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

IL-8 (CXCL8) Correlations with Psychoneuroimmunological Processes and Neuropsychiatric Conditions

Interleukin-8 (IL-8/CXCL8), an essential CXC chemokine, significantly influences psychoneuroimmunological processes and affects neurological and psychiatric health. It exerts a profound effect on immune cell activation and brain function, suggesting potential roles in both neuroprotection and neuroinflammation. IL-8 production is stimulated by several factors, including reactive oxygen species (ROS) known to promote inflammation and disease progression. Additionally, CXCL8 gene polymorphisms can alter IL-8 production, leading to potential differences in disease susceptibility, progression, and severity across populations. IL-8 levels vary among neuropsychiatric conditions, demonstrating sensitivity to psychosocial stressors and disease severity. IL-8 can be detected in blood circulation, cerebrospinal fluid (CSF), and urine, making it a promising candidate for a broad-spectrum biomarker. This review highlights the need for further research on the diverse effects of IL-8 and the associated implications for personalized medicine. A thorough understanding of its complex role could lead to the development of more effective and personalized treatment strategies for neuropsychiatric conditions.

Hallmarks of Cancer Applied to Oral and Oropharyngeal Carcinogenesis: A Scoping Review of the Evidence Gaps Found in Published Systematic Reviews

Simple Summary

This scoping review of systematic reviews aims to accurately assess the degree of existing scientific evidence on the cancer hallmarks proposed in 2011 by Hanahan and Weinberg, in the form of systematic reviews and meta-analyses, applied to oral potentially malignant disorders, oral cavity and oropharyngeal squamous cell carcinomas, in order to point out gaps in evidence and lines of research that should be implemented in the future to improve the malignant transformation prediction, diagnosis and/or prognosis of these diseases.

Abstract

In 2000 and 2011, Hanahan and Weinberg published two papers in which they defined the characteristics that cells must fulfil in order to be considered neoplastic cells in all types of tumours that affect humans, which the authors called “hallmarks of cancer”. These papers have represented a milestone in our understanding of the biology of many types of cancers and have made it possible to reach high levels of scientific evidence in relation to the prognostic impact that these hallmarks have on different tumour types. However, to date, there is no study that globally analyses evidence-based knowledge on the importance of these hallmarks in oral and oropharyngeal squamous cell carcinomas. For this reason, we set out to conduct this scoping review of systematic reviews with the aim of detecting evidence gaps in relation to the relevance of the cancer hallmarks proposed by Hanahan and Weinberg in oral and oropharyngeal cancer, and oral potentially malignant disorders, and to point out future lines of research in this field.

Associations of TLR4 and IL-8 genes polymorphisms with age-related macular degeneration (AMD): a systematic review and meta-analysis

BACKGROUND

The results of different studies have indicated the possible associations of TLR4 and IL-8 genes polymorphisms with Age-related Macular Degeneration (AMD). A meta-analysis study was designed to evaluate the possible associations of TLR4 (rs4986790/c.896A>G and rs4986791/ c.1196 C > T) and IL-8 (rs4073/c.251A>T and rs2227306/c.781 C > T) genes polymorphisms with AMD.

METHOD

A systematic literature search was carried out in PubMed, Embase, Web of Science, and Scopus databases to identify relevant publications. Pooled Odds Ratio (OR) with 95% Confidence Interval (CI) was used to evaluate the power of association.

RESULTS

A total of 12 case-control studies with 4804 AMD patients and 4422 healthy controls were included in this meta-analysis. The analysis of genotypic and allelic models demonstrated significant associations between IL-8 c.781 C > T (CC vs. TT+TC: OR = 0.62 [0.48-0.81], P < .01; CC vs. TC: OR = 0.65 [0.48-0.89], P < .01; TT vs. CC: OR = 1.64 [1.04-2.57], P = .03; and C vs. T: OR = 0.71 [0.65-0.79], P < .01) and risk of AMD, which all of them passed Bonferroni correction for multiple testing (P-value≤0.01), except for TT vs. CC model. In addition, we found associations under the genotypic model of TLR4 c.896A>G (AA vs. AG+GG: OR = 0.73 [0.55-0.97], P = .03; and AA vs. AG: OR = 0.71 [0.53-0.95], P = .02) although after Bonferroni correction (P'-value<0.02) none of these associations remained significant. However, the data from this meta-analysis declined the associations of TLR4 c.1196 C > T and IL-8 c.251A>T polymorphisms with AMD.

