Association between IL6 -174G/C and cancer: A meta-analysis of 105,482 individuals

Analysis of Interleukin-6 Gene Variants (rs1800795, rs1800796, rs1554606, rs1800797, rs2069840, rs12700386, and rs2069861) as Prognostic Markers in Breast Cancer: A Systematic Review, Meta-Analysis, and Network Analysis

Interleukin-6 (IL-6) has obviously tumor-promoting and tumor-inhibitory effects and can induce an epithelial-mesenchymal transition phenotype in human breast cancer (BC) cells and implicate its potential to promote BC metastasis. Herein, we aimed to evaluate the association of IL-6 variants (rs1800795, rs1800796, rs1554606, rs1800797, rs2069840, rs12700386, and rs2069861) with the susceptibility to BC. The databases of PubMed/Medline, Web of Science, Scopus, and Cochrane Library were searched until December 19, 2022, without any restrictions. The quality assessment of each study was performed based on the Newcastle-Ottawa Scale tool. The Review Manager 5.3 software presented the effect sizes including odds ratio (OR) along with a 95% confidence interval (CI). Both publication bias and sensitivity analyses were carried out by the Comprehensive Meta-Analysis version 2.0 software. A total of 2,508 records were identified among databases and at last, 27 articles were entered into the meta-analysis. Seven polymorphisms of IL-6 were entered into the analyses. Just rs1800797 polymorphism in the dominant model (OR = 1.51; 95% CI = 1.15-2.00; P = 0.003) and rs2069840 polymorphism in heterozygous (OR = 0.89; 95% CI = 0.81-0.97; P = 0.008) and dominant (OR = 0.91; 95% CI = 0.84-0.99; P = 0.02) models had a significant association with the BC risk. In conclusion, among 7 polymorphisms and despite a few included cases, the present meta-analysis recommended that the AA+GA genotype of rs1800797 polymorphism had a significantly elevated risk and the GC and the CC+GC genotypes of rs2069840 polymorphism had a protective role in the BC patients.

Gene polymorphisms of Interleukin 6 (−174 G/C) and transforming growth factor β-1(+915 G/C) in ovarian cancer patients

Background

In the study on hand, we investigated the effect of IL-6 (−174 G/C; rs 1800795) and TGF-β1 (+915G/C; rs 1800471) gene polymorphisms on the susceptibility to Ovarian Cancer and their effect on plasma levels. IL-6 (−174 G/C) SNP was analyzed using mutagenically separated polymerase chain reaction (MS-PCR) while TGF-β1 +915G/C (codon 25) SNP was investigated by the sequence-specific primer polymerase chain reaction (SSP-PCR). An enzyme-linked immunosorbent assay (ELISA) was used to quantify IL-6 and TGF-β1 plasma levels in 48 ovarian cancer patients and 48 normal controls.

Results

Regarding IL 6 (−174 G/C), a significant increase in CC and GC+CC genotypes parallel with the C allele was considered as risk factors for ovarian cancer; on the other hand, the G allele was considered as a protective factor for ovarian cancer. TGF-β1 (+915G/C) investigations showed a significant elevation in GC and GC+CC genotypes which can be considered as a risk factor for ovarian cancer. Plasma IL-6 and TGF-β1 were higher in ovarian cancer patients compared with controls. No specific genotype or allele could be responsible for the elevation of TGF-β1 in ovarian cancer patients’ plasma, while the highest significant value for IL6 in subjects carrying GG and CC genotypes in comparison with GC genotype.

Conclusions

This study supports an association of IL6 (−174G/C) and TGF-β1 (+915G/C) gene polymorphisms with the susceptibility to ovarian cancer.

