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1.  Genetic modulation of the interleukin 6 (IL-6) system in patients with advanced gastric cancer: a background for an alternative target therapy 
BMC Cancer  2014;14:357.
IL-6 triggers oncogenic/angiogenic signals and the cytokine-dependent pro-cachexia cascade. The prognostic role of the functional IL-6 (promoter) rs1800795 and the IL-6R (receptor) rs8192284 single nucleotide polymorphisms (SNP) was studied in patients with advanced gastric cancer treated with palliative chemotherapy.
One-hundred-sixty-one patients were genotyped for rs1800795 and rs8192284 SNPs using polymerase chain reaction based restriction fragment length polymorphism (PCR-RFLP) analysis assay. These results were studied for association with overall survival (OS).
In 161 assessable patients, frequencies of rs1800795 G/G, G/C and C/C genotypes were 46%, 42% and 12%, respectively. Frequencies of rs8192284 A/A, A/C and C/C genotypes were 36%, 45% and 19%, respectively. Carriers of the rs1800795 G/G and rs8192284 C/C genotypes showed the worst OS. In the multivariate model, rs1800795 G/G (1.69 hazard ratio; 95% confidence interval 1.18-2.42), and rs8192284 C/C (1.78 hazard ratio; 95% confidence interval 1.12-2.83) confirmed an adverse prognostic impact.
In this population, genetic variants that up-regulate the IL-6 system showed impact on OS. This findings sustain the hypothesis that anti-IL-6 compounds deserve clinical studies as novel therapeutics in the palliative treatment of cancer patients.
PMCID: PMC4046495  PMID: 24886605
Interleukin 6; Gastric cancer; Survival; Prognosis; Chemotherapy; Polymorphism
2.  Impact of Interleukin-6 –174 G>C Gene Promoter Polymorphism on Neuroblastoma 
PLoS ONE  2013;8(10):e76810.
Common variants in DNA may predispose to onset and progression of neuroblastoma (NB). The genotype GG of single nucleotide polymorphism (SNP) rs1800795 (−174 G>C) in interleukin (IL)-6 promoter has been associated with lower survival of high-risk NB.
To evaluate the impact of IL-6 SNP rs1800795 on disease risk and phenotype, we analyzed 326 Italian NB patients and 511 controls. Moreover, we performed in silico and quantitative Real Time (qRT)-PCR analyses to evaluate the influence of the SNP on gene expression in 198 lymphoblastoid cell lines (LCLs) and in 31 NB tumors, respectively. Kaplan-Meier analysis was used to verify the association between IL-6 gene expression and patient survival. We found that IL-6 SNP is not involved in susceptibility to NB development. However, our results show that a low frequency of genotype CC is significantly associated with a low overall survival, advanced stage, and high-risk phenotype. The in silico (p = 2.61×10−5) and qRT-PCR (p = 0.03) analyses showed similar trend indicating that the CC genotype is correlated with increased level of IL-6 expression. In report gene assay, we showed that the −174 C variant had a significantly increased transcriptional activity compared with G allele (p = 0.0006). Moreover, Kaplan-Meier analysis demonstrated that high levels of IL-6 are associated with poor outcome in children with NB in two independent gene expression array datasets.
The biological effect of SNP IL-6–174 G>C in relation to promotion of cancer progression is consistent with the observed decreased survival time. The present study suggests that SNP IL-6–174 G>C may be a useful marker for NB prognosis.
PMCID: PMC3804531  PMID: 24204677
Neuroscience letters  2011;506(2):312-316.
The −174G>C (rs1800795) single nucleotide polymorphism (SNP) in the promoter of the interleukin-6 (IL6) gene and the 1730G>A (rs4986938) SNP in the estrogen receptor beta (ESR2) may influence the risk of Parkinson’s Disease (PD). We investigated these SNPs in 380 unrelated US Caucasian PD cases and 522 controls, including 452 individuals of Ashkenazi Jewish (AJ) origin (260 PD, 192 controls). The G allele of the −174G>C SNP was more common in AJ PD cases (p=0.033) as well as in Non-Jewish (NJ) men with PD (p=0.022). The GG genotype increased the risk of PD by over two fold in NJ men (OR=2.11, 95%CI: 1.14–3.89, p=0.017), and approached significance in the total AJ group with PD (OR=1.42, 95%CI: 0.97–2.06, p=0.067). The A allele of the ESR2 1730G>A SNP was associated with a decreased risk for PD in AJ women, and in this group, having the AA genotype decreased the risk of PD by half (OR=0.45, 95%CI: 0.22–0.92, p=0.029). Our data supports a role for the IL6 −174G>C G allele in AJ individuals overall. In NJ Caucasians, this role appears to be gender mediated. In both groups, the effect is independent from ESR2 1730G>A. A separate association for the ESR2 1730G>A SNP was found exclusively in women of AJ descent. Other polymorphisms in tight linkage disequilibrium with the SNP differentially influencing expression, ethnic differences in allele distribution, and gender differences in genetic load related to PD, may underlie our findings. Larger studies in diverse populations, including analysis of surrounding regions are recommended.
PMCID: PMC3249002  PMID: 22155094
Interleukin 6; Parkinson’s disease; estrogen receptor; polymorphism; inflammation; gender
4.  Proinflammatory gene polymorphisms are potentially associated with Korean non-Sjogren dry eye patients 
Molecular Vision  2011;17:2818-2823.
To determine whether proinflammatory cytokine genes were potential susceptibility candidate genes for Korean patients with non-Sjogren dry eye, we investigated the association of the interleukin 1 beta (IL1B), interleukin 6 (IL6), and interleukin 6 receptor (IL6R) variations with this disease in Korean patients.
Genomic DNA was extracted from blood samples of unrelated non-Sjogren dry eye patients and healthy control individuals who visited the Eye Center and Health Promotion Center of St. Mary’s Hospital in Seoul, Korea. For screening genetic variations in proinflammatory cytokine genes, the 511 (rs16944) and 31 (rs1143627) positions in the promoter region of IL1B, rs1143634 in exon 5 of IL1B, rs1800795 of the IL6 promoter, and Asp358Ala (rs8192284) of IL6R were genotyped using the polymerase chain reaction, restriction fragment length polymorphisms, and direct sequencing.