CONCLUSION

The current meta-analysis study suggested that IL-8 c.781 C > T polymorphism is associated with susceptibility to AMD.

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.

Association of polymorphisms in IL-8, MMP-1 and MMP-13 with the risk and prognosis of oral and oropharyngeal squamous cell carcinoma

OBJECTIVE

This study investigated the risk and prognostic value of single nucleotide polymorphisms (SNP) inIL-8, MMP-1 and MMP-13 in oral and oropharyngeal squamous cell carcinomas (SCCs).

DESIGN

SNPs rs2227532 and rs4073 inIL-8, rs2071230 and rs470558 in MMP-1, and rs2252070 in MMP-13 were genotyped in 125 oral and oropharyngeal SCC patients and 130 healthy controls, using TaqMan allelic discrimination assays. Multiple logistic regression models were used to explore the association between SNPs and cancer development, as well as SNP-SNP interaction and gene-environmental factor (GxE) interaction. Univariate and multivariate methods were applied for survival analyses.

RESULTS

With exception of rs2227532, all the SNPs were in Hardy-Weinberg equilibrium in the control. No associations between rs4073 in IL-8 and rs2071230 and rs470558 in MMP-1 were observed, but rs2252070 in MMP-13, in the dominant model, was associated in a protective manner to oral and oropharyngeal SCC (OR: 0.20, 95% CI: 0.06-0.71, p = 0.007). All SNPs interact significantly with cigarette smoking and alcohol consumption on susceptibility to oral and oropharyngeal SCC, but they showed no influence on survival of the patients.

CONCLUSIONS

Our results show that rs2252070 inMMP-13 may confer protection effect against oral and oropharyngeal SCC. In addition, the combined effects of IL-8 (rs4073), MMP-1 (rs2071230 and rs470558) and MMP-13 (rs2252070) with environmental carcinogens, such as tobacco and alcohol, are related to increased risk for oral and oropharyngeal SCC development.

Contribution of Genetic Polymorphisms of Inflammation Response Genes on Sporadic Colorectal Cancer Predisposition Risk in Malaysian Patients - A Case Control Study

AIM:

To investigate the frequencies and association of polymorphic genotypes of IL-8 -251 T>A, TNF-α -308 G>A, ICAM-1 K469E, ICAM-1 R241G, IL-6 -174 G>C, and PPAR-γ 34 C>G in modulating susceptibility risk in Malaysian colorectal cancer (CRC) patients.

Methods:

In this case-control study, peripheral blood samples of 560 study subjects (280 CRC patients and 280 controls) were collected, DNA extracted and genotyped using PCR-RFLP and Allele Specific PCR. The association between polymorphic genotype and CRC susceptibility risk was determined using Logistic Regression analysis deriving Odds ratio (OR) and 95% CI.

Results:

On comparing the frequencies of genotypes of all single nucleotide polymorphisms ( SNPs ) in patients and controls, the homozygous variant genotypes IL-8 -251 AA and TNF-α -308 AA and variant A alleles were significantly higher in CRC patients. Investigation on the association of the variant alleles and genotypes singly, with susceptibility risk showed the homozygous variant A alleles and genotypes IL-8 -251 AA and TNF-α -308 AA to be at higher risk for CRC predisposition. Analysis based on age, gender and smoking habits showed that the polymorphisms IL8 -251 T>A and TNF – α 308 G>A contribute to a significantly higher risk among male and female who are more than 50 years and for smokers in this population.

Conclusion:

We observed an association between variant allele and genotypes of IL-8-251 T>A and TNF-α-308 G>A polymorphisms and CRC susceptibility risk in Malaysian patients. These two SNPs in inflammatory response genes which undoubtedly contribute to individual risks to CRC susceptibility may be considered as potential genetic predisposition factors for CRC in Malaysian population.

