The association of polymorphisms in nucleotide excision repair genes with ovarian cancer susceptibility

Nucleotide excision repair gene polymorphisms and hepatoblastoma susceptibility in Eastern Chinese children: A five-center case-control study

Objective

Nucleotide excision repair (NER) plays a vital role in maintaining genome stability, and the effect of NER gene polymorphisms on hepatoblastoma susceptibility is still under investigation. This study aimed to evaluate the relationship between NER gene polymorphisms and the risk of hepatoblastoma in Eastern Chinese Han children.

Methods

In this five-center case-control study, we enrolled 966 subjects from East China (193 hepatoblastoma patients and 773 healthy controls). The TaqMan method was used to genotype 19 single nucleotide polymorphisms (SNPs) in NER pathway genes, including ERCC1, XPA, XPC, XPD, XPF, and XPG. Then, multivariate logistic regression analysis was performed, and odds ratios (ORs) and 95% confidence intervals (95% CIs) were utilized to assess the strength of associations.

Results

Three SNPs were related to hepatoblastoma risk. XPC rs2229090 and XPD rs3810366 significantly contributed to hepatoblastoma risk according to the dominant model (adjusted OR=1.49, 95% CI=1.07-2.08, P=0.019; adjusted OR=1.66, 95% CI=1.12-2.45, P=0.012, respectively). However, XPD rs238406 conferred a significantly decreased risk of hepatoblastoma under the dominant model (adjusted OR=0.68, 95% CI=0.49-0.95; P=0.024). Stratified analysis demonstrated that these significant associations were more prominent in certain subgroups. Moreover, there was evidence of functional implications of these significant SNPs suggested by online expression quantitative trait loci (eQTLs) and splicing quantitative trait loci (sQTLs) analysis.

Conclusions

In summary, NER pathway gene polymorphisms (XPC rs2229090, XPD rs3810366, and XPD rs238406) are significantly associated with hepatoblastoma risk, and further research is required to verify these findings.

Structural modeling and analyses of genetic variations in the human XPC nucleotide excision repair protein

Xeroderma pigmentosum C (XPC) is a key initiator in the global genome nucleotide excision repair pathway in mammalian cells. Inherited mutations in the XPC gene can cause xeroderma pigmentosum (XP) cancer predisposition syndrome that dramatically increases the susceptibility to sunlight-induced cancers. Various genetic variants and mutations of the protein have been reported in cancer databases and literature. The current lack of a high-resolution 3-D structure of human XPC makes it difficult to assess the structural impact of the mutations/genetic variations. Using the available high-resolution crystal structure of its yeast ortholog, Rad4, we built a homology model of human XPC protein and compared it with a model generated by AlphaFold. The two models are largely consistent with each other in the structured domains. We have also assessed the degree of conservation for each residue using 966 sequences of XPC orthologs. Our structure- and sequence conservation-based assessments largely agree with the variant's impact on the protein's structural stability, computed by FoldX and SDM. Known XP missense mutations such as Y585C, W690S, and C771Y are consistently predicted to destabilize the protein's structure. Our analyses also reveal several highly conserved hydrophobic regions that are surface-exposed, which may indicate novel intermolecular interfaces that are yet to be characterized.Communicated by Ramaswamy H. Sarma.

DNA Damage Response Alterations in Ovarian Cancer: From Molecular Mechanisms to Therapeutic Opportunities

The DNA damage response (DDR), a set of signaling pathways for DNA damage detection and repair, maintains genomic stability when cells are exposed to endogenous or exogenous DNA-damaging agents. Alterations in these pathways are strongly associated with cancer development, including ovarian cancer (OC), the most lethal gynecologic malignancy. In OC, failures in the DDR have been related not only to the onset but also to progression and chemoresistance. It is known that approximately half of the most frequent subtype, high-grade serous carcinoma (HGSC), exhibit defects in DNA double-strand break (DSB) repair by homologous recombination (HR), and current evidence indicates that probably all HGSCs harbor a defect in at least one DDR pathway. These defects are not restricted to HGSCs; mutations in ARID1A, which are present in 30% of endometrioid OCs and 50% of clear cell (CC) carcinomas, have also been found to confer deficiencies in DNA repair. Moreover, DDR alterations have been described in a variable percentage of the different OC subtypes. Here, we overview the main DNA repair pathways involved in the maintenance of genome stability and their deregulation in OC. We also recapitulate the preclinical and clinical data supporting the potential of targeting the DDR to fight the disease.