Among the polymorphisms, rs1143634 (F105F) in exon 5 of IL1B was significantly different between the patient and control groups. The frequency of the C/T genotype in dry eye patients was decreased relative to that of the control subjects (10.4% versus 3.9%, p=0.043, OR=3.337). For the IL6R gene, the genotypic and allelic distribution of rs8192284 was different between the dry eye patients and the controls: CC genotype (p=0.017, OR=2.12) and C allele (OR=1.26).
This is the first report of genetic variation screening of proinflammatory cytokine genes in Korean non-Sjogren dry eye patients. It is suggested that rs1143634 of IL1B and rs8192284 of IL6R act as susceptibility variations in Korean non-Sjogren dry eye patients.
PMCID: PMC3224841  PMID: 22128229
5.  IL6 genotype, tumour ER-status, and treatment predicted disease-free survival in a prospective breast cancer cohort 
BMC Cancer  2014;14(1):759.
In breast cancer, high levels of the inflammatory cytokine interleukin-6 (IL-6) have been associated with disease-free survival and treatment resistance. Increased serum levels of IL-6 have been correlated with increased levels of NF-κβ and aromatase expression in adipose tissue. Several IL6 single nucleotide polymorphisms have been associated with breast cancer prognosis, but the impact may differ depending on tumour oestrogen receptor (ER) status. This translational study investigated the association between IL6 genotypes, ER-status, and treatment on the risk of early events among breast cancer patients.
The study included 634 25- to 99-year-old primary breast cancer patients in Sweden from 2002–2008. Genotyped IL6 single nucleotide polymorphisms rs1800797, rs1800796, rs1800795, and rs2069849 were analysed separately and as diplotypes. Disease-free survival was assessed for 567 patients. Clinical data, patient-, and tumour-characteristics were obtained from questionnaires, patient charts, population registries, and pathology reports.
The median follow-up time was 5.1 years. IL6 diplotype was not associated with early events for all 567 patients, but AGCC/AGCC diplotype-carriers with ER-negative tumours had an increased risk, (adjusted Hazard Ratio (HR) = 5.91, 95% CI: 1.28–27.42). Any C-carriers (rs1800795) with ER-negative tumours had a higher risk of early events than GG-carriers with ER-negative tumours, (adjusted HR = 3.76, 95% CI: 1.05–13.43), particularly after radiotherapy (adjusted HR = 7.17, 95% CI: 1.16–32.28). Irrespective of ER-status, chemotherapy-treated Any C-carriers had a higher risk of early events than GG-carriers (adjusted HR = 3.42, 95% CI: 1.01–11.54).
The main finding of the present study was that IL6 genotype was strongly associated with early events among patients with ER-negative tumours, particularly among radiotherapy-treated patients, and among chemotherapy-treated patients irrespective of ER-status. The high risk for early events observed in these subgroups of patients suggests that combined information on IL6 genotype, tumour ER-status, and breast cancer treatment may represent a tool for identifying patients who require more personalised treatment.
Electronic supplementary material
The online version of this article (doi:10.1186/1471-2407-14-759) contains supplementary material, which is available to authorized users.
PMCID: PMC4198733  PMID: 25305747
Breast cancer; IL6; Oestrogen receptor; Chemotherapy; Radiotherapy; Treatment resistance
6.  Effect of interleukin-6 polymorphism on risk of preterm birth within population strata: a meta-analysis 
BMC Genetics  2013;14:30.
Because of the role of inflammation in preterm birth (PTB), polymorphisms in and near the interleukin-6 gene (IL6) have been association study targets. Several previous studies have assessed the association between PTB and a single nucleotide polymorphism (SNP), rs1800795, located in the IL6 gene promoter region. Their results have been inconsistent and SNP frequencies have varied strikingly among different populations. We therefore conducted a meta-analysis with subgroup analysis by population strata to: (1) reduce the confounding effect of population structure, (2) increase sample size and statistical power, and (3) elucidate the association between rs1800975 and PTB.
We reviewed all published papers for PTB phenotype and SNP rs1800795 genotype. Maternal genotype and fetal genotype were analyzed separately and the analyses were stratified by population. The PTB phenotype was defined as gestational age (GA) < 37 weeks, but results from earlier GA were selected when available. All studies were compared by genotype (CC versus CG+GG), based on functional studies.
For the maternal genotype analysis, 1,165 PTBs and 3,830 term controls were evaluated. Populations were stratified into women of European descent (for whom the most data were available) and women of heterogeneous origin or admixed populations. All ancestry was self-reported. Women of European descent had a summary odds ratio (OR) of 0.68, (95% confidence interval (CI) 0.51 – 0.91), indicating that the CC genotype is protective against PTB. The result for non-European women was not statistically significant (OR 1.01, 95% CI 0.59 - 1.75). For the fetal genotype analysis, four studies were included; there was no significant association with PTB (OR 0.98, 95% CI 0.72 - 1.33). Sensitivity analysis showed that preterm premature rupture of membrane (PPROM) may be a confounding factor contributing to phenotype heterogeneity.
IL6 SNP rs1800795 genotype CC is protective against PTB in women of European descent. It is not significant in other heterogeneous or admixed populations, or in fetal genotype analysis.
Population structure is an important confounding factor that should be controlled for in studies of PTB.
PMCID: PMC3639799  PMID: 23617681
Preterm birth; Preterm delivery; Premature birth; Premature delivery; Genetic polymorphism; Genetic variant; Single nucleotide polymorphism; SNP; Interleukin-6; Cytokine; Population structure; HapMap project; Phenotype heterogeneity
7.  Phenotype Restricted Genome-Wide Association Study Using a Gene-Centric Approach Identifies Three Low-Risk Neuroblastoma Susceptibility Loci 
PLoS Genetics  2011;7(3):e1002026.