Association of IL-8 gene promoter -251 A/T and IL-18 gene promoter -137 G/C polymorphisms with head and neck cancer risk: a comprehensive meta-analysis

Purpose

No consensus exists on the impact of polymorphisms in cytokines (such as interleukin IL-8 and IL-18) on cancer risk; moreover, there is very little evidence regarding head and neck cancer (HNC).

Methods

Thus, a meta-analysis including 22 studies with 4731 cases and 8736 controls was conducted to evaluate this association. The summary odds ratio (OR) and corresponding 95% confidence intervals (CIs) for C-X-C motif chemokine ligand 8 (CXCL8, which encodes IL-8) and IL-18 polymorphisms and HNC risk were estimated.

Results

The results showed a significantly increased risk of HNC susceptibility for IL18 −137 G/C in five genetic models, but, interestingly, no significant association was found for the CXCL8 −251 A/T polymorphism. When stratified by cancer type, an increased risk of nasopharyngeal cancer was found for both −137 G/C and −251A/T. When the studies were stratified by ethnicity and genotyping method, there were significant associations between Asian populations and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) studies for −137 G/C, and African populations for −251 A/T in some genetic models. A positive association was also found between the population-based groups in some models for −137 G/C; conversely, significantly decreased risk was found among the −251 A/T hospital-based group. Meta-regression was also conducted. The publication year, control source, and cancer type contributed to CXCL8 −251 A/T heterogeneity; however, no factors were found that contributed to IL-18 −137 G/C heterogeneity. Marginal significance was found in the recessive model for IL-18 −137 G/C by Egger’s test, whereas no publication bias was detected for CXCL8 −251 A/T.

Conclusions

The results indicate that the IL-18 −137 G/C polymorphism is associated with HNC risk, especially nasopharyngeal cancer, in Asian populations and, when using PCR-RFLP, CXCL8 −251 A/T polymorphisms play a complex role in HNC development.

Comprehensive analysis of interleukin-8 gene polymorphisms and periodontitis susceptibility

Background

Associations between interleukin-8 (IL-8) gene polymorphisms and periodontitis susceptibility have been investigated in many published studies, but the conclusions are still inconsistent. Therefore, we performed this systematic review and meta-analysis to review which polymorphisms have been researched and to obtain a precise result of the same polymorphism from different studies.

Results

Finally 10 publications involving 1938 patients and 1569 controls were yielded, including 12 polymorphisms. Six studies investigated rs4073 polymorphism; two focused on rs2227306 and rs2227307; two referred to rs2227532 and T-738A; one detected rs2230054, rs1126579 and rs1126580; one inspected A2767T, T₁1722T₂ and C1633T, and one for rs2234671 polymorphism. Of them, IL-8 C1633T and rs1126580 polymorphisms showed positive association while the other ten polymorphisms revealed negative results.

Materials and methods

A comprehensive literature search from PubMed, Web of Science, and Chinese National Knowledge Infrastructure was conducted for all potentially relevant studies published before January 2, 2017. Two authors selected the studies and extracted data. The pooled analysis was conducted using the RevMan 5.1 software if a polymorphism was reported by two or more studies.

Conclusions

Based on current evidence, the IL-8 rs4073, A2767T, T₁1722T₂, rs2234671, rs2230054, rs1126579, rs2227306, rs2227307, rs2227532, and T-738A polymorphisms were not associated with periodontitis susceptibility; the IL-8 C1633T and rs1126580 polymorphisms were associated with increased risk of periodontitis.

Cytokine Gene Polymorphisms Associated With Various Domains of Quality of Life in Women With Breast Cancer

CONTEXT

Little is known about the phenotypic and molecular characteristics associated with various domains of quality of life (QOL) in women after breast cancer surgery.

OBJECTIVES

In a sample of women with breast cancer (n = 398), purposes were as follows: to identify latent classes with distinct trajectories of QOL from before surgery through six months after surgery and to evaluate for differences in demographic and clinical characteristics, as well as for polymorphisms in cytokine genes, between these latent classes.

