Interleukin-17A and -17F genes polymorphisms in lung cancer

The role of IL-17 in lung cancer growth

Interleukin 17 (IL-17) is an inflammatory cytokine with multiple roles in immune protection, immunopathology, and inflammation-related tumors. Lung cancer is inflammation-related cancer, and a large number of studies have shown that IL-17 contributes to the metastasis and progression of lung cancer. However, some studies have shown that IL17 inhibits the occurrence of lung cancer. At present, there is still some controversy about the role of IL17 in the occurrence and development of lung cancer. This review introduces the basic characteristics of IL-17 and focuses on its role in lung cancer, in order to provide a certain theoretical basis for the prevention, diagnosis, and treatment of lung cancer.

Associations of IL-17 and IL-17 receptor polymorphisms with Behçet's disease in Denizli Province of Turkey

Although the etiopathogenesis of Behçet's disease is not known, studies conducted in different populations show that it is a multifactorial disease that is thought to develop as a result of the interaction of environmental and genetic factors. IL-17 is thought to induce the neutrophilic inflammation and the tissue damage mediated by immune response in patients. Polymorphisms in the gene region encoding IL-17 and IL-17R molecules may play a critical role in the pathogenesis of the disease and contribute to the elucidation of disease mechanism. We aimed to show the association of IL-17A, IL-17F, and IL-17RC polymorphisms and haplotypes in Behçet's disease patients and its clinical features. We genotyped IL-17A (rs4711998 (A/G), rs8193036 (C/T), rs2275913 (A/G), rs3819025 (A/G), rs8193038 (A/G), rs3804513 (A/T), rs1974226 (C/T), rs3748067 (C/T)); IL-17F (rs763780 (T/C), rs2397084 (T/C)); and IL-17R (IL-17RC) (rs708567 (C/T)) polymorphisms in 88 patients with Behçet's disease and 133 healthy controls using PCR-RFLP-based approach. The results of our study showed that polymorphisms of IL-17A, rs8193036 (C/T), rs3819025 (G/A), rs3804513 (A/T), IL-17F rs2397084 (T/C), and IL-17RC rs708567 (C/T) are associated with the susceptibility to the BD. When the haplotype distributions of all loci of IL-17Aand IL-17A/IL-17F together were examined and in contrast to the data obtained from the controls, the GTGGAACC (27.84%) and GTGGAACCTT (25.57%) have the highest frequencies. In conclusion, the allele and genotype frequency differences of the IL-17A, IL-17F, and IL-17R and haplotype frequencies between Behçet's disease and controls indicate that the genetic structure of Behçet's disease may be different.

Cumulative evidence for associations between genetic variants in interleukin 17 family gene and risk of human diseases

Background

Genetic association studies have elucidated the link of variants in the interleukin 17 (IL-17) family genes with susceptibility to human diseases, yet have obtained controversial outcomes. Therefore, we sought to update comprehensive synopsis of variants in the IL-17 family genes with susceptibility to human diseases.

Methods

Our study screened the Pubmed and Web of Science to enroll eligible articles and performed a meta-analysis, then graded the cumulative evidence of significant association using Venice criteria and false-positive report probability test, and finally assessed the function of variants with strong evidence.

Results

Seven variants in IL-17 family genes had significant relationships with susceptibility to 18 human diseases identified by meta-analyses. Strong evidence was assigned to 4 variants (IL-17A rs2275913, IL-17A rs8193037, IL-17F rs1889570, IL-17F rs763780) with susceptibility to 6 human diseases (lung and cervical cancer, spondyloarthritis, asthma, multiple sclerosis, rheumatoid arthritis), moderate to 2 variants with risk of 5 diseases, weak to 5 variants with risk of 10 diseases. Bioinformatics analysis suggested that the variants with strong evidence might fall in putative functional regions. Additionally, positive relationships for 5 variants with risk of 4 diseases (based on two datasets) and 14 variants with risk of 21 diseases (based on one dataset) were considered noteworthy.

Conclusions

This study offers updated and comprehensive clues that variants in the IL-17 family genes are significantly linked with susceptibility to cervical, lung cancer, asthma, multiple sclerosis, rheumatoid arthritis and spondyloarthritis, and elucidates the crucial role of the IL-17 regions in the genetic predisposition to cancer or noncancerous diseases.

Variable roles of interleukin-17F in different cancers

BACKGROUND

Interleukin (IL)-17 family is a group of six cytokines that plays a central role in inflammatory processes and participates in cancer progression. Interleukin-17A has been shown to have mainly a protumorigenic role, but the other members of the IL-17 family, including IL-17F, have received less attention.

METHODS

We applied systematic review guidelines to study the role of IL-17F, protein and mRNA expression, polymorphisms, and functions, in cancer. We carried out a systematic search in PubMed, Ovid Medline, Scopus, and Cochrane libraries, yielding 79 articles that met the inclusion criteria.

