-174G/C polymorphism in the interleukin-6 promoter is differently associated with prostate cancer incidence depending on race

Genetic and biological drivers of prostate cancer disparities in Black men

Black men with prostate cancer have historically had worse outcomes than white men with prostate cancer. The causes of this disparity in outcomes are multi-factorial, but a potential basis is that prostate cancers in Black men are biologically distinct from prostate cancers in white men. Evidence suggests that genetic and ancestral factors, molecular pathways involving androgen and non-androgen receptor signalling, inflammation, epigenetics, the tumour microenvironment and tumour metabolism are contributing factors to the racial disparities observed. Key genetic and molecular pathways linked to prostate cancer risk and aggressiveness have potential clinical relevance. Describing biological drivers of prostate cancer disparities could inform efforts to improve outcomes for Black men with prostate cancer.

Interleukins-6 -174G/C (rs1800795) and -572C/G (rs1800796) polymorphisms and prostate cancer risk

Prostate cancer (PCa) is an aggressive cancer influenced by a complex interplay of genetic and environmental factors. Amongst these risk factors, the impact of Interleukin6 (IL6) gene polymorphisms in PCa risk has received a lot of attention. IL-6 is a cytokine that has been implicated in the pathogenesis of several malignancies, including PCa. Two IL-6 gene polymorphisms, - 174 G/C (rs1800795) and - 572 C/G (rs1800796), have received intellectual attention due to their potential role as modulators of prostate cancer risk. The main objective of this research was to comprehensively explore the potential associations between IL-6 rs1800795 and rs1800796 polymorphisms, and their impact on the occurrence of PCa. A case-control study was carried out with a well-defined cohort comprising 110 PCa cases and 110 controls (total n = 220). The genotyping of rs1800795 and rs1800796 was carefully performed using the highly sensitive and accurate Polymerase Chain Reaction-High Resolution Melting Curve (PCR-HRM) technique. The assessment of genetic associations was evaluated using various R packages, such as Haplo-Stats, SNP stat, pheatmap, and LD heatmap. The present study applied odds ratio (OR) analysis to reveal significant evidence of strong associations between the genotypes of rs1800795 and rs1800796 and the susceptibility to PCa. The findings of this study underscore the noteworthy impact of genetic variations in the IL-6 gene on the development of prostate cancer. Specifically, the C/G and G/G genotypes of rs1800795 demonstrated increased PCa risk, with odds ratios (OR) of 1.650 (95% CI = 1.068-2.549, p = 0.032) and 2.475 (95% CI = 1.215-5.043, p < 0.001), respectively. Similarly, the G/C genotype of rs1800796 exhibited an OR of 2.374 (95% CI = 1.363-4.130, p = 0.012) for elevated prostate cancer risk, while the C/C genotype had an OR of 1.81 (95% CI = 1.02-3.22, p = 0.7). Furthermore, our haplotype analysis have revealed an association between haplotype 4 (C-G) and increased risk of PCa (OR = 1.69, 95% CI = 1.05-2.73, p = 0.032). In conclusion, this case-control analysis presents compelling evidence for a significant association between IL-6 variants (rs1800795 and rs1800796) and increased susceptibility to prostate cancer.

Evaluation the -174G>C Genetic Polymorphism of Interleukin-6 in Iranian Patients with Chronic Lymphocytic Leukemia

Background & Objective

Interleukin-6 (IL-6) is involved in inflammation and has a significant role in chronic lymphocytic leukemia (CLL) progression. Accordingly, IL-6 level may increase in CLL-affected patients compared to healthy individuals. The -174G>C single nucleotide polymorphism (SNP) in IL-6 promoter region has been related to differences in IL-6 transcription. Therefore, we investigated the possible association of IL-6 polymorphism with CLL.

Methods

We examined the -174G>C SNP in IL-6 gene and studied its possible relationship with CLL in affected patients and in healthy controls using Amplification Refractory Mutation System- polymerase chain reaction genotyping method. IL-6 plasma level was measured in both studied groups.

Results

According to the results, IL-6 mean plasma concentration was increased significantly in the CLL patients compared to the controls. However, 174G>C genotype of the IL-6 gene was not associated with CLL. Furthermore, there were no significant differences in the distribution of allele and genotype frequencies between the CLL-affected patients and the controls (P>0.05).