METHODS

Latent class analyses were done to identify subgroups of patients with distinct QOL outcomes. Candidate gene analyses were done to identify cytokine gene polymorphisms associated with various domains of QOL (i.e., physical, psychological, spiritual, social).

RESULTS

One latent class was identified for the psychological and spiritual domains. Two latent classes were identified for the social domain and overall QOL scores. Three latent classes were identified for the physical domain. For the physical and social domains, as well as for the overall QOL scores, distinct phenotypic characteristics (i.e., younger age, poorer functional status, higher body mass index, and receipt of adjuvant chemotherapy) and a number of cytokine gene polymorphisms (CXCL8, NFKB2, TNFSF, IL1B, IL13, and NFKB1) were associated with membership in the lower QOL classes.

CONCLUSIONS

Findings suggest that women experience distinctly different physical well-being, social well-being, and total QOL outcomes during and after breast cancer surgery. The genetic associations identified suggest that cytokine dysregulation influences QOL outcomes. However, specific QOL domains may be impacted by different cytokines.

Low Survival Rates of Oral and Oropharyngeal Squamous Cell Carcinoma

Aim

To assess the epidemiological and clinical factors that influence the prognosis of oral and oropharyngeal squamous cell carcinoma (SCC).

Methods

One hundred and twenty-one cases of oral and oropharyngeal SCC were selected. The survival curves for each variable were estimated using the Kaplan-Meier method. The Cox regression model was applied to assess the effect of the variables on survival.

Results

Cancers at an advanced stage were observed in 103 patients (85.1%). Cancers on the tongue were more frequent (23.1%). The survival analysis was 59.9% in one year, 40.7% in two years, and 27.8% in 5 years. There was a significant low survival rate linked to alcohol intake (p = 0.038), advanced cancer staging (p = 0.003), and procedures without surgery (p < 0.001). When these variables were included in the Cox regression model only surgery procedures (p = 0.005) demonstrated a significant effect on survival.

Conclusion

The findings suggest that patients who underwent surgery had a greater survival rate compared with those that did not. The low survival rates and the high percentage of patients diagnosed at advanced stages demonstrate that oral and oropharyngeal cancer patients should receive more attention.

Investigation of association between IL-8 serum levels and IL8 polymorphisms in Chinese patients with sepsis

OBJECTIVE

To assess the clinical relevance of IL8 gene polymorphisms in patients with sepsis and its association with systemic IL-8 levels.

METHODS

PCR and DNA sequencing were used to examine the polymorphism of IL8 in 152 patients with sepsis and in 199 healthy volunteers in China. The distribution frequencies of the genotype and allele were compared among different groups. The serum IL-8 was measured by ELISA and analyzed in relation to polymorphisms of IL8.

RESULTS

The homozygote TT genotype and T allele of rs4073 (genotype: p=0.01, allele: p=0.002), the homozygote CC genotype and C allele (genotype: p=0.03, allele: p=0.003) of rs2227306, homozygote AA genotype and A allele of re1126647 (genotype: p=0.01, allele: p=0.002) were associated with susceptibility to sepsis in males. Serum IL-8 levels were significantly increased in patients with sepsis but showed no correlation with IL8 rs4073, rs2227306 and rs1126647 polymorphisms.

CONCLUSIONS

The male population carrying the homozygote TT genotype and T allele of rs4073, the homozygote CC genotype and C allele of rs2227306 and homozygote AA genotype and A allele of rs1126647 are more susceptible to sepsis, suggesting there is a protective effect in females carrying these genotypes and alleles respectively. There was no association between rs4073, rs2227306 and rs1126647 polymorphisms and serum levels of IL-8 in patients with sepsis.

Association between interleukin 8-251 T/A and +781 C/T polymorphisms and glioma risk

Background

Gliomas are aggressive tumors of the central nervous system that rely on production of growth factors for tumor progression. Interleukin 8 (IL-8) is up-regulated in gliomas to promote angiogenesis and proliferation. The aim of this study was to evaluate the association of the IL-8 -251 T/A and +781 C/T polymorphisms and glioma risk.