Complex molecular profile of DNA repair genes in epithelial ovarian carcinoma patients with different sensitivity to platinum-based therapy

Epithelial ovarian carcinoma (EOC) is known for high mortality due to diagnosis at advanced stages and frequent therapy resistance. Previous findings suggested that the DNA repair system is involved in the therapeutic response of cancer patients and DNA repair genes are promising targets for novel therapies. This study aimed to address complex inter-relations among gene expression levels, methylation profiles, and somatic mutations in DNA repair genes and EOC prognosis and therapy resistance status. We found significant associations of DUT expression with the presence of peritoneal metastases in EOC patients. The high-grade serous EOC subtype was enriched with TP53 mutations compared to other subtypes. Furthermore, somatic mutations in XPC and PRKDC were significantly associated with worse overall survival of EOC patients, and higher FAAP20 expression in platinum-resistant than platinum-sensitive patients was observed. We found higher methylation of RAD50 in platinum-resistant than in platinum-sensitive patients. Somatic mutations in BRCA1 and RAD9A were significantly associated with higher RBBP8 methylation in platinum-sensitive compared to platinum-resistant EOC patients. In conclusion, we discovered associations of several candidate genes from the DNA repair pathway with the prognosis and platinum resistance status of EOC patients, which deserve further validation as potential predictive biomarkers.

The association between single nucleotide polymorphisms and ovarian cancer risk: A systematic review and network meta-analysis

BACKGROUND

The relationship between single nucleotide polymorphisms (SNPs) and ovarian cancer (OC) risk remains controversial. This systematic review and network meta-analysis was aimed to determine the association between SNPs and OC risk.

METHODS

Several databases (PubMed, EMBASE, China National Knowledge Infrastructure, Wanfang databases, China Science and Technology Journal Database, and China Biology Medicine disc) were searched to summarize the association between SNPs and OC published throughout April 2021. Direct meta-analysis was used to identify SNPs that could predict the incidence of OC. Ranking probability resulting from network meta-analysis and the Thakkinstian's algorithm was used to select the most appropriate gene model. The false positive report probability (FPRP) and Venice criteria were further tested for credible relationships. Subgroup analysis was also carried out to explore whether there are racial differences.

RESULTS

A total of 63 genes and 92 SNPs were included in our study after careful consideration. Fok1 rs2228570 is likely a dominant risk factor for the development of OC compared to other selected genes. The dominant gene model of Fok1 rs2228570 (pooled OR = 1.158, 95% CI: 1.068-1.256) was determined to be the most suitable model with a FPRP <0.2 and moderate credibility.

CONCLUSIONS

Fok1 rs2228570 is closely linked to OC risk, and the dominant gene model is likely the most appropriate model for estimating OC susceptibility.

Xeroderma Pigmentosum Complementation Group C (XPC): Emerging Roles in Non-Dermatologic Malignancies

Xeroderma pigmentosum complementation group C (XPC) is a DNA damage recognition protein essential for initiation of global-genomic nucleotide excision repair (GG-NER). Humans carrying germline mutations in the XPC gene exhibit strong susceptibility to skin cancer due to defective removal via GG-NER of genotoxic, solar UV-induced dipyrimidine photoproducts. However, XPC is increasingly recognized as important for protection against non-dermatologic cancers, not only through its role in GG-NER, but also by participating in other DNA repair pathways, in the DNA damage response and in transcriptional regulation. Additionally, XPC expression levels and polymorphisms likely impact development and may serve as predictive and therapeutic biomarkers in a number of these non-dermatologic cancers. Here we review the existing literature, focusing on the role of XPC in non-dermatologic cancer development, progression, and treatment response, and highlight possible future applications of XPC as a prognostic and therapeutic biomarker.

Potentially functional variants in nucleotide excision repair pathway genes predict platinum treatment response of Chinese ovarian cancer patients

