Gene expression polymorphisms of interleukins-1 beta, -4, -6, -8, -10, and tumor necrosis factors-alpha, -beta: regression analysis of their effect upon oral squamous cell carcinoma

Dürsteler K, Beatrix Brühl A, Cordier D, Sadeghi-Bahmani D. Association between IL-8 (-251T/A) and IL-6 (-174G/C) Polymorphisms and Oral Cancer Susceptibility: A Systematic Review and Meta-Analysis

Background and objective: Inflammation and cell-mediated immunity can have significant roles in different stages of carcinogenesis. The present meta-analysis aimed to evaluate the association between the polymorphisms of IL-8 (-251T/A) and IL-6 (-174G/C) and the risk of oral cancer (OC). Methods: PubMed/MEDLINE, Web of Science, Cochrane Library, and Scopus databases were searched until December 18, 2020 without any restrictions. RevMan 5.3 software was used to calculate the results of forest plots (odds ratios (ORs) and 95% confidence intervals (CIs)); CMA 2.0 software was used to calculate funnel plots (Begg’s and Egger’s tests), and SPSS 22.0 was used for the meta-regression analysis. Moreover, trial sequential analysis was conducted to estimate the robustness of the results. Results: Eleven articles including twelve studies were selected for the meta-analysis. The pooled ORs for the association between IL-8 (-251T/A) polymorphism and the risk of OC in the models of A vs. T, AA vs. TT, TA vs. TT, AA + TA vs. TT, and AA vs. TT + TA were 0.97 (p = 0.78), 0.86 (p = 0.55), 0.78 (p = 0.37), 0.83 (p = 0.45), and 1.10 (p = 0.34), respectively. The pooled ORs IL-6 (-174G/C) polymorphism and the risk of OC in the models of C vs. G, CC vs. GG, GC vs. GG, CC + GC vs. GG, and CC vs. GG + GC were 1.07 (p = 0.87), 1.17 (p = 0.82), 1.44 (p = 0.38), 1.28 (p = 0.61), and 0.96 (p = 0.93), respectively. There was no association between IL-8 (-251T/A) polymorphism and OC susceptibility, but the C allele and GC and CC genotypes of IL-6 (-174G/C) polymorphism were associated with the risk of OC based on subgroup analyses, that is to say, the source of control and the genotyping method might bias the pattern of association. Conclusions: The meta-analysis confirmed that there was no association between the polymorphisms of IL-6 (-174G/C) and IL-8 (-251T/A) and the susceptibility of OC. However, the source of control and the genotyping method could unfavorably impact on the association between the polymorphisms of IL-6 (-174G/C) and the risk OC.

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.

Association between interleukin-10 gene polymorphisms and risk of oral carcinoma: A meta-analysis

BACKGROUND

The single nucleotide polymorphisms (SNPs) of Interleukin-10 (IL-10) gene have been linked with the risk of oral carcinoma (OC) in a relatively small sample size. Our study aims to investigate the pooled associations by conducting a meta-analysis of published studies.

METHODS

PubMed, Web of Science and Google Scholar databases were searched to identify eligible studies published in English before October 2019. The odds ratio (OR) with a 95% confidence interval (CI) was used to assess association. The publication bias was detected by Begg's test. Sensitivity and cumulative analyses were performed to evaluate the stability of crude results.

RESULTS

The meta-analysis involved eight studies. Significant associations were certified between IL-10 gene -1082A/G polymorphism and susceptibility of OC for A vs. G (OR=1.817, 95% CI: 1.481-2.230), AA vs. GG (OR=3.436, 95% CI: 2.281-5.175), dominant genetic model (OR=2.913, 95% CI: 1.939-4.376), and recessive genetic model (OR=1.886, 95% CI: 1.372-2.594) in overall population, East Asians and South Asians. In addition, the significant association between -592A/C polymorphism of the gene and susceptibility of OC were detected in South Asians.

CONCLUSIONS

The meta-analysis results support that the IL-10 gene -1082G allele is a risk factor for OC in East Asians and South Asians, and IL-10 gene -592C allele is a protective factor for the disease.

Association study indicates combined effect of interleukin-10 and angiotensin-converting enzyme in basal cell carcinoma development

Cytokines involved in inflammatory and immune response have been associated with risk for development of basal cell carcinoma (BCC). In this study, three functional DNA polymorphisms affecting gene expression were investigated in 54 BCC patients and 111 healthy controls: interleukin-1b (IL-1b) +3953C/T, interleukin-10 (IL-10) - 1082G/A and angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphisms. Significant increase of the variant alleles was observed in IL-10 - 1082G (P = 0.019) and in ACE D (P = 0.003) in BCC patients in comparison to controls. Multivariate logistic regression models evaluated the contribution of homozygous and heterozygous variant polymorphisms to the risk for BCC development. The studied polymorphisms influencing the expression of IL-10 and ACE genes were recognized as potential predictive factors for BCC. These findings suggest a possible molecular mechanism leading to BCC development that is likely to involve the activation of angiotensin receptors in combination with increased plasma levels of IL-10 in patients.

Increased Phosphatidylserine on Blood Cells in Oral Squamous Cell Carcinoma

The specific function of phosphatidylserine (PS) in the context of the development of a hypercoagulable state among individuals with oral squamous cell carcinoma (OSCC) is uncertain. The goal of this study was therefore to assess the exposure of PS on microparticles (MPs) as well as on endothelial and blood cells and to assess procoagulant activity (PCA) as a function of the stage of OSCC progression. We recruited patients with OSCC (n = 63) as well as healthy controls (n = 26) to participate in this study. PS exposure was then assessed via confocal microscopy and flow cytometry, revealing that patients with stage III/IV OSCC exhibited higher frequencies of PS-exposing blood cells, MPs, and serum-cultured endothelial cells (ECs) than did patients with stage I/II OSCC or healthy controls. When we conducted functional coagulation assays, we discovered that PS⁺ blood cells, MPs, and serum-cultured ECs from patients with stage III/IV OSCC mediated more rapid coagulation and more substantial production of FXa, thrombin, and fibrin as compared with controls. When samples were treated with the PS antagonist lactadherin, this resulted in an 80% disruption of PCA. Strikingly, when pre- and postoperative samples were compared from patients with stage III/IV OSCC undergoing resective surgery, PCA was significantly reduced in the postoperative samples. After stimulating ECs with inflammatory cytokines, we found by confocal microscopy that they expose PS on their cell membranes, thus generating FVa and FXa binding sites and mediating the formation of fibrin. Together our findings provide evidence that PS⁺ blood cells and MPs are important mediators of the development of a hypercoagulable and prothrombotic state among individuals afflicted by advanced-stage OSCC. As such, a PS blockade may be a viable therapeutic strategy for treating such patients.