The -174G>C and -596G>A Polymorphisms Are Not Associated with Circulating IL-6 Levels in Breast Cancer Patients from Jalisco, México

Introduction: Interleukin-6 (IL-6) is a circulating proinflammatory cytokine that fulfills an important role in the survival and proliferation of cancer cells. Overexpression of IL-6, possibly due to the -174G>C and -596G>A polymorphisms in the IL6 gene, has been shown to be related to breast cancer (BC) and a more aggressive course of the disease. Aim: To determine the influence of the -174G>C and -596G>A polymorphisms of the IL6 gene on the circulating levels of IL-6 in BC patients from Jalisco, México. Methodology: Genotyping of the two polymorphisms was carried out on 208 BC patients and 219 healthy controls through polymerase chain reaction-restriction fragment length polymorphism analyses. In addition, the plasma IL-6 concentration levels were measured in the BC patients. Results: There was no significant association between BC and the IL-6 alleles and genotypes (-174G>C, p = 0.276; -596G>A, p = 0.762) under study. Similarly, there were no significant differences in the mean plasma IL-6 concentrations associated with the polymorphisms that were analyzed (-174G>C, p = 0.839; -596G>A, p = 0.848). Conclusions: No evidence was found that the analyzed polymorphisms are associated with the IL-6 expression or concentration in patients suffering from BC from Jalisco, Mexico.

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.

Interleukins as new prognostic genetic biomarkers in non-small cell lung cancer

BACKGROUND

Surgery is the standard treatment for early-stage NSCLC, and platinum-based chemotherapy remains as the treatment of choice for advanced-stage NSCLC patients with naïve EGFR status. However, overall 5-years relative survival rates are low. Interleukins (ILs) are crucial for processes associated with tumor development. In NSCLC, IL1B, IL6, IL12A, IL13 and IL16 gene polymorphisms may contribute to individual variation in terms of patient survival. The purpose of this study was to evaluate the association between IL gene polymorphisms and survival in NSCLC patients.

METHODS

A prospective cohorts study was performed, including 170 NSCLC patients (114 Stage IIIB-IV, 56 Stage I-IIIA). IL1B (C > T; rs1143634), IL1B (C > T; rs12621220), IL1B (C > G; rs1143623), IL1B (A > G; rs16944), IL1B (C > T; rs1143627), IL6 (C > G; rs1800795), IL12A (C > T; rs662959), IL13 (A > C; rs1881457) and IL16 (G > T; rs7170924) gene polymorphisms were analyzed by PCR Real-Time.

RESULTS

Patients with IL16 rs7170924-GG genotype were in higher risk of death (p = 0.0139; HR = 1.82; CI_95% = 1.13-2.94) Furthermore, carriers of the TT genotype for IL12A rs662959 presented higher risk of progression in the non-resected NSCLC patient subgroup (p = 0.0412; HR = 4.49; CI_95% = 1.06-18.99). The rest of polymorphisms showed no effect of on outcomes.

CONCLUSIONS

Our results suggest that IL16 rs7170924-GG and IL12A rs662959-TT genotypes predict higher risk of death and progression, respectively, in NSCLC patients. No influence of IL1B rs12621220, IL1B rs1143623, IL1B rs16944, IL1B rs1143627, IL6 rs1800795, IL13 rs1881457 on NSCLC clinical outcomes was found in our patients.

Interleukin-6 Signaling Pathway and Its Role in Kidney Disease: An Update

Interleukin-6 (IL-6) is a pleiotropic cytokine that not only regulates the immune and inflammatory response but also affects hematopoiesis, metabolism, and organ development. IL-6 can simultaneously elicit distinct or even contradictory physiopathological processes, which is likely discriminated by the cascades of signaling pathway, termed classic and trans-signaling. Besides playing several important physiological roles, dysregulated IL-6 has been demonstrated to underlie a number of autoimmune and inflammatory diseases, metabolic abnormalities, and malignancies. This review provides an overview of basic concept of IL-6 signaling pathway as well as the interplay between IL-6 and renal-resident cells, including podocytes, mesangial cells, endothelial cells, and tubular epithelial cells. Additionally, we summarize the roles of IL-6 in several renal diseases, such as IgA nephropathy, lupus nephritis, diabetic nephropathy, acute kidney injury, and chronic kidney disease.

Strong association of interleukin-6 −174G/C promoter single nucleotide polymorphism with a decreased risk of colorectal cancer in ethnic Kashmiri population: A case control study

Chronic inflammation increases the risk of development of various cancers, including colorectal cancer. Interleukin-6 has been described as a key regulator of colorectal cancer development and is important in the process of colorectal tumorigenesis largely through the regulation of tumor-promoting inflammation. Several studies have reported the association of various polymorphisms in human interleukin-6 gene including IL-6 −174G/C single nucleotide polymorphism with various cancers, including colorectal cancer, but the results are mixed and inconclusive.

