Association between the DNA Repair Gene XRCC3 rs861539 Polymorphism and Risk of Osteosarcoma: a Systematic Review and Meta-Analysis

Association between XRCC2 Arg188His Polymorphism and Breast Cancer Susceptibility: A Systematic Review and Meta-Analysis

Breast cancer is one of the most common cancers in the world and leading cause of cancer-related death among women. Several studies indicated that Arg188His (rs3218536) polymorphism of X-ray repair cross-complementing 2 (XRCC2) may be associated with breast cancer risk. However, this association remains ambiguous. Thus, we performed a meta-analysis to provide more precise conclusion on this issue. A comprehensive search in PubMed, Google Scholar and ISI Web of Science was performed to select all relevant studies. Odds ratios (OR) with corresponding 95% confidence intervals (CI) were applied to assess the strength of the relationships. A total of 17 studies with 5694 breast cancer cases and 6450 healthy subjects were identified. The pooled data revealed that XRCC2 Arg188His polymorphism was marginally with susceptibility to breast cancer globally under the heterozygote contrast (OR = 0.929, 95% CI = 0.873-0.987, p=0.018). Moreover, subgroup analysis by ethnicity revealed that this polymorphism was associated with breast cancer risk among Caucasians. On the whole, the present study demonstrates that the XRCC2 Arg188His polymorphism may contribute to an increased risk of breast cancer.

Molecular Epidemiology in Amerindians of the Brazilian Amazon Reveals New Genetic Variants in DNA Repair Genes

Native American populations from the Brazilian Amazon have a low genetic diversity and a different genetic profile when compared to people from other continents. Despite this, few studies have been conducted in this group, and there is no description of their genetic data in the various currently existent international databases. The characterization of the genomic profile of a population not only has an impact in studies of population genetics, but also helps to advance diagnostic and therapeutic response studies, leading to the optimization of clinical applicability. Genetic variations in DNA repair genes have been associated with the modulation of susceptibility to various pathologies, as well as in their prognosis and therapy. This is the first study to investigate DNA repair genes in Amerindians from the Brazilian Amazon region. We investigated 13 important DNA repair genes in the exome of 63 Native Americans, comparing our results with those found in 5 continental populations, whose data are available in the Genome Aggregation Database. Our results showed that 57 variants already described in literature were differentially distributed in the Amerindian populations in relation to the continental populations, 7 of which have significant clinical relevance. In addition, 9 new variants were described, suggesting that they are unique to these populations. Our study reinforces the understanding that the Amazonian Native American population presents a unique genetic profile, and our findings may collaborate with the creation of public policies that optimize the quality of life of these groups as well as the Brazilian population, which presents a high degree of interethnic mixing with Amerindian groups.

Association between RAD51, XRCC2 and XRCC3 gene polymorphisms and risk of ovarian cancer: a case control and an in silico study

Homologous recombination (HR) is one of the important mechanisms in repairing double-strand breaks to maintain genomic integrity and DNA stability from the cytotoxic effects and mutations. Various studies have reported that single nucleotide polymorphisms (SNPs) in the HR-associated genes may have a significant association with ovarian cancer (OCa) risk but the results were inconclusive. In the present study, five polymorphisms of HR-associated genes (RAD51, XRCC2 and XRCC3) were genotyped by allelic discrimination assay in 200 OCa cases and 200 healthy individuals. The association with OCa risk was evaluated by unconditional logistic regression analyses. The results revealed that the mutant allele in both rs1801320 (CC) and rs1801321 (TT) of RAD51 gene was associated with increased risk of OCa (odds ratio [OR] 3.79, 95% confidence interval [CI] 1.21-11.78, p = 0.014 and OR 1.61, 95% CI 1.06-2.45, p = 0.025, respectively). Moreover, a significant association of TT allele (OR 4.68, 95% CI 1.27-17.15, p = 0.011) of rs3218536 of XRCC2 gene with OCa was observed. Stratified analysis results showed that patients with early menarche and stages 3 and 4 were found to be associated with rs1801321 of RAD51 gene and rs1799794 of XRCC3 gene. In silico analysis predicted that the two missense SNPs (rs3218536 and rs1799794) were found to have an impact on the protein structure, stability and function. The present study suggested that RAD51 and XRCC2 gene polymorphisms might have an impact on the OCa risk in the South Indian population. However, studies with a larger sample and on different populations are needed to support the conclusions.