Association of Interleukin-10 Genotypes and Oral Cancer Susceptibility in Selected Malaysian Population: A Case- Control Study

Background:

Interleukin-10 (IL10) genotypes have been closely correlated to the susceptibility for oral squamous cell carcinoma. More than half of oral cancers in the world occur in Asia with estimated 168,850 new cases were diagnosed in this geographical region alone. Considering the rising numbers of oral cancer cases in Malaysia, association of IL10 A1082G gene polymorphism was correlated.

Methodology:

41 oral squamous cell carcinoma (OSCC) cases and 48 healthy controls of comparable age, gender, and with habits like smoking, alcohol consumption and betel quid chewing were selected. In this case-control study, samples were collected from the Oral Cancer Research and Coordinating Centre (OCRCC), Faculty of Dentistry, University of Malaya, Malaysia. Genotyping conditions were evaluated by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). The PCR products were subjected to digestion by MnlI enzyme (NEB, UK) to screen for the IL10 A-1082G. Digested DNA products were analyzed by electrophoresis on 4% (w/v) agarose gel, stained with ethidium bromide and imaged under UV illumination. Chi-square test and Fisher’s Exact test were used in statistical analysis.

Results:

AG genotypes were present in 81.3% and 86.0% of healthy control and OSCC cases respectively (OR=0.468, 95% CI=0.133-1.653). No significant association was found between IL10 A1082G polymorphism with risk habits, clinico-pathological parameters and 5-years overall survival. The findings also show no significant correlation between the IL10 genotype and features of OSCC within the case group as measured by tumor size, lymph node involvement, stage, invasive front, grading, depth, pattern of invasion.

Conclusion:

This study suggests that functional polymorphism AG of IL10 A1082G may have no influence with OSCC susceptibility. However, further investigation with larger sample sizes can be conducted to provide additional evidence to support the lack of association of IL10 A1082G polymorphism in oral cancer.

[Relationship between interleukins in the saliva and oral cavity cancer]

Saliva is being attached great importance for its application in illness diagnosis and have more advantage on the diagnose in oral cavity cancer (OCC). Studies have showed that interleukin (IL) in the saliva could be used as a potential biomarker for OCC diagnosis. Moreover, they have a close connection with tumor genesis, invasion, and metastasis in OCC. Therefore, we reviewed research progress on the relationship between salivary interleukins and OCC.

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.

Associations of common IL-4 gene polymorphisms with cancer risk: A meta-analysis

Cancer incidence is dramatically increasing worldwide, therefore improved prediction and therapeutic methods are needed. Single nucleotide polymorphisms in cytokine genes may contribute to carcinogenesis. Interleukin (IL)-4 gene polymorphisms have been intensively studied with regard to their associations with cancer. However, the results of these previous studies remain inconclusive. The present study, therefore, aimed to conduct a meta-analysis of previously published studies in order to clarify the association of IL-4 with cancer risk. Eligible published articles were searched in Medline, PubMed, Embase and China National Knowledge Infrastructure databases up to March 2016. Odds ratios and 95% confidence intervals were used to identify potential associations between IL-4 genetic polymorphisms and the risk of cancer. A meta-analysis was then performed on 10,873 patients and 14,328 controls for IL-4 rs2243250 polymorphism, 3,970 patients and 5,686 controls for IL-4 rs2070874 polymorphism, and 1,896 patients and 2,526 controls for IL-4 rs79071878 polymorphism. A significant association with cancer risk was observed for rs2243250 and rs79071878 polymorphisms. In the subgroup analysis by cancer type, rs2243250 polymorphism was demonstrated to be associated with an increased risk of gastric cancer and breast cancer, rs2070874 polymorphism was correlated with leukemia and oral carcinoma, and rs79071878 polymorphism was relevant to bladder carcinoma risk. In the subgroup analysis by ethnicity, IL-4 rs2243250 polymorphism was demonstrated to be associated with cancer risk in both Caucasian and Asian populations, rs2070874 was associated with cancer risk in Asian populations, while rs79071878 polymorphism was associated with cancer risk in Caucasian populations. In conclusion, the present results suggested that the IL-4 rs2243250 and rs79071878 polymorphisms were associated with cancer susceptibility. Further subgroup analyses revealed that the effects of IL-4 gene polymorphisms on cancer risk may vary by cancer type and by ethnicity.

No association of TNF-α-308G/A polymorphisms with head and neck cancer risk: A PRISMA-compliant meta-analysis

BACKGROUND

A number of studies had reported the association between tumor necrosis factor-alpha (TNF-α) gene polymorphisms and head and neck cancer (HNC) risk. However, the results remained controversial. Therefore, we performed a meta-analysis to derive a more precise evaluation of the association between TNF-α-308G/A polymorphism and overall HNC risk and evaluated influence of cancer types and ethnicities.

METHODS

A systematic literature search was performed using Pubmed, Embase, Cochrane Library, and Web of science. In total, we identified 15 studies including 2005 cancer cases and 2876 controls to evaluate the association of TNF-α-308G/A polymorphism with risk for HNC.

RESULTS

Overall, there was no significant association between TNF-α-308G/A polymorphism and the risk of HNC. Furthermore, subgroup analyses were performed according to the types of tumor and the ethnicities, we also found there was no significant association between TNF-α-308G/A polymorphism and the risk of NPC and OC, and European and Asian populations had no statistically significant difference in the relationship of TNF-α-308G/A polymorphism and HNC susceptibility.

