Antioxidant Vitamins Intake, Ataxia Telangiectasia Mutated (ATM) Genetic Polymorphisms, and Breast Cancer Risk

Identification of the genetic basis of pediatric neurogenetic disorders at a tertiary referral hospital in Indonesia: Contribution of whole exome sequencing

BACKGROUND

Neurogenetic disorders (NGDs) are complex Mendelian disorders that affect the neurological system. A molecular diagnosis will provide more information about pathophysiology, prognosis, and therapy, including future genetic therapy options. Whole-Exome Sequencing (WES) can rapidly discover the genetic basis in NGDs.

OBJECTIVE

The purpose of this study was to assess the WES results and its value in diagnosing pediatric NGDs, especially those with unspecified clinical features.

METHODS

A retrospective chart review was performed from May 2021- February 2023 in Dr. Sardjito General Hospital, a tertiary referral hospital in Yogyakarta, Indonesia. WES proband only was conducted on children aged 0 to 17 years old who met one or more of the following criteria: (1) epileptic encephalopathy and familial epilepsy; (2) complex neurodevelopmental phenotypes; (3) leukodystrophy; (4) movement disorders; and (5) neurocutaneous disorder. The WES was conducted in the certified laboratory, 3Billion, in Seoul, Korea.

RESULTS

The diagnosis yield of WES in our study was 45% (9/20). We identified nine positive results, including eight pathogenic single nucleotide variants (SNVs) in 8 genes (KCNQ2, ARSA, UBE3A, IRF2BPL, ATM, MECP2, TSC2, and NF1), and one variant with uncertain significance (VUS) in the ADK gene that has not been able to explain the observed clinical features. Of the nine patients with positive WES results, five had missense mutations, three frameshift mutations, and one nonsense mutation. Additionally, we identified two suggestive copy number variants (CNVs) in 15q11.2q13.1 and 1p31.3.

CONCLUSIONS

Whole-Exome Sequencing is an essential diagnostic tool for pediatric NGDs, especially those with unspecified clinical features. It ends multi-year diagnostic odysseys, provides personalized medicine therapy, and optimizes genetic counselling for these families.

Association of folate intake and plasma folate level with the risk of breast cancer: a dose-response meta-analysis of observational studies

Epidemiological studies showing the correlation between folate and the breast cancer risk have revealed inconsistent results. Hence, we conducted a dose-response meta-analysis of observational studies to obtain more reliable conclusions. We searched PubMed and Embase for studies published before April 2019 and identified 39 studies on folate intake and 12 studies on plasma folate level. The combined odds ratios (ORs) and 95% confidence intervals (CIs) were extracted to estimate the breast cancer risk. Folate intake was inversely correlated with the breast cancer risk when the highest and lowest categories (OR = 0.85, 95% CI = 0.79-0.92) were compared, and the dose-response result showed that folate intake had a linear correlation with the breast cancer risk. Moreover, a higher folate intake correlated with a lower breast cancer risk in premenopausal women (OR = 0.80, 95% CI = 0.66-0.97), but not in postmenopausal women (OR = 0.94, 95% CI = 0.83-1.06). However, plasma folate levels were not correlated with the breast cancer risk (OR = 0.98, 95% CI = 0.82-1.17). Folate intake was negatively correlated with the breast cancer risk; however, its practical clinical significance requires further study. Furthermore, additional folate supplements should be considered carefully.

Association between single nucleotide polymorphisms of DNA damage response pathway genes and increased risk in breast cancer

Aim: We aimed to evaluate the role of selected single nucleotide polymorphisms of DNA damage response pathway genes in breast cancer (BC). Materials & methods: In present study, 500 BC patients and 500 controls was used to estimate the frequency of single nucleotide polymorphisms of DNA damage response pathway genes. Tetra-amplification refractory mutation system-PCR technique was used for screening of the six selected polymorphisms. Results: Logistic regression analysis showed that heterozygous mutant genotype of rs1800057 (p < 0.0001) and homozygous mutant genotype of rs1801516 (p < 0.0001) was associated with significant increased risk of BC. In the ATR gene, heterozygous mutant genotype of rs2227931 (p < 0.0001) was associated with significant increased risk of BC. However, significant decreased risk of BC was found associated with heterozygous mutant genotype of rs2227928 (p < 0.0002) and homozygous mutant genotype of rs2229032 (p < 0.0001) in patients compared with controls. Conclusion: The present results showed that alteration in DNA damage response pathway gene (ATM & ATR) results in increased BC risk.