Methods

We enrolled 300 glioma patients and 300 age- and gender-matched healthy controls. A prospective hospital-based case–control design and logistic regression analysis were utilized. The IL-8 gene polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

Results

Glioma patients had a significantly higher frequency of IL-8 -251 AA genotype [odds ratio (OR) =1.91, 95 % confidence interval (CI) = 1.22, 3.00; P = 0.005] and IL-8 -251 A allele (OR =1.36, 95 % CI = 1.08, 1.70; P = 0.009) than controls. When stratified by the grade of glioma, patients with WHO IV glioma had a significantly higher frequency of IL-8 -251 AA genotype (OR =1.56, 95 % CI = 1.01, 2.39; P = 0.04).

Conclusions

To the best of our knowledge, this is the first report in the literature that the IL-8 -251 AA genotype and A allele were at a higher risk for glioma.

Chemokine function in periodontal disease and oral cavity cancer

The chemotactic cytokines, or chemokines, comprise a superfamily of polypeptides with a wide range of activities that include recruitment of immune cells to sites of infection and inflammation, as well as stimulation of cell proliferation. As such, they function as antimicrobial molecules and play a central role in host defenses against pathogen challenge. However, their ability to recruit leukocytes and potentiate or prolong the inflammatory response may have profound implications for the progression of oral diseases such as chronic periodontitis, where tissue destruction may be widespread. Moreover, it is increasingly recognized that chronic inflammation is a key component of tumor progression. Interaction between cancer cells and their microenvironment is mediated in large part by secreted factors such as chemokines, and serves to enhance the malignant phenotype in oral and other cancers. In this article, we will outline the biological and biochemical mechanisms of chemokine action in host–microbiome interactions in periodontal disease and in oral cancer, and how these may overlap and contribute to pathogenesis.

Association between IL-8 -251A/T and IL-10 -1082A/G genetic polymorphisms and susceptibility to colorectal cancer: A case-control study in a population in Shaanxi

AIM: To explore the association between IL-8 -251A/T and IL-10 -1082A/G polymorphisms and susceptibility to colorectal cancer (CRC) in the population in Shaanxi, China.

METHODS: A case-control study was performed to compare the distribution of genetic frequencies and genotype of IL-8 -251A/T and IL-10 -1082A/G among colorectal cancer patients (n = 102) and control healthy individuals (n = 105) using allele specific PCR (AS-PCR). The relationship between IL-8 -251A/T and IL-10 -1082A/G polymorphisms and susceptibility to colorectal cancer was explored.

RESULTS: There was a significant difference in the distribution of genotype of IL-8 -251A/T between the healthy control group and CRC group (χ² = 8.278, P = 0.016). The genetic frequency of IL-8 -251A allele in CRC was 0.54 (111/204), which was significantly higher than that of the controls (0.43, 91/210) (χ² = 5.083; P = 0.024). The subjects carrying AA genotype were more likely to suffer from CRC (OR = 3.84, 95%CI: 1.44-10.23). Stratified analysis suggested that the association between the AA genotype of IL-8 -251A/T and the risk of CRC was more profound in subjects less than 55 years old and smokers. However, no difference was discovered in the distribution of genotype of IL-10 -1082A/G between the CRC group and healthy control group (χ² = 1.808, P = 0.405).

CONCLUSION: The IL-8 -251AA genotype may be a risk factor of CRC in the population in Shaanxi, and people with A allele may be more likely to suffer from CRC, especially in those less than 55 years old and smokers. No correlation is found between IL-10 -1082A/G polymorphism and the risk of CRC.

Association between interleukin-8 -251A/T polymorphism and risk of lung cancer: a meta-analysis

This study is to evaluate the association between IL-8 -251A/T polymorphism and lung cancer risk in diverse populations. We performed a meta-analysis of six case-control studies that included 3,265 lung-cancer cases and 3,607 case-free controls. Overall, results showed that the IL-8 -251A/T polymorphism was not associated with a significantly increased risk of lung cancer in all genetic models. However, stratified by ethnicity, a significantly increased risk was found among Asians. In conclusion, IL-8 -251A/T polymorphism is associated with lung cancer susceptibility in Asians and the -251 A allele may increase risk of lung cancer in Asians.