CONCLUSION

This meta-analysis indicates that the TNF-α-308G/A polymorphism is not associated with HNC risk. In the future, large and well-designed case-control studies are needed to validate our findings.

Single nucleotide polymorphisms in an Indian cohort and association of CNTN4, MMP2 and SNTB1 variants with oral cancer

Oral cancer is a high incidence cancer in India primarily due to the prevalent tobacco/areca nut chewing habits and hence a major health concern. India constitutes 26% of the global oral cancer burden. Besides the well-established risk factors, the genomic constitution of an individual plays a role in oral cancer. The aim of the current study was to analyse genomic variants represented as single nucleotide polymorphisms (SNPs), analyse their prevalence and investigate risk association of allelotypes/genotypes to oral cancers. Eleven SNPs in genes associated with biological functions were analysed in an Indian cohort (n = 1000) comprising 500 oral cancer patients and 500 long term tobacco habitués as controls, using Allelic discrimination Real-Time PCR assay with SYBR Green dye. Fisher's exact test and Odds Ratio were used for statistical analysis. Increased risk was observed for rs9849237 CC [P = 0.008; OR 1.412 (1.09-1.82)] and rs243865 CT [P = 0.004; OR 1.469 (1.13-1.90)] genotypes, whereas rs9849237 CT [P = 0.034; OR 0.755 (0.58-0.97)], rs243865 CC [P = 0.002; OR 0.669 (0.51-0.86)] and rs10090787 CC [P = 0.049; OR 0.774 (0.60-0.99)] genotypes indicated decreased risk to oral cancer. The other SNPs showed equidistribution in both groups. Our data indicated genotypes and alleles in specific SNPs rs9849237, rs243865 and rs10090787 with increased/decreased risk to oral cancer.

Emerging Cytokine Biosensors with Optical Detection Modalities and Nanomaterial-Enabled Signal Enhancement

Protein biomarkers, especially cytokines, play a pivotal role in the diagnosis and treatment of a wide spectrum of diseases. Therefore, a critical need for advanced cytokine sensors has been rapidly growing and will continue to expand to promote clinical testing, new biomarker development, and disease studies. In particular, sensors employing transduction principles of various optical modalities have emerged as the most common means of detection. In typical cytokine assays which are based on the binding affinities between the analytes of cytokines and their specific antibodies, optical schemes represent the most widely used mechanisms, with some serving as the gold standard against which all existing and new sensors are benchmarked. With recent advancements in nanoscience and nanotechnology, many of the recently emerging technologies for cytokine detection exploit various forms of nanomaterials for improved sensing capabilities. Nanomaterials have been demonstrated to exhibit exceptional optical properties unique to their reduced dimensionality. Novel sensing approaches based on the newly identified properties of nanomaterials have shown drastically improved performances in both the qualitative and quantitative analyses of cytokines. This article brings together the fundamentals in the literature that are central to different optical modalities developed for cytokine detection. Recent advancements in the applications of novel technologies are also discussed in terms of those that enable highly sensitive and multiplexed cytokine quantification spanning a wide dynamic range. For each highlighted optical technique, its current detection capabilities as well as associated challenges are discussed. Lastly, an outlook for nanomaterial-based cytokine sensors is provided from the perspective of optimizing the technologies for sensitivity and multiplexity as well as promoting widespread adaptations of the emerging optical techniques by lowering high thresholds currently present in the new approaches.

Host and clinical aspects in patients with benign migratory glossitis

OBJECTIVE

Investigate the association of clinical, cytological and genetic characteristics with benign migratory glossitis (BMG).

STUDY DESIGN

Sample consisted of 175 patients, 44 with BMG and 131 control patients. Clinical examination and DMFT index were assessed. Cytological evaluation determined cell morphology and morphometry. Genetic evaluation was performed by analysing IL6 polymorphisms by real-time PCR. Univariate and multivariate analyses were performed (p<0.05).

RESULTS

There was a higher level of anxiety, DMFT score and a prevalence of fissured tongue in BMG group. A high mean nuclear/cytoplasmic area ratio was observed in patients with BMG. There was predominance of Papanicolaou class II I BMG group. IL6 allele G rs2069843 polymorphism was associated with BMG in the dominant model. In multivariate analysis, DMFT and anxiety scale remained associated with BMG.

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.

Salivary Immunosuppressive Cytokines IL-10 and IL-13 Are Significantly Elevated in Oral Squamous Cell Carcinoma Patients

Oral squamous cell carcinoma (OSCC) is considered to be one of the most fatal diseases worldwide, owing to its late diagnosis and lack of availability of established reliable biomarkers. The aim of this study was to highlight the significance of immunosuppressive cytokines as potential biomarkers in OSCC. Whole unstimulated saliva was collected from each individual (30 OSCC patients and 33 age- and gender-matched healthy controls). Immunosuppressive cytokines, including IL-4, IL-10, IL-13, and IL-1RA, were evaluated in each sample using Luminex multianalyte profiling (xMAP) technology on BioPlex instrument. Our results showed that all the studied salivary cytokines were raised in OSCC patients as compared to controls, where IL-10 and IL-13 salivary levels showed statistically significant difference (p = .004 and p = .010, respectively). Mean levels of salivary cytokines in three histologically defined OSCC categories, compared employing one-way ANOVA, showed that salivary levels of IL-1RA were highest in patients having poorly differentiated OSCC tumors as compared to those having moderately and well-differentiated tumors (p = .000 and p = .002, respectively). Among OSCC individuals, duration of smokeless tobacco correlated positively with IL-1RA (p = .036). We conclude that salivary levels of immunosuppressive cytokines, IL-4, IL-10, IL-13, and IL-1RA, could prove to be potential biomarkers of OSCC and can be further investigated as markers of early detection and disease progression.