The association between XRCC3 rs1799794 polymorphism and cancer risk: a meta-analysis of 34 case-control studies

Background

Studies on the XRCC3 rs1799794 polymorphism show that this polymorphism is involved in a variety of cancers, but its specific relationships or effects are not consistent. The purpose of this meta-analysis was to investigate the association between rs1799794 polymorphism and susceptibility to cancer.

Methods

PubMed, Embase, the Cochrane Library, Web of Science, and Scopus were searched for eligible studies through June 11, 2019. All analyses were performed with Stata 14.0. Subgroup analyses were performed by cancer type, ethnicity, source of control, and detection method. A total of 37 studies with 23,537 cases and 30,649 controls were included in this meta-analysis.

Results

XRCC3 rs1799794 increased cancer risk in the dominant model and heterozygous model (GG + AG vs. AA: odds ratio [OR] = 1.04, 95% confidence interval [CI] = 1.00–1.08, P = 0.051; AG vs. AA: OR = 1.05, 95% CI = 1.00–1.01, P = 0.015). The existence of rs1799794 increased the risk of breast cancer and thyroid cancer, but reduced the risk of ovarian cancer. In addition, rs1799794 increased the risk of cancer in the Caucasian population.

Conclusion

This meta-analysis confirms that XRCC3 rs1799794 is related to cancer risk, especially increased risk for breast cancer and thyroid cancer and reduced risk for ovarian cancer. However, well-designed large-scale studies are required to further evaluate the results.

Association of interleukin 10 rs1800896 polymorphism with susceptibility to breast cancer: a meta-analysis

Objective

To evaluate the correlation between interleukin 10 (IL-10) −1082A/G polymorphism (rs1800896) and breast cancers by performing a meta-analysis.

Methods

The Embase and Medline databases were searched through 1 September 2018 to identify qualified articles. Odds ratios (OR) and corresponding 95% confidence intervals (CIs) were applied to evaluate associations.

Results

In total, 14 case-control studies, including 5320 cases and 5727 controls, were analyzed. We detected significant associations between the IL10 −1082 G/G genotype and risk of breast cancer (AA + AG vs. GG: OR = 0.88, 95% CI = 0.80–0.97). Subgroup analyses confirmed a significant association in Caucasian populations (OR = 0.89, 95% CI = 0.80–0.99), in population-based case-control studies (OR = 0.87, 95% CI = 0.78–0.96), and in studies with ≥500 subjects (OR = 0.88, 95% CI = 0.79–0.99) under the recessive model (AA + AG vs. GG). No associations were found in Asian populations.

Conclusions

The IL10 −1082A/G polymorphism is associated with an increased risk of breast cancer. The association between IL10 −1082 G/G genotype and increased risk of breast cancer is more significant in Caucasians, in population-based studies, and in larger studies.

Association of ESRα XbaI A > G, ESRα PvuII T > C and ESRβ AlwNI T > C Polymorphisms with the Risk of Developing Adolescent Idiopathic Scoliosis: A Systematic Review and Genetic Meta-analysis

Several association studies of genes polymorphisms on estrogen receptors-α and β with respect to adolescent idiopathic scoliosis (AIS) have been published in the past two decades. However, the association with AIS, especially among different ethnic subgroups, still remains controversial. Thus, we investigated these inconclusive data by performing a meta-analysis to systematically evaluate the association.

A literature search was conducted in the PubMed, ISI Web of Science, EMBASE, SCOPUS, EBSCO, Cochrane Library, China National Knowledge Infrastructure (CNKI) and Wanfang databases until January 20, 2018. The strength of relationship was assessed using odds ratios (ORs) and 95% confidence intervals (95%CIs).

A total of 12 case–control studies with 4,304 cases of AIS and 3,123 controls met our criteria. The pooled ORs indicated that the ESRα XbaI A > G, ESRα PvuII T > C and ESRβ AlwNI T > C polymorphisms were not significantly associated with the risk of developing AIS in the overall analysis. However, we found a significant association between the ESRα XbaI A > G polymorphism and AIS under the homozygote model (GG versus AA; OR = 1.448, 95%CI: 1.052–1.993; p  = 0.023).

The present meta-analysis suggests that the ESRα XbaI A > G, ESRα PvuII T > C and ESRβ AlwNI T > C polymorphisms may not be associated with the risk of developing AIS in the overall analysis. However, ESRα XbaI A > G might have an influence on the susceptibility to develop AIS among Asians. Considering the limited sample size and ethnicity, further larger studies are needed to provide a more precise estimation of the associations.

