0.002), XPD rs238406 (dominant: adjusted OR = 0.64, 95% CI = 0.48-0.84, p = 0.002; recessive: adjusted OR = 0.67, 95% CI = 0.48-0.94, p = 0.021), and XPG rs2094258 (recessive: adjusted OR = 1.44, 95% CI = 1.03-2.04, p = 0.036). Stratified analysis was carried out. Furthermore, these findings were strengthened by false-positive report probability (FPRP) analysis and expression quantitative trait loci (eQTL) analysis. In conclusion, our study indicates that five SNPs in NER genes are correlated with neuroblastoma susceptibility in the eastern Chinese population, providing novel insight into the genetic underpinnings of neuroblastoma. However, further large-scale studies are required to verify these findings.

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

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

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

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

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

XPC as breast cancer susceptibility gene: evidence from genetic profiling, statistical inferences and protein structural analysis

BACKGROUND

Gene polymorphisms that affect nucleotide excision repair (NER) pathway may link with higher susceptibility of breast cancer (BC); however, the significance of these associations may vary conferring to the individual ethnicity. Xeroderma pigmentosum complementation gene (XPC) plays a substantial role in recognizing damaged DNA during NER process.

OBJECTIVE AND METHODS

To estimate the relationship among XPC polymorphisms and breast cancer (BC) risk, we carried out a case-control-association study with 493 BC cases and 387 controls using TETRA-ARMS-PCR. Distributional differences of clinical features, demographic factors and XPC polymorphisms among BC cases and controls were examined by conditional logistic regression model. Kaplan-Meier test was applied to predict survival distributions and protein structure was predicted using computational tools.

RESULTS

Obesity, consanguinity, positive marital status and BC family history were associated (P ≤ 0.01) with higher BC risk. Genotyping revealed significant involvement (P ≤ 0.01) of two XPC polymorphisms rs2228001-A > C (OR = 3.8; CI 1.9-7.6) and rs2733532-C > T (OR = 2.6; CI 1.4-5.03) in BC development, asserting them potential risk factors for increased BC incidence. However, no association (P > 0.05) was detected for overall or progression free survival for both XPC polymorphisms possibly due to shorter follow-up time (45 months). As compared to normal XPC structure, pronounced conformational changes have been observed in the C-terminus of XPC^Q939K, bearing rs2228001-A > C substitution. In XPC^Q939K, two additional α-helices were observed at A292-E297 and Y252-R286, while L623-M630 and L649-L653 helices were converted into loop conformation.

CONCLUSION

In conclusion, both XPC polymorphisms confer significant association with increased BC risk. rs2228001 substitution may change the structural and functional preferences of XPC C-terminus, while rs2733532 may have regulatory role thereby leading to potential BC risk.

Effects of Xeroderma pigmentosum group C polymorphism on the likelihood of prostate cancer

Background

Numerous studies have assessed the association between xeroderma pigmentosum complementation group C (XPC) polymorphisms and susceptibility of prostate cancer (PCa); however, the findings remain inconsistent.

Methods

We performed an updated analysis utilizing data from electronic databases to obtain a more accurate estimation of the relationship between XPC rs2228001 A/C polymorphism and PCa risk. We further used in silico tools to investigate this correlation.

Results

Totally, 5,305 PCa cases and 6,499 control subjects were evaluated. When all studies pooled together, we detected no positive result (recessive genetic model: OR = 1.14, 95% CI = 0.93‐1.40, P_{heterogeneity} = 0.001, P = .212); nevertheless, the XPC rs2228001 A/C variant was associated with PCa risk in Asian descendants in the subgroup analysis (OR = 1.21, 95% CI = 1.01‐1.43, P_{heterogeneity} = 0.008, P = .034). In silico tools showed that more than 20 proteins can participate in the protein crosstalk with XPC. The expression of XPC was down‐regulated in all Gleason scores of prostate cancer.

Conclusions

The present study indicated that the XPC rs2228001 A/C variant may be associated with elevated PCa risk in Asian patients.