RESULTS

The findings indicated that IL-17F has both anti- and protumorigenic roles, which depend on cancer type and the molecular form and location of IL-17F. As an example, the presence of IL-17F protein in tumor tissue and patient serum has a protective role in oral and pancreatic cancers, whereas it is protumorigenic in prostate and bladder cancers. These effects are proposed to be based on multiple mechanisms, such as inhibition of angiogenesis, vasculogenic mimicry and cancer cell proliferation, migration and invasion, and aggravating the inflammatory process. No solid evidence emerged for the correlation between IL-17F polymorphisms and cancer incidence or patients' prognosis.

CONCLUSION

IL-17F is a multifaceted cytokine. There is a clear demand for more well-designed studies of IL-17F to elucidate its molecular mechanisms in different types of cancer. The studies presented in this article examined a variety of different designs, study populations and primary/secondary outcomes, which unfortunately reduces the value of direct interstudy comparisons.

Association of Interleukin-17F Polymorphism and Mortality Predictors with the Risk of COVID-19

BACKGROUND

Th-17 cells, a proinflammatory subset of CD4 T lymphocytes, have been suggested as a possible cause of coronavirus disease-19 (COVID-19)-related immunological injuries. The aim of this study was to investigate the relationship between IL-17F (rs763780) polymorphism and the susceptibility to and outcomes of COVID-19 infection and to determine the clinical and laboratory predictors of COVID-19 death.

METHODS

This case-control study included 132 COVID-19 patients and 135 healthy age- and sex-matched controls. The participants were tested for IL-17F rs763780 polymorphism via TaqMan-based genotyping and for the expression of IL-17 by enzyme-linked immunosorbent assay. This study also investigated the predictors for COVID-19 mortality.

RESULTS

A non-statistically significant association was observed between IL-17F alleles and genotypes with COVID-19 (P=0.309, P=0.138, respectively). Moreover, no significant difference in the IL-17F genotypes was observed between non-survivors and survivors (P=0.482). In the multivariate analysis, the participants with the following characteristics had 17.7-, 11.2-, 8-, and 17.9-fold higher odds of exhibiting in-hospital mortality, respectively: (1) hypertension, (2) age of >57 years, (3) WBC count of >12.6 × 10³/mm³, and (4) D-dimer of >0.9 ng/ml. The ROC curve analysis showed that IL-17 at a cutoff point of >46 pg/ml was a perfect discriminator of COVID-19 patients from control subjects (AUC = 1.0).

CONCLUSION

The findings indicate that the IL-17F H161R variant does not influence the risk of COVID-19. However, the IL-17 level is a perfect discriminator of COVID-19 infection. Hypertension, age of >57 years, white blood cell count of >12.6 × 10³/mm³, and D-dimer of >0.9 ng/ml are the independent predictors for death among COVID-19 patients.

Rationalizing heptadecaphobia: TH 17 cells and associated cytokines in cancer and metastasis

Cancer is one of the leading causes of death worldwide. When cancer patients are diagnosed with metastasis, meaning that the primary tumor has spread to at least one different site, their life expectancy decreases dramatically. In the past decade, the immune system´s role in fighting cancer and metastasis has been studied extensively. Importantly, immune cells and inflammatory reactions generate potent antitumor responses but also contribute to tumor development. However, the molecular and cellular mechanisms underlying this dichotomic interaction between the immune system and cancer are still poorly understood. Recently, a spotlight has been cast on the distinct subsets of immune cells and their derived cytokines since evidence has implicated their crucial impact on cancer development. T helper 17 cell (TH 17) cells, which express the master transcriptional factor Retinoic acid-receptor-related orphan receptor gamma t, are among these critical cell subsets and are defined by their production of type 3 cytokines, such as IL-17A, IL-17F, and IL-22. Depending on the tumor microenvironment, these cytokines can also be produced by other immune cell sources, such as T cytotoxic 17 cell, innate lymphoid cells, NKT cells, or γδ T cells. To date, a lot of data have been collected describing the divergent functions of IL-17A, IL-17F, and IL-22 in malignancies. In this comprehensive review, we discuss the role of these TH 17- and non-TH 17-derived type 3 cytokines in different tumor entities. Furthermore, we will provide a structured insight into the strict regulation and subsequent downstream mechanisms of these cytokines in cancer and metastasis.