Association of Promoter Region Polymorphisms of IL-10 Gene with Susceptibility to Lung Cancer: Systematic Review and Meta-Analysis

Objective: Epidemiological studies have suggested that the promoter region polymorphisms of interleukin-10 (IL-10) gene may be associated with an increased risk of lung cancer. However, those studies results are controversial. Thus, a comprehensive meta-analysis was performed to evaluate the association of promoter region polymorphisms of IL-10 gene with susceptibility to lung cancer. Methods: a comprehensive search of PubMed, EMBASE, and CNKI databases was performed to find all eligible studies up to September 15, 2018. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of such association. Results: A total number of 19 case-control studies with 4084 cases and 6,131 controls were selected. The overall meta-analysis results showed that the -592A>C polymorphism was significantly associated with lung cancer risk under four genetic models, i.e., allele (CT vs. TT: OR= 1.17, 95% CI 1.01-1.35, p=0.02), homozygote (CC vs. AA: OR= 1.64, 95% CI 1.29-2.02, p≤0.001), heterozygote (CA vs. AA: OR= 1.26, 95% CI 1.06-1.50, p≤0.001), and dominant (CC+CA vs. AA: OR= 1.31, 95% CI 1.11-1.54, p=0.001). However, there was no significant association between -819T>C and -1082A>G polymorphisms of IL-10 and lung cancer risk. Similarly, subgroup analyses by ethnicity detected significant association between IL-10 -592A>C and lung cancer among Asians and Caucasians. Conclusions: Our meta-analysis suggests that the IL-10 -592A>C polymorphism might be risk factor for lung cancer, especially among Asian and Caucasians. In contrast, the IL-10 -819T>C and -1082A>G polymorphisms are not significantly associated with increased risk of lung cancer.

Association of GSTM1, GSTT1, GSTM3, and GSTP1 Genes Polymorphisms with Susceptibility to Osteosarcoma: a Case- Control Study and Meta-Analysis

Background: Some studies have investigated the association of GSTM1, GSTT1, GSTM3, and GSTP1 polymorphisms with susceptibility to osteosarcoma; however, these studies results are inconsistent and inconclusive. In order to drive a more precise estimation, the present case-control study and meta-analysis was performed to investigate association of GSTM1, GSTT1, GSTM3, and GSTP1 polymorphisms with osteosarcoma. Methods: Eligible articles were identified by a search of several electronic databases for the period up to May 5, 2018. Odds ratios were pooled using either fixed-effects or random effects models. Results: Finally, a total of 24 case-control studies with 2,405 osteosarcoma cases and 3,293 controls were included in the present meta-analysis. Overall, significantly increased osteosarcoma risk was found when all studies were pooled into the meta-analysis of GSTT1 (Null vs. Present: OR= 1.247 95% CI 1.020-1.524, P= 0.031) and GSTP1 polymorphism (B vs. A: OR= 8.899 95% CI 2.722-29.094, P≤0.001). In the stratified, significantly increased osteosarcoma risk was observed for GSTT1 polymorphism among Asians (Null vs. Present: OR= 1.300 95% CI 1.034-1.635, P= 0.025), but not among Caucasians. Conclusions: This meta-analysis demonstrated that GSTP1 and GSTT1 null genotype are associated with the risk of osteosarcoma. Future large welldesigned epidemiological studies are warranted to validate our results.

Angiotensin Converting Enzyme Insertion/Deletion Polymorphism is Associated with Breast Cancer Risk: A Meta-Analysis

Background: A number of case-control studies were conducted to investigate the association of angiotensin converting enzyme insertion/deletion (ACE I/D) polymorphism with breast cancer. But the results remain controversial. This meta-analysis aims to comprehensively evaluate the association of ACE I/D polymorphism with breast cancer. Method: A comprehensive literature search on PubMed, Google Scholar, SCOPUS and ISI Web of Knowledge databases for studies published up to June 01, 2018 was performed. Summary odds ratios (ORs) and 95% confidence intervals (CI) were estimated. Publication bias of literatures was evaluated using funnel plots and Egger’s test. Results: A total of 20 studies including 2846 breast cancer cases 9,299 controls meeting the predefined criteria were involved in the meta-analysis. Overall, the ACE I/D polymorphisms was significantly associated with breast cancer under the allele model (I vs. D: OR= 0.803, 95% CI 0.647-0.996, p=0.046), the homozygote model (II vs. DD: OR= 0.662, 95% CI 0.462-0.947, p=0.024), the heterozygote model (ID vs. DD: OR= 0.707, 95% CI 0.528-0.946, p=0.020), the dominant model (II+ID vs. DD: OR= 0.691, 95% CI 0.507-0.941, p=0.019). In the subgroup analysis by ethnicity, a significant association was found among Asian and Caucasian populations, but not among mixed populations. Conclusions: This meta-analysis suggests that ACE I/D polymorphism may be associated with increased risk of breast cancer, especially among Asian and Caucasians. However, well-designed studies with larger sample size and more ethnic groups are needed to further validate the results.