Conclusion

Our study showed that -174G>C SNP in promotor of IL-6 gene could not be considered a risk factor for CLL. Larger prospective studies should be performed to confirm our results.

Statistical meta-analysis to investigate the association between the Interleukin-6 (IL-6) gene polymorphisms and cancer risk

A good number of genome-wide association studies (GWAS), including meta-analyses, reported that single nucleotide polymorphisms (SNPs) of the IL-6 gene are significantly associated with various types of cancer risks, though some other studies reported insignificant association with cancers, in the literature. These contradictory results may be due to variations in sample sizes and/or deficiency of statistical modeling. Therefore, an attempt is made to provide a more comprehensive understanding of the association between the IL-6 gene SNPs (rs1800795, rs1800796, rs1800797) and different cancer risks, giving the weight on a large sample size, including different cancer types and appropriate statistical modeling with the meta-dataset. In order to attain a more reliable consensus decision about the association between the IL-6 gene polymorphisms and different cancer risks, in this study, we performed a multi-case statistical meta-analysis based on the collected information of 118 GWAS studies comprising of 50053 cases and 65204 control samples. Results from this Meta-analysis indicated a significant association (p-value < 0.05) of the IL-6 gene rs1800796 polymorphism with an overall increased cancer risk. The subgroup analysis data based on cancer types exhibited significant association (p-value < 0.05) of the rs1800795 polymorphism with an overall increased risk of cervical, liver and prostate cancers; the rs1800796 polymorphism with lung, prostate and stomach cancers; and the rs1800797 polymorphism with cervical cancer. The subgroup analysis of ethnicity data showed a significant association (p-value < 0.05) of an overall cancer risk with the rs1800795 polymorphism for the African and Asian populations, the rs1800796 polymorphism for the Asian only and the rs1800797 polymorphism in the African population. Comparative discussion showed that our multi-case meta-analyses received more support than any previously reported individual meta-analysis about the association between the IL-6 gene polymorphisms and cancer risks. Results from this study, more confidently showed that the IL-6 gene SNPs (rs1800795, rs1800796 and rs1800797) in humans are associated with increased cancer risks. Therefore, these three polymorphisms of the IL-6 gene have the potential to be evaluated as a population based rapid, low-cost PCR prognostic biomarkers for different types of cancers diagnosis and research.

Interaction of tobacco chewing and smoking habit with interleukin 6 promoter polymorphism in oral precancerous lesions and oral cancer

OBJECTIVE

Our study aims to determine the influence of smoking or tobacco chewing and the association of Interleukin 6 (IL-6) polymorphism, where G is substituted by A at the position - 596 (IL-6 - 596 G/A) and substitution of G by cytosine (C) at position - 572 (IL-6 - 572 G/C) on the susceptibility of precancerous oral lesions and oral cancer.

MATERIALS AND METHODS

The participants consisted of 250 subjects among which 75 were suffering from oral cancer, 75 subjects with precancerous oral lesions and 100 were healthy controls. Single-nucleotide polymorphism study (SNP) was done by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP).

RESULTS

IL-6 - 596 G/A SNP revealed genotypes, GG, and GA in subjects with precancerous oral lesions and oral cancer, and AA genotype was not found in any subject. IL-6 - 596 G/A was strongly associated with oral precancerous lesions but not with oral cancer. The present study reports that smokers carrying GA for IL-6 - 596 G/A were at several folds higher risk of developing oral precancerous lesions. Smokers with GC and CC for IL-6 - 572 G/C were at higher risk of developing oral precancerous lesions. No significant interaction was observed between these habits and IL-6 - 596 G/A and IL-6 - 572 G/C SNP with oral cancer.

CONCLUSION

The interaction of variant A allele of IL-6 - 596 G/A and C allele of IL-6 - 572 G/C polymorphism with smoking and increases the risk of oral precancerous lesions. Tobacco chewing was not related with IL-6 - 596 G/A or IL-6 - 572 G/C in oral precancerous lesions or oral cancer.

CLINICAL RELEVANCE

The study will help to determine the susceptibility of individuals with smoking or chewing habits to the development of oral precancerous lesion and oral cancer by monitoring the IL-6 SNPs which can be used as a biomarker for risk determination.