Combined expression of metastasis related markers Naa10p, SNCG and PRL-3 and its prognostic value in breast cancer patients

Combinations of multiple biomarkers representing distinct aspects of metastasis may have better prognostic value for breast cancer patients, especially those in late stages. In this study, we evaluated the protein levels of N-α-acetyltransferase 10 protein (Naa10p), synuclein-γ (SNCG), and phosphatase of regenerating liver-3 (PRL-3) in 365 patients with breast cancer by immunohistochemistry. Distinct prognostic subgroups of breast cancer were identified by combination of the three biomarkers. The Naa10p+SNCG-PRL-3- subgroup showed best prognosis with a median distant metastasis-free survival (DMFS) of 140 months, while the Naa10p-SNCG+PRL-3+ subgroup had the worst prognosis with a median DMFS of 60.5 months. Multivariate analysis indicated Naa10p, SNCG, PRL-3, and the TNM classification were all independent prognostic factors for both DMFS and overall survival (OS). The three biomarker combination of Naa10p, SNCG and PRL-3 performed better in patients with lymph node metastasis, especially those with more advanced tumors than other subgroups. In conclusion, the combined expression profile of Naa10p, SNCG and PRL-3, alone or in combination with the TNM classification system, may provide a precise estimate of prognosis of breast cancer patients.

Role of cytokine gene (interferon-γ, transforming growth factor-β1, tumor necrosis factor-α, interleukin-6, and interleukin-10) polymorphisms in the risk of oral precancerous lesions in Taiwanese

Oral squamous cell carcinoma can be preceded by some benign oral lesions with malignant potential, including leukoplakia, erythroplakia, oral lichen planus, and oral submucous fibrosis. There are different degrees of inflammatory cells infiltration in histopathology. Inflammatory cytokines may play a pathogenic role in the development of oral precancerous lesions (OPCLs). Genetic polymorphisms of cytokine-encoding genes are known to predispose to malignant disease. We hypothesized that the risk of OPCLs might be associated with cytokine gene polymorphisms of interferon (IFN)-γ, transforming growth factor (TGF)-β1, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10. In the present study, 42 OPCL patients and 128 controls were analyzed for eight polymorphisms in five different cytokine genes [IFN-γ (+874 T/A), TGF-β1 (codons 10 T/C and 25 G/C), TNF-α (-308 G/A), IL-6 (-174 G/C), and IL-10 (-1082 A/G, -819 T/C, and -592 A/C)]. Cytokine genotyping was determined by the polymerase chain reaction sequence-specific primer technique using commercial primers. Allele and genotype data were analyzed for significance of differences between cases and controls using the Chi-square (χ(2)) test. Two-sided p < 0.05 were considered to be statistically significant. A series of multivariate logistic regression models, adjusted for age, sex, betel quid chewing, alcohol consumption, and smoking, was constructed in order to access the contribution of homozygous or heterozygous variant genotypes of polymorphisms. The TNF-α (-308) polymorphism was significantly associated with OPCLs. There were significant differences in the distribution of AA, GA, and GG genotypes between OPCL patients and controls (p = 0.0004). Patients with the AA or GA genotype had a 3.63-fold increased risk of OPCLs. The TGF-β1 (codon 10 and 25) polymorphism was also significantly associated with OPCLs (p < 0.001). The IL-6 polymorphism was significantly associated with OPCLs. There are significant differences in the distribution of CC, GC, and GG genotypes between OPCL patients and controls (p < 0.001). Patients with the CC or GC genotype had a 35- or 20.59-fold increased risk of OPCLs. There were no significant differences in the distribution of IL-10 and IFN-γ genotypes between different groups of control individuals and OPCL patients. The IL-6, TGF-β1, and TNF-α gene polymorphisms may have a significant association with the development of OPCLs.

Association of IL-8-251A>T polymorphisms with oral cancer risk: evidences from a meta-analysis

The findings of associations between interleukin-8 (IL-8) polymorphisms and risk of oral cancer are controversial. We conducted a meta-analysis on the basis of data from all published studies to provide evidence of the current understanding of the genetic association with oral cancer. Eligible studies were identified by means of an electronic search of PubMed, Elsevier, ScienceDirect, EMBASE, EBSCO, and CBM databases for studies published up to March 2013. In accordance with the inclusion and exclusion criteria, a total of six eligible studies were included in the pooled analyses. In the overall analysis, we did not observe any significant associations between the IL-8-251A>T polymorphism and oral cancer risk under any of the genetic models (all P > 0.05). In the stratified analysis by ethnicity, Caucasian individuals with genotype AA had a higher risk of oral cancer under the dominant model (OR = 1.35, 95 % CI 1.09-1.67, P = 0.006). This meta-analysis indicated that the IL-8-251A>T polymorphism was not associated with the susceptibility of oral cancer, while individuals in the Caucasian population with genotype AA had a higher risk of oral cancer under the dominant model.

Cytokines and tumor metastasis gene variants in oral cancer and precancer in Puerto Rico

Objectives

A cross-sectional epidemiological study explored genetic susceptibility to oral precancer and cancer in Puerto Rico (PR).

Materials and Methods

Three hundred three individuals with a benign oral condition, oral precancer (oral epithelial hyperplasia/hyperkeratosis, oral epithelial dysplasia), or oral squamous cell carcinoma (SCCA) were identified via PR pathology laboratories. A standardized, structured questionnaire obtained information on epidemiological variables; buccal cells were collected for genetic analysis. Genotyping was performed using Taqman® assays. Allelic frequencies of single nucleotide polymorphisms (SNPs) were evaluated in cytokine genes and genes influencing tumor metastasis. Risk estimates for a diagnosis of oral precancer or SCCA while having a variant allele were generated using logistic regression. Adjusted models controlled for age, gender, ancestry, education, smoking and alcohol consumption.

Results

Relative to persons with a benign oral lesion, individuals with homozygous recessive allelic variants of tumor necrosis factor (TNF-α) −238 A/G SNP had a reduced odds of having an oral precancer (OR_adjusted = 0.15; 95% CI 0.03–0.70). The transforming growth factor beta-1 (TGFβ-1 −509 C/T) polymorphism was inversely associated with having an oral SCCA among persons homozygous for the recessive variant (OR_crude = 0.27; 95% CI 0.09–0.79). The matrix metalloproteinase gene (MMP-1) variant, rs5854, was associated with oral SCCA; participants with even one variant allele were more likely to have oral SCCA (OR_adjusted = 2.62, 95% CI 1.05–6.53) compared to people with ancestral alleles.