Neuroblastoma is a malignant neoplasm of the developing sympathetic nervous system that is notable for its phenotypic diversity. High-risk patients typically have widely disseminated disease at diagnosis and a poor survival probability, but low-risk patients frequently have localized tumors that are almost always cured with little or no chemotherapy. Our genome-wide association study (GWAS) has identified common variants within FLJ22536, BARD1, and LMO1 as significantly associated with neuroblastoma and more robustly associated with high-risk disease. Here we show that a GWAS focused on low-risk cases identified SNPs within DUSP12 at 1q23.3 (P = 2.07×10−6), DDX4 and IL31RA both at 5q11.2 (P = 2.94×10−6 and 6.54×10−7 respectively), and HSD17B12 at 11p11.2 (P = 4.20×10−7) as being associated with the less aggressive form of the disease. These data demonstrate the importance of robust phenotypic data in GWAS analyses and identify additional susceptibility variants for neuroblastoma.
Author Summary
Neuroblastoma is the most common solid tumor outside the central nervous system and is accountable for 10% of the mortality rate of all children's cancers. It has distinctive clinical behaviors and is categorized into different risk groups: high-risk, intermediate-risk, and low-risk. Genome-wide association studies have reported a number of genetic variations predisposing to high-risk neuroblastoma. This study focuses on the low-risk neuroblastoma group and identifies four novel genes (DUSP12, DDX4, IL31RA, and HSD17B12) at three distinct genomic positions that harbor disease-causing variants. This study also reports several gene sets that are enriched in overall neuroblastoma as well as in both high-risk and low-risk groups. Also of importance is that this study adopts a new computational method that identifies genes, instead of only one single nucleotide polymorphism, as disease-causing variants. Shown to have superior power of detection genome-wide association signals for neuroblastoma, the methodology presented in this study has great potential applications in case-control association studies in other diseases.
PMCID: PMC3060064  PMID: 21436895
8.  CASP8 SNP D302H (rs1045485) Is Associated with Worse Survival in MYCN-Amplified Neuroblastoma Patients 
PLoS ONE  2014;9(12):e114696.
Neuroblastoma is a pediatric cancer that exhibits a wide clinical spectrum ranging from spontaneous regression in low-risk patients to fatal disease in high-risk patients. The identification of single nucleotide polymorphisms (SNPs) may help explain the heterogeneity of neuroblastoma and assist in identifying patients at higher risk for poor survival. SNPs in the TP53 pathway are of special importance, as several studies have reported associations between TP53 pathway SNPs and cancer. Of note, less than 2% of neuroblastoma tumors have a TP53 mutation at diagnosis.
Patients and Methods
We selected 21 of the most frequently studied SNPs in the TP53 pathway and evaluated their association with outcome in 500 neuroblastoma patients using TaqMan allelic discrimination assays.
Results and Conclusion
We investigated the impact of 21 SNPs on overall survival, event-free survival, age at diagnosis, MYCN status, and stage of the disease in 500 neuroblastoma patients. A missense SNP in exon 10 of the CASP8 gene SNP D302H was associated with worse overall and event-free survival in patients with MYCN-amplified neuroblastoma tumors.
PMCID: PMC4263607  PMID: 25502557
9.  Cytokine Genetic Variations and Fatigue Among Patients With Breast Cancer 
Journal of Clinical Oncology  2013;31(13):1656-1661.
Fatigue is a common adverse effect of cancer treatment and may persist for years after treatment completion. However, risk factors for post-treatment fatigue have not been determined. On the basis of studies suggesting an inflammatory basis for fatigue, this study tested the hypothesis that expression-regulating polymorphisms in proinflammatory cytokine genes would predict post-treatment fatigue in breast cancer survivors.
Patients and Methods
Women diagnosed with early-stage breast cancer (n = 171) completed questionnaires to assess fatigue and other behavioral symptoms (ie, depressive symptoms, memory complaints, sleep disturbance) and provided blood for genotyping within 3 months after primary treatment. Genomic DNA was extracted from peripheral-blood leukocytes and assayed for single nucleotide polymorphisms (SNPs) in the promoter regions of three cytokine genes: ILB −511 C>T (rs16944), IL6 −174 G>C (rs1800795), and TNF −308 G>A (rs1800629). An additive genetic risk score was computed by summing the number of high-expression alleles (zero, one, or two) across all three polymorphisms.
The genetic risk index was significantly associated with fatigue; as the number of high-expression alleles increased, so did self-reported fatigue severity (P = .002). Analyses of individual SNPs showed that TNF −308 and IL6 −174 were independently associated with fatigue (P = .032). The genetic risk index was also associated with depressive symptoms (P = .007) and memory complaints (P = .016).
These findings further implicate inflammatory processes as contributors to cancer-related fatigue and suggest a new strategy for identifying and treating patients at risk for this symptom based on genetic variants in proinflammatory cytokine genes.
PMCID: PMC3635681  PMID: 23530106
10.  Interleukin-6 gene (IL-6): a possible role in brain morphology in the healthy adult brain 
Cytokines such as interleukin 6 (IL-6) have been implicated in dual functions in neuropsychiatric disorders. Little is known about the genetic predisposition to neurodegenerative and neuroproliferative properties of cytokine genes. In this study the potential dual role of several IL-6 polymorphisms in brain morphology is investigated.
In a large sample of healthy individuals (N = 303), associations between genetic variants of IL-6 (rs1800795; rs1800796, rs2069833, rs2069840) and brain volume (gray matter volume) were analyzed using voxel-based morphometry (VBM). Selection of single nucleotide polymorphisms (SNPs) followed a tagging SNP approach (e.g., Stampa algorigthm), yielding a capture 97.08% of the variation in the IL-6 gene using four tagging SNPs.