Racial Differences in Immunological Landscape Modifiers Contributing to Disparity in Prostate Cancer

Prostate cancer affects African Americans disproportionately by exhibiting greater incidence, rapid disease progression, and higher mortality when compared to their Caucasian counterparts. Additionally, standard treatment interventions do not achieve similar outcome in African Americans compared to Caucasian Americans, indicating differences in host factors contributing to racial disparity. African Americans have allelic variants and hyper-expression of genes that often lead to an immunosuppressive tumor microenvironment, possibly contributing to more aggressive tumors and poorer disease and therapeutic outcomes than Caucasians. In this review, we have discussed race-specific differences in external factors impacting internal milieu, which modify immunological topography as well as contribute to disparity in prostate cancer.

The Role of Polymorphisms in Genes of PI3K/Akt Signaling Pathway on Prostate

Background and Objective: Increasing evidence suggested that polymorphisms in genes of PI3K/Akt pathway were closely related to prostate cancer (PCa) risk. Nevertheless, these results are controversial and inconclusive. Here, we conducted a comprehensive updated meta-analysis and systematic review to precisely illustrate the association between polymorphisms in genes of PI3K/Akt signaling pathway and PCa risk.

Materials and Methods: The gene set of PI3K/Akt pathway was referenced from the Kyoto Encyclopedia of Genes and Genomes (KEGG) website. Relevant studies were identified by the systematically researching on PubMed, Web of Science and Google Scholar databases up to October 1, 2017. The odds ratios (ORs) with a corresponding 95% confidential intervals (95%CIs) were applied to test their associations. All the analyses were conducted by using Stata 12.0 (Stata Corporation, USA).

Results: Finally, 38 articles comprising 62 case-control studies were enrolled for 13 polymorphisms in genes of PI3K/Akt pathway. However, overall results failed to present a positive association between polymorphisms in genes of PI3K/Akt pathway and PCa risk. Nevertheless, in the subgroup analysis by ethnicity, we identified that IL-6-rs1800795 polymorphism was associated with an increased risk of PCa for Caucasian individuals in dominant model (MM + MW vs. WW: OR = 1.245, 95%CI = 1.176-1.318, P < 0.001).

Conclusion: Our work suggests that polymorphisms in genes of PI3K/Akt Signaling Pathway are not risk factor for PCa. Further well-designed studies with larger samples and precise designs are demanded to corroborate our findings.

An Interleukin-6 Single Nucleotide Polymorphism and Susceptibility to Prostate Adenocarcinoma and Bone Metastasis in an Iranian Population

Objective:

Interleukin-6 (IL-6) is an inflammatory cytokine shown to be a strong factor for growth, proliferation and metastasis with many malignancies. The promoter single nucleotide polymorphism (SNPs) -174G>C (rs1800795) can alter the transcriptional pattern of this gene. The present study was aimed at assessing effects of the IL-6 (rs1800795) SNP on risk of benign prostate hyperplasia (BPH) and prostatic adenocarcinoma (PCa).

Methods:

The project was performed on 112 men with PCa, 118 with BPH and 250 healthy controls. After DNA extraction, genotyping of IL-6 (rs1800795) was performed using PCR TaqMan Allelic Discrimination (ABI MGB).

Results:

The G allele frequency for rs1800795 of the IL-6 gene was 74.1%, 68.6% and 67% in PCa patients, BPH patients and healthy men, respectively. PCa and control groups showed significant differences (P =0.030, OR = 1.73, 95% CI: 1.05-2.21). The GG genotype was more frequent in the PCa group, whereas the GC genotype was more common in the BPH in comparison to other groups.

Conclusion:

The current study identified IL-6 -174G>C (rs1800795) as a significant predictor of susceptibility for prostate cancer and bone metastasis in a northwest Iranian population.