Conclusion

Our exploratory analyses suggest that genetic alterations in immune system genes and genes with metastatic potential are associated with oral precancer and SCCA risk in PR.

Positive association between lymphotoxin-alpha variation rs909253 and cancer risk: a meta-analysis based on 36 case-control studies

Lymphotoxin-alpha (LTA) polymorphism rs909253 has been reported to be a risk factor for cancers, but some results are inconsistent. To establish a more conclusive association, we performed a meta-analysis of this variant with cancers. A systematic search was performed for informative case-control studies of rs909253 with cancers among literature databases, including PubMed, Web of Science, Embase, China National Knowledge Infrastructure (CNKI), and Wanfang Chinese Periodical Database. After a comprehensive filtration procedure, 36 publications involved with 35,677 participants were selected for the current meta-analysis. Stratified factors, such as cancer type, populations, and source of control, were used for a better interpretation of this variant. Minimal heterogeneity was shown in the current meta-analysis (I (2) = 0.0%, P = 0.48). Our results show a significant association of rs909253 and cancer risk (odds ratio (OR) = 1.12, P (z) < 0.001). In the subgroup analysis, significant association of rs909253 was found in adenocarcinoma (OR = 1.16, P (z) < 0.001) and hematological malignancy (OR = 1.10, P (z) < 0.001). Our meta-analyses established a significant association of rs909253 with cancer risk among multiple populations including North Americans, Asians, and Europeans.

A high IL-4 production diplotype is associated with an increased risk but better prognosis of oral and pharyngeal carcinomas

OBJECTIVE

Interleukin (IL)-4 is a key cytokine in humoral and adaptive immunity. This study aimed to evaluate the association of IL-4 genetic variants (-590C>T and VNTR in intron 3) with the risk and prognosis of oral and pharyngeal squamous cell carcinoma (OPSCC).

DESIGN

A total of 1215 subjects, which included 623 healthy controls and 592 OPSCC cases (463 oral squamous cell carcinoma (OSCC) and 129 pharyngeal squamous cell carcinoma (PSCC) cases), were recruited. The genotypes were determined by TaqMan real-time assay and PCR-based assay.

RESULTS

The IL-4 genotypes at locus -590C>T and intron 3 VNTR were not correlated with increased risk of OSCC, PSCC, and OPSCC, with the exception of early-stage OPSCC (at -590C>T: T/T vs. C/C+C/T, adjusted odds ratio (AOR)=1.42, 95% CI: 1.02-1.98; at intron 3 VNTR: RP1/RP1 vs. RP2/RP2+RP2/RP1, AOR=1.46, 95% CI: 1.05-2.04). Compared with other IL-4 diplotypes, the T,RP1/T,RP1 diplotype was associated with an increased risk of OPSCC (AOR=1.37, 95% CI: 1.03-1.81), particularly early-stage OSCC (AOR=1.43, 95% CI: 1.02-2.00), PSCC (AOR=2.35, 95% CI: 1.06-5.19), and OPSCC (AOR=1.52, 95% CI: 1.10-2.11). Interactions between the IL-4 diplotype and the alcohol drinking status were found to contribute to the risk of early-stage OPSCC (p=0.024). In addition, the T,RP1/T,RP1 diplotype was correlated with better disease-specific survival (T,RP1/T,RP1 vs. other diplotypes, adjusted hazard ratio=0.70, 95% CI: 0.50-0.97).

CONCLUSION

The T, RP1/T, RP1 diplotype of IL-4 was associated with an increased risk but favourable prognosis of OPSCC.

Association of tumor necrosis factor-alpha promoter variants with risk of HPV-associated oral squamous cell carcinoma

Background

Tumor necrosis factor alpha (TNF-α) plays an important role in inflammation, immunity, and defense against infection and clearance of human papillomavirus (HPV). Thus, genetic variants may modulate individual susceptibility to HPV-associated oral squamous cell carcinoma (OSCC).

Methods

In this study we genotyped four common single nucleotide polymorphisms (SNPs) in the TNF-α promoter [ −308G > A(rs1800629), -857C > T (rs1799724), -863C > A (rs1800630), and -1031T > C (rs1799964)] and determined HPV16 serology in 325 OSCC cases and 335 matched controls and tumor HPV status in 176 squamous cell carcinomas of the oropharynx (SCCOP) patients. Univariate and multivariable logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

Results

We found that HPV16 seropositivity alone was associated with an increased risk of OSCC (OR, 3.1; 95% CI, 2.1–4.6), and such risk of HPV16-associated OSCC was modified by each SNP. Patients with both HPV16 seropositivity and variant genotypes for each SNP had the highest risk when using patients with HPV16 seronegativity and a wild-type genotype as a comparison group. Moreover, similar results were observed for the combined risk genotypes of four variants and all such significant associations were more pronounced in several subgroups, particularly in SCCOP patients and never smokers. Notably, the combined risk genotypes of four variants were also significantly associated with tumor HPV-positive SCCOP.

Conclusion

Taken together, these results suggest that TNF-α SNPs may individually or, more likely, jointly affect individual susceptibility to HPV16-associated OSCC, particularly SCCOP and never smokers. Validation of our findings is warranted.

Expression of oral cytokines in HIV-infected subjects with long-term use of antiretroviral therapy

OBJECTIVES

The objectives of this study were to determine (i) the expression of oral pro-inflammatory cytokines in HIV-infected subjects compared with non-HIV individuals, (ii) the cytokine expression in the subjects with antiretroviral therapy (ART) compared with those without ART, and (iii) factors associated with the expression of the cytokines.

MATERIALS AND METHODS

Oral examination was performed and saliva samples were collected and analyzed for the expression of pro-inflammatory cytokines using ELISA. Logistic regression analysis was performed to determine the association between HIV/ART status and the cytokine expression.

RESULTS

One hundred and fifty-seven HIV-infected subjects with and without ART, and 50 non-HIV individuals were enrolled. TNF-α and IL-6 in saliva were significantly decreased, while IL-8 was significantly increased in HIV infection (P < 0.05). Changes in the expression of IL-8 were also observed between HIV-infected subjects who were and were not on ART (P < 0.05). Duration of HIV infection and smoking was significantly associated with the expression of pro-inflammatory cytokines in saliva (P < 0.05).