Acquired platinum resistance impedes successful treatment of epithelial ovarian cancer (EOC), and this resistance may be associated with inherited DNA damage-repair response. In the present study, we performed a two-phase analysis to assess associations between 8191 single-nucleotide polymorphisms within 127 genes of nucleotide excision repair pathway from a genome-wide association study dataset and platinum treatment response in 803 Han Chinese EOC patients. As a result, we identified that platinum-based chemotherapeutic response was associated with two potentially functional variants MNAT1 rs2284704 T>C [TC + CC versus TT, adjusted odds ratio (OR) = 0.89, 95% confidence interval (CI) = 0.83-0.95 and P = 0.0005] and HUS1B rs61748571 A>G (AG + GG versus AA, OR = 1.10, 95% CI = 1.03-1.18 and P = 0.005). Compared with the prediction model for clinical factors only, models incorporating HUS1B rs61748571 [area under the curve (AUC) 0.652 versus 0.672, P = 0.026] and the number of unfavorable genotypes (AUC 0.652 versus 0.668, P = 0.040) demonstrated a significant increase in the AUC. Further expression quantitative trait loci analysis suggested that MNAT1 rs2284704 T>C significantly influenced mRNA expression levels of MNAT1 (P = 0.003). These results indicated that MNAT1 rs2284704 T>C and HUS1B rs61748571 A>G may serve as potential biomarkers for predicting platinum treatment response of Chinese EOC patients, once validated by further functional studies.

Contribution of XPD and XPF Polymorphisms to Susceptibility of Non-Small Cell Lung Cancer in High-Altitude Areas

BACKGROUND

We aimed to explore the relation of XPD and XPF variants with non-small cell lung cancer (NSCLC) risk and the effect of these variants on the sensitivity to cisplatin-based chemotherapy among the Chinese Han population in high-altitude areas.

METHODS

Eight single-nucleotide polymorphisms (SNPs) in XPD and XPF were genotyped by Agena MassARRAY platform among 506 NSCLC cases and 510 healthy controls. Correlation of XPD and XPF gene polymorphisms with NSCLC susceptibility and the response of cis-platin-based chemotherapy were analyzed with logistic regression by calculating odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

XPD rs13181 (OR = 1.53, 95% CI: 1.04-2.24, p = 0.029) and rs1052555 (OR = 1.63, 95% CI: 1.05-2.53, p = 0.029) possibly contributed to the increased risk of lung adenocarcinoma, while XPD rs238406 (OR = 0.63, 95% CI: 0.43-0.94, p = 0.024) was a protective factor for lung squamous cell carcinoma. Age, gender, BMI, smoking, and drinking might affect the correlation of XPD and XPF polymorphisms with NSCLC risk. More importantly, XPD rs13181 (OR = 2.91, p = 0.015), XPD rs1052555 (OR = 2.67, p = 0.022), and XPF rs231127 (OR = 4.15, p = 0.008) were associated with treatment response in NSCLC patients underwent cisplatin-based chemotherapy.

CONCLUSION

This study found that XPD and XPF variants might contribute to NSCLC risk and the response of cisplatin-based chemotherapy among the Chinese Han population in high-altitude areas.

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.

The Association of Polymorphisms in Base Excision Repair Genes with Ovarian Cancer Susceptibility in Chinese Women: A Two-Center Case-Control Study

Base excision repair (BER) acts upon the most important mechanism of the DNA repair system, protecting DNA stability and integrity from the mutagenic and cytotoxic effects. Multiple researches have indicated that single-nucleotide polymorphisms (SNPs) in the BER-related gene may be associated with the susceptibility of ovarian cancer. However, the results are controversial. In this two-center case-control study, 19 potentially functional SNPs in six BER-related genes (hOGG1, APE1, PARP1, FEN1, LIG3 and XRCC1) was genotyped in 196 ovarian cancer cases and 272 cancer-free controls. And, their associations with ovarian cancer risk were assessed by unconditional logistic regression analyses. We found that PARP1 rs8679 and hOGG1 rs293795 polymorphisms were associated with a decreased risk of ovarian cancer under dominant model (adjusted OR=0.39, 95% CI=0.17-0.90, P=0.026; and adjusted OR=0.36, 95% CI=0.13-0.99, P=0.049, respectively). Stratification analysis demonstrated that this association was more pronounced in the subgroups of lower BMI and patients with early menarche and serous carcinoma. Moreover, LIG3 rs4796030 AA/AC variant genotypes performed an increased risk of ovarian cancer under recessive model (adjusted OR=1.54, 95% CI=1.01-2.35, P=0.046), especially in the subgroups of higher BMI, early clinic stage and the carcinoma at the left. These results suggested that PARP1, hOGG1 and LIG3 polymorphisms might impact on the risk of ovarian cancer. However, more researches with larger and different ethnic populations are warranted to support our findings.

Inhabitual presentation of Sertoli-Leydig cell tumor of the ovary with xeroderma pigmentosum: Case report with review of literature

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Sertoli-Leydig cell tumors are rare sex-cord stromal tumors of the ovary.