Contribution of xeroderma pigmentosum complementation group D gene polymorphisms in breast and ovarian cancer susceptibility: A protocol for systematic review and meta analysis

BACKGROUND

The role of xeroderma pigmentosum complementation group D (XPD) gene polymorphisms in breast and ovarian cancer development has long been controversial and existing data were inconsistent. Here, we conducted a comprehensive systemic review and meta-analysis to better clarify the association.

METHODS

Relevant case-control studies published in electronic data base from October 1999 to September 2019 were assessed. The statistical analyses of the pooled odds ratios (ORs) and the corresponding 95% confidence intervals (95%CIs) were calculated by using Revman 5.2 software (Cochrane Collaboration, Copenhagen).

RESULTS

31 articles including 38 case-control studies and 2 XPD polymorphisms (rs1799793 and rs238406) were analyzed. The results showed statistical significance in heterozygous mutants among Asian population for rs1799793 (GA vs GG + AA: OR = 1.38, 95%CI = 1.21-1.56), and Caucasian population for rs238406 (CA vs AA + CC: OR = 0.63, 95%CI = 0.49-0.80), while the rest comparisons including overall groups and subgroups stratified by cancer types and ethnicity failed to indicate any association with breast and ovarian cancer risk.

CONCLUSIONS

The current meta-analysis suggested no concrete correlation of XPD rs1799793(G/A) and rs238406(C/A) polymorphisms with breast cancer or ovarian cancer susceptibility. However, it indicated that heterozygous genotypes might share different pathophysiologic mechanism from not only homozygous wildtypes but also homozygous mutants. More case-control studies with well-adjusted data and diverse populations are essential for validation of our conclusion.

Interplay between BRCA1 and GADD45A and Its Potential for Nucleotide Excision Repair in Breast Cancer Pathogenesis

A fraction of breast cancer cases are associated with mutations in the BRCA1 (BRCA1 DNA repair associated, breast cancer type 1 susceptibility protein) gene, whose mutated product may disrupt the repair of DNA double-strand breaks as BRCA1 is directly involved in the homologous recombination repair of such DNA damage. However, BRCA1 can stimulate nucleotide excision repair (NER), the most versatile system of DNA repair processing a broad spectrum of substrates and playing an important role in the maintenance of genome stability. NER removes carcinogenic adducts of diol-epoxy derivatives of benzo[α]pyrene that may play a role in breast cancer pathogenesis as their accumulation is observed in breast cancer patients. NER deficiency was postulated to be intrinsic in stage I of sporadic breast cancer. BRCA1 also interacts with GADD45A (growth arrest and DNA damage-inducible protein GADD45 alpha) that may target NER machinery to actively demethylate genome sites in order to change the expression of genes that may be important in breast cancer. Therefore, the interaction between BRCA1 and GADD45 may play a role in breast cancer pathogenesis through the stimulation of NER, increasing the genomic stability, removing carcinogenic adducts, and the local active demethylation of genes important for cancer transformation.

Polymorphisms in XPC Gene and Risk of Uterine Leiomyoma in Reproductive Women

XPC gene belongs to DNA repair pathway, which is involved in the development of uterine leiomyoma. However, its relationships with leiomyoma risk were never reported. We here hypothesized that XPC gene was associated with the risk of uterine leiomyoma. In this case-control study with a total of 391 leiomyoma cases and 493 tumor-free controls in a reproductive women population in South China, two missense polymorphisms rs2228001 A > C (Lys939Gln) and rs2228000 C > T (Ala499Val) were genotyped by quantitative polymerase chain reaction (qPCR). Then, the associations between these two polymorphisms and leiomyoma risk were investigated. It was revealed that the rs2228000 CT/TT variant genotypes had a decreased leiomyoma risk (adjusted odds ratio = 0.73, 95% confidence interval = 0.54-0.94) compared with rs2228000 CC genotype. Further stratified analysis also revealed that the protective effect of rs2228000 CT/TT on the risk of uterine leiomyoma was more evident among subjects who were younger than 35 years old compared with those with larger tumors (diameter of tumor >5 cm), and those with fewer number of myomas (only one). However, no significant association was observed for leiomyoma risk for rs2228001 A > C. This study indicated that genetic variations in XPC gene are associated with leiomyoma susceptibility in a reproductive women population. It warrants further confirmation in larger prospective studies with different populations.

