Polymorphisms in the promoter region of ESR2 gene and susceptibility to ovarian cancer

Susceptibility to ovarian cancer might be affected by genetic variations in genes involved in estrogen biosynthesis, metabolism or signal transduction. In this study we tested the hypothesis that single nucleotide polymorphisms (SNPs) in the promoter of human ESR2 gene, coding for estrogen receptor β, may be associated with increased risk for ovarian cancer. Three SNPs in the promoter region of human ESR2 gene were genotyped by means of allele-specific tetra-primer PCR. A total of 184 ovarian cancer cases and the same numbers of controls were included in the study. With regard to homozygous analysis, the AA genotype of SNP rs3020449 was found to be significantly more frequent in ovarian cancer cases staged as FIGO III + IV than in cases staged as I + II (OR 2.717, p = 0.027). With regard to allele frequency, the G allele of this SNP was less frequent in FIGO I + II cases than in cases with higher FIGO stages (OR 1.739, p = 0.018). With regard to genotype frequency, allele frequency, allele positivity or haplotype frequency of SNPs rs2987983, rs3020449 and rs3020450 we did not observe a significant difference between the cancer and the control group. Our data suggest that SNPs in the promoter region of ESR2 gene do not affect susceptibility to ovarian cancer, but SNP rs3020449 might affect progression of this disease.     

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.     

Dihydrofolate reductase gene variations in susceptibility to disease and treatment outcomes

Dihydrofolate reductase (DHFR) catalyzes the reduction of dihydrofolate to tetrahydrofolate (THF). THF is needed for the action of folate-dependent enzymes and is thus essential for DNA synthesis and methylation. The importance of this reaction is demonstrated by the effectiveness of antifolate medications used to treat cancer by inhibiting DHFR, thereby depleting THF and slowing DNA synthesis and cell proliferation. Due to the pivotal role that DHFR plays in folate metabolism and cancer treatment, changes in the level of DHFR expression can affect susceptibility to a variety of diseases dependent on folate status such as spina bifida and cancer. Likewise, variability in DHFR expression can affect sensitivity to anti-cancer drugs such as the folate antagonist methotrexate. Alterations in DHFR expression can be due to polymorphisms in the DHFR gene. Several variations have recently been described in DHFR, including promoter polymorphisms, the 19-bp deletion allele and variations in 3'UTR. These polymorphisms seem to be functional, affecting mRNA levels through various interesting mechanisms, including regulation through RNA interference. Several groups have assessed the association of these polymorphisms with folate levels, risk of cancer and spina bifida as well as the outcome of diseases treated with MTX. The latter may lead to different treatment schedules, improving treatment efficacy and/or allowing for a reduction in drug side effects. This review will summarize present knowledge regarding the predictive potential of DHFR polymorphisms in disease and treatment.     

共济失调毛细血管扩张症致病基因与乳腺癌易感性

乳腺癌是与环境因素密切相关的肿瘤之一,致癌因素诱发的DNA损伤信号被传送到多个效应因子,最终导致细胞坏死和癌变。其中,共济失调性毛细血管扩张症致病基因(Ataxia-telangiectasia mutated,ATM)编码的ATM蛋白激酶是DNA损伤应答的主要调控因子,其通过磷酸化一系列下游底物来应对DNA损伤,这在抑制乳腺癌的发生发展中起到了重要的作用。ATM基因突变后,导致损伤DNA不能得到正确修复,最终加速了乳腺癌的转化和增殖。随着对ATM基因结构、功能及乳腺癌易感性机制研究的深入,ATM基因与乳腺癌易感性关系已引起广泛的重视。以下就ATM基因突变、多态性和甲基化等几个方面与乳腺癌易感性的关系进行了简要概述。     