Principal findings/results
In a whole-brain analysis, the polymorphism rs1800795 (−174 C/G) showed a strong main effect of genotype (43 CC vs. 150 CG vs. 100 GG; x = 24, y = −10, z = −15; F(2,286) = 8.54, puncorrected = 0.0002; pAlphaSim-corrected = 0.002; cluster size k = 577) within the right hippocampus head. Homozygous carriers of the G-allele had significantly larger hippocampus gray matter volumes compared to heterozygous subjects. None of the other investigated SNPs showed a significant association with grey matter volume in whole-brain analyses.
These findings suggest a possible neuroprotective role of the G-allele of the SNP rs1800795 on hippocampal volumes. Studies on the role of this SNP in psychiatric populations and especially in those with an affected hippocampus (e.g., by maltreatment, stress) are warranted.
PMCID: PMC3464888  PMID: 22695063
Genetics; Inflammation; Interleukin 6; Neuroprotection; Voxel-based morphometry
11.  A genome-wide association study identifies a susceptibility locus to clinically aggressive neuroblastoma at 6p22 
The New England journal of medicine  2008;358(24):2585-2593.
Neuroblastoma is a malignancy of the developing sympathetic nervous system that most commonly affects young children and is often lethal. The etiology of this embryonal cancer is not known.
We performed a genome-wide association study by first genotyping 1,032 neuroblastoma patients and 2,043 controls of European descent using the Illumina HumanHap550 BeadChip. Three independent groups of neuroblastoma cases (N=720) and controls (N=2128) were then genotyped to replicate significant associations.
We observed highly significant association between neuroblastoma and the common minor alleles of three single nucleotide polymorphisms (SNPs) within a 94.2 kilobase (Kb) linkage disequilibrium block at chromosome band 6p22 containing the predicted genes FLJ22536 and FLJ44180 (P-value range = 1.71×10-9-7.01×10-10; allelic odds ratio range 1.39-1.40). Homozygosity for the at-risk G allele of the most significantly associated SNP, rs6939340, resulted in an increased likelihood of developing neuroblastoma of 1.97 (95% CI 1.58-2.44). Subsequent genotyping of these 6p22 SNPs in the three independent case series confirmed our observation of association (P=9.33×10-15 at rs6939340 for joint analysis). Furthermore, neuroblastoma patients homozygous for the risk alleles at 6p22 were more likely to develop metastatic (Stage 4) disease (P=0.02), show amplification of the MYCN oncogene in the tumor cells (P=0.006), and to have disease relapse (P=0.01).
Common genetic variation at chromosome band 6p22 is associated with susceptibility to neuroblastoma.
PMCID: PMC2742373  PMID: 18463370
12.  Sequencing of the IL6 gene in a case–control study of cerebral palsy in children 
BMC Medical Genetics  2013;14:126.
Cerebral palsy (CP) is a group of nonprogressive disorders of movement and posture caused by abnormal development of, or damage to, motor control centers of the brain. A single nucleotide polymorphism (SNP), rs1800795, in the promoter region of the interleukin-6 (IL6) gene has been implicated in the pathogenesis of CP by mediating IL-6 protein levels in amniotic fluid and cord plasma and within brain lesions. This SNP has been associated with other neurological, vascular, and malignant processes as well, often as part of a haplotype block.
To refine the regional genetic association with CP, we sequenced (Sanger) the IL6 gene and part of the promoter region in 250 infants with CP and 305 controls.
We identified a haplotype of 7 SNPs that includes rs1800795. In a recessive model of inheritance, the variant haplotype conferred greater risk (OR = 4.3, CI = [2.0-10.1], p = 0.00007) than did the lone variant at rs1800795 (OR = 2.5, CI = [1.4-4.6], p = 0.002). The risk haplotype contains one SNP (rs2069845, CI = [1.2-4.3], OR = 2.3, p = 0.009) that disrupts a methylation site.
The risk haplotype identified in this study overlaps with previously identified haplotypes that include additional promoter SNPs. A risk haplotype at the IL6 gene likely confers risk to CP, and perhaps other diseases, via a multi-factorial mechanism.
PMCID: PMC3881497  PMID: 24314052
Cerebral palsy; Sanger sequencing; IL-6; Interleukin-6; Haplotype
13.  Copy number variation at 1q21.1 associated with neuroblastoma 
Nature  2009;459(7249):987-991.
Common copy number variations (CNVs) represent a significant source of genetic diversity, yet their influence on phenotypic variability, including disease susceptibility, remains poorly understood. To address this problem in cancer, we performed a genome-wide association study (GWAS) of CNVs in the childhood cancer neuroblastoma, a disease where SNP variations are known to influence susceptibility1,2. We first genotyped 846 Caucasian neuroblastoma patients and 803 healthy Caucasian controls at 550,000 single nucleotide polymorphisms, and performed a CNV-based test for association. We then replicated significant observations in two independent sample sets comprised of a total of 595 cases and 3,357 controls. We identified a common CNV at 1q21.1 associated with neuroblastoma in the discovery set, which was confirmed in both replication sets (Pcombined = 2.97 × 10−17; OR = 2.49, 95% CI: 2.02 to 3.05). This CNV was validated by quantitative PCR, fluorescent in situ hybridization, and analysis of matched tumor specimens, and was shown to be heritable in an independent set of 713 cancer-free trios. We identified a novel transcript within the CNV which showed high sequence similarity to several “Neuroblastoma breakpoint family” (NBPF) genes3,4 and represents a new member of this gene family (NBPFX). This transcript was preferentially expressed in fetal brain and fetal sympathetic nervous tissues, and expression level was strictly correlated with CNV state in neuroblastoma cells. These data demonstrate that inherited copy number variation at 1q21.1 is associated with neuroblastoma and implicate a novel NBPF gene in early tumorigenesis of this childhood cancer.
PMCID: PMC2755253  PMID: 19536264
14.  Genome-wide promoter methylation analysis in neuroblastoma identifies prognostic methylation biomarkers 
Genome Biology  2012;13(10):R95.