The crosstalk between trace elements with DNA damage response, repair, and oxidative stress in cancer

DNA damage response (DDR) is a regulatory system responsible for maintaining genome integrity and stability, which can sense and transduce DNA damage signals. The severity of damage appears to determine DDRs, which can include damage repair, cell-cycle arrest, and apoptosis. Furthermore, defective components in DNA damage and repair machinery are an underlying cause for the development and progression of various types of cancers. Increasing evidence indicates that there is an association between trace elements and DDR/repair mechanisms. In fact, trace elements seem to affect mediators of DDR. Besides, it has been revealed that oxidative stress (OS) and trace elements are associated with cancer development. In this review, we discuss the role of some critical trace elements in the risk of cancer. In addition, we provide a brief introduction on DDR and OS in cancer. Finally, we will further review the interactions between some important trace elements including selenium, zinc, chromium, cadmium, and arsenic, and DDR, and OS in cancer.

The association of single nucleotide polymorphism rs189037C>T in ATM gene with coronary artery disease in Chinese Han populations: A case control study

Accumulated evidence has indicated that ataxia telangiectasia mutated (ATM) is closely related to atherosclerosis and cardiovascular diseases. So we aimed to examine potential association between a gene variant [single nucleotide polymorphisms (SNPs), i.e., rs189037C>T] in the promoter of ATM gene and coronary artery disease (CAD) in Chinese Han populations.In this hospital-based case-control study, a total of 1308 participants were divided into CAD group (652 patients) and control group (656 subjects) after performing coronary angiography. The SNP rs189037 was genotyped by using polymerase chain reaction-restriction fragment length polymorphism.The distribution of rs189037 genotypes and alleles showed a significant difference between CAD and control subjects (genotypes: P = .032; alleles: P = .028). The percentage of the TT genotype is much higher in control group than that in CAD group (22.0% vs 16.3%, P = .009). After adjustment of the major confounding factors, such difference remained significant (OR = 0.62, 95% CI = 0.43-0.89, P = .010). After analyzing data from different groups divided by genders and smoking status respectively, we found that the protective effect of TT genotype on CAD was significant in males (P = .007) and smokers (P = .031). The difference remained statistically significant after multivariate adjustment (adjusted in males: OR = 0.60, 95% CI = 0.38-0.93, P = .022; adjusted in smokers: OR = 0.47, 95% CI = 0.27-0.81, P = .006).Our study suggests that ATM rs189037 polymorphism is associated with CAD in Chinese Han populations. The TT genotype of rs189037 seems to be associated with a lower risk of CAD and a protective genetic marker of CAD, especially in males and smokers.

Association between ATM gene polymorphisms, lung cancer susceptibility and radiation-induced pneumonitis: a meta-analysis

BACKGROUND

Previous studies have suggested that DNA double-strand break (DSB) repair is an important protective pathway after damage. The ataxia telangiectasia mutated (ATM) gene plays an important role in the DNA DSB repair pathway. DNA damage is a major cytotoxic effect that can be caused by radiation, and the ability to repair DNA after damage varies among different tissues. Impaired DNA repair pathways are associated with high sensitivity to radiation exposure. Hence, ATM gene polymorphisms are thought to influence the risk of cancer and radiation-induced pneumonitis (RP) risk in cancer patients treated with radiotherapy. However, the results of previous studies are inconsistent. We therefore conducted this comprehensive meta-analysis.

METHODS

A systematic literature search was performed in the PubMed, Embase, China National Knowledge Internet (CNKI) and Wanfang databases to identify studies that investigated the association between the ATM gene polymorphisms and both lung cancer and RP radiotherapy-treated lung cancer (the last search was conducted on Dec.10, 2015). The odds ratio (OR) and 95% confidence interval (CI) were used to investigate the strength of these relationships. Funnel plots and Begg's and Egger's tests were conducted to assess the publication bias. All analyses were performed in STATA 13.0 software.