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We present a case of Sertoli-Leydig cell tumors with rhabdomyomatous differentiation on the setting of xeroderma pigmentosum.

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We describe clinical, gross and microscopic examinations for diagnosis and treatment.

Introduction

Sertoli-Leydig cell tumors (SLCTs) are rare sex-cord stromal tumors of the ovary. Heterologous components may be present, most commonly in the intermediate differentiated and poorly differentiated groups. Because of their scarcity, SLCTs with heterologous differentiation represent a challenge in both diagnosis and management, with limited available experience.

Presentation of case

We report a case of a 27-year-old, Tunisian woman, followed in the Dermatology Department since the age of six months for xeroderma pigmentosum, with a history of basal cell carcinoma of the face operated on several times. The patient presented with abdominal pain and bloating associated with a medium abundance ascites on physical exam. Ultrasound showed a large left adnexal mass associated with an elevated cancer antigen 125 on serological exam. The patient underwent unilateral salpingo-oophorectomy with resection of two omental nodules. Microscopic examination concluded to poorly differentiated Sertoli-Leydig tumor with rhabdomyomatous differentiation. Adjuvant chemotherapy was performed and there was no clinical evidence of tumor recurrence during the three years of follow-up.

Discussion

SLCTs with rhabdomyomatous differentiation on the setting of xeroderma pigmentosum are exceptional, microscopic diagnosis and management is challenging, considering the tumor scarcity.

Conclusion

Further case reports and retrospective studies are required to more understand the pathogenesis of SLCTs and to determine their optimal treatment regimen.

MassArray analysis of genomic susceptibility variants in ovarian cancer

Ovarian cancer (OC), a multifaceted and genetically heterogeneous malignancy is one of the most common cancers among women. The aim of the study is to unravel the genetic factors associated with OC and the extent of genetic heterogeneity in the populations of Jammu and Kashmir (J&K).Using the high throughput Agena MassARRAY platform, present case control study was designed which comprises 200 histopathological confirmed OC patients and 400 age and ethnicity matched healthy controls to ascertain the association of previously reported eleven single nucleotide polymorphisms (SNPs) spread over ten genes (DNMT3A, PIK3CA, FGFR2, GSTP1, ERCC5, AKT1, CASC16, CYP19A1, BCL2 and ERCC1) within the OC population of Jammu and Kashmir, India. The association of each variant was estimated using logistic regression analyses. Out of the 11 SNPs the odds ratio observed for three SNPs; rs2699887 was (1.72 at 95% CI: 1.19-2.48, p = 0.004), rs1695 was (1.87 at 95% CI: 1.28-2.71, p = 0.001), and rs2298881 was (0.66 at 95% CI: 0.46-0.96, p = 0.03) were found significantly associated with the OC after correction with confounding factors i.e. age & BMI. Furthermore, the estimation of interactive analyses was performed and odds ratio observed was 2.44 (1.72-3.47), p value < 0. 001 suggests that there was a strong existence of interplay between the selected genetic variants in OC, which demonstrate that interactive analysis highlights the role of gene-gene interaction that provides an insight among multiple little effects of various polymorphisms in OC.

Distribution and susceptibility of ERCC1/XPF gene polymorphisms in Han and Uygur women with breast cancer in Xinjiang, China

This study aimed to explore the roles of ERCC1/XPF gene polymorphisms in the occurrence of breast cancer in the Uygur and Han ethnic groups in Xinjiang, China. Single nucleotide polymorphisms (SNPs) were detected by TaqMan real‐time PCR. The rs11615 G>A and rs2276466 C>G variant frequencies were higher in Uygur patients with breast cancer than in Han patients, while the frequency of rs2298881 C>A was higher in Han patients. We found that rs2298881 C>A (CA vs. CC: OR = 0.35, 95% CI = 0.20‐0.60; AA vs. CC: OR = 0.13, 95% CI = 0.04‐0.34; CA + AA vs. CC: OR = 0.33, 95% CI = 0.18‐0.51; AA vs. CA + CC: OR = 0.24, 95% CI = 0.08‐0.62; CA vs. AA + CC: OR = 0.49, 95% CI = 0.29‐0.82) was associated with a reduced breast cancer risk and rs3212986 C>A (AA vs. CC: OR = 4.80, 95% CI = 1.79‐15.29,; CA+AA vs. CC: OR = 1.71, 95% CI = 1.06‐2.77; AA vs. CA+CC: OR = 4.12, 95% CI =1.58‐12.89) and rs11615 G > A (AA vs. GG: OR = 3.49, 95% CI =1.54‐8.55; GA + AA vs. GG: OR = 1.98, 95% CI = 1.21‐3.27; AA vs. GA+GG: OR = 2.87, 95% CI = 1.30‐6.85) were associated with an elevated breast cancer risk among Uygur individuals. In addition, Uygur patients with breast cancer with 2‐3 combined risk genotypes of ERCC1 had a higher risk than patients with 0‐1 risk genotypes (OR = 2.91; 95% CI = 1.54‐5.71, p = 0.001). However, we failed to detect a statistically significant association between ERCC1/XPF polymorphisms and breast cancer risk in five genetic models among Han individuals. Our results showed that ERCC1/XPF gene polymorphisms predispose Uygur individuals to breast cancer; this finding should be verified by further large‐scale analyses.