The aim of this study was to analyze the association of IL-6 −174G/C promoter single nucleotide polymorphism with colorectal cancer risk and also to evaluate the modifying effects of possible IL-6 −174G/C single nucleotide polymorphism genotypes on different risk factors of colorectal cancer or the reciprocal effect in ethnic Kashmiri population through a case control setup. The genotype frequencies of IL-6 −174G/C promoter single nucleotide polymorphism were compared between 142 colorectal cancer patients and 184 individually matched healthy controls by using polymerase chain reaction–restriction fragment length polymorphism method. The association between the IL-6 −174G/C single nucleotide polymorphism and colorectal cancer risk was examined through conditional logistic regression models adjusted for multiple possible confounding (third) variables. The possible effect measure modification of the association between the relevant single nucleotide polymorphism genotypes and colorectal cancer risk by various colorectal cancer risk factors including age, gender, and smoking status was also evaluated. Furthermore, the associations between these single nucleotide polymorphisms and various clinicopathological parameters, demographic variables, and environmental factors within the case group subjects with regard to colorectal cancer risk were also analyzed.

The overall association between the IL-6 −174G/C single nucleotide polymorphism and the modulation of colorectal cancer risk was found to be highly significant (p = 0.001). The variant genotype (CC) was significantly associated with a decreased risk of colorectal cancer (odds ratio, 0.15 (95% confidence interval, 0.04–0.54); p = 0.004). Furthermore, the less common IL-6-174C allele was associated with a decreased risk of colorectal cancer (odds ratio, 0.49 (95% confidence interval, 0.33–0.73); p = 0.0006). The combined variant genotype (GC + CC) was also significantly associated with a decreased risk of colorectal cancer (odds ratio, 0.54 (95% confidence interval, 0.33–0.89); p = 0.015).

This study demonstrates that there is a strong and highly significant association between the IL-6 −174G/C promoter single nucleotide polymorphism and a decreased risk of colorectal cancer in ethnic Kashmiri population. However, in order to substantiate our findings, this study needs to be replicated with larger sample size and with other ethnically defined populations with comparable colorectal cancer incidence.

Study of IL4-590C/T and IL6-174G/C Gene Polymorphisms in Type 2 Diabetic Patients With Chronic Kidney Disease in North Indian Population

To explore the associations between potential functional promoter polymorphisms in pro-inflammatory and anti-inflammatory (IL-4(-590C/T) and IL-6(-174G/C) cytokine genes, and kidney dysfunction in North Indian type 2 diabetic subjects with chronic kidney disease. A total of 150 subjects aged 25-75 year were included in this study. The glomerular filtration rate (GFR) and serum creatinine were estimated. PCR was performed to analyse genotype distribution in IL-4 (-590T/C) and IL-6 (-174G/C) among healthy, type 2 diabetic patients with or without CKD. The genotype distributions were determined by Hardy-Weinberg equilibrium. CKD patients showed lower GFR (59.36 ± 1.33 ml/min/1.73 m² ) and higher serum creatinine (1.93 ± 0.99% mg) level in comparison to diabetic patients without CKD and healthy subjects. Genotypic distribution of the different genotypes among the study groups in IL-4 gene was genotype CC = 30, TC = 12, and TT = 8 in CKD patients. In type 2 diabetic patients without CKD, genotype distribution was CC = 38, TC = 10, and TT = 2. In healthy subjects, distribution of genotype was CC = 35, TC = 14, and TT = 1. The distribution of different genotype among the study groups for IL-6 gene was GG = 27, GC = 20, and CC = 3 in healthy subjects; GG = 28, GC = 19, and CC = 3 in diabetic patients without CKD and GG = 38, GC = 11, and CC = 1 in diabetic patients with CKD. There was no significant difference in the distribution of genotype frequencies between healthy subjects and diabetic patients without CKD but a significant difference was found in diabetic patients with CKD. The functional promoter polymorphisms IL4-590C/T and IL6-174G/C, which affect the IL-4 and IL-6 levels in north Indian subjects, were associated with kidney dysfunction and CKD. J. Cell. Biochem. 118: 1803-1809, 2017. © 2016 Wiley Periodicals, Inc.