Exploiting DNA repair defects in breast cancer: from chemotherapy to immunotherapy

Introduction: Impaired DNA damage response (DDR) and subsequent genomic instability are associated with the carcinogenic process itself, but it also results in sensitivity of tumor cells to certain drugs and can be exploited to treat cancer by inducing deadly mutations or mitotic catastrophe. Exploiting DDR defects in breast cancer cells has been one of the main strategies in both conventional chemotherapy, targeted therapies, or immunotherapies. Areas covered: In this review, the authors first discuss DDR mechanisms in healthy cells and DDR defects in breast cancer, then focus on current therapies and developments in the treatment of DDR-deficient breast cancer. Expert opinion: Among conventional chemotherapeutics, platinum-based regimens, in particular, seem to be effective in DDR-deficient patients. PARP inhibitors represent one of the successful models of translational research in this area and clinical data showed high efficacy and reasonable toxicity with these agents in patients with breast cancer and BRCA mutation. Recent studies have underlined that some subtypes of breast cancer are highly immunogenic. Promising activity has been shown with immunotherapeutic agents, particularly in DDR-deficient breast cancers. Chemotherapeutics, DNA-repair pathway inhibitors, and immunotherapies might result in further improved outcomes in certain subsets of patients with breast cancer and DDR.

Association of excision repair cross-complimentary group 1 gene polymorphisms with breast and ovarian cancer susceptibility

The role of excision repair cross-complimentary group 1 (ERCC1) gene polymorphisms in breast and ovarian cancer development has long been controversial and existing data were inconsistent. Here, we conducted a comprehensive meta-analysis to better clarify the association. Case-control studies published from December 2008 to November 2018 were assessed. The statistical analyses of the pooled odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were calculated. Fifteen articles with 24 case-control studies and 3 ERCC1 polymorphisms were enrolled. A total of 20 923 participants including 9896 cases and 11 027 controls were analyzed. The results showed that C to T variation in the ERCC1 rs11615 (C/T) polymorphisms was correlated with breast cancer susceptibility (T vs C: OR = 1.19, 95% CI = 1.02-1.38; TT + CT vs CC: OR = 1.24, 95% CI = 1.12-1.36). ERCC1 rs3212986 (C/A) polymorphisms posed an increased risk for breast and ovarian cancer as whole (A vs C: OR = 1.12, 95% CI = 1.01-1.25; AA + CA vs CC: OR = 1.11, 95% CI = 1.02-1.22), and presented especially higher risk for ovarian cancer (A vs C: OR = 1.31, 95% CI = 1.05-1.63; AA vs CA + CC: OR = 1.66, 95% CI = 1.12-2.47; AA vs CC: OR = 1.72, 95% CI = 1.12-2.64). Meanwhile, neither overall group analyses nor stratified analyses displayed any association of ERCC1 rs2298881 (A/C) polymorphisms in breast and ovarian cancer susceptibility. This meta-analysis suggested that ERCC1 rs11615 (C/T) polymorphisms were associated with breast cancer susceptibility and rs3212986 (C/A) polymorphisms were especially correlated with ovarian cancer risk. More case-control studies with well-adjusted data and diverse populations are essential for validation of our conclusion.