Plasminogen Activator Inhibitor-1 4G/5G Polymorphism Contributes to Osteonecrosis of the Femoral Head Susceptibility: Evidence from a Systematic Review and Meta-analysis

BACKGROUND

The Plasminogen Activator Inhibitor-1 gene 4G/5G (PAI-1 4G/5G) polymorphism has been suggested to be associated with osteonecrosis of the femoral head (ONFH) susceptibility; however, the results are conflicting and inconclusive. We have carried out a comprehensive meta-analysis to derive a more precise estimation of the association.

METHODS

A comprehensive search in PubMed, EMBASE, Google Scholar, and ISI Web of Knowledge databases was conducted to identify all eligible case-control publications investigating the association between PAI-1 4G/5G polymorphism and ONFH risk. Odds ratios (OR) and corresponding 95% confidence intervals (CI) were used to assess the association.

RESULTS

A total of six studies with 456 cases and 1,019 controls were included in this review. Three studies were from Caucasian descendants and the three others were from East Asian descendants. Overall analysis suggests a significant association between PAI-1 4G/5G polymorphism and ONFH risk under the allele model (4G vs. 5G: OR =1.540, 95% CI =1.055-2.248, P=0.025) and the recessive model (4G4G vs. 4G5G+5G5G: OR=1.931, 95% CI: 1.162-3.207, P=0.011). When stratified by ethnicity, we have found a significant association between PAI-1 4G/5G polymorphism and ONFH risk among the Caucasian (4G5G vs. 5G5G: OR=1.806, 95% CI: 1.064-3.067, P=0.029) and East Asians (4G4G vs. 5G5G: OR=1.619, 95% CI: 1.025-2.556, P=0.039 and 4G4G vs. 4G5G+5G5G: OR=1.665, 95% CI: 1.207-2.297, P=0.002).

CONCLUSION

The present meta-analysis suggested that PAI-1 4G/5G (rs1799889) polymorphism is a potential risk factor for development of ONFH. However, large-scale and well-designed case-control studies in different ethnicities are required to validate these results.

Genetic susceptibility to bone and soft tissue sarcomas: a field synopsis and meta-analysis

Background

The genetic architecture of bone and soft tissue sarcomas susceptibility is yet to be elucidated. We aimed to comprehensively collect and meta-analyze the current knowledge on genetic susceptibility in these rare tumors.

Methods

We conducted a systematic review and meta-analysis of the evidence on the association between DNA variation and risk of developing sarcomas through searching PubMed, The Cochrane Library, Scopus and Web of Science databases. To evaluate result credibility, summary evidence was graded according to the Venice criteria and false positive report probability (FPRP) was calculated to further validate result noteworthiness. Integrative analysis of genetic and eQTL (expression quantitative trait locus) data was coupled with network and pathway analysis to explore the hypothesis that specific cell functions are involved in sarcoma predisposition.

Results

We retrieved 90 eligible studies comprising 47,796 subjects (cases: 14,358, 30%) and investigating 1,126 polymorphisms involving 320 distinct genes. Meta-analysis identified 55 single nucleotide polymorphisms (SNPs) significantly associated with disease risk with a high (N=9), moderate (N=38) and low (N=8) level of evidence, findings being classified as noteworthy basically only when the level of evidence was high. The estimated joint population attributable risk for three independent SNPs (rs11599754 of ZNF365/EGR2, rs231775 of CTLA4, and rs454006 of PRKCG) was 37.2%. We also identified 53 SNPs significantly associated with sarcoma risk based on single studies.Pathway analysis enabled us to propose that sarcoma predisposition might be linked especially to germline variation of genes whose products are involved in the function of the DNA repair machinery.