RESULTS

Ten eligible case-control studies (4731 cases and 5142 controls) on lung cancer susceptibility and four (192 cases and 772 controls) on RP risk were included. The results of the overall and subgroup analyses indicated that in the ATM gene, the rs189037 (-111G > A, -4519G > A), rs664677 (44831C > T, 49238C > T) and rs664143 (131,717 T > G) polymorphisms were significantly associated with lung cancer susceptibility (OR = 1.21, 95% CI = 1.04-1.39, P = 0.01; OR = 1.26, 95% CI = 1.06-1.49, P = 0.01; OR = 1.43, 95% CI = 1.15-1.78, P < 0.01). Additionally, the rs189037 variant was significantly associated with RP risk (OR = 1.74, 95% CI = 1.02-2.97, P = 0.04). No publication bias was found in the funnel plots, Begg's tests or Egger's tests.

CONCLUSIONS

The results indicate that the ATM rs189037, rs664677 and rs664143 gene polymorphisms are risk factors for lung cancer, while the ATM rs189037 variant was significantly associated with RP risk.

Polymorphism rs189037C > T in the promoter region of the ATM gene may associate with reduced risk of T2DM in older adults in China: a case control study

Background

Recent evidence indicates that ataxia telangiectasia mutated (ATM) is a cytoplasmic protein that involves in insulin signaling pathways. When ATM gene is mutated, this event appears to contribute to the development of insulin resistance and type 2 diabetes mellitus (T2DM). Up to date, little information about the relationship between ATM gene polymorphism and T2DM is available. This study aimed to explore potential association between a genetic variant [single nucleotide polymorphism (SNP), i.e. rs189037C > T] in the ATM promoter region and T2DM in older adults in China.

Methods

We conducted a 1:1 age- and sex-matched case-control study. It enrolled 160 patients including 80 type 2 diabetic and 80 nondiabetic patients who were aged 60 years and above. Genotyping of the polymorphism rs189037 in the promoter of the ATM gene was performed using polymerase chain reaction-restriction fragment length polymorphism. Chi-square test or Fisher’s exact test (when an expected cell count was <5) and unpaired Student’s t test were used for categorical and continuous variables, respectively. Logistic regression was used to estimate odds ratio (OR) and 95% confidence interval (CI) with adjustment for factors associated with T2DM.

Results

Significant association was found between the genotypes of the ATM rs189037 polymorphism and T2DM (P = 0.037). The frequency of CT genotype is much higher in patients without T2DM than in diabetics (60.0% versus 40.0%, P = 0.012). After adjustment of the major confounding factors, such difference remained significant (OR for non-T2DM is 2.62, 95%CI = 1.05–6.53, P = 0.038). Similar effect of CT genotype on T2DM was observed in male population (adjusted: OR = 0.27, 95%CI = 0.09–0.84, P = 0.024). In addition, the percentage of TT genotype in diabetics with coronary artery disease (CAD) was considerably lower than in those without CAD (17.9% versus 61.5%, P = 0.004).

Conclusions

Our study suggests that the ATM rs189037 polymorphism is associated with reduced risk of T2DM in older adult population in China. Specifically, CT heterozygote seems to be associated with a lower risk of T2DM than CC or TT genotype, especially in male older adults. Moreover, TT genotype may reduce the risk of CAD in diabetic patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-017-0446-z) contains supplementary material, which is available to authorized users.

Oxidative stress, mitochondrial abnormalities and antioxidant defense in Ataxia-telangiectasia, Bloom syndrome and Nijmegen breakage syndrome