Genetic susceptibility to sporadic ovarian cancer: A systematic review

Ovarian cancer is a highly lethal disease. Many researchers have, therefore, attempted to identify high risk populations. In this perspective, numerous genetic association studies have been performed to discover common ovarian cancer susceptibility variants. Accordingly, there is an increasing need to synthesize the evidence in order to identify true associations. A comprehensive and systematic assessment of all available data on genetic susceptibility to sporadic ovarian cancer was carried out. The evidence of statistically significant findings was evaluated based on the number of positive replications, the ratio of positive and negative studies, and the false-positive report probability (FPRP). The authors reviewed three genome-wide association studies (GWAS) and 147 candidate gene studies, published from 1990 to October 2010, including around 1100 genetic variants in more than 200 candidate genes and 20 intergenic regions. Genetic variants with the strongest evidence for an association with ovarian cancer include the rs2854344 in the RB1 gene and SNPs on chromosomes 9p22.2, 8q24, 2q31, and 19p13. Promising genetic pathways for ovarian cancer include the cell cycle, DNA repair, sex steroid hormone and oncogenic pathway. Concluding, this review shows that many genetic association studies have been performed, but only a few genetic variants show strong evidence for an association with ovarian cancer. More research is needed to elucidate causal genetic variants, taking into consideration gene-gene and gene-environment interactions, combined effects of common and rare variants, and differences between histological subtypes of this cancer.     

TLR7 and TLR8 gene variations and susceptibility to hepatitis C virus infection

Toll-like receptors (TLRs) play pivotal roles in the innate immune system and control inflammatory responses and adaptive immunity. We previously evaluated associations between TLR7 and TLR8 gene SNPs and susceptibility to hepatitis C virus (HCV) infection. Our results suggested that TLR7IVS2-151G and TLR8-129G alleles were present at higher frequency in males of an HCV-infected group as compared to a control group (24.1% vs. 14.4%, p = 0.028; 17.6% vs. 6.8%, p = 0.004, respectively). Based upon their recognition of single stranded viral RNA, this suggested that TLR7 and TLR8 played a significant role in anti-HCV immune responses. Here, we studied the functional effects of these polymorphisms by analyzing the mRNA expressions of TLR7 and TLR8 and cytokine production induced ex vivo by TLR7- and TLR8-specific agonists using whole blood of subjects with different genotypes. The percentage of CD14+ cells from those with an AG haplotype that expressed TLR7 and TLR8 was significantly lower, but higher in intensity compared to cells from those with GG and AC haplotypes. Cells from those with an AG haplotype produced more IFN-α and less amounts of pro-inflammatory cytokines upon stimulation. This suggests that variations in TLR7 and TLR8 genes might impair immune responses during HCV infection.     

Comparisons of gene coexpression network modules in breast cancer and ovarian cancer

Background

Breast cancer and ovarian cancer are hormone driven and are known to have some predisposition genes in common such as the two well known cancer genes BRCA1 and BRCA2. The objective of this study is to compare the coexpression network modules of both cancers, so as to infer the potential cancer-related modules.

Methods

We applied the eigen-decomposition to the matrix that integrates the gene coexpression networks of both breast cancer and ovarian cancer. With hierarchical clustering of the related eigenvectors, we obtained the network modules of both cancers simultaneously. Enrichment analysis on Gene Ontology (GO), KEGG pathway, Disease Ontology (DO), and Gene Set Enrichment Analysis (GSEA) in the identified modules was performed.

Results

We identified 43 modules that are enriched by at least one of the four types of enrichments. 31, 25, and 18 modules are enriched by GO terms, KEGG pathways, and DO terms, respectively. The structure of 29 modules in both cancers is significantly different with p-values less than 0.05, of which 25 modules have larger densities in ovarian cancer. One module was found to be significantly enriched by the terms related to breast cancer from GO, KEGG and DO enrichment. One module was found to be significantly enriched by ovarian cancer related terms.

Conclusion

Breast cancer and ovarian cancer share some common properties on the module level. Integration of both cancers helps identifying the potential cancer associated modules.