IL6-174 G>C Polymorphism (rs1800795) Association with Late Effects of Low Dose Radiation Exposure in the Portuguese Tinea Capitis Cohort

Head and neck cancers, and cardiovascular disease have been described as late effects of low dose radiation (LDR) exposure, namely in tinea capitis cohorts. In addition to radiation dose, gender and younger age at exposure, the genetic background might be involved in the susceptibility to LDR late effects. The -174 G>C (rs1800795) SNP in IL6 has been associated with cancer and cardiovascular disease, nevertheless this association is still controversial. We assessed the association of the IL6-174 G>C SNP with LDR effects such as thyroid carcinoma, basal cell carcinoma and carotid atherosclerosis in the Portuguese tinea capitis cohort. The IL6-174 G>C SNP was genotyped in 1269 individuals formerly irradiated for tinea capitis. This sampling group included thyroid cancer (n = 36), basal cell carcinoma (n = 113) and cases without thyroid or basal cell carcinoma (1120). A subgroup was assessed for atherosclerosis by ultrasonography (n = 379) and included matched controls (n = 222). Genotypes were discriminated by real-time PCR using a TaqMan SNP genotyping assay. In the irradiated group, we observed that the CC genotype was significantly associated with carotid plaque risk, both in the genotypic (OR = 3.57, CI = 1.60–7.95, p-value = 0.002) and in the recessive (OR = 3.02, CI = 1.42–6.42, p-value = 0.004) models. Irradiation alone was not a risk factor for carotid atherosclerosis. We did not find a significant association of the IL6-174 C allele with thyroid carcinoma or basal cell carcinoma risk. The IL6-174 CC genotype confers a three-fold risk for carotid atherosclerotic disease suggesting it may represent a genetic susceptibility factor in the LDR context.

Helicobacter pylori infection and gastric carcinoma: Not all the strains and patients are alike

Gastric carcinoma (GC) develops in only 1%-3% of Helicobacter pylori (H. pylori) infected people. The role in GC formation of the bacterial genotypes, gene polymorphisms and host's factors may therefore be important. The risk of GC is enhanced when individuals are infected by strains expressing the oncoprotein CagA, in particular if CagA has a high number of repeats containing the EPIYA sequence in its C'-terminal variable region or particular amino acid sequences flank the EPIYA motifs. H. pylori infection triggers an inflammatory response characterised by an increased secretion of some chemokines by immunocytes and colonised gastric epithelial cells; these molecules are especially constituted by proteins composing the interleukin-1beta (IL-1β) group and tumour necrosis factor-alpha (TNF-α). Polymorphisms in the promoter regions of genes encoding these molecules, could account for high concentrations of IL-1β and TNF-α in the gastric mucosa, which may cause hypochlorhydria and eventually GC. Inconsistent results have been attained with other haplotypes of inflammatory and anti-inflammatory cytokines. Genomic mechanisms of GC development are mainly based on chromosomal or microsatellite instability (MSI) and deregulation of signalling transduction pathways. H. pylori infection may induce DNA instability and breaks of double-strand DNA in gastric mucocytes. Different H. pylori strains seem to differently increase the risk of cancer development run by the host. Certain H. pylori genotypes (such as the cagA positive) induce high degrees of chronic inflammation and determine an increase of mutagenesis rate, oxidative-stress, mismatch repair mechanisms, down-regulation of base excision and genetic instability, as well as generation of reactive oxygen species that modulate apoptosis; these phenomena may end to trigger or concur to GC development.

A study on the effect of IL-6 gene polymorphism on the prognosis of non-small-cell lung cancer

Background

Lung cancer is one of the most commonly diagnosed clinical diseases. IL-6 is a multifunctional cytokine that is related to chemotactic factors and tumor biological regulation. −174G/C polymorphism in the promoter region of the IL-6 gene single-nucleotide polymorphism is the −174 position change from G to C. However, the relationship between the IL-6 gene polymorphism and prognosis of lung cancer is elusive. Therefore, the aim of this study was to evaluate the effect of −174G/C polymorphism on the prognosis of patients with non-small-cell lung cancer (NSCLC).