Rare pleiotropic genetic disorders, Ataxia-telangiectasia (A-T), Bloom syndrome (BS) and Nijmegen breakage syndrome (NBS) are characterised by immunodeficiency, extreme radiosensitivity, higher cancer susceptibility, premature aging, neurodegeneration and insulin resistance. Some of these functional abnormalities can be explained by aberrant DNA damage response and chromosomal instability. It has been suggested that one possible common denominator of these conditions could be chronic oxidative stress caused by endogenous ROS overproduction and impairment of mitochondrial homeostasis. Recent studies indicate new, alternative sources of oxidative stress in A-T, BS and NBS cells, including NADPH oxidase 4 (NOX4), oxidised low-density lipoprotein (ox-LDL) or Poly (ADP-ribose) polymerases (PARP). Mitochondrial abnormalities such as changes in the ultrastructure and function of mitochondria, excess mROS production as well as mitochondrial damage have also been reported in A-T, BS and NBS cells. A-T, BS and NBS cells are inextricably linked to high levels of reactive oxygen species (ROS), and thereby, chronic oxidative stress may be a major phenotypic hallmark in these diseases. Due to the presence of mitochondrial disturbances, A-T, BS and NBS may be considered mitochondrial diseases. Excess activity of antioxidant enzymes and an insufficient amount of low molecular weight antioxidants indicate new pharmacological strategies for patients suffering from the aforementioned diseases. However, at the current stage of research we are unable to ascertain if antioxidants and free radical scavengers can improve the condition or prolong the survival time of A-T, BS and NBS patients. Therefore, it is necessary to conduct experimental studies in a human model.

Dexamethasone improves redox state in ataxia telangiectasia cells by promoting an NRF2-mediated antioxidant response

Ataxia telangiectasia (A-T) is a rare incurable neurodegenerative disease caused by biallelic mutations in the gene for ataxia-telangiectasia mutated (ATM). The lack of a functional ATM kinase leads to a pleiotropic phenotype, and oxidative stress is considered to have a crucial role in the complex physiopathology. Recently, steroids have been shown to reduce the neurological symptoms of the disease, although the molecular mechanism of this effect is largely unknown. In the present study, we have demonstrated that dexamethasone treatment of A-T lymphoblastoid cells increases the content of two of the most abundant antioxidants [glutathione (GSH) and NADPH] by up to 30%. Dexamethasone promoted the nuclear accumulation of the transcription factor nuclear factor (erythroid-derived 2)-like 2 to drive expression of antioxidant pathways involved in GSH synthesis and NADPH production. The latter effect was via glucose 6-phosphate dehydrogenase activation, as confirmed by increased enzyme activity and enhancement of the pentose phosphate pathway rate. This evidence indicates that glucocorticoids are able to potentiate antioxidant defenses to counteract oxidative stress in ataxia telangiectasia, and also reveals an unexpected role for dexamethasone in redox homeostasis and cellular antioxidant activity.

Haplotypes of the MTHFR gene are associated with an increased risk of breast cancer in a Han Chinese population in Gansu province

Elevated homocysteine levels are a risk factor for breast cancer, although the mechanism underlying this effect is unknown. Genome-wide association studies were used to systematically identify genetic variants which were significantly associated with the circulating homocysteine concentration. To examine the role of homocysteine-related variants in the occurrence of breast cancer, we investigated the association between these variants and breast cancer in a Han Chinese population. Five variants of genome-wide significant homocysteine-related genes were selected for the analysis in a case-control study, with a total of 487 patients with breast cancer and 605 controls. We found that none of the studied polymorphisms were related to the altered breast cancer risk. In the haplotypic analysis, the 5,10-methylenetetrahydrofolate reductase (MTHFR) haplotypes rs12085006A/rs1999594G/rs1801133C (OR = 3.44, 95% CI = 1.58-7.50, P = 0.0019) and rs12085006A/rs1999594G/rs1801133T (OR = 16.21, 95% CI = 2.19- 120.32, P = 0.0065) were significantly associated with an increased breast cancer risk when compared with the wild-type haplotype. Both of the risky MTHFR haplotypes were correlated with decreased MTHFR gene expression and elevated homocysteine concentrations, indicating a genetic component for hyperhomocysteinemia. The MTHFR haplotypes reconstructed with homocysteine-related variants were associated with the occurrence of breast cancer. This finding further emphasizes the importance of homocysteine metabolism genes in breast carcinogenesis and highlights the interplay of diet, genetics, and human cancers. © 2016 IUBMB Life, 68(7):526-534, 2016.