Conclusions

We built the first knowledgebase on the evidence linking DNA variation to sarcomas susceptibility, which can be used to generate mechanistic hypotheses and inform future studies in this field of oncology.

Vasohibin 1 inhibits Adriamycin resistance in osteosarcoma cells via the protein kinase B signaling pathway

Vasohibin (VASH)1 functions as a negative feedback modulator of angiogenesis in vascular endothelial cells. Mesenchymal VASH1 has been demonstrated to be negatively associated with tumor progression, however studies regarding VASH1 in tumor cells and its functions remain limited. The function of VASH1 in osteosarcoma remains unknown. In the present study, it was confirmed that osteosarcoma cells express decreased levels of VASH1 compared with that expressed by human osteoblast cells. 143B cells with decreased VASH1 expression revealed increased Adriamycin (ADR) resistance compared with U-2OS cells with increased VASH1 expression. Subsequent to manipulating VASH1 expression via transfection, results revealed that overexpression of VASH1 in 143B cells inhibited P-glycoprotein (P-gp) expression and ADR resistance significantly; silencing VASH1 in U-2OS cells enhanced P-gp expression and ADR resistance significantly. Research into the molecular mechanism was performed and the results identified that protein kinase B (AKT) and extracellular signal-related kinase signal pathways were both stimulated by VASH1, but only AKT inhibitor LY294002 was identified to efficiently counteract increases in P-gp expression that had been induced by silencing of VASH1 in U-2OS cells. ADR resistance promoted by silencing VASH1 in U-2OS cells was also counteracted by LY294002. In conclusion, the present study confirmed the low expression of VASH1 in osteosarcoma cells. It was identified that VASH1 was able to inhibit drug resistance in osteosarcoma cells through regulation of P-gp via the AKT signal pathway. This demonstrated a negative regulation function of VASH1 in osteosarcoma, deepened understanding of the function of VASH1 in tumors and suggests a basis for further studies in to the functions of VASH1.

Association of vitamin D receptor BsmI, TaqI, FokI, and ApaI polymorphisms with susceptibility of chronic periodontitis: A systematic review and meta-analysis based on 38 case -control studies

BACKGROUND

There has been increasing interest in the study of the association between Vitamin D receptor (VDR) gene polymorphisms and risk of chronic periodontitis. However, the results remain inconclusive. To better understand the roles of VDR polymorphisms (BsmI, TaqI, FokI, and ApaI) in chronic periodontitis susceptibility, we conducted this systematic review and meta-analysis.

MATERIALS AND METHODS

The PubMed, Google Scholar, and Web of Science database were systemically searched to determine all the eligible studies about VDR polymorphisms and risk of chronic periodontitis up to April 2017. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the associations between VDR polymorphisms and chronic periodontitis risk. All the statistical analyses were performed by Comprehensive Meta-Analysis. All P values were two-tailed with a significant level at 0.05.

RESULTS

Finally, a total of 38 case-control studies in 19 publications were identified which met our inclusion criteria. There are ten studies with 866 chronic periodontitis cases and 786 controls for BsmI, 16 studies with 1570 chronic periodontitis cases and 1676 controls for TaqI, five studies with 374 chronic periodontitis cases and 382 controls for FokI, and seven studies with 632 chronic periodontitis cases and 604 controls for ApaI. Overall, no significant association was observed between VDR gene BsmI, TaqI, FokI, and ApaI polymorphisms and risk of chronic periodontitis in any genetic model. Subgroup analysis stratified by ethnicity suggested a significant association between BsmI polymorphism and chronic periodontitis risk in the Caucasian subgroup under allele model (A vs. G: OR = 1.747, 95% CI = 1.099-2.778, P = 0.018). Further, no significant associations were observed when stratified by Hardy-Weinberg equilibrium status for BsmI, TaqI, and ApaI.

CONCLUSION

Our results suggest that BsmI, TaqI, FokI, and ApaI polymorphisms in the VDR gene might not be associated with risk of chronic periodontitis in overall population.

Association of ESRα Gene Pvu II T>C, XbaI A>G and BtgI G>A Polymorphisms with Knee Osteoarthritis Susceptibility: A Systematic Review and Meta-Analysis Based on 22 Case-Control Studies

BACKGROUND

Many studies have reported the association of estrogen receptor α gene (ESRα) ESRα PvuII T>C, XbaI A>G and BtgI G>A polymorphisms with Knee osteoarthritis (KOA) risk, but the results remained controversial. In order to drive a more precise estimation, the present systematic review and meta-analysis was performed to investigate the association between ESRα polymorphisms and KOA susceptibility.