     

Expression of EMSY gene in sporadic ovarian cancer

The majority of familial breast and ovarian cancers arise from mutations in the BRCA1 and BRCA2 genes. Amplification at the 11q13.5 locus is commonly observed in breast and ovarian cancers. In 2003, Hughes-Davies et al. identified a novel gene (EMSY) at this locus which binds BRCA2 within a region deleted in some cancers. Although little is known about the cellular role of EMSY, indirect evidence suggests that this nuclear protein is capable of silencing the activation potential of BRCA2. In this study we aimed to investigate expression of the EMSY gene and its protein product in sporadic ovarian cancer. Real-time quantitative RT-PCR was performed in 50 ovarian cancer and 17 normal ovarian tissue samples. Overexpression of the EMSY gene was found in 6/50 cases (12%), but in none of the control samples. To determine the EMSY protein by Western blotting, semi-quantitative analysis of the EMSY protein was performed using the Scion Image Gel Analysis Program. Statistical analysis was performed using SPSS 11.5. All patients having EMSY overexpression also displayed increased levels of the EMSY protein. Sporadic ovarian cancer shows overexpression of EMSY at a prevalence similar to that found in breast cancer and the overexpression is correlated with the protein level.     

Role of DNA repair and cell cycle control genes in ovarian cancer susceptibility

Recent studies have identified several single nucleotide polymorphisms (SNPs) in the population that are associated with variations in the risks of many different cancer diseases. For ovarian cancer, the known highly penetrant susceptibility genes (BRCA1 and BRCA2) are probably responsible for only 40 % of the excess familial ovarian cancer risks, suggesting that other susceptibility genes of lower penetrance exist. The aim of the present study was to evaluate the role of SNPs in three genes, XRCC2 (R188H), ERCC2 (K751Q) and CDKN1B (V109G) which are with moderate risk for ovarian cancer susceptibility in Egyptian women. We further investigated the potential combined effect of these genes variants on ovarian cancer risk. The three genes polymorphisms were characterized in 100 ovarian cancer Egyptian females and 100 healthy women by (RFLP–PCR) method in a case control study. Our results revealed that the frequencies of AC genotypes of ERCC2 (K751Q), and GG genotypes of CDKN1B (V109G) polymorphisms were significantly higher in EOC patients than in normal individual (P = 0.007, 0.02 respectively). The frequencies of AA genotype of XRCC2 (R188H) and CC genotype of ERCC2 (K751Q) were higher in EOC patients than in normal individual but without significance (P = 0.06, 0.38 respectively). Also, no association between any one of the three studied genes polymorphisms and the clinical characteristics of disease. The combination of GA (XRCC2) + AC (ERCC2) + GG (CDKN1B) was significantly associated with increased EOC risk. Also, the combination for GA (XRCC2) + AC (ERCC2) and the combination of AA (XRCC2) + CC (ERCC2) were significantly associated with increased EOC risk. There was significant difference in CA125 values between EOC and control Group (P < 0.001). Our results suggested that, XRCC2, ERCC2 and CDKN1B genes are important candidate genes for susceptibility to EOC. Also, gene–gene interaction between GA (XRCC2) + AC (ERCC2) + GG (CDKN1B) polymorphism may be associated with increased risk of EOCC in Egyptian women.     

Analysis of the gyrA gene of clinical Yersinia ruckeri isolates with reduced susceptibility to quinolones

Antimicrobial susceptibility of seven clinical strains of Yersinia ruckeri representative of those isolated between 1994 and 2002 from a fish farm with endemic enteric redmouth disease was studied. All isolates displayed indistinguishable pulsed-field gel electrophoresis restriction patterns, indicating that they represented a single strain. However, considering both inhibition zone diameters (IZD) and MICs, the isolates recovered in 2001-2002 formed a separate cluster with lower levels of susceptibility to all the quinolones tested, especially nalidixic acid (NA) and oxolinic acid (OA), compared with the isolates recovered between 1994 and 1998. Analysis of the PCR product of the quinolone resistance-determining region of the gyrA gene from clinical isolates of Y. ruckeri with reduced susceptibility to OA and NA revealed a single amino acid substitution, Ser-83 to Arg-83 (Escherichia coli numbering). Identical substitution was observed in induced OA-resistant mutant strains, which displayed IZD and MICs of quinolones similar to those of the clinical isolates of Y. ruckeri with reduced susceptibility to these antimicrobial agents. These data indicate in that for Y. ruckeri, the substitution of Ser by Arg at position 83 of the gyrA gene is associated with reduced susceptibility to quinolones.     