ATM gene single nucleotide polymorphisms predict regimen-related gastrointestinal toxicity in patients allografted after reduced conditioning

Polymorphisms of genes involved in innate and adaptive immunity have become an object of major interest in regard to hematopoietic stem cell transplantation (HSCT) complications. Regimen-related gastrointestinal toxicity (RR-GIT) is the dominant complication during the pre-engraftment period and has been linked to increased risk of graft-versus-host disease (GVHD) development. According to our hypothesis, functional variants of genes participating in DNA damage response (DDR) may have an impact on the extent of tissue damage caused by the conditioning regimen. In our single-center study, we analyzed 62 patients who underwent HSCT from HLA-identical donors after reduced conditioning. The patients were genotyped for 5 single nucleotide polymorphisms (SNPs, rs4585 T/G, rs189037 A/G, rs227092 T/G, rs228590 C/T, and rs664677 T/C) of the ATM gene-the essential member of the DDR pathways, using allele-specific matrix-assisted laser desorption/ionization, time-of-flight (MALDI-TOF) mass spectrometry assay. Because of almost absolute linkage disequilibrium observed among all 5 SNPs, association of 2 major ATM haplotypes (ATM1/ATM2) with RR-GIT and acute GVHD (aGVHD) was analyzed. Importantly, the univariate and multivariate analysis showed that patients homozygous for ATM2 haplotype (rs4585*T, rs189037*A, rs227092*T, rs228590*C, and rs664677*T) are more likely to suffer from high-grade RR-GIT than ATM1 homozygous patients. The association with aGVHD was not significant. To our knowledge, this is the first report showing the ATM gene variability in relation to RR-GIT in the allogeneic HSCT setting.

Single nucleotide polymorphisms of ataxia telangiectasia mutated and the risk of papillary thyroid carcinoma

Genetic factors associated with susceptibility to papillary thyroid carcinoma (PTC) are not well known. We evaluated the association between single nucleotide polymorphisms (SNPs) of ataxia telangiectasia mutated (ATM) and the risk of PTC. A total of 437 histologically confirmed PTC cases and 184 cancer-free controls without thyroid nodules were recruited. Genotypes with respect to five ATM SNPs (rs189037, rs664677, rs373759, rs664143, and rs4585) were determined by the TaqMan assay, and odds ratios and 95% confidence intervals were obtained by logistic regression analysis. Linkage disequilibria and haplotypes were examined from the genotype data. When evaluated separately the genotype distributions of the five ATM SNPs were similar in the PTC cases and controls. Three ATM SNPs (rs373759, rs664143, and rs4585) were found to be in strong linkage disequilibrium (D' = 1.00, P < 0.001). When the three haplotypes (C-A-G), (T-G-T), and (C-G-T) of these three ATM SNP sites were analyzed, ATM haplotype (C-G-T) +/- was associated with a lower risk of PTC than ATM haplotype (C-G-T) -/- (P = 0.03) after adjusting for age and gender. Our results suggest that genetic polymorphisms of ATM may play an important role in the development of thyroid cancer in the Korean population.

Folate intake and the risk of breast cancer: a systematic review and meta-analysis

There is conflicting epidemiological evidence on the role of folate and breast cancer risk. We conducted a systematic review and quantitative meta-analysis of folate intake and folate blood levels and the risk of breast cancer. Four electronic databases (Medline, PubMed, Embase, and Current Contents Connect) were searched to April 11, 2014, with no language restrictions for observational studies that measured folate intake or blood levels and the risk of breast cancer. The meta-analysis of dietary folate intake comprising 36 studies with 34,602 cases, and a total sample size of 608,265 showed a decreased risk of breast cancer, with an odds ratio (OR) of 0.84 [95 % confidence interval (CI) 0.77-0.91]. When stratified by menopausal status and by study design, none of the meta-analyses of prospective studies showed any statistically significant decrease in the risk of breast cancer. The meta-analysis of total folate showed no statistically significant association with breast cancer OR of 0.98 (95 % CI 0.91-1.07). There was no significant association between either dietary or total folate intake and breast cancer when stratified by hormonal receptor status. The meta-analysis of blood folate levels found no significant association with the risk of breast cancer, with an OR of 0.86 (95 % CI 0.60-1.25). Breast cancer does not appear to be associated with folate intake, and this did not vary by menopausal status or hormonal receptor status. Folate blood levels also do not appear to be associated with breast cancer risk.

Higher dietary folate intake reduces the breast cancer risk: a systematic review and meta-analysis

Background:

Many epidemiological studies have investigated the association between folate intake, circulating folate level and risk of breast cancer; however, the findings were inconsistent between the studies.