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.

DNA Repair and Ovarian Carcinogenesis: Impact on Risk, Prognosis and Therapy Outcome

There is ample evidence for the essential involvement of DNA repair and DNA damage response in the onset of solid malignancies, including ovarian cancer. Indeed, high-penetrance germline mutations in DNA repair genes are important players in familial cancers: BRCA1, BRCA2 mutations or mismatch repair, and polymerase deficiency in colorectal, breast, and ovarian cancers. Recently, some molecular hallmarks (e.g., TP53, KRAS, BRAF, RAD51C/D or PTEN mutations) of ovarian carcinomas were identified. The manuscript overviews the role of DNA repair machinery in ovarian cancer, its risk, prognosis, and therapy outcome. We have attempted to expose molecular hallmarks of ovarian cancer with a focus on DNA repair system and scrutinized genetic, epigenetic, functional, and protein alterations in individual DNA repair pathways (homologous recombination, non-homologous end-joining, DNA mismatch repair, base- and nucleotide-excision repair, and direct repair). We suggest that lack of knowledge particularly in non-homologous end joining repair pathway and the interplay between DNA repair pathways needs to be confronted. The most important genes of the DNA repair system are emphasized and their targeting in ovarian cancer will deserve further attention. The function of those genes, as well as the functional status of the entire DNA repair pathways, should be investigated in detail in the near future.

Overcoming Platinum and PARP-Inhibitor Resistance in Ovarian Cancer

Platinum chemotherapy remains the cornerstone of treatment for epithelial ovarian cancer (OC) and Poly (ADP-ribose) polymerase inhibitors (PARPi) now have an established role as maintenance therapy. The mechanisms of action of these agents is, in many ways, complementary, and crucially reliant on the intracellular DNA Damage Repair (DDR) response. Here, we review mechanisms of primary and acquired resistance to treatment with platinum and PARPi, examining the interplay between both classes of agents. A key resistance mechanism appears to be the restoration of the Homologous Recombination (HR) repair pathway, through BRCA reversion mutations and epigenetic upregulation of BRCA1. Alterations in non-homologous end-joint (NHEJ) repair, replication fork protection, upregulation of cellular drug efflux pumps, reduction in PARP1 activity and alterations to the tumour microenvironment have also been described. These resistance mechanisms reveal molecular vulnerabilities, which may be targeted to re-sensitise OC to platinum or PARPi treatment. Promising therapeutic strategies include ATR inhibition, epigenetic re-sensitisation through DNMT inhibition, cell cycle checkpoint inhibition, combination with anti-angiogenic therapy, BET inhibition and G-quadruplex stabilisation. Translational studies to elucidate mechanisms of treatment resistance should be incorporated into future clinical trials, as understanding these biologic mechanisms is crucial to developing new and effective therapeutic approaches in advanced OC.

Association of human XPA rs1800975 polymorphism and cancer susceptibility: an integrative analysis of 71 case-control studies

BACKGROUND

The objective of the present study is to comprehensively evaluate the impact of the rs1800975 A/G polymorphism within the human xeroderma pigmentosum group A (XPA) gene on susceptibility to overall cancer by performing an integrative analysis of the current evidence.

METHODS

We retrieved possible relevant publications from a total of six electronic databases (updated to April 2020) and selected eligible case-control studies for pooled assessment. P-values of association and odds ratio (OR) were calculated for the assessment of association effect. We also performed Begg's test and Egger's test, sensitivity analysis, false-positive report probability (FPRP) analysis, trial sequential analysis (TSA), and expression/splicing quantitative trait loci (eQTL/sQTL) analyses.