METHODS

Eligible articles were identified by search of databases including PubMed, ISI Web of Knowledge and Google scholar up to March 1, 2017. Data were extracted by two independent authors and pooled odds ratio (OR) with 95% confidence interval (CI) was calculated.

RESULTS

A total of 22 case-control studies in eleven publications with 6,575 KOA cases and 7,459 controls were included in the meta-analysis. By pooling all the studies, either ESRα PvuII T>C and XbaI A>G polymorphisms was not associated with KOA risk in the overall population. However, ESRα BtgI G>A was significantly associated with KOA risk under all five genetic models. In the subgroup analysis by ethnicity, a significant association was observed between ESRα PvuII T>C polymorphism and KOA risk in Asians under heterozygote model. In addition, significant association was found between ESRα XbaI A>G polymorphism and KOA in Caucasians under allelic, homozygote, dominant and recessive models.

CONCLUSION

The present meta-analysis suggests that ESRα BtgI G>A rather than ESRα PvuII T>C and XbaI A>G polymorphisms is associated with an increased KOA risk in overall population. Moreover, we have found that ESRα PvuII T>C and XbaI A>G polymorphisms associated with KOA susceptibility by ethnicity backgrounds.

Association between Polymorphisms of ERCC5 Gene and Susceptibility to Gastric Cancer: A Systematic Review and Meta-Analysis

Background:

several epidemiological studies have suggested that polymorphisms of the Excision Repair Cross Complementing Group-5 (ERCC5) gene might be related to gastric cancer risk; however, the results have been inconsistent or controversial. Therefore, we have performed a systematic review and meta-analysis to clarify the association between the ERCC5 gene polymorphisms and gastric cancer risk.

Materials and Methods:

An electronic search was conducted of several databases, including PubMed, Web of Science, and Google Scholar for articles that describe the association between polymorphisms of the ERCC5 gene and susceptibility of gastric cancer.

Results:

A total of 33 case control studies in 15 publications were included in the present meta-analysis. There were significant associations between gastric cancer susceptibility and ERCC5 gene rs751402 C>T (T vs. C: OR = 1.166, 95% C = 1.066-1.274, p= 0.001; TT vs. CC: OR = 0.723, 95% CI = 0.587-0.890, p = 0.002; TT+TC vs. CC: OR = 0.853, 95% CI = 0.757-0.961, p = 0.009; TT vs. TC+CC: OR = 0.793, 95% CI = 0.659-0.955, p = 0.015), rs2296147 T>C (C vs. T: OR = 1.268, 95% C = 1.049-1.532, p= 0.014), rs873601 G>A polymorphisms (A vs. G, OR = 1.087, 95% C = 1.021-1.159, p= 0.010; AA vs. GG, OR = 1.184, 95% CI = 1.043-1.343, p = 0.009, AA vs. AG+GG, OR = 1.156, 95% CI = 1.040-1.284, p = 0.007), but not rs2094258 C>T and rs1047768 T>C.

Conclusion:

the current meta-analysis demonstrates that rs751402 C>T, rs2296147 T>C, and rs873601 G>A polymorphisms of ERCC5 gene are associated with the susceptibility of gastric cancer.

Association of XRCC2 rs3218536 Polymorphism with Susceptibility of Breast and Ovarian Cancer: A Systematic Review and Meta-Analysis

Background: Previous studies have investigated the association of X-Ray Repair Cross-Complementing Group 2 (XRCC2) rs3218536 polymorphism with breast and ovarian cancer. However, this association remains conflicting. Therefore, we have performed the current systematic review and meta-analysis to clarify the association between XRCC2 rs3218536 polymorphism with risk of breast and ovarian cancer. Methods: We conducted a search in PubMed, Google Scholar and ISI Web of Science to select relevant studies on the association of XRCC2 rs3218536 polymorphism with breast and ovarian cancer susceptibility. We calculated the odds ratios (OR) and 95% confidence intervals (CI) for five genetic contrasts. In addition, a stratified analysis was conducted cancer type, ethnicity and HWE status. Results: A total of 17 studies with 5694 cases and 6450 controls for breast cancer and nine case-control studies with 4464 cases and 6353 controls for ovarian cancer were identified for the analysis of the association with XRCC2 rs3218536 polymorphism. The pooled ORs revealed that XRCC2 rs3218536 polymorphism was associated with breast cancer under the heterozygote contrast (AG vs. GG: OR = 0.929, 95% CI = 0.873-0.987, p=0.018) and ovarian cancer under dominant contrast (AA+AG vs. GG: OR = 0.725, 95% CI = 0.537-0.979, p=0.036) in the overall population. The stratified analysis indicated a significant association of XRCC2 rs3218536 polymorphism with breast and ovarian cancer risk among Caucasians. Conclusion: Inconsistent with previous meta-analysis, this meta-analysis shows that the XRCC2 rs3218536 polymorphism was associated with breast and ovarian cancer risk in overall population, especially among Caucasians.