RECQL: a new breast cancer susceptibility gene

Identifying and characterizing novel genetic risk factors for BRCA1/2 negative breast cancers is highly relevant for early diagnosis and development of a management plan. Mutations in a number of DNA repair genes have been associated with genomic instability and development of breast and various other cancers. Whole exome sequencing efforts by 2 groups have led to the discovery in distinct populations of multiple breast cancer susceptibility mutations in RECQL, a gene that encodes a DNA helicase involved in homologous recombination repair and response to replication stress. RECQL pathogenic mutations were identified that truncated or disrupted the RECQL protein or introduced missense mutations in its helicase domain. RECQL mutations may serve as a useful biomarker for breast cancer. Targeting RECQL associated tumors with novel DNA repair inhibitors may provide a new strategy for anti-cancer therapy.     

CHEK2 is a multiorgan cancer susceptibility gene

A single founder allele of the CHEK2 gene has been associated with predisposition to breast and prostate cancer in North America and Europe. The CHEK2 protein participates in the DNA damage response in many cell types and is therefore a good candidate for a multisite cancer susceptibility gene. Three founder alleles are present in Poland. Two of these result in a truncated CHEK2 protein, and the other is a missense substitution of an isoleucine for a threonine. We ascertained the prevalence of each of these alleles in 4,008 cancer cases and 4,000 controls, all from Poland. The majority of the common cancer sites were represented. Positive associations with protein-truncating alleles were seen for cancers of the thyroid (odds ratio [OR] 4.9; P=.0006), breast (OR 2.2; P=.02), and prostate (OR 2.2; P=.04). The missense variant I157T was associated with an increased risk of breast cancer (OR 1.4; P=.02), colon cancer (OR 2.0; P=.001), kidney cancer (OR 2.1; P=.0006), prostate cancer (OR 1.7; P=.002), and thyroid cancer (OR 1.9; P=.04). The range of cancers associated with mutations of the CHEK2 gene may be much greater than previously thought.     

The supply of breast/ovarian cancer genetic susceptibility tests in France

One example of the recent advances of scientific research on the human genome is the identification of two susceptibility genes to breast/ovarian cancer, BRCA1 and BRCA2, making possible the introduction in medical practices of genetic testing to detect patients with an increased risk of developing such cancers. In this context of diffusion, two surveys were carried out to appraise the activity profiles in 1998 and in 2001 of all the different participants in those new medical practices in France, physicians in charge of genetic counselling, medical centres where consultations take place and laboratories. Results show that over the period 1998-2001, few changes occurred, mainly the reduction of the average waiting time to get the result of a genetic test, the increase in the annual number of BRCA2 families identified to a level similar to the one of BRCA1 and the automation of the biological analyses without noting a considerable increase in the annual output of laboratories till 2001 however. This surprising moderate evolution must be connected to the existence of some particular external factors making the framework of the development of these new medical and biological practices and their future really uncertain. The diffusion of BRCA1/2 genetic testing has been carried out facing the traditional difficulties of any innovating activities, but also the uncertainties related to intellectual property rights on genes and the reimbursement of genetic counselling and biological testing. These uncertainties have certainly restrained the pace of change as many actors in this field have opted for a wait and see strategy bearing in mind the possible future constraints imposed to their future activity, especially if European patents on the BRCA1/2 genes are finally granted by the European patent office (EPO).     

p53 gene status and chemosensitivity in ovarian cancer.