Accurate outcome prediction in neuroblastoma, which is necessary to enable the optimal choice of risk-related therapy, remains a challenge. To improve neuroblastoma patient stratification, this study aimed to identify prognostic tumor DNA methylation biomarkers.
To identify genes silenced by promoter methylation, we first applied two independent genome-wide methylation screening methodologies to eight neuroblastoma cell lines. Specifically, we used re-expression profiling upon 5-aza-2'-deoxycytidine (DAC) treatment and massively parallel sequencing after capturing with a methyl-CpG-binding domain (MBD-seq). Putative methylation markers were selected from DAC-upregulated genes through a literature search and an upfront methylation-specific PCR on 20 primary neuroblastoma tumors, as well as through MBD- seq in combination with publicly available neuroblastoma tumor gene expression data. This yielded 43 candidate biomarkers that were subsequently tested by high-throughput methylation-specific PCR on an independent cohort of 89 primary neuroblastoma tumors that had been selected for risk classification and survival. Based on this analysis, methylation of KRT19, FAS, PRPH, CNR1, QPCT, HIST1H3C, ACSS3 and GRB10 was found to be associated with at least one of the classical risk factors, namely age, stage or MYCN status. Importantly, HIST1H3C and GNAS methylation was associated with overall and/or event-free survival.
This study combines two genome-wide methylation discovery methodologies and is the most extensive validation study in neuroblastoma performed thus far. We identified several novel prognostic DNA methylation markers and provide a basis for the development of a DNA methylation-based prognostic classifier in neuroblastoma.
PMCID: PMC3491423  PMID: 23034519
15.  -174G/C polymorphism in the interleukin-6 promoter is differently associated with prostate cancer incidence depending on race 
Interleukin-6 (IL-6), a pro-inflammatory cytokine, is involved in prostate cancer progression, including androgen independence. Serum IL-6 levels also correlate with prostate tumor burden, prostate-specific antigen levels and metastasis. Since circulating cytokine levels vary considerably inter-individually, such variation could be linked to genetic factors, including genetic polymorphism. The -174G>C/rs1800795 polymorphism in the IL-6 promoter is functionally relevant in terms of transcriptional regulation and disease association. We investigated a possible association of the -174G/C polymorphism with prostate cancer. Since significant racial disparities exist in prostate cancer incidence, we also investigated this association between the -174G/C polymorphism and prostate cancer in Caucasians and African-Americans, separately. Direct sequencing of the PCR amplicon from genomic DNA was used for genotyping rs1800795 in all subjects [age-matched controls (N = 140) and prostate cancer patients (N = 164)]. Sample size and power was calculated using the PGA software. We found the GG genotype to be associated with increased risk of prostate cancer in Caucasian subjects, whereas the CC genotype was associated with increased risk in the African-American sample set. Such a dimorphic genotypic association with cancer and race is unique and suggests a complex gene-gene and gene-environment interaction.
PMCID: PMC4038121  PMID: 24446297
IL-6; Polymorphism; Prostate; Cancer; Disparities
16.  Insulin-like growth factor-1- and interleukin-6-related gene variation and risk of multiple myeloma 
Insulin-like growth factor (IGF)-1 and interleukin (IL)-6 promote the proliferation and survival of multiple myeloma cells. Variation in genes related to IGF-1 and IL-6 signaling may influence susceptibility to multiple myeloma. To assess their etiologic role, we examined the association of 70 tagging single nucleotide polymorphisms (SNP) in seven IGF-1 and three IL-6 pathway genes with multiple myeloma risk in two prospective cohorts, the Nurses' Health Study and Health Professionals Follow-up Study. Among participants who provided DNA specimens, we identified 58 women and 24 men with multiple myeloma and matched two controls per case. We used multivariable logistic regression models to assess the association of the SNPs or tagged haplotypes with multiple myeloma risk. Several SNPs had suggestive associations with multiple myeloma based on large odds ratios (OR), although corresponding omnibus p-values were not more than nominally significant (i.e., at p<0.05). These SNPs included rs1801278 in the gene encoding insulin receptor substrate-1 (IRS1; C/T v. C/C genotypes; OR=4.3, 95% confidence interval (CI)=1.5-12.1), and three IL-6 receptor SNPs: rs6684439 (T/T v. C/C: 2.9, 1.2-7.0), rs7529229 (C/C v. T/T; 2.5, 1.1-6.0), and rs8192284 (C/C v. A/A; 2.5, 1.1-6.0). Additional SNPs in genes encoding IGF-1, IGF binding protein-2, IRS2, and gp130 also demonstrated suggestive associations with multiple myeloma risk. We conducted a large number of statistical tests, and the findings may be due to chance. Nonetheless, the data are consistent with the hypothesis that IGF-1- and IL-6-related gene variation influences susceptibility to multiple myeloma and warrant confirmation in larger populations.
PMCID: PMC2661109  PMID: 19124510
multiple myeloma; genetic sceptibility; IGF-1; IL-6; epidemiology
17.  Interleukin and interleukin receptor gene polymorphisms and susceptibility to melanoma 
Melanoma research  2008;18(5):330-335.
Genetic variation in immune-regulating components such as cytokines may lead to interindividual differences in immunosuppression response and susceptibility to melanoma. We evaluated the associations between genetic variants in 5 interleukin (IL) and IL receptor genes (IL-4, IL-4R, IL-6, IL-6R, and IL-10) and the risk of melanoma. Twenty-five single nucleotide polymorphisms (SNPs) were selected that are functionally relevant or tagging SNPs of each gene. We conducted a nested case-control study of 219 female cases and 219 matched controls within the Nurses' Health Study. We observed that in the IL-6R gene, 4 SNPs in linkage disequilibrium were associated with an increased risk of melanoma. Three are located in introns (rs6684439, rs4845618, and rs4845622), and one is a nonsynonymous SNP in exon 9 (rs8192284 [Asp358Ala]). An elevated risk of melanoma was observed in the heterozygous groups of these SNPs with odds ratio of 1.74 ((95% confidence interval, 1.07, 2.81) for rs6684439, 1.72 (1.04, 2.84) for rs4845618, 1.69 (1.03, 2.75) for rs4845622, and 1.68 (1.04, 2.73) for rs8192284. But these associations were not observed in the homozygous variant group with odds ratios ranging from 0.93 to 1.03. We did not find significant results for the SNPs in the other 4 genes. These data suggest the involvement of IL-6R in melanoma development. Further studies are needed to confirm these findings.