RESULTS

In total, 71 case-control studies with 19,257 cases and 30,208 controls from 52 publications were included for pooling analysis. We observed an enhanced overall cancer susceptibility in cancer cases compared with negative controls in the Caucasian subgroup analysis for the genetic models of allelic G vs. A, carrier G vs. A, homozygotic GG vs AA, heterozygotic AG vs. AA, dominant AG + GG vs. AA and recessive GG vs. AA + AG (P < 0.05, OR > 1). A similar positive conclusion was also detected in the "skin cancer" or "skin basal cell carcinoma (BCC)" subgroup analysis of the Caucasian population. Our FPRP analysis and TSA results further confirmed the robustness of the conclusion. However, our eQTL/sQTL data did not support the strong links of rs1800975 with the gene expression or splicing changes of XPA in the skin tissue. In addition, even though we observed a decreased risk of lung cancer under the homozygotic, heterozygotic and dominant models (P < 0.05, OR < 1) and an enhanced risk of colorectal cancer under the allelic, homozygotic, heterozygotic, dominant (P < 0.05, OR > 1), our data from FPRP analysis and another pooling analysis with only the population-based controls in the Caucasian population did not support the strong links between the XPA rs1800975 A/G polymorphism and the risk of lung or colorectal cancer.

CONCLUSIONS

Our findings provide evidence of the close relationship between the XPA rs1800975 A/G polymorphism and susceptibility to skin cancer in the Caucasian population. The potential effect of XPA rs1800975 on the risk of developing lung or colorectal cancer still merits the enrollment of larger well-scaled studies.

Identification of a Prognostic Signature Associated With DNA Repair Genes in Ovarian Cancer

Introduction: Ovarian cancer is a highly malignant cancer with a poor prognosis. At present, there is no accurate strategy for predicting the prognosis of ovarian cancer. A prognosis prediction signature associated with DNA repair genes in ovarian cancer was explored in this study.

Methods: Gene expression profiles of ovarian cancer were downloaded from the GEO, UCSC, and TCGA databases. Cluster analysis, univariate analysis, and stepwise regression were used to identify DNA repair genes as potential targets and a prognostic signature for ovarian cancer survival prediction. The top genes were evaluated by immunohistochemical staining of ovarian cancer tissues, and external data were used to assess the signature.

Results: A total of 28 DNA repair genes were identified as being significantly associated with overall survival (OS) among patients with ovarian cancer. The results showed that high expression of XPC and RECQL and low expression of DMC1 were associated with poor prognosis in ovarian cancer patients. The prognostic signature combining 14 DNA repair genes was able to separate ovarian cancer samples associated with different OS times and showed robust performance for predicting survival (Training set: p < 0.0001, AUC = 0.759; Testing set: p < 0.0001, AUC = 0.76).

Conclusion: Our study identified 28 DNA repair genes related to the prognosis of ovarian cancer. Using some of these potential biomarkers, we constructed a prognostic signature to effectively stratify ovarian cancer patients with different OS rates, which may also serve as a potential therapeutic target in ovarian cancer.

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.

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.

The influence of genetic variability of DNA repair mechanisms on the risk of malignant mesothelioma

Background Malignant mesothelioma (MM) is a rare aggressive tumour of mesothelium caused by asbestos exposure. It has been suggested that the genetic variability of proteins involved in DNA repair mechanisms affects the risk of MM. This study investigated the influence of functional polymorphisms in ERCC1 and XRCC1 genes, the interactions between these polymorphisms as well as the interactions between these polymorphisms and asbestos exposure on MM risk. Patients and methods In total, 237 cases with MM and 193 controls with no asbestos-related disease were genotyped for ERCC1 and XRCC1 polymorphisms. Results ERCC1 rs3212986 polymorphism was significantly associated with a decreased risk of MM (odds ratio [OR] = 0.61; 95% confidence interval [CI] = 0.41-0.91; p = 0.014). No associations were observed between other genetic polymorphisms and MM risk. Interactions between polymorphisms did not significantly influence MM risk. Interaction between ERCC1 rs11615 and asbestos exposure significantly influenced MM risk (OR = 3.61; 95% CI = 1.12-11.66; p = 0.032). Carriers of polymorphic ERCC1 rs11615 allele who were exposed to low level of asbestos had a decreased risk of MM (OR = 0.40; 95% CI = 0.19-0.84; p = 0.016). Interactions between other polymorphisms and asbestos exposure did not significantly influence MM risk. Conclusions Our findings suggest that the genetic variability of DNA repair mechanisms could contribute to the risk of developing MM.