Associations of interleukin-6 gene polymorphisms with cancer risk: Evidence based on 49,408 cancer cases and 61,790 controls

Many molecular epidemiologic studies have shown that interleukin-6 (IL-6) polymorphisms are significantly associated with susceptibility for various cancers. However, the conclusions of these studies are inconsistent. The purpose of the present study was to explore the association between three common IL-6 loci (rs1800795, rs1800796, and rs1800797) and the risk for various cancers. We systematically searched the PubMed, Web of Science, Wanfang and China national knowledge infrastructure (CNKI) databases for relevant publications and obtained 108 eligible studies, involving 49,408 cancer patients and 61,790 cancer-free controls. Odds ratio (OR), 95% confidence interval (CI), and false positive reporting probability (FPRP) were used to evaluate cancer risk. All statistical analyses were performed using the R software meta package. We observed a non-significant association between rs1800795 and overall cancer risk, while rs1800797 was found to have a false positive association with overall risk of cancer. Subgroup analyses of rs1800797 also suggested non-significant association and rs1800795 played a protective role in liver cancer. Rs1800796 was found to be associated with overall cancer risk, particularly in Asian patients and those with prostate cancer. These findings provide evidence that IL-6 polymorphisms may affect cancer risk.

Genetic polymorphisms of IL-6 promoter in cancer susceptibility and prognosis: a meta-analysis

IL-6 is critical for tumorigenesis. However, previous studies on the association of IL-6 promoter polymorphisms with predisposition to different cancer types are somewhat contradictory. Therefore, we performed this meta-analysis regarding the relationship between IL-6 promoter single nucleotide polymorphisms and cancer susceptibility and prognosis. Up to April 2017, 97 original publications were identified covering three IL-6 promoter SNPs. Our results showed statistically significant association between IL-6 promoter and cancer risk and prognosis. Subgroup analysis indicated that rs1800795 was significantly associated with increased risk of cervical cancer, colorectal cancer, breast cancer, prostate cancer, lung cancer, glioma, non-Hodgkin’s lymphoma and Hodgkin’s lymphoma but not gastric cancer and multiple myeloma. Furthermore, rs1800796 was significantly associated with increased risk of lung cancer, prostate cancer and colorectal cancer but not gastric cancer. Additionally, rs1800797 was significantly association with breast cancer, non-Hodgkin’s lymphoma, B-cell lymphoma and diffuse large B-cell lymphoma but not gastric cancer. Simultaneously, rs1800795 and rs1800796 were associated with a significantly higher risk of cancer in Asia and Caucasian, rs1800797 was associated with a significantly risk of cancer in Caucasian but not in Asia. Furthermore, IL-6 promoter polymorphisms were significantly associated with the prognosis of cancer. Considering these promising results, IL-6 promoter including rs1800795, rs1800796 and rs1800797 may be a tumor marker for cancer therapy.

Meta-analysis of the role of IL-6 rs1800795 polymorphism in the susceptibility to prostate cancer: Evidence based on 17 studies

Playing critical roles in immune responses, interleukin-6 (IL-6) has been proposed to be involved in the development of multiple cancers, including prostate cancer. The rs1800795 polymorphism in the promoter of the gene IL-6 can affect the transcription and expression of the gene, becoming a common target in association studies on tumors. We therefore carried out this meta-analysis to further discuss the relationship of this polymorphism with the risk of prostate cancer.Relevant publications were retrieved from the electronic databases. The strength of the correlation between IL-6 rs1800795 polymorphism and prostate cancer risk was evaluated using pooled odds ratios (ORs) with their 95% confidence intervals (95% CIs). Q test was adopted to examine between-study heterogeneity, with P < 0.05 as significant level. Subgroup and meta-regression analyses were conducted to explore potential source of heterogeneity. Sensitivity analysis was implemented to test the statistical stability of the final results. In addition, funnel plot and Egger test were employed to inspect publication bias among included studies.A total of 13 132 cases and 15 282 controls were ultimately incorporated into the present study. Overall estimates revealed no significant relationship between IL-6 rs1800795 polymorphism and prostate cancer risk in total analysis, but a risk-increasing effect of the polymorphism was detected in African-American subgroup under CC versus GG and CC versus GG + GC contrasts (OR 3.43, 95% CI 1.01-11.71; OR 3.51, 95% CI 1.04-11.82) after subgroup analysis by ethnicity.IL-6 rs1800795 polymorphism may enhance the susceptibility to prostate cancer in African-American men.