Quantitative assessment of the associations between interleukin-8 polymorphisms and periodontitis susceptibility

BACKGROUND

This review assesses the associations of interleukin-8 gene (IL-8) -251A/T (rs4073) and -845T/C (rs2227532) polymorphisms with susceptibility to periodontitis.

METHODS

Several electronic databases were searched for eligible articles. Twelve studies involving 2,233 cases and 2,655 controls were retrieved and analyzed. Odds ratios (ORs) along with 95% confidence intervals (CIs) were calculated to assess the strength of relationship between the IL-8 polymorphisms and periodontitis risk.

RESULTS

No significant association was found for IL-8 -251A/T polymorphism with periodontitis in the overall analysis and stratification by periodontitis type and smoking status. Subgroup analysis by ethnicity revealed that -251A/T T allele and TT genotype were associated with decreased risk of periodontitis in a Brazilian mixed population (T allele versus A allele: OR 0.80, 95% CI 0.68 to 0.94, Pheterogeneity = 0.30; TT versus AA: OR 0.65, 95% CI 0.46 to 0.93, Pheterogeneity = 0.39; TT versus

AA/AT

OR 0.58, 95% CI 0.35 to 0.98, Pheterogeneity = 0.01). In addition, -251A/T T allele was associated with increased periodontitis risk in Asians. Pooled estimates showed that the -845T/C polymorphism was associated with periodontitis susceptibility in overall analysis and the chronic periodontitis subgroup. In addition, marginal associations were observed between -845T/C polymorphism and periodontitis in a Brazilian mixed population. Moreover, this association was also confirmed to be significant in Brazilian non-smokers.

CONCLUSION

This meta-analysis indicated that both IL-8 -251A/T and -845T/C polymorphisms may be involved in the development of periodontitis in a Brazilian mixed population, whereas the -251A/T allele T appeared to be a risk factor for periodontitis in Asians.

Association between interleukin 8 -251 A/T and +781 C/T polymorphisms and osteoarthritis risk

PURPOSE

Interleukin 8 (IL-8), as a member of the CXC chemokine family, has a regulatory role in joint inflammation and cartilage degradation, and contribute to the pathophysiology of osteoarthritis. The aim of the current study was to examine the influence of the IL-8 gene polymorphisms at positions -251 (rs4073) and +781 (rs2227306) on the risk of osteoarthritis.

METHODS

This hospital-based case-control study comprised 150 patients with osteoarthritis and 150 age- and gender-matched controls. IL-8 251 A/T and +781 C/T polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

Patients with osteoarthritis had a significantly higher frequency of IL-8 -251 TT genotype [odds ratio (OR)=2.16, 95% confidence interval (CI)=1.09, 4.26; P=0.03], IL-8 -251 T allele (OR=1.41, 95% CI=1.02, 1.94; P=0.04), IL-8 +781 TT genotype (OR=2.79, 95% CI=1.10, 7.08; P=0.03) and IL-8 +781 T allele (OR=1.48, 95% CI=1.02, 2.14; P=0.04) than controls. But the findings are less emphatic by the Bonferroni correction. When stratifying by body mass index, type, articular involvement, and Kellgren-Lawrence grade, no significant differences were found in any groups.

CONCLUSIONS

For the first time, the current data suggested that the TT genotype and T allele of the IL-8 gene polymorphisms at positions -251 and +781 might confer a high risk of osteoarthritis. In the future, additional well-designed large studies were required for the validation of our results.

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.