PMCID: PMC2643877  PMID: 18781131
interleukins; interleukin receptors; single nucleotide polymorphism; melanoma
18.  Host Genetic Variants in the Interleukin-6 Promoter Predict Poor Outcome in Patients with Estrogen Receptor-Positive, Node-Positive Breast Cancer 
Cancer research  2009;69(10):4184-4191.
Interleukin-6 (IL-6) modulates immune response, estrogen production and growth pathways in breast cancer. We evaluated the effect of several common, functional IL-6 promoter variants in node-positive breast cancer patients enrolled on a multicenter, cooperative group, adjuvant chemotherapy trial to determine whether these variants were associated with clinical outcome overall and by estrogen-receptor tumor phenotype.
Genomic DNA and clinical data were collected from a clinical trial of adjuvant anthracycline-based chemotherapy followed by randomization to high-dose cyclophosphamide/thiotepa or observation (INT-0121). Genotyping for -174G>C (rs1800795), -597G>A (rs1800797) and -572G>C (rs1800796) was performed by site-specific PCR and PyroSequencing, while the -373AnTn repeat was directly sequenced. Log-rank tests and Cox modeling were used to compare outcomes by genotype/haplotype and other factors.
346 patients (64% of trial) had corresponding genotype/clinical data available and did not differ from overall trial participants. After adjustment, patients with ER positive tumors and genotypes 597GG or 174GG had significantly worse disease-free survival (DFS) (HR 1.6, p=0.02 and HR 1.71, p=0.007, respectively), while the 373 8A12T repeat appeared to be protective (HR 0.62, p=0.02). The presence of at least one copy of the haplotype [-597G;-572G;-373[10A/11T];-174G]) was associated with worse DFS (HR 1.46, p=0.04). Kaplan-Meier plots show that all patients in this group relapsed by 24 months from diagnosis. This poor risk haplotype was quite common overall (estimated frequency 0.20) and twice as frequent among Blacks (estimated frequency 0.41).
PMCID: PMC4304767  PMID: 19435922
Breast Cancer; Polymorphism; Cytokines; Interleukin-6
19.  Design of a multi-signature ensemble classifier predicting neuroblastoma patients' outcome 
BMC Bioinformatics  2012;13(Suppl 4):S13.
Neuroblastoma is the most common pediatric solid tumor of the sympathetic nervous system. Development of improved predictive tools for patients stratification is a crucial requirement for neuroblastoma therapy. Several studies utilized gene expression-based signatures to stratify neuroblastoma patients and demonstrated a clear advantage of adding genomic analysis to risk assessment. There is little overlapping among signatures and merging their prognostic potential would be advantageous. Here, we describe a new strategy to merge published neuroblastoma related gene signatures into a single, highly accurate, Multi-Signature Ensemble (MuSE)-classifier of neuroblastoma (NB) patients outcome.
Gene expression profiles of 182 neuroblastoma tumors, subdivided into three independent datasets, were used in the various phases of development and validation of neuroblastoma NB-MuSE-classifier. Thirty three signatures were evaluated for patients' outcome prediction using 22 classification algorithms each and generating 726 classifiers and prediction results. The best-performing algorithm for each signature was selected, validated on an independent dataset and the 20 signatures performing with an accuracy > = 80% were retained.
We combined the 20 predictions associated to the corresponding signatures through the selection of the best performing algorithm into a single outcome predictor. The best performance was obtained by the Decision Table algorithm that produced the NB-MuSE-classifier characterized by an external validation accuracy of 94%. Kaplan-Meier curves and log-rank test demonstrated that patients with good and poor outcome prediction by the NB-MuSE-classifier have a significantly different survival (p < 0.0001). Survival curves constructed on subgroups of patients divided on the bases of known prognostic marker suggested an excellent stratification of localized and stage 4s tumors but more data are needed to prove this point.
The NB-MuSE-classifier is based on an ensemble approach that merges twenty heterogeneous, neuroblastoma-related gene signatures to blend their discriminating power, rather than numeric values, into a single, highly accurate patients' outcome predictor. The novelty of our approach derives from the way to integrate the gene expression signatures, by optimally associating them with a single paradigm ultimately integrated into a single classifier. This model can be exported to other types of cancer and to diseases for which dedicated databases exist.
PMCID: PMC3314564  PMID: 22536959
20.  Cytokine gene polymorphisms and progression-free survival in classical Hodgkin lymphoma by EBV status: Results from two independent cohorts 
Cytokine  2013;64(2):523-531.
Cytokines are important immune mediators of classical Hodgkin lymphoma (CHL) pathogenesis, and circulating levels at diagnosis may help predict prognosis. Germline single nucleotide polymorphisms (SNPs) in immune genes have been correlated with cytokine production and function.
We investigated whether selected germline SNPs in IL10 (rs1800890, rs1800896, rs1800871, rs1800872), TNFA (rs1800629), IL6 (rs1800795), ILRN (rs419598), INFG (rs2430561) and CCL17 (rs223828) were associated with circulating levels of related cytokines at diagnosis and progression-free survival (PFS) in CHL. Patients were from France (GELA, N = 464; median age = 32 years) and the United States (Iowa/Mayo Specialized Program Of Research Excellence [SPORE], N = 239; median age = 38 years); 22% of 346 CHL cases with EBV tumor status were positive.