Circulating interleukin-6 and rheumatoid arthritis: A Mendelian randomization meta-analysis

Interleukin-6 (IL-6), as a pleiotropic cytokine, has been demonstrated to be closely associated with the pathogenisis of rheumatoid arthritis (RA). However, whether this association is causal or not remains unclear, because of the multifactorial role of IL-6 and related confounding factors. We aimed to evaluate the causal relevance between circulating IL-6 levels and the risk of RA through meta-analytical Mendelian randomization approach. IL-6 gene -174G/C variant was selected as an instrument in this Mendelian randomization meta-analysis. Article identification and data collection were conducted in duplicate and independently by 2 authors. The STATA software was used for data analysis. In total, 15 and 5 articles on the association of the -174G/C variant with RA risk and circulating IL-6 level, respectively, were included. The overall analysis showed that C allelic and GC+CC genotype were significantly with 1.59-fold (95% CI: 1.19-2.14) and 1.63-fold (95% CI: 1.17-2.26) increased risk of developing RA, respectively. Asian populations showed stronger association with 4.55-fold (95% CI: 1.62-12.75), 1.84-fold (95% CI: 1.13-2.99), and 4.69-fold (95% CI: 1.68-13.14) increased RA risk in carriers of -174C allelic, CC, and GC+CC genotype, respectively. Carriers of GC+CC genotype showed significant reduction in the circulating IL-6 level compared with GG carriers (WMD = -0.77; 95% CI: -1.16 to -0.38; P = 0.000) in overall populations. Mendelian randomization presented 6% and 22% increased risk of RA with 0.1 pg/mL reduction of circulating IL-6 level in overall and Asian populations, respectively. This Mendelian randomization meta-analysis demonstrated that the long-term genetically reduced circulating IL-6 level might be causally related to a higher risk of RA, especially in Asian populations.

Association between interleukin-6 polymorphisms and urinary system cancer risk: evidence from a meta-analysis

Background

Interleukin-6 (IL-6) is a multifunctional proinflammatory cytokine involved in cancer initiation and progression. Numerous studies have investigated the associations between IL-6 polymorphisms (IL-6 −174G>C, −592G>C, −597G>A) and risk of urinary system cancers, including prostate cancer, bladder cancer, and renal cell cancer. However, conclusions from these studies were controversial. Thus, we conducted the current meta-analysis to obtain the comprehensive profile regarding the association between IL-6 polymorphisms and urinary system cancer risk.

Methods

According to inclusion and exclusion criteria, the associations of IL-6 polymorphisms with urinary system cancer were searched from database and analyzed using STATA 12.0 statistical software. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the associations.

Results

A total of 20 previous publications consisting of 15,033 cases and 17,655 controls were involved in this meta-analysis. Significant association was observed in overall population regarding IL-6 −592G>C polymorphisms (G vs C: OR =0.1.30, 95% CI =1.13−2.52; GG vs CC: OR =1.81, 95% CI =1.31−2.52; GG vs GC + CC: OR =1.33, 95% CI =1.02−1.75; GG + GC vs CC: OR =1.41, 95% CI =1.09−1.83). In the stratified analyses by ethnicity, the significant associations were found among Asian (GG vs CC: OR =1.89, 95% CI =1.34−2.66; GG + GC vs CC: OR =1.43, 95% CI =1.09−1.87) and Black population (GC vs CC: OR =0.20, 95% CI =0.05−0.82) rather than Caucasian men. Likewise, there were noticeable associations in almost all the other subanalyses such as cancer types, control sources, genotyped methods, and sample sizes. However, no significant associations were identified between any of IL-6 −174G>C polymorphisms with urinary system cancer, except for Asian population (G vs C: OR =0.81, 95% CI =0.70−0.95; GG vs CC: OR =0.51, 95% CI =0.35−0.74; GC vs CC: OR =0.49, 95% CI =0.33−0.72; GG + GC vs CC: OR =0.50, 95% CI =0.35−0.72; respectively). In addition, no significant associations were detected between IL-6 −597G>A polymorphism and urinary system cancer, regardless of whole or subgroups.

Conclusion

This meta-analysis presents a relatively comprehensive view of the associations between IL-6 polymorphism and urinary system cancer risk to explore the carcinogenic mechanisms, which will help shed light on the clinical diagnosis and therapy for urinary system cancer. However, further detailed studies are needed to verify our conclusion.