The polymorphism interleukin-8 -251A/T is associated with a significantly increased risk of cancers from a meta-analysis

Emerging evidences show that interleukin-8 (IL-8) has important regulatory functions in tumorigenesis. IL-8 -251A/T is a single nucleotide polymorphism in the promoter region of the IL-8 gene and affects IL-8 production. Analysis of previous studies on the association of -251A/T polymorphism with different cancer types remained to be illustrated. To further assess the effect of -251A/T polymorphism on cancer risks, we performed this meta-analysis, up to November 2013, of 12,917 cases with different cancer types and 17,689 controls from 47 published case-control designed studies. Statistical analyses were performed using STATA 11.0 software. Crude odds ratios (ORs) with 95 % confidence intervals (CIs) were used to assess the strength of associations. ORs with 95 % CIs for IL-8 -251A/T polymorphism and cancer were estimated using fixed- and random-effects models when appropriate. Significantly increased risks were found in overall under the models of A allele vs. T allele, AA vs. TT, and AA vs. AT/TT. Significantly elevated risks were observed in breast cancer under the models of A allele vs. T allele, AT vs. TT, AA/AT vs. TT, and AA vs. AT/TT, and in nasopharyngeal carcinoma under the models of AT vs. TT, AA/AT vs. TT, and AA vs. AT/TT. We found that significantly elevated risks were observed in the Asian population and hospital-based studies in all comparison models. Thus, this meta-analysis indicates that IL-8 -251A/T polymorphism is associated with a significantly increased risk of cancers and may provide evidence-based medical certificate to study the cancer susceptibility.

Association of tea consumption and the risk of oral cancer: a meta-analysis

OBJECTIVES

Epidemiological studies evaluating the association of tea consumption and the risk of oral cancer risk have produced inconsistent results. Thus, we conducted a meta-analysis to assess the relationship between tea consumption and oral cancer risk.

METHODS

Pertinent studies were identified by a search in PubMed, Web of Knowledge and Wan Fang Med Online. The fixed or random effect model was used based on heterogeneity test. Publication bias was estimated using Egger's regression asymmetry test.

RESULTS

Finally, 14 articles with 19 studies comprising 4675 oral cancer cases were included in this meta-analysis. The relative risk (95% confidence interval) of oral cancer for the highest versus the lowest category of tea consumption was 0.853 (0.779-0.934), and the association was significant between oral cancer risk and green tea consumption [0.798 (0.673-0.947)] but not in the black tea consumption [0.953 (0.792-1.146)]. The associations were also significant in Asian and Caucasian.

CONCLUSIONS

Our analysis indicated that tea consumption may have a protective effect on oral cancer, especially in green tea consumption.

Positive association between Interleukin-8 -251A > T polymorphism and susceptibility to gastric carcinogenesis: a meta-analysis

Backgrounds

The associations between the polymorphisms of interleukin-8 (IL-8) gene and gastric carcinogenesis have been extensively investigated in recent years. However, the results remain conflicting rather than conclusive.

Methods

A meta-analysis of 18 eligible studies was performed to evaluate the association of IL-8 -251A > T polymorphism with risk of gastric carcinogenesis. A systematic literature search of MEDLINE, Embase, and Web of Science, CNKI databases was conducted. Statistical analysis was performed by using the Revman 5.1 software and the Stata 12.0 software.

Results

Of the 293 unique studies identified using our search criteria, 18 studies fulfilled our inclusion criteria and were included in the meta-analysis. These studies cumulatively reported 5,321 cases and 6,465 controls. The combined results based on all studies showed that the IL-8 -251A > T polymorphism was associated with the risk of gastric carciongenesis (A vs. T: OR: 1.14 [1.02, 1.26], P = 0.02), especially gastric cancer (A vs. T: OR: 1.15 [1.03, 1.29], P = 0.02), but not associated with the risk of precancerous lesion (A vs. T: OR: 1.09 [0.99, 1.20], P = 0.08). Analysis stratified by ethnicity may seem that IL-8 -251A > T polymorphism was susceptible to gastric cancer in Asian population, but not in Caucasian population.

Conclusions

Our meta-analysis results provide evidence that IL-8 -251A > T polymorphism is significantly associated with increased risk of gastric carcinogenesis in Asian population, particularly in gastric cancer. Further large and well-designed studies are required to confirm this conclusion.