Association between Thrombophilic Genes Polymorphisms and Recurrent Pregnancy Loss Susceptibility in the Iranian Population: a Systematic Review and Meta-Analysis

Studies have indicated that thrombophilic genes polymorphisms are associated with recurrent pregnancy loss (RPL) in the Iranian population. We aimed to evaluate the precise association between thrombophilic genes polymorphisms (MTHFR C677T, MTHFR A1298C, Prothrombin G20210A, FVLG1691A, and PAI-1 4G/5G) and RPL risk in the Iranian population. PubMed, Web of Science, Google Scholar, and ISC were searched for eligible articles published up to April 1, 2017. In total, 37 case-control studies in 18 relevant publications were selected: 1,199, 1,194, 630, 830, and 955 RPL cases and 1,079, 1079, 594, 794, and 499 controls for MTHFR C677T, MTHFR A1298C,Prothrombin G20210A, FVL G1691A, and PAI-1 4G/5G, respectively. The results indicated a significant increased risk of RPL in all genetic models in the population. Also, Prothrombin G20210A and FVL G1691A as well as PAI-1 4G/5G polymorphisms were associated with RPL risk in the Iranian population. Hence, thrombophilic genes polymorphisms are associated with an increased RPL risk in the Iranian population.

Genetic Association between ERCC2, NBN, RAD51 Gene Variants and Osteosarcoma Risk: a Systematic Review and Meta-Analysis

Background:

To date, only a few studies have investigated associations between ERCC2, NBN, and RAD51 variants and risk of developing osteosarcoma. In this systematic review and meta-analysis, we focused on clarifying links.

Materials and Methods:

We systematically searched PubMed, Google Scholar, and ISI web of knowledge databases to identify relevant studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to calculate the strength of associations with fixed effect models.

Results:

No statistical evidence of association was found between ERCC2 rs13181 (G vs. T: OR= 1.224, 95% CI: 0.970-1.545, p= 0.088; GT vs. TT OR= 1.135, 95% CI: 0.830-1.552, p= 0.428; GG vs. TT: OR= 1.247, 95% CI: 0.738-2.108, p= 0.409; GG+GT vs. TT: OR= 1.174, 95% CI: 0.929-1.484, p= 0.179; GG vs. GT+ TT: OR= 1.476, 95% CI: 0.886-2.460, p= 0.135), ERCC2 rs1799793 (GA+AA vs. GG: OR= 1.279, 95% CI: 0.912-1.793, p= 0.154), NBN rs709816 (OR= 1.047, 95% CI: 0.763-1.437, p= 0.775), NBN rs1805794 (OR= 1.126, 95% CI: 0.789-1.608, p= 0.513), RAD51 rs1801320 (OR= 0.977, 95% CI: 0.675-1.416, p= 0.904), RAD51 rs1801321 (TT+GT vs. GG OR= 1.167, 95% CI: 0.848-1.604, p= 0.343), RAD51 rs12593359 (GG+GT vs. TT OR= 0.761, 95% CI: 0.759-1.470, p= 0.744) polymorphisms and osteosarcomas. The lack of the original data limited our further evaluation of the adjusted ORs concerning age and gender; however, the previous individual studies results indicated the age-and gender-specific effects of two ERCC2 rs1799793 and NBN rs1805794 variants on osteosarcoma risk.

Conclusion:

The results suggested a lack of association between the ERCC2 (rs13181 and rs1799793), NBN (rs709816 and rs1805794), and RAD51 (rs1801320, rs1801321, and rs12593359) variants with osteosarcoma risk. Further comprehensive and well-designed studies are required to assess the role for ERCC2, NBN, RAD51 variants in osteosarcoma development more adequately.