African American Participation in Oncology Clinical Trials--Focus on Prostate Cancer: Implications, Barriers, and Potential Solutions

In the United States, the incidence and mortality rates of many cancers, especially prostate cancer, are disproportionately high among African American men compared with Caucasian men. Recently, mortality rates for prostate cancer have declined more rapidly in African American versus Caucasian men, but prostate cancer is still the most common cancer and the second leading cause of cancer deaths in African American men in the United States. Compared with Caucasian men, prostate cancer occurs at younger ages, has a higher stage at diagnosis, and is more likely to progress after definitive treatments in African American men. Reasons for racial discrepancies in cancer are multifactorial and potentially include socioeconomic, cultural, nutritional, and biologic elements. In addition to improving access to novel therapies, clinical trial participation is essential to adequately establish the risks and benefits of treatments in African American populations. Considering the disproportionately high mortality rates noted in these groups, our understanding of the natural history and responses to therapies is limited. This review will explore African American underrepresentation in clinical trials with a focus on prostate cancer, and potentially effective strategies to engage African American communities in prostate cancer research. Solutions targeting physicians, investigators, the community, and health care systems are identified. Improvement of African American participation in prostate cancer clinical trials will benefit all stakeholders.

Circulating interleukin-6 and cancer: A meta-analysis using Mendelian randomization

Interleukin-6 (IL-6) plays a contributory role in the progression and severity of many forms of cancer; it however remains unclear whether the relevance between circulating IL-6 and cancer is causal. We therefore meta-analyzed published articles in this regard using IL-6 gene -174G/C variant as an instrument. Seventy-eight and six articles were eligible for the association of -174G/C variant with cancer and circulating IL-6, respectively. Overall analyses failed to identify any significance between -174G/C and cancer risk. In Asians, carriers of the -174CC genotype had an 1.95-fold increased cancer risk compared with the -174GG genotype carriers (P = 0.009). By cancer type, significance was only attained for liver cancer with the -174C allele conferring a reduced risk under allelic (odds ratio or OR = 0.74; P = 0.001), homozygous genotypic (OR = 0.59; P = 0.029) and dominant (OR = 0.67; P = 0.004) models. Carriers of the -174CC genotype (weighted mean difference or WMD = −4.23 pg/mL; P < 0.001) and -174C allele (WMD = −3.43 pg/mL; P < 0.001) had circulating IL-6 reduced significantly compared with the non-carriers. In further Mendelian randomization analysis, a reduction of 1 pg/mL in circulating IL-6 was significantly associated with an 12% reduced risk of liver cancer. Long-term genetically-reduced circulating IL-6 might be causally associated with a lower risk of liver cancer.

Association of interleukin-6 genetic polymorphisms with risk of OSCC in Indian population

Purpose

Interleukin-6 (IL-6) encodes a cytokine protein, which causes inflammation, maintains immune homeostasis and plays an essential role in oral pathogenesis. The aim of this study was to evaluate the association between IL-6 (− 174 and − 572) G/C promoter gene polymorphisms and risk of OSCC among Indians.

Methods

Single nucleotide polymorphism in IL-6 genes was genotyped in OSCC patients and healthy controls by PCR-RFLP method. Genotype and allele frequencies were analyzed by chi-square test and strength of associations by odds ratio with 95% confidence intervals.

Results

Frequency distribution of IL-6 (− 174) G/C gene polymorphism was significantly associated with OSCC patients in comparison to healthy controls (OR: 0.541, CI: 0.356–0.822; p: 0.004. However, frequency of IL-6 (− 572) G/C gene polymorphism was not significantly associated with OSCC patients (p > 0.05).

Conclusion

The genotype GC and allele C of IL-6 (− 174) G/C gene polymorphism play a significant role in OSCC susceptibility.

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We first demonstrate the IL-6 polymorphism in OSCC patients in Indian population.

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We obtained the SNP of IL-6 (-174) is increase the risk of OSCC.

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We also obtained the SNP of IL-6 (-572) and risk of OSCC

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We evaluate the correlation of these IL-6 polymorphisms and progression of OSCC.

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We identified the environmental factors and gene interactions with pathogenesis of OSCC.

IL-6 polymorphism in non-small cell lung cancer: a prognostic value?