Association between NER Pathway Gene Polymorphisms and Wilms Tumor Risk

Nucleotide excision repair (NER) is an essential mechanism of the body to defend against exogenous carcinogen-induced DNA damage. Defects in NER may impair DNA repair capacity and, therefore, increase genome instability and cancer susceptibility. To explore genetic predispositions to Wilms tumor, we conducted a case-control study totaling 145 neuroblastoma cases and 531 healthy controls. We systematically selected 19 potentially functional SNPs in six key genes within the NER pathway (ERCC1, XPA, XPC, XPD, XPF, and XPG). The odds ratio (OR) and 95% confidence interval (CI) were calculated to measure the strength of associations. We identified significant associations between two XPD SNPs and Wilms tumor risk. The XPD rs3810366 polymorphism significantly enhanced Wilms tumor risk (dominant model: adjusted OR = 2.12, 95% CI = 1.26-3.57). Likewise, XPD rs238406 conferred a significantly increased risk for the disease (dominant model: adjusted OR = 2.30, 95% CI = 1.40-3.80; recessive model: adjusted OR = 1.64, 95% CI = 1.11-2.44). Moreover, online expression quantitative trait locus (eQTL) analysis demonstrated that these two polymorphisms significantly affected XPD gene expression in transformed fibroblast cells. Our study provides evidence of the association between the two XPD polymorphisms and Wilms tumor risk. However, these findings warrant validation in larger studies.

Contribution of excision repair cross-complementing group 1 genotypes to triple negative breast cancer risk

Compared with other subgroups of breast cancer, triple negative breast cancer (TNBC) is considered to be the one with the greatest invasiveness and metastatic mobility, and the highest recurrence rate. Considering the lack of predictive markers for TNBC, we aimed to examine the contribution of excision repair cross complementing-group 1 (ERCC1) genotypes to TNBC. The rs11615 and rs3212986 of ERCC1 were investigated and evaluated for their associations with susceptibility to breast cancer, especially TNBC, in Taiwan. In this study, 1,232 breast cancer patients (104 were TNBC) and 1,232 healthy controls were recruited and their genotypes at ERCC1 rs11615 and rs3212986 were revealed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis. Our results indicated that genotypes of ERCC1 rs11615 (Ptrend = 2.2*10E-9), but not rs3212986 (Ptrend = 0.6181), were associated with breast cancer risk. In the allelic frequency distribution analysis, breast cancer patients carried the T allele of ERCC1 rs11615 a higher rate than the control subjects, further supporting the idea that ERCC1 rs11615 TT genotype is positively associated with breast cancer susceptibility. More importantly, the frequency of the ERCC1 rs11615 TT genotype was even higher among TNBC patients than among other subtypes of breast cancer patients (P = 0.0001, odds ratio = 1.73, 95% confidence interval = 1.15-2.63). The genotypes of ERCC1 rs11615 were not associated with Ki67 status. Our findings firstly show that the T allele of ERCC1 rs11615 can serve as a predictive biomarker for breast cancer and TNBC. We believe that ERCC1 could serve as a target for personalized treatment of breast cancer, especially for TNBC.

ERCC1 rs11615 polymorphism increases susceptibility to breast cancer: a meta-analysis of 4547 individuals

Excision repair cross-complementation group 1 (ERCC1), a DNA repair protein, is vital for maintaining genomic fidelity and integrity. Despite the fact that a mounting body of case-control studies has concentrated on investigating the association of the ERCC1 rs11615 polymorphism and breast cancer risk, there is still no consensus on it. We conducted the current meta-analysis of all eligible articles to reach a much more explicit conclusion on this ambiguous association. A total of seven studies involving 2354 breast cancer cases and 2193 controls were elaborately selected for this analysis from the Embase, EBSCO, PubMed, WanFang, and China National Knowledge Infrastructure (CNKI) databases. Pooled odds ratios (ORs) and their 95% confidence intervals (CIs) were estimated in our meta-analysis. We found that the ERCC1 rs11615 polymorphism was significantly associated with breast cancer risk under all genetic models. When excluded, the studies that deviated from Hardy-Weinberg equilibrium (HWE), the pooled results of what remained significantly increase the risk of breast cancer under the allele model (OR = 1.14, 95% CI = 1.02-1.27, P=0.02), heterozygote model (OR = 1.24, 95% CI = 1.06-1.44, P=0.007), and dominant model (OR = 1.21, 95% CI = 1.05-1.41, P=0.01). This increased breast cancer risk was found in Asian population as well as under the heterozygote model (OR = 1.24, 95% CI = 1.05-1.48, P=0.013) and dominant model (OR = 1.20, 95% CI = 1.02-1.42, P=0.03). Our results suggest that the ERCC1 rs11615 polymorphism is associated with breast cancer susceptibility, and in particular, this increased risk of breast cancer existence in Asian population.