Recent studies suggest that drug induced apoptosis relates to the sensitivity. p53 gene, which has a pivotal role in inducing apoptosis, frequently mutates in ovarian cancer. Therefore, p53 gene status and chemosensitivity in epithelial ovarian cancer is discussed. Nonresponders to chemotherapy had mutations of the p53 gene more frequently (83% for nonresponders vs. 16% for responders) in patients with epithelial ovarian cancer undergoing platinum-base chemotherapy. Apoptotic index was significantly greater in tumors with wild-type p53 gene than those without the gene. p53 gene transduction markedly enhanced the sensitivity to cisplatin (CDDP) and CDDP-induced apoptosis, but did not affect the sensitivity to paclitaxel (PTX) nor PTX-induced apoptosis in ovarian cancer cells without p53 gene. The combination treatment with a recombinant adenovirus carrying a wild-type p53 gene (AxCAp53) and CDDP significantly suppressed tumor growth of ovarian cancer cells with and without p53 gene, compared with a single treatment of either AxCAp53 or CDDP in ovarian cancer xenograft. Apoptotic index was significantly higher and proliferating cell nuclear antigen labeling index was relatively lower in an ovarian cancer xenograft without p53 gene receiving combination treatment, compared with a single treatment of either CDDP or AxCAp53, suggesting that the transduction of p53 gene induces apoptosis, but does not enhance the DNA repair system. A significant survival advantage was observed in the combination treatment compared with other treatments in carcinoma peritonitis models. In conclusion, p53 gene status contributes the sensitivity to CDDP in ovarian cancer. Additionally, combination treatment of p53 gene transduction and CDDP may be an effective therapeutic modality for ovarian cancer without wild-type p53 gene.     

鲍曼不动杆菌的临床分布及药物敏感性结果分析

目的了解鲍曼不动杆菌的临床分布及药物敏感性分析。方法收集2004年5月至2006年5月抚顺市中心医院住院及门诊患者的临床标本,从中分离鲍曼不动杆菌。质控菌株:大肠埃希菌ATCC 25922,铜绿假单胞菌ATCC 27853,采用美国BD公司生产的凤凰微生物鉴定/药敏分析仪,对62株鲍曼不动杆菌进行鉴定和药物敏感测定并分析其临床分布。结果62株鲍曼不动杆菌感染率高的有呼吸病房22例(35.5%),干部病房14例(22.6%),标本类型以痰为主52例(83.9%)。药敏监测该细菌对17种抗生素的耐药情况为亚胺培南、美洛培南、氨苄西林/舒巴坦、左氧氟沙星的敏感率较高,分别为100%、100%、75.8%、70.9%。有头孢唑林、氨苄西林、奥格门丁、氨曲南耐药率为90.3%、88.7%、80.6%、77.4%。结论鲍曼不动杆菌最有效的抗生素是亚胺培南、美洛培南,一旦临床发生感染,应及时调整和选用合理抗生素治疗,避免滥用抗生素,防止耐药菌株的产生,提高临床治愈率。     

Role of microRNAs in ovarian cancer pathogenesis and potential clinical implications

Despite important improvements over the past two decades, the overall cure rate of epithelial ovarian cancer (EOC) remains only ～30%. Although much has been learned about the proteins and pathways involved in early events of malignant transformation and drug resistance, a major challenge still remaining is the identification of markers for early diagnosis and prediction of response to chemotherapy.Recently, it has become clear that alterations in the expression of microRNAs (miRNAs) contribute to the pathogenesis and progression of several human malignancies. In this review we discuss current data concerning the accumulating evidence of the role of miRNAs in EOC pathogenesis and tumor characterization; their dysregulated expression in EOC; and their still undefined role in diagnosis, prognosis and prediction of response to therapy. The most frequently deregulated miRNAs are members of the let-7 and miR-200 families, the latter involved in epithelial-to-mesenchymal transition (EMT). EMT is part of normal ovarian surface epithelium physiology, being the key regulator of the post-ovulatory repair process, and failure to undergo EMT may be one of the events leading to transformation. A general down-modulation of miRNA expression is observed in EOC compared to normal tissue. However, a clear consensus on the miRNA signatures associated with prognosis or prediction of response to therapy has not yet been reached.