Lung cancer was found to be the most commonly diagnosed cancer, as well as the primary cause of cancer-related mortality for males worldwide and the second leading cause of cancer-related deaths for women. Cytokines are fundamental for several biological processes-associated malignant tumors. The IL-6 is a cytokine involved in the regulation of cellular functions including processes associated with cancer, such as proliferation, apoptosis, angiogenesis, and differentiation. Furthermore, IL-6 is a potent pleiotropic inflammatory cytokine that is considered a key growth-promoting and antiapoptotic factor. The polymorphism-174G/C SNP is a G to C transition in the -174 position of the promoter region of the IL-6 gene. The aim of our study was to evaluate the influence of -174G/C polymorphism in clinical outcome of non-small cell cancer (NSCLC) patients. DNA was extracted from peripheral blood of 424 patients diagnosed with cytologically or histologically NSCLC. The characterization of IL-6 -174G/C genotypes was performed by PCR-RFLP (NlaIII). IL-6 polymorphism's genotypes were divided according to functional activity, so the G carriers (CG/GG) is the high-producer IL-6, and CC genotype is the low-producer IL-6. Regarding survival, we verify that patients with genotypes carrying the G allele (CG/GG) had a statistically significant diminished survival when compared with patients with CC genotype (62.79 and 42.31 months, respectively; P = 0.032). In the promoter region of the IL-6 gene, polymorphic variants were located and may be responsible for alterations in transcription that consequently affect serum levels of the cytokine. With our study, we demonstrated that genetic variant (-174G/G and G/C) can be responsible for changes in prognosis of NSCLC patients.

Gene of the month: Interleukin 6 (IL-6)

The Interleukin 6 (IL-6) gene encodes the classic proinflammatory cytokine IL-6. It is also known as interferon-β2 (IFN-β2), B cell stimulatory factor-2 and hybridoma/plasmacytoma growth factor. IL-6 is a multifunctional cytokine with a central role in many physiological inflammatory and immunological processes. Due to its major role in initiation as well as resolving inflammation, deregulation of IL-6 is a mainstay of chronic inflammatory and autoimmune diseases. Additionally, IL-6 has been shown to be implicated in pathogenesis of many human malignancies. Thus, a better understanding of IL-6 and its role in various pathological conditions could enable the development of strategies to use it as a therapeutic target. This short review focuses on the structure, regulation and biological activities of IL-6. In addition we discuss the role of IL-6 in diseases with inflammatory background and cancer and also the therapeutic applications of anti-IL-6 agents.

Association of interleukin-6 (-174 G/C) polymorphism with the prostate cancer risk: A meta-analysis

The aim of the present study was to determine whether the interleukin-6 (IL-6) (-174 G/C) gene polymorphism correlates with prostate cancer. A meta-analysis based on former studies was conducted and the results suggest that there was no significant association between IL-6 (-174 G/C) polymorphism and the prostate cancer risk. However, a recent study published in January 2014 showed that the GG genotype may be associated with an increased risk of prostate cancer in Caucasian subjects, whereas the CC genotype was associated with an increased risk in the African-American subjects, which was inconsistent with former studies. Databases, including PubMed, Embase, Web of Science, the Cochrane Library, Chinese Biomedical Literature Database and Wanfang database, were searched between January 1994 and March 2014 to determine the eligible IL-6 (-174 G/C) polymorphism studies and the susceptibility of the prostate cancer risk. A total of 11 studies with 10,745 cases and 13,473 controls fulfilled the inclusion criteria subsequent to assessment by two investigators. The pooled odds ratio (OR) with 95% confidence interval (95% CI) was calculated to examine the associations, and subgroup analyses were performed according to the ethnicity. Overall, no significant association was found between the IL-6 (-174 G/C) polymorphism and prostate cancer risk, whereas the subgroup analysis suggested that the association between the IL-6 (-174 G/C) polymorphism and prostate cancer was slightly significant under the homozygote (CC vs. GG: OR, 3.43; 95% CI, 1.01-11.71; P=0.049) and recessive models (CC vs.

GG/GC

OR, 3.51; 95% CI, 1.04-11.82; P=0.042) in African-American patients. However, no significant association was found in the Caucasian, Asian or mixed populations under the five genetic models by stratifying studies for ethnicity. In conclusion, the present study suggested that there was no significant association between the IL-6 (-174 G/C) polymorphism and prostate cancer risk in Caucasian and Asian patients, whereas the CC genotype may be associated with an increased risk in the African-American patients.