Methods:

We searched the PubMed and MEDLINE databases updated to January, 2014 and performed the systematic review and meta-analysis of the published epidemiological studies to assess the associations between folate intake level, circulating folate level and the overall risk of breast cancer.

Results:

In all, 16 eligible prospective studies with a total of 744 068 participants and 26 205 breast cancer patients and 26 case–control studies with a total of 16 826 cases and 21 820 controls that have evaluated the association between folate intake and breast cancer risk were identified. Pooled analysis of the prospective studies and case–control studies suggested a potential nonlinearity relationship for dietary folate intake and breast cancer risk. Prospective studies indicated a U-shaped relationship for the dietary folate intake and breast cancer risk. Women with daily dietary folate intake between 153 and 400 μg showed a significant reduced breast cancer risk compared with those <153 μg, but not for those >400 μg. The case–control studies also suggested a significantly negative correlation between the dietary folate intake level and the breast cancer risk. Increased dietary folate intake reduced breast cancer risk for women with higher alcohol intake level, but not for those with lower alcohol intake. No significant association between circulating folate level and breast cancer risk was found when the results of 8 identified studies with 5924 participants were pooled.

Conclusions:

Our studies suggested that folate may have preventive effects against breast cancer risk, especially for those with higher alcohol consumption level; however, the dose and timing are critical and more studies are warranted to further elucidate the questions.

Redox processes in neurodegenerative disease involving reactive oxygen species

Much attention has been devoted to neurodegenerative diseases involving redox processes. This review comprises an update involving redox processes reported in the considerable literature in recent years. The mechanism involves reactive oxygen species and oxidative stress, usually in the brain. There are many examples including Parkinson’s, Huntington’s, Alzheimer’s, prions, Down’s syndrome, ataxia, multiple sclerosis, Creutzfeldt-Jacob disease, amyotrophic lateral sclerosis, schizophrenia, and Tardive Dyskinesia. Evidence indicates a protective role for antioxidants, which may have clinical implications. A multifaceted approach to mode of action appears reasonable.

The association between ATM IVS 22-77 T>C and cancer risk: a meta-analysis

Background and Objectives

It has become increasingly clear that ATM (ataxia-telangiectasia-mutated) safeguards genome stability, which is a cornerstone of cellular homeostasis, and ATM IVS 22-77 T>C affects the normal activity of ATM proteins. However, the association between the ATM IVS 22-77 T>C genetic variant and cancer risk is controversial. Therefore, we conducted a systematic meta-analysis to estimate the overall cancer risk associated with the polymorphism and to quantify any potential between-study heterogeneity.

Methods

A total of nine studies including 4,470 cases and 4,862 controls were analyzed for ATM IVS 22-77 T>C association with cancer risk in this meta-analysis. Heterogeneity among articles and their publication bias were also tested.

Results

Our results showed that no association reached the level of statistical significance in the overall risk. Interestingly, in the stratified analyses, we observed an inverse relationship in lung and breast cancer.

Conclusion

Further functional research on the ATM mechanism should be performed to explain the inconsistent results in different cancer types.

Association between ATM polymorphisms and cancer risk: a meta-analysis

To date, epidemiological studies have assessed the association between Ataxia-telangiectasia mutated (ATM) gene polymorphisms and cancer risk, including lung cancer, breast cancer, glioma and pancreatic cancer. However, the results of these studies remain controversial. We aimed to examine the associations between two SNPs (rs664143 and rs664677) and cancer risk by conducting a meta-analysis of case-control studies. A total of 12 publications were included in this meta-analysis, 8 for rs664143 and 7 for rs664677. Overall, rs664143 heterozygote carriers turned out to be associated with cancer risk (OR = 1.18, 95% CI 1.02-1.36). In the subgroup analysis by cancer type, we observed that the ATM rs664143 polymorphism was significantly associated with lung cancer risk (GA vs. GG: OR = 1.48, 95% CI 1.18-1.85, AA vs. GG: OR = 1.51, 95% CI 1.18-1.93) and rs664677 polymorphism was associated with decreased lung cancr risk and increased breast cancer risk (for lung cancer: TC vs. TT: OR = 0.76, 95% CI 0.62-0.92, CC vs. TT: OR = 0.80, 95% CI 0.64-0.99 and for breast cancer: TC vs. TT: OR = 1.42, 95% CI 1.17-1.73, CC vs. TT: OR = 1.51, 95% CI 1.21-1.87). In the subgroup analysis by region, we also observed that individuals with ATM rs664143 GA or AA genotype had an obvious increased cancer risk among Asian people (GA vs. GG: OR = 1.40, 95% CI 1.20-1.63, AA vs. GG: OR = 1.37, 95% CI 1.16-1.62). In conclusion, ATM rs664143 polymorphism was associated with cancer susceptibility. ATM rs664143 polymorphism was significantly associated with lung cancer risk. ATM rs664677 polymorphism was associated with decreased lung cancer risk as well as increased breast cancer risk.