CONCLUSION

Oral innate immunity is affected by HIV infection and use of ART. IL-8 may be the useful biomarker to identify subjects at risk of infection and malignant transformation due to HIV infection and long-term use of ART.

Three common polymorphisms in the IL-4 gene and cancer risk: a meta-analysis involving 5,392 cases and 6,930 controls

Interleukin-4 (IL-4) is a typical pleiotropic T helper 2 (Th2) cytokine. This cytokine is a critical mediator of the Th1/Th2 balance and apoptosis potential and involved in the process of inflammation-mediated carcinogenesis in human organs. IL-4 gene polymorphisms influence IL-4 transcription and have been implicated in cancer risks. However, current published data show conflicts among of them. To assess the relationship between IL-4 polymorphisms and cancer risks, we performed a meta-analysis which includes 14 studies involving 3,562 cancer cases for IL-4 rs2243250 polymorphism, 6 studies involving 2,052 subjects for IL-4 rs2070874 polymorphism, and 5 studies involving 791 subjects for IL-4 intron-3 polymorphism. As for rs2243250 polymorphism, no significant association of cancer risk was found in the overall analysis. When stratified by cancer type, we observed that the IL-4 rs2243250 polymorphism was significantly associated with decreased oral cancer risk and increased renal cell cancer risk (for oral cancer, TT vs. CC: odds ratio (OR) = 0.40, 95 % confidence interval (95 % CI) 0.19-0.84, P heterogeneity = 0.662, P = 0.016; TT/CT vs. CC: OR = 0.45, 95 % CI 0.22-0.94, P heterogeneity = 0.407, P = 0.033; and for renal cell cancer, TT vs. CC: OR = 1.98, 95 % CI 1.06-3.69, P heterogeneity = 0.535, P = 0.031; TT vs.

CC/CT

OR = 1.43, 95 % CI 1.05-1.95, P heterogeneity = 0.959, P = 0.022). For rs2070874 and intron-3 polymorphisms, no significant association of cancer risk was found in the overall analysis. However, in the subgroup analysis by source of controls and ethnicities, a significant association between cancer risk and rs2070874 polymorphism was found in population-based studies (A allele vs. G allele: OR = 1.18, 95 % CI 1.03-1.35, P heterogeneity = 0.621, P = 0.0172; AA vs.

AG/GG

OR = 1.23, 95 % CI 1.03-1.47, P heterogeneity = 0.196, P = 0.024) and Caucasian populations (A allele vs. G allele: OR = 1.24, 95 % CI 1.03-1.48, P heterogeneity = 0.925, P = 0.022), but not in Asian populations. Taken together, our results indicated that IL-4 rs2243250 polymorphism was associated with decreased oral cancer risk in both the homozygote contrasts and the dominant genetic model, as well as increased renal cell cancer risk in both the homozygote contrasts and the recessive genetic model. The A allele of rs2070874 polymorphism in the IL-4 gene may be a risk factor for cancer development among Caucasians. Further larger, preferably prospective studies are needed to confirm these results.

Association between -251A>T polymorphism in the interleukin-8 gene and oral cancer risk: a meta-analysis

BACKGROUND

Emerging evidence showed that the most common functional polymorphism (-251A>T, rs4073) in the promoter region of the interleukin-8 (IL-8) gene is involved in the regulation of the activities of interleukin-8, thus increasing an individual's susceptibility to oral cancer; but individually published results are inconclusive. The aim of this meta-analysis was to investigate the associations between IL-8 -251A>T polymorphism and oral cancer risk.

METHODS

The PubMed, Embase, Web of Science and CBM databases were searched for all articles published up to October 1st, 2012 that addressed IL-8 -251A>T polymorphism and oral cancer risk. Statistical analyses were performed using STATA 12.0 software. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

RESULTS

Six case-control studies were included with a total of 1324 oral cancer cases and 1879 healthy controls. When all available studies were pooled into the meta-analysis, the results showed that the AA and AT genotypes of IL-8 -251A>T polymorphism were associated with increased risk of oral cancer (OR=1.23, 95% CI: 1.03-1.46, P=0.025; OR=1.25, 95% CI: 1.07-1.47, P=0.006; respectively). In the subgroup analysis by ethnicity, significant associations were observed between the AA and AT genotypes of IL-8 -251A>T polymorphism and increased risk of oral cancer among Caucasian populations (OR=1.40, 95% CI: 1.14-1.72, P=0.001; OR=1.29, 95% CI: 1.06-1.57, P=0.011; respectively). However, no statistically significant associations were found between IL-8 -251A>T polymorphism and oral cancer risk among Asian populations.

CONCLUSIONS

Results from the current meta-analysis indicate that the AA and AT genotypes of IL-8 -251A>T polymorphism might increase the risk of oral cancer, especially among Caucasian populations.

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

Interleukin-6 (IL6) is a pleiotropic inflammatory cytokine, which is implicated in the development and progression of several types of cancer. The -174G/C polymorphism of the IL6 gene controls serum levels of IL6 and may be associated with cancer risk, but the results from the published studies on the association between this polymorphism and cancer risk are conflicting. A comprehensive meta-analysis was conducted to assess the association of IL6 -174G/C with cancer risk. Studies were identified by searches of MEDLINE and HuGE Published Literature databases, with no restrictions. An eligible 83 articles involving 44,735 cancer patients and 60,747 controls were included. Combined odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the association between the IL6 -174 G/C polymorphism and cancer risk. Potential sources of heterogeneity were explored by meta-regression and sensitivity analysis. Overall, the IL6 -174G/C polymorphism was not significantly associated with cancer risk. However, cancer risk was increased for individuals with the CC genotype compared to those carrying the GG genotype in African populations (OR=1.83, 95% CI 1.26-2.67, P=0.002), but not in Caucasian populations (OR=1.00, 95% CI 0.92-1.08, P=0.938). The present meta-analysis provides the first evidence of the ethnic-specific association of the IL6 -174G/C polymorphism with cancer risk. Further investigations with a large number of cases and controls are required to confirm the associations between this polymorphism and cancer in Africans.