Associations Between XPD Lys751Gln Polymorphism and Leukemia: A Meta-Analysis

Objectives: The aim of the present study was to define the potential relationship between xeroderma pigmentosum group D (XPD) Lys751Gln polymorphisms and the risk of leukemia.

Methods: A comprehensive search of Pubmed, Web of Science, EBSCO, the Cochrane Library and China National Knowledge Infrastructure was conducted to identify original articles published before March 2017 concerning the association between XPD Lys751Gln polymorphisms and leukemia risk. A literature quality assessment was performed using the Newcastle-Ottawa Scale. Heterogeneity across studies was assessed using I² statistics. Random- or fixed-effects models were used to calculate pooled odds ratios (ORs) in the presence or absence of heterogeneity, respectively. Sensitivity analysis was used to assess the influence of individual studies on the pooled estimate. Publication bias was investigated using funnel plots and Egger’s regression test. All data analyses were performed using Stata 14.0 and Revman 5.3.

Results: Fourteen studies with a total of 7525 participants (2,757 patients; 4,768 controls) were included in this meta-analysis. We found that XPD Lys751Gln polymorphisms significantly increased the risk of developing leukemia in both dominant OR = 1.21, 95%CI [1.10–1.35], P ≤ 0.001) and heterozygote (OR = 1.22, 95%CI [1.09–1.36], P ≤ 0.001) model. An allele model showed a borderline significant increase in leukemia risk (OR = 1.13, 95%CI [1.00–1.27], P = 0.05). A subgroup analysis revealed a consistent association between XPD Lys751Gln polymorphisms and leukemia risk for some genetic models in Caucasian populations, adult or chronic groups, and in almost all models of childhood or acute groups.

Conclusion: Our results indicate that XPD Lys751Gln polymorphism increases the risk of leukemia, especially in childhood and acute cases.

Significant association between ERCC2 and MTHR polymorphisms and breast cancer susceptibility in Moroccan population: genotype and haplotype analysis in a case-control study

Background

Genetic determinants of breast cancer (BC) remained largely unknown in the majority of Moroccan patients. The purpose of this study was to explore the association of ERCC2 and MTHFR polymorphisms with genetic susceptibility to breast cancer in Moroccan population.

Methods

We genotyped ERCC2 polymorphisms (rs1799793 (G934A) and rs13181 (A2251C)) and MTHFR polymorphisms (rs1801133 (C677T) and rs1801131 (A1298C)) using TaqMan SNP Genotyping Assays. Genotypes were compared in 151 BC cases and 156 population-matched controls. Allelic, genotypic and haplotype associations with the risk and clinicopathological features of BC were assessed using logistic regression analyses.

Results

ERCC2-rs1799793-AA genotype was associated with high risk of BC compared to wild type genotype (recessive model: OR: 2.90, 95% CI: 1.34–6.26, p = 0.0069) even after Bonferroni correction (p < 0,0125). MTHFR rs1801133-TT genotype was associated with increased risk of BC (recessive model, OR: 2.49, 95% CI: 1.17–5.29, p = 0.017) but the association turned insignificant after Bonferroni correction. For the rest of SNPs, no statistical associations to BC risk were detected.