Serum total oxidant/antioxidant status and trace element levels in breast cancer patients

BACKGROUND

Oxidative stress and trace elements have been implicated in the development of breast cancer. However, how they contribute to the pathogenesis of the disease and the relationship between them remain unclear. In addition, most previous studies detecting one or a few oxidant/antioxidant markers failed to consider the overall oxidant/antioxidant status of the subjects. This study was designed to address this and to investigate the association between oxidative status and trace elements in the pathogenesis of breast cancer.

METHODS

Fifty-six patients with breast carcinoma at different clinical stages, 32 patients with benign breast tumor, and 20 healthy subjects (controls) were recruited into this study. Their serum total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), and levels of Cu, Zn, Fe, Se, Mg, and Mn were measured.

RESULTS

Levels of TAS, TOS, OSI, and trace elements significantly differed between the study groups. Among subgroups of patients with different clinical stages of breast cancer, the levels of all the trace elements except Zn were similar, whereas TAS, TOS, and OSI levels were all significantly different. There were significant correlations between oxidative stress parameters and levels of trace elements in patients with breast carcinoma but not in patients with benign breast tumor or in the healthy controls.

CONCLUSIONS

Disturbed oxidative stress status and trace element levels may contribute to the pathogenesis of breast tumors. TAS, TOS, and OSI may be useful biomarkers for monitoring the clinical status of breast cancer.

Common genetic polymorphisms of microRNA biogenesis pathway genes and risk of breast cancer: a case-control study in Korea

Recent compelling evidence indicates that mutation, aberrant expression, and dysregulation of microRNA (miRNA) biogenesis are implicated in cancer development and progression. Based on the important role of miRNA biogenesis pathway in carcinogenesis, we hypothesized that genetic variations in this pathway genes may play a role as susceptibility factors for breast cancer. To test this hypothesis, we investigated the associations between 41 single nucleotide polymorphisms (SNPs) in 14 genes involved in miRNA biogenesis pathway and breast cancer risk in a case-control study of 559 Korean breast cancer cases and 567 controls frequency-matched by age. In all women, 3 SNPs (AGO1 rs595055, AGO2 rs3864659, and p68 rs1991401) were significantly associated with breast cancer risk. In stratified analysis by menopausal status, altered risk associations were observed for 7 SNPs in postmenopausal breast cancer. When subjects were grouped by the number of high-risk genotypes, we found a progressive increase in gene-dosage effect (P (trend) = 9.46E-7). The protective effects of AGO2 rs3864659 and HIWI rs11060845 were more pronounced in progesterone receptor-positive (PR+) cancer than in progesterone receptor-negative (PR-) cancer (odds ratio (OR), 0.50; 95% confidence interval (CI), 0.30-0.84 vs. OR, 0.94; 95% CI, 0.60-1.84; P (heterogeneity) = 0.04 and OR, 0.57; 95% CI, 0.37-0.88 vs. OR, 0.97; 95% CI, 0.65-1.44; P (heterogeneity) = 0.02, respectively), and the DROSHA rs644236 had stronger association with estrogen receptor-negative (ER-) cancer than for estrogen receptor-positive (ER+) cancer (OR, 1.39; 95% CI, 1.08-1.78 vs. OR, 1.05; 95% CI, 0.85-1.29; P (heterogeneity) = 0.04). Our results suggest that genetic variants in miRNA biogenesis pathway genes may be associated with breast cancer risk, and the modifiable effects might be different according to the menopausal status and hormone receptor status.