Methods

DNA was extracted from the peripheral blood of 434 cases diagnosed with NSCLC by cytologic or histologic examination. Polymerase chain reaction–restriction fragment length polymorphism (NlaIII) was used to detect the genotype of −174G/C. Based on the functional activity of the IL-6 gene polymorphism, genotypes were divided into G vector (CG/GG) (high yield) and CC genotype (low yield). Prognosis of patients was analyzed and independent risk factors evaluated. A quantitative analysis of the degree of pain after diagnosis was performed to evaluate the correlations between gene polymorphisms and the degree of pain and use of analgesics.

Results

Survival analysis showed that survival of the patients carrying the G allele (CG/GG) was significantly lower than that of patients with CC genotype (42.31 versus 62.79 months; P=0.032). The IL-6 gene promoter region revealed the presence of polymorphic variants, which may be associated with changes in the gene transcription process that affect the level of serum cytokines. IL-6 −174G/C gene polymorphism is associated with a significant morphine equivalent daily dose (IL-6 GG, 69.61; GC, 73.17; CC, 181.67; P=0.004). Homozygous IL-6 −174C/C genotype carriers required higher doses of opioids than GG or GC carriers.

Conclusion

Polymorphism of −174G/C in IL-6 is closely related to cancer pain in NSCLC patients, the use of analgesics, and survival prognosis. It is necessary to further confirm the related results and determine the underlying pathogenic mechanisms.

Interleukin-12 and interleukin-6 gene polymorphisms and risk of bladder cancer in the Iranian population

Interleukin-12 (IL-12) as an antitumor and interleukin-6 (IL-6) as an inflammatory cytokine, are immunomodulatory products that play important roles in responses in cancers and inflammation. We tested the association between two polymorphisms of IL-12(1188A>C; rs3212227) and IL-6 (-174 C>G) and the risk of bladder cancer in 261 patients and 251 healthy individuals. We also investigated the possible association of these SNPs in patients with high-risk jobs and smoking habits with the incidence of bladder cancer. The genotype distributions of IL-6 (-174 C/G) genotype were similar between the cases and the control groups; however, among patients with smoking habits, the association between IL-6 gene polymorphism and incidence of bladder cancer was significant. After a control adjustment for age and sex, the following results were recorded: CC genotype (OR= 2.11, 95%CI=1.56-2.87, p=0.007), GC genotype (OR=2.18, 95%CI=1.16-4.12, p=0.014) and GC+ CC (OR=2.6, 95%CI=1.43-4.47, p=0.011). A significant risk of bladder cancer was observed for the heterozygous genotype (AC) of IL-12 (OR=1.47, 95%CI=1.01-2.14, p=0.045) in all cases, and among smokers (AC) (OR=3.13, 95%CI=1.82-5.37, p=0.00014), combined AC+CC (OR=3.05, 95%CI=1.8-5.18, p=0.000015). Moreover among high risk job patients, there was more than a 3-fold increased risk of cancer in the carriers of IL-12 beta heterozygous (OR=3.7, 95%CI=2.04-6.57, p=0.000056) and combined AC+CC(OR=3.29, 95%CI=1.58-5.86, p=0.00002) genotypes as compared with the AA genotype with low-risk jobs. As a conclusion, this study suggests that IL-12(3'UTR A>C) and IL-6 (-174 C>G) genotypes are significantly associated with an increased risk of bladder cancer in the Iranian population with smoking habits and/or performing high-risk jobs.

Meta-analysis of the associations between TNF-α or IL-6 gene polymorphisms and susceptibility to lung cancer

BACKGROUND

Several studies have indicated an association between tumor necrosis factor-alpha (TNF-α) or interleukin (IL)-6 gene polymorphisms and lung cancer risk. However, the conclusions remain controversial.