Significant association with clinical features was detected for MTHFR-rs1801133-TC genotype with early age at diagnosis and familial BC. Following Bonferroni correction, only association with familial BC remained significant. MTHFR-rs1801131-CC genotype was associated with sporadic BC. ERCC2-rs1799793-AA genotype correlated with ER+ and PR+ breast cancer. ERCC2-rs13181-CA genotype was significantly associated large tumors (T ≥ 3) in BC patients. None of these associations passed Bonferroni correction.

Haplotype analysis showed that ERCC2 A-C haplotype was significantly associated with increased BC risk (OR: 3.71, 95% CI: 1.7–8.12, p = 0.0002 and p = 0.0008 before and after Bonferroni correction, respectively) and positive expression of ER and PR in BC patients. ERCC2 G-C haplotype was correlated with PR negative and larger tumor (T4). We did not find any MTHFR haplotypes associated with BC susceptibility. However, the less common haplotype MTHFR T-C was more frequent in young patients and in familial breast cancer, while MTHFR C-C haplotype was associated with sporadic BC form.

Conclusions

Our findings are a first observation of association between ERCC2 SNPs and breast cancer in Moroccan population. The results suggested that ERCC2 and MTHFR polymorphisms may be reliable for assessing risk and prognosis of BC in Moroccan population.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Genetic variants in ERCC1 and XPC predict survival outcome of non-small cell lung cancer patients treated with platinum-based therapy

Nucleotide excision repair (NER) plays a vital role in platinum-induced DNA damage during chemotherapy. We hypothesize that regulatory single nucleotide polymorphisms (rSNPs) of the core NER genes modulate clinical outcome of patients with advanced non-small cell lung cancer (NSCLC) treated with platinum-based chemotherapy (PBS). We investigated associations of 25 rSNPs in eight NER genes with progression free survival (PFS) and overall survival (OS) in 710 NSCLC patients. We found that ERCC1 rs3212924 AG/GG and XPC rs2229090 GC/CC genotypes were associated with patients’ PFS (HR_adj = 1.21, 95% CI = 1.03–1.43, P_adj = 0.021 for ERCC1 and HR_adj = 0.80, 95% CI = 0.68–0.94, P_adj = 0.007 for XPC), compared with the AA and GG genotypes, respectively. The association of XPC rs2229090 was more apparent in adenocarcinoma than in squamous cell carcinoma patients. Additionally, ERCC4 rs1799798 GA/AA genotypes were associated with poorer OS (HR_adj = 1.32, 95% CI = 1.04–1.69, P_adj = 0.026), compared with the GG genotype. The expression quantitative trait loci analysis revealed that ERCC1 rs3212924 and XPC rs2229090 might regulate transcription of their genes, which is consistent with their associations with survival. Larger studies are needed to validate our findings with further functional studies to elucidate the mechanisms underlying these observed associations.

XPG gene rs751402 C>T polymorphism and cancer risk: Evidence from 22 publications

The Xeroderma pigmentosum group G (XPG) gene promotes recognition and excision of damaged DNA during the DNA repair process. We conducted a comprehensive search of the MEDLINE, EMBASE, and Chinese Biomedical databases for publications evaluating the association XPG gene rs751402 C>T polymorphism and overall cancer risk. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were adopted to assess the strength of the association. A total of 22 publications encompassing 10538 cases and 10511 control subjects were included in the final meta-analysis. We found the polymorphism to be associated with increased cancer risk (TT vs. CC: OR = 1.18, 95% CI = 1.01-1.38, P = 0.040; CT vs. CC: OR = 1.12, 95% CI = 1.01-1.24, P = 0.040; and CT/TT vs. CC: OR = 1.12, 95% CI = 1.002-1.26, P = 0.045). Stratification by cancer type indicated that this polymorphism may increase the risk of gastric cancer and hepatocellular carcinoma, which was further confirmed by a false-positive report probability analysis. Genotype-based mRNA expression provides further evidence that this polymorphism is associated with altered XPG mRNA expression. This meta-analysis suggests XPG gene rs751402 C>T polymorphism correlates with overall cancer risk, especially for gastric cancer and hepatocellular carcinoma.