Education, tobacco smoking, alcohol consumption, and IL-2 and IL-6 gene polymorphisms in the survival of head and neck cancer

The association of education, tobacco smoking, alcohol consumption, and interleukin-2 (IL-2 +114 and -384) and -6 (IL-6 -174) DNA polymorphisms with head and neck squamous cell carcinoma (HNSCC) was investigated in a cohort study of 445 subjects. IL-2 and IL-6 genotypes were determined by real-time PCR. Cox regression was used to estimate hazard ratios (HR) and 95% confidence intervals (95%CI) of disease-specific survival according to anatomical sites of the head and neck. Mean age was 56 years and most patients were males (87.6%). Subjects with 5 or more years of schooling had better survival in larynx cancer. Smoking had no effect on HNSCC survival, but alcohol consumption had a statistically significant effect on larynx cancer. IL-2 gene +114 G/T (HR = 0.52; 95%CI = 0.15-1.81) and T/T (HR = 0.22; 95%CI = 0.02-3.19) genotypes were associated with better survival in hypopharynx cancer. IL-2 +114 G/T was a predictor of poor survival in oral cavity/oropharynx cancer and larynx cancer (HR = 1.32; 95%CI = 0.61-2.85). IL-2 -384 G/T was associated with better survival in oral cavity/oropharynx cancer (HR = 0.80; 95%CI = 0.45-1.42) and hypopharynx cancer (HR = 0.68; 95%CI = 0.21-2.20), but an inverse relationship was observed for larynx cancer. IL-6 -174 G/C was associated with better survival in hypopharynx cancer (HR = 0.68; 95%CI = 0.26-1.78) and larynx cancer (HR = 0.93; 95%CI = 0.42-2.07), and C/C reduced mortality in larynx cancer. In general, our results are similar to previous reports on the value of education, smoking, alcohol consumption, and IL-2 and IL-6 genetic polymorphisms for the prognosis of HNSCC, but the risks due to these variables are small and estimates imprecise.

A review on salivary genomics and proteomics biomarkers in oral cancer

Oral cancer has emerged as an alarming public health problem with increasing incidence and mortality rates all over the world. Therefore, the implementation of newer screening and early detection approaches are of utmost importance which could reduce the morbidity and mortality associated with this disease. Sensitive and specific biomarkers for oral cancer are likely to be most effective for screening, diagnosis, staging and follow-up for this dreaded malignancy. Unlike other deep cancers, oral cancer is located in oral cavity. Hence, the direct contact between saliva and oral cancer lesion makes the measurement of tumor markers in saliva an attractive alternative to serum and tissue testing. The DNA, RNA and protein molecules derived from the living cancer cells can be conveniently obtained from saliva. Thus, salivary biomarkers, a non-invasive alternative to serum and tissue-based biomarkers may be an effective modality for early diagnosis, prognostication and monitoring post therapy status. In the current post-genomic era, various technologies provide opportunities for high-throughput approaches to genomics and proteomics; which have been used to evaluate altered expressions of gene and protein targets in saliva of oral cancer patients. The emerging field of salivary biomarkers has great potentials to prove its clinical significance to combat oral cancer. Hence, we have reviewed importance of several salivary genomics and proteomics biomarkers for oral cancer.

Polymorphisms of interleukin-4, -10 and 12B genes and diabetic retinopathy

In diabetic retinopathy (DR) and other angiogenesis-associated diseases, increased levels of cytokines, inflammatory cells, and angiogenic factors are present. We investigated the hypothesis that rs2243250 polymorphism of the interleukin 4 (IL-4) gene or rs1800896 polymorphism of the interleukin 10 (IL-10) gene, and rs3212227 polymorphism of the 3’ untranslated region (3’ UTR) of the interleukin-12 p40 gene (IL12B) may be associated with the development of proliferative diabetic retinopathy (PDR) in Caucasians with type 2 diabetes (DM2). This cross sectional case — control study included 189 patients with PDR and 187 patients with type 2 diabetes without PDR. Polymorphisms rs1800896 of the IL-10 gene, rs2243250 of the IL-4 gene, and rs3212227 of IL12B gene were analyzed by ARMS -PCR and RFLP -PCR methods. Multivariate analysis demonstrated the GG genotype of the rs1800896 polymorphism of the IL-10 gene to be associated with increased risk for PDR (OR=1.99; 95% CI=1.11–3.57; P=0.02), whereas the TT genotype of the rs2243250 polymorphism of the IL-4 gene and the AA genotype of the rs3212227 polymorphism of the IL-12 gene were not independent risk factors for PDR. Our findings suggest that the genetic variations at the IL-10 promoter gene might be a genetic risk factor for PDR in Caucasians with type 2 diabetes.

Interleukin-23 receptor polymorphism as a risk factor for oral cancer susceptibility

BACKGROUND

The purpose of this study was to evaluate the influence of genetic polymorphisms of interleukin (IL)-23 and the IL-23 receptor (IL-23R) on the susceptibility to oral cancer.

METHODS

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to measure polymorphisms of these genes in 240 controls and 240 patients with oral cancer.

RESULTS

Individuals with at least 1 varied C allele of rs10889677 (IL-23R polymorphism) had a 1.553-fold risk (95% confidence interval [CI], 1.073-2.241) of developing oral cancer compared with patients with the wild-type A/A homozygote. Patients with oral cancer with at least 1 varied C allele of rs10889677 had a 1.931-fold risk of tumor lymph node metastasis compared with patients with the C/C homozygote.

CONCLUSION

The varied C allele of the IL-23R gene may be considered a factor contributing to increased susceptibility and may be a predictive factor for tumor lymph node metastasis in Taiwanese with oral cancer.