METHODS

An English literature screening about case-control trials with regard to TNF-α (-308G/A) or IL-6 (174G/C) polymorphisms and lung cancer susceptibility was performed on PubMed, EMBASE, and EBSCO until November 2012. The pooled odds ratio (OR) and 95% confidence intervals (CI) were calculated using STATA 11.0. Sensitivity analysis was performed by sequential omission of individual studies. Publication bias was evaluated by Egger's linear regression test and funnel plots.

RESULTS

Eight eligible studies, including 1,690 patients and 1,974 controls, were identified in this meta-analysis. Compared with the control, no significant association was revealed between TNF-α-308G/A (GG + GC vs. CC: OR = 1.10, 95% CI: 0.73 to 1.64; GG vs. GC + CC: OR = 1.02, 95% CI: 0.81 to 1.27; GC vs. CC: OR = 1.13, 95% CI: 0.73 to 1.77; GG vs. CC: OR = 1.04, 95% CI: 0.80 to 1.36; G vs. C: OR = 1.03, 95% CI: 0.90 to 1.18) or IL-6 174G/C (GG + GC vs. CC: OR = 1.10, 95% CI: 0.73 to 1.64; GG vs. GC + CC: OR = 1.02, 95% CI: 0.81 to 1.27; GC vs. CC: OR = 1.13, 95% CI: 0.73 to 1.77; GG vs. CC: OR = 1.04, 95% CI: 0.80 to 1.36; G vs. C: OR = 1.03, 95% CI: 0.90 to 1.18) and lung cancer risk. The pooled OR remained unchanged after removing the maximum-weight study and no publication bias was observed.

CONCLUSIONS

The study raises the possibility of no correlation between the polymorphisms of the two genes and lung cancer susceptibility. However, further researches with large-sample or subgroup analyses are necessary to validate the conclusions.

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.

Interleukin 6 -174G>C polymorphism and cancer risk: meta-analysis reveals a site dependent differential influence in Ancestral North Indians

In our earlier studies, single nucleotide polymorphisms (SNPs) associated with anti-inflammatory cytokines were found to influence risk for breast cancer in western Indian women. Analysis of Interleukin 6 (IL-6) -174G>C polymorphism in this cohort (patients = 182; controls = 236) suggested a protective role for IL-6 -174C allele associated with the lower expression of the cytokine (OR = 0.54; 95% CI 0.32-0.89, dominant model). Together these observations suggested that in comparison to Caucasians, inflammation associated-cytokine gene polymorphisms may have higher influence on risk for cancer in this population. To examine this possibility we analyzed data assessing influence of Interleukin 6 (IL-6) -174G>C polymorphism on risk for various cancers. Overall, there was a marginally higher risk for rare allele homozygotes compared to wild type homozygotes (OR = 1.07; 95% CI 1.00-1.15). Increased risks for genitourinary cancers and for skin cancer were also indicated. The ethnicity based analysis indicated a protective effect of the minor allele in Ancestral North Indians (OR = 0.73; 95% CI 0.55-0.97). Site by ethnicity analysis once again revealed a significant protection against breast cancer (OR = 0.51; 95% CI = 0.37-0.70; dominant model) but an opposite influence on the risk of genitourinary malignancies (OR = 2.51; 95% CI 1.59-3.96; recessive model) in this population alone. The observations imply that contribution of IL-6 to inflammation or effector immunity may depend on the site of malignancy. Assessment of available data in relation to prognosis in breast cancer patients also revealed trends that are compatible with the observations of the meta-analysis. Thus, IL-6 -174G>C polymorphism clearly represents a potential modulator of risk for malignant disorders with ethnicity and site dependent trends. The results also support the possibility of higher influence of inflammation related cytokine gene polymorphisms on the risk for cancers in Ancestral North Indians.