There was no association with any of the SNPs with cytokine levels. Overall, there was no association of any of the SNPs with PFS. In exploratory analyses by EBV status, TNFA rs1800629 (HRAA/AG = 2.41; 95%CI, 1.17–4.94) was associated with PFS in EBV-negative GELA patients, with similar trends in the SPORE patients (HRAA/AG = 1.63; 95%CI, 0.61–4.40). In a meta-analysis of the two studies, TNFA (HRAA/AG = 2.11; 95%CI, 1.18–3.77; P = 0.01) was statistically significant, and further adjustment for the international prognostic system did not alter this result.
This study showed that germline variation in TNFA was associated with CHL prognosis for EBV-negative patients, which will require confirmation. These results support broader studies on the differential impact of genetic variation in immune genes on EBV-positive vs. EBV-negative CHL pathogenesis.
PMCID: PMC4017856  PMID: 24008079
Hodgkin lymphoma; Cytokines; Polymorphism; TNFA; EBV
21.  Polymorphisms in the Calcium-Sensing Receptor Gene Are Associated with Clinical Outcome of Neuroblastoma 
PLoS ONE  2013;8(3):e59762.
Neuroblastic tumors include the neuroblastomas, ganglioneuroblastomas, and ganglioneuromas. Clinical behavior of these developmental malignancies varies from regression to aggressive growth with metastatic dissemination. Several clinical, histological, genetic, and biological features are associated with this diversity of clinical presentations. The calcium-sensing receptor (CaSR) is a G-protein coupled receptor with a key role in calcium homeostasis. We have previously reported that it is expressed in benign, differentiated neuroblastic tumors, but silenced by genetic and epigenetic events in unfavorable neuroblastomas. We have now analyzed three functionally relevant polymorphisms clustered at the signal transduction region of the CaSR (rs1801725, rs1042636 and rs1801726) to assess if genetic variants producing a less active receptor are associated with more aggressive disease course.
Polymorphisms were analyzed in DNA samples from 65 patients using specific Taqman Genotyping Assays.
Mildly inactivating variant rs1801725 was associated with clinical stage 4 (P = 0.002) and the histological subgroup of undifferentiated neuroblastomas (P = 0.046). Patients harboring this polymorphism had significantly lower overall (P = 0.022) and event-free survival (P = 0.01) rates than those who were homozygous for the most common allele among Caucasians. However, this single locus genotype was not independently associated with outcome in multivariate analyses. Conversely, the tri-locus haplotype TAC was independently associated with an increased risk of death in the entire cohort (Hazard Ratio = 2.45; 95% Confidence Interval [1.14–5.29]; P = 0.022) and also in patients diagnosed with neuroblastomas (Hazard Ratio = 2.74; 95% Confidence Interval [1.20–6.25]; P = 0.016).
The TAC haplotype includes the moderately inactivating variant rs1801725 and absence of the gain-of-function rs1042636 polymorphism. Thus, its association with metastatic disease and poor outcome would add to our previous data and further support that inactivation of the CaSR gene is a mechanism associated with neuroblastoma malignant behavior.
PMCID: PMC3606108  PMID: 23533647
22.  Impact of interleukin-6 promoter polymorphism and serum interleukin-6 level on the acute inflammation and neovascularization stages of patients with Eales’ disease 
Molecular Vision  2011;17:2552-2563.
To evaluate the role of interleukin-6 (IL-6) in the inflammatory and proliferative stages of Eales’ disease (ED) and to determine the influence of IL-6–174G/C polymorphism in the IL-6 and IL-6-regulated protein expression, as well as the development of ED.
One hundred and twenty-one patients diagnosed with ED, 223 matched healthy controls, and 16 control patients with macular holes were recruited from the eastern Indian population. Serum and vitreous levels of IL-6 and vascular endothelial growth factors (VEGF) were measured by enzyme-linked immunosorbent assay. Serum levels of high-sensitivity C-reactive protein (hsCRP) were measured by enzyme immunoassay. Subjects were genotyped for the IL-6–174G/C polymorphism (rs1800795) by a custom TaqMan single-nucleotide polymorphism (SNP) Genotyping Assays system.
Serum IL-6 (p<0.0001), hsCRP (p<0.0001), and VEGF (p=0.0031) levels were significantly higher in the inflammatory stage of ED than in healthy controls. Serum IL-6 also significantly correlated with hsCRP (Spearman’s correlation coefficient; r=0.4992, p=0.0009), but not with VEGF in this stage in ED patients. At the proliferative stage of ED, significantly higher levels of vitreous IL-6 (p=<0.0001) and VEGF (p=<0.0001) were found compared with the vitreous of patients with macular holes. A significant correlation was observed between vitreous IL-6 and VEGF in ED patients (Spearman’s correlation coefficient; r=0.5834, p=0.0087). A statistically significant association was found between the −174GG genotype (p=0.006) and occurrence of ED. Mean serum and vitreous concentrations of IL-6 were also higher in the subjects with the GG genotype than in those with the GC or CC genotype in this population.
IL-6 expression, regulated by the allelic distribution of −174 loci and the enhanced level of IL-6, modulates CRP and VEGF concentration depending respectively on the acute inflammatory stimulation at the initial stage and angiogenic stimulation at the advanced stage of ED.
PMCID: PMC3198485  PMID: 22025890
23.  Clinical Potentials of Methylator Phenotype in Stage 4 High-Risk Neuroblastoma: An Open Challenge 
PLoS ONE  2013;8(5):e63253.