Salivary cytokines in cell proliferation and cancer

While the presence of multiple systemic steroids, amines and peptides in saliva has been reported, other hormones of the circulation do not appear in saliva. Substances present within saliva may be classified in different groups: first, those which passively display blood plasma concentrations and constitute a promising alternative to evaluate certain systemic parameters. Second, molecules which seem to play a more active, regulatory role within the upper gastrointestinal tract. Concerning the latter, a growing awareness, especially with regards to salivary peptides has been established. Up to now, understanding the distinct effects of salivary peptides known so far is in its infancy. Various publications, however, emphasize important effects of their presence. Salivary peptides can influence inflammatory processes and cell proliferation in epithelia of the upper digestive tract. These include transforming growth factors (TGFs), epidermal growth factors (EGFs), vascular endothelial growth factors (VEGFs) as well as amines such as melatonin. Of those, candidate cytokines like interleukin 8, tumor necrosis factors (TNFs) and leptin are involved in neoplastic activities of salivary glands and the oral cavity. The exact mechanisms of action are not yet completely understood, but their presence can be utilized for diagnostic purposes. Salivary gland tumors in patients may, in certain circumstances, be identified by saliva diagnostics. Saliva samples of the concerned patients, for instance, reveal significantly higher leptin concentrations than those of healthy individuals. Numerous studies postulate that, beside single indicators, the establishment of salivary hormone profiles may assist clinicians and researchers in detecting tumors and other pathologies of the oral cavity, including adjacent tissues, with high sensitivity and specificity.

-251 T/A polymorphism of the interleukin-8 gene and cancer risk: a HuGE review and meta-analysis based on 42 case-control studies

The -251T/A (rs4073), a single nucleotide polymorphism, has been identified in the promoter region of the interleukin-8 (IL-8) gene. It's presence could influence the production of IL-8 protein by regulating the transcriptional activity of the gene. A large number of studies have been performed to evaluate the role of -251T/A polymorphism on various cancers, with inconsistent results being reported. In this paper, we summarized 13,189 cases and 16,828 controls from 42 case-control studies and attempted to assess the susceptibility of -251T/A polymorphism to cancers by a comprehensive meta-analysis. Pooled odds ratios and 95% confidence intervals were calculated by using the random-effects model. Publication bias, subgroup, and sensitivity analysis were also performed. Results showed that the carriers of the -251A allele had about a 12-21% increased risk for the reviewed cancer, in total. The carriers of -251A had an elevated risk to breast cancer, gastric cancer and nasopharyngeal cancer and a reduced risk to prostate cancer, but no evidence was found to indicate that the -251A allele predisposed its carriers to colorectal and lung cancers. When stratified separately by 'racial descent' and 'study design', it was found that the carriers of the -251A allele among the African group, Asian group and hospital-based case-control study group were at a higher risk for cancer, but not in European group and population-based case-control study. These results show that -251A allele is susceptible in the development of low-penetrance cancers.

Interleukin-6 promotes tumorigenesis by altering DNA methylation in oral cancer cells

Worldwide oral squamous cell carcinoma (OSCC) accounts for more than 100,000 deaths each year. Chronic inflammation constitutes one of the key risk factors for OSCC. Accumulating evidence suggests that aberrant DNA methylation may contribute to OSCC tumorigenesis. This study investigated whether chronic inflammation alters DNA methylation and expression of cancer-associated genes in OSCC. We established an in vitro model of interleukin (IL)-6 mediating chronic inflammation in OSCC cell lines. Thereafter, we measured the ability of IL-6 to induce global hypomethylation of long interspersed nuclear element-1 (LINE-1) sequences, as well as CpG methylation changes using multiple methodologies including quantitative pyrosequencing, methylation-specific multiplex ligation-dependent probe amplification and sensitive melting analysis after real-time-methylation-specific polymerase chain reaction (PCR). Gene expression was investigated by quantitative reverse transcriptase-PCR. IL-6 induced significant global LINE-1 hypomethylation (p=0.016) in our in vitro model of inflammatory stress in OSCC cell lines. Simultaneously, IL-6 induced CpG promoter methylation changes in several important putative tumor suppressor genes including CHFR, GATA5 and PAX6. Methylation changes correlated inversely with the changes in the expression of corresponding genes. Our results indicate that IL-6-induced inflammation promotes tumorigenesis in the oral cavity by altering global LINE-1 hypomethylation. In addition, concurrent hypermethylation of multiple tumor suppressor genes by IL-6 suggests that epigenetic gene silencing may be an important consequence of chronic inflammation in the oral cavity. These findings have clinical relevance, as both methylation and inflammation are suitable targets for developing novel preventive and therapeutic measures.

Single nucleotide polymorphisms of 8 inflammation-related genes and their associations with smoking-related cancers

Tobacco smoke and its metabolites are carcinogens that increase tissue oxidative stress and induce target tissue inflammation. We hypothesized that genetic variation of inflammatory pathway genes plays a role in tobacco-related carcinogenesis and is modified by tobacco smoking. We evaluated the association of 12 single nucleotide polymorphisms of 8 inflammation-related genes with tobacco-related cancers (lung, oropharynx, larynx, esophagus, stomach, liver, bladder, and kidney) using 3 case-control studies from: Los Angeles (population-based; 611 lung and 553 upper aero-digestive tract cancer cases and 1,040 controls), Taixing, China (population-based; 218 esophagus, 206 stomach, 204 liver cancer cases, and 415 controls), and Memorial Sloan-Kettering Cancer Center (hospital-based; 227 bladder cancer cases and 211 controls). After adjusting for age, education, ethnicity, gender, and tobacco smoking, IL10 rs1800871 was inversely associated with oropharyngeal cancer (CT+TT vs. CC adjusted odds ratio [aOR]: 0.69, 95% confidence interval [CI]: 0.50-0.95), and was positively associated with lung cancer among never smokers (TT vs. CT+CC aOR: 2.5, 95% CI: 1.3-5.1) and inversely with oropharyngeal cancer among ever smokers (CT+TT vs. CC aOR: 0.63, 95% CI: 0.41-0.95). Among all pooled never smokers (588 cases and 816 controls), TNF rs1799964 was inversely associated with smoking-related cancer (CC vs. CT+TT aOR: 0.36, 95% CI: 0.17-0.77). Bayesian correction for multiple comparisons suggests that chance is unlikely to explain our findings (although epigenetic mechanisms may be in effect), which support our hypotheses, suggesting that IL10 rs1800871 is a susceptibility marker for oropharyngeal and lung cancers, and that TNF rs1799964 is associated with smoking-related cancers among never smokers.