Ethnic variation in interleukin-6 -174 (g/c) polymorphism in the malaysian population

Interleukin-6 (IL-6) is one of the cytokines that has been well studied and implicated in many diseases including cancers. The frequency of the IL-6 –174 (G/C) polymorphism had been proven to differ in various populations. Malaysia is a country with three major ethnic populations, Malays, Chinese and Indians. In this study, we proposed to determine the G or C allele frequency of the IL-6 –174 polymorphism in these three populations. A total of 348 blood samples were available for analysis. The median age for the subjects was 31 years. There were a total of 245 males and 103 females. A total of 86 Malays (25.0%), 122 Chinese (33.0%) and 140 Indians (40.0%) were genotyped. The result showed a significant difference in the G or C allele frequency of the –174 polymorphism. The total frequencies for the G and C alleles were 91.0 and 9.0%, respectively. In the Malays, the allele frequency of the C allele was 4.0% compared with 19.0% in the Indians. The C allele was not detected in the Chinese population. This finding is the first reported on the Malaysian population and may be important in determining risk of diseases associated with the IL-6 polymorphism in these three populations.

The association of the 174G>C polymorphism of interleukin 6 gene with diabetic nephropathy in patients with type 2 diabetes mellitus

AIMS

To evaluate the association of 174G>C polymorphism on interleukin-6 (IL-6) gene with diabetic nephropathy in patients with type 2 diabetes.

METHODS

A total of 393 Greek subjects with type 2 diabetes (mean age 66.5±10.0years, men n=203, women n=190) were examined. Diabetic nephropathy was defined as presence of microalbuminuria and/or proteinuria. The IL-6 174G>C polymorphism was detected by polymerase chain reaction and appropriate restriction enzyme digestion. High sensitivity C-reactive protein was assayed by particle-enhanced immunonephelometry.

RESULTS

The genotype distribution (%) was GG: 49.1, GC: 26.8 and CC: 24.1, with no gender difference. The CC homozygotes had lower albumin excretion (mg/24h) in comparison with the GC genotype [CC: 8.9 (4.0-20.9) vs GC: 21.95 (9.1-53.35), P=0.004]. Participants with the GC genotype tended to have more frequently nephropathy than those with the GG or the CC genotype [GC: 44.55% vs GG: 35.1% and CC: 28.3%, P=0.07)]. The CC homozygotes in comparison with GC heterozygotes had lower odds to have nephropathy (odds ratio: 0.51, 95% confidence intervals=0.28-0.91, P=0.02), even after adjustment for sex, age, duration of diabetes, body mass index, smoking, hypertension, lipids and glycated hemoglobin, (P=0.01).

CONCLUSION

In type 2 diabetes states, CC homozygotes have lower albumin excretion and are protected from nephropathy in comparison with GC genotypes.

A two-SNP IL-6 promoter haplotype is associated with increased lung cancer risk

BACKGROUND

Aberrant expression of interleukin-6 (IL-6) may play an important role in lung carcinogenesis. Whether IL-6 promoter haplotypes are associated with lung cancer risk and their functions have not yet been studied. We tested the hypothesis that single-nucleotide polymorphism (SNP) and/or haplotypes of IL-6 promoter are associated with risk of lung cancer.

METHODS

Two functional IL-6 promoter SNPs (-6331T>C and -572C>G) were genotyped in the discovery group including 622 patients and 614 controls, and the results were replicated in an independent validation group including 615 patients and 638 controls. Luciferase reporter gene assays were conducted to examine the function of IL-6 promoter haplotypes.

RESULTS

None of the functional IL-6 promoter SNPs were associated with lung cancer risk in either study. However, a two-SNP CC (-6331C and -572C) IL-6 promoter haplotype was significantly more common among cases than among controls in both groups (P = 0.031 and P = 0.035, respectively), indicating that this haplotype is associated with increased lung cancer risk {adjusted odds ratio [OR], 1.56 [95 % confidence interval (95 % CI), 1.04-2.34] and 1.51 [95 % CI, 1.03-2.22], respectively}. Combined analysis of both studies showed a strong association of this two-SNP haplotype with increased lung cancer risk (adjusted OR, 1.53; 95 % CI, 1.16-2.03; P = 0.003). Comparably, luciferase reporter assays of A549 lung cancer cell lines transfected with the CC haplotype revealed that the two-SNP haplotype had significantly higher IL-6 transcriptional activity compared with cells transfected with the common haplotype.

CONCLUSIONS

This is the first evidence of identifying an IL-6 promoter haplotype (CC) associated with increased risk of lung cancer.