Approximately 20% of stage 4 high-risk neuroblastoma patients are alive and disease-free 5 years after disease onset while the remaining experience rapid and fatal progression. Numerous findings underline the prognostic role of methylation of defined target genes in neuroblastoma without taking into account the clinical and biological heterogeneity of this disease. In this report we have investigated the methylation of the PCDHB cluster, the most informative member of the “Methylator Phenotype” in neuroblastoma, hypothesizing that if this epigenetic mark can predict overall and progression free survival in high-risk stage 4 neuroblastoma, it could be utilized to improve the risk stratification of the patients, alone or in conjunction with the previously identified methylation of the SFN gene (14.3.3sigma) that can accurately predict outcome in these patients. We have utilized univariate and multivariate models to compare the prognostic power of PCDHB methylation in terms of overall and progression free survival, quantitatively determined by pyrosequencing, with that of other markers utilized for the patients' stratification utilizing methylation thresholds calculated on neuroblastoma at stage 1–4 and only on stage 4, high-risk patients. Our results indicate that PCDHB accurately distinguishes between high- and intermediate/low risk stage 4 neuroblastoma in agreement with the established risk stratification criteria. However PCDHB cannot predict outcome in the subgroup of stage 4 patients at high-risk whereas methylation levels of SFN are suggestive of a “methylation gradient” associated with tumor aggressiveness as suggested by the finding of a higher threshold that defines a subset of patients with an extremely severe disease (OS <24 months). Because of the heterogeneity of neuroblastoma we believe that clinically relevant methylation markers should be selected and tested on homogeneous groups of patients rather than on patients at all stages.
PMCID: PMC3661569  PMID: 23717404
24.  A Common Variation in the Promoter Region of Interleukin-6 Gene Shows Association with Exercise Performance 
Skeletal muscle-derived interleukin-6 (IL-6) is a pleiotropic cytokine which regulates body metabolism during strenuous physical exercise. OBJECTIVE: The effect of a potentially functional single nucleotide polymorphism (SNP) -174G/C of the IL6 gene (rs1800795) promoter was examined on maximal oxygen uptake (VO2max), body mass index (BMI) and plasma IL-6 levels in response to physical training. Fifty four male military conscripts were studied for 8 weeks during their basic training. At weeks 1, 5 and 8, VO2max and anthropometrics were measured, and blood samples collected before and after acute aerobic exercise. Acute exercise increased plasma IL-6 in subjects with genotype CG. Moreover, during the 8-week training period, a tendency for increased plasma IL-6 was observed in subjects with this genotype. VO2max values increased in all genotype groups, but subjects with genotype CG made the greatest gains in VO2max. Training significantly decreased BMI only in subjects with genotype CG. Our findings suggest that the allele C may have an effect on plasma IL-6 response to acute exercise in healthy male subjects. Exercise training has a favourable effect on VO2max and BMI, with the most prominent effects in subjects with genotype CG. Thus we conclude that this SNP may account for individual response to exercise training.
Key pointsAllele C of the IL6 promoter SNP -174G/C may have an effect on plasma IL-6 response to acute exercise.All subjects responded to physical exercise, but the improvement in VO2max and decrease in BMI after training are more pronounced in the individuals with genotype CG, hence the IL6 promoter SNP -174G/C may have an influence on training responses.The small number of subjects investigated in the present study warrants further research to confirm these findings in large cohorts.
PMCID: PMC3761487  PMID: 24149537
Maximal oxygen uptake; IL-6; polymorphism; body mass index; training.
25.  The interleukin-6 receptor as a target for prevention of coronary heart disease: a mendelian randomisation analysis 
Lancet  2012;379(9822):1214-1224.
A high circulating concentration of interleukin 6 is associated with increased risk of coronary heart disease. Blockade of the interleukin-6 receptor (IL6R) with a monoclonal antibody (tocilizumab) licensed for treatment of rheumatoid arthritis reduces systemic and articular inflammation. However, whether IL6R blockade also reduces risk of coronary heart disease is unknown.
Applying the mendelian randomisation principle, we used single nucleotide polymorphisms (SNPs) in the gene IL6R to evaluate the likely efficacy and safety of IL6R inhibition for primary prevention of coronary heart disease. We compared genetic findings with the effects of tocilizumab reported in randomised trials in patients with rheumatoid arthritis.
In 40 studies including up to 133 449 individuals, an IL6R SNP (rs7529229) marking a non-synonymous IL6R variant (rs8192284; p.Asp358Ala) was associated with increased circulating log interleukin-6 concentration (increase per allele 9·45%, 95% CI 8·34–10·57) as well as reduced C-reactive protein (decrease per allele 8·35%, 95% CI 7·31–9·38) and fibrinogen concentrations (decrease per allele 0·85%, 95% CI 0·60–1·10). This pattern of effects was consistent with IL6R blockade from infusions of tocilizumab (4–8 mg/kg every 4 weeks) in patients with rheumatoid arthritis studied in randomised trials. In 25 458 coronary heart disease cases and 100 740 controls, the IL6R rs7529229 SNP was associated with a decreased odds of coronary heart disease events (per allele odds ratio 0·95, 95% CI 0·93–0·97, p=1·53×10−5).
On the basis of genetic evidence in human beings, IL6R signalling seems to have a causal role in development of coronary heart disease. IL6R blockade could provide a novel therapeutic approach to prevention of coronary heart disease that warrants testing in suitably powered randomised trials. Genetic studies in populations could be used more widely to help to validate and prioritise novel drug targets or to repurpose existing agents and targets for new therapeutic uses.
UK Medical Research Council; British Heart Foundation; Rosetrees Trust; US National Heart, Lung, and Blood Institute; Du Pont Pharma; Chest, Heart and Stroke Scotland; Wellcome Trust; Coronary Thrombosis Trust; Northwick Park Institute for Medical Research; UCLH/UCL Comprehensive Medical Research Centre; US National Institute on Aging; Academy of Finland; Netherlands Organisation for Health Research and Development; SANCO; Dutch Ministry of Public Health, Welfare and Sports; World Cancer Research Fund; Agentschap NL; European Commission; Swedish Heart-Lung Foundation; Swedish Research Council; Strategic Cardiovascular Programme of the Karolinska Institutet; Stockholm County Council; US National Institute of Neurological Disorders and Stroke; MedStar Health Research Institute; GlaxoSmithKline; Dutch Kidney Foundation; US National Institutes of Health; Netherlands Interuniversity Cardiology Institute of the Netherlands; Diabetes UK; European Union Seventh Framework Programme; National Institute for Healthy Ageing; Cancer Research UK; MacArthur Foundation.
PMCID: PMC3316968  PMID: 22421340

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