Potential Impacts of Interleukin-17A Promoter Polymorphisms on the EGFR Mutation Status and Progression of Non-Small Cell Lung Cancer in Taiwan

Non-small cell lung cancer (NSCLC) is a typical inflammation-associated cancer, and lung adenocarcinoma (LUAD) is the most common histopathological subtype. Epidermal growth factor receptor (EGFR) mutations are the most common driver mutations of LUAD, and they have been identified as important therapeutic targets by EGFR tyrosine kinase inhibitors. Interleukin (IL)-17A secreted by T-helper 17 lymphocytes is a proinflammatory cytokine that plays an important role in cancer pathogenesis. The present study was designed to investigate the possible associations among IL-17A genetic polymorphisms, EGFR mutation status, and the clinicopathologic development of LUAD in a Taiwanese population. Our study population consisted of 277 LUAD patients harboring the wild-type (WT) EGFR or a mutant (MT) EGFR. Four single-nucleotide polymorphisms (SNPs) of IL-17A in the peripheral blood, including rs8193036(C > T), rs8193037(G > A), rs2275913(G > A), and rs3748067(C > T) loci, were genotyped using a TaqMan allelic discrimination assay. Our results showed that none of these IL-17A SNPs were correlated with the risk of developing mutant EGFR. However, patients with a smoking habit who carried the GA genotype of IL-17A rs8193037 had a significantly lower susceptibility to EGFR mutations (adjusted odds ratio (AOR): 0.225; 95% confidence interval (CI): 0.056~0.900, p = 0.035). Moreover, compared to individuals carrying the CC genotype of rs8193036 at IL-17A, T-allele carriers (CT + TT) were at higher risk of developing more-advanced stages (stage III or IV; p = 0.020). In the WT EGFR subgroup analysis, IL-17A rs8193036 T-allele carriers had higher risks of developing an advanced tumor stage (p = 0.016) and lymphatic invasion (p = 0.049). Further analyses of clinical datasets revealed correlations of IL-17 receptor A (IL-17RA) and IL-17RC expressions with a poor prognosis of LUAD patients with a smoking history or with higher levels of tumor-infiltrating lymphocytes. In conclusion, our results suggested that two functional promoter polymorphisms of IL-17A, i.e., rs8193036 and rs8193037, were associated with the EGFR mutation status and progression in LUAD patients, indicating that these two genetic variants might act as possible markers for predicting patients’ clinical prognoses.

A Review of Cancer Genetics and Genomics Studies in Africa

Cancer is the second leading cause of death globally and is projected to overtake infectious disease as the leading cause of mortality in Africa within the next two decades. Cancer is a group of genomic diseases that presents with intra- and inter-population unique phenotypes, with Black populations having the burden of morbidity and mortality for most types. At large, the prevention and treatment of cancers have been propelled by the understanding of the genetic make-up of the disease of mostly non-African populations. By the same token, there is a wide knowledge gap in understanding the underlying genetic causes of, and genomic alterations associated with, cancer among black Africans. Accordingly, we performed a review of the literature to survey existing studies on cancer genetics/genomics and curated findings pertaining to publications across multiple cancer types conducted on African populations. We used PubMed MeSH terms to retrieve the relevant publications from 1990 to December 2019. The metadata of these publications were extracted using R text mining packages: RISmed and Pubmed.mineR. The data showed that only 0.329% of cancer publications globally were on Africa, and only 0.016% were on cancer genetics/genomics from Africa. Although the most prevalent cancers in Africa are cancers of the breast, cervix, uterus, and prostate, publications representing breast, colorectal, liver, and blood cancers were the most frequent in our review. The most frequently reported cancer genes were BRCA1, BRCA2, and TP53. Next, the genes reported in the reviewed publications’ abstracts were extracted and annotated into three gene ontology classes. Genes in the cellular component class were mostly associated with cell part and organelle part, while those in biological process and molecular function classes were mainly associated with cell process, biological regulation, and binding, and catalytic activity, respectively. Overall, this review highlights the paucity of research on cancer genomics on African populations, identified gaps, and discussed the need for concerted efforts to encourage more research on cancer genomics in Africa.

Role of interleukins 12B and 17A genetic variation in house dust mites allergy

Background

The house dust mites (HDM) constitute a major cause of allergic diseases all over the world. Genes encoding interleukins 12B and 17A which determine the course of T cell-mediated immune response are prime candidates as allergic disease susceptibility. The purpose of this study was to evaluate whether a single-nucleotide polymorphisms (SNP) of interleukins 12B + 1188A/C (rs3212227) and 17A −197G/A (rs2275913) confers susceptibility to HDM allergic diseases. Through a case-control study, 120 subjects served as 60 dust mites' allergic patients and 60 healthy non-allergic controls. Total immunoglobulin (Ig) E level, eosinophilic count, serum interleukins 4, 10, 12B, and 17A levels for the studied subjects were measured. Then, genotyping of single-nucleotide polymorphisms (SNPs) at +1188A/C for IL12B and −197G/A for IL17A gene were conducted using restriction fragment length polymorphisms (RFLP-PCR).

Results

The present study showed that in HDMs' allergic subjects there was a significant increase in IL12B (+1188 A/C) and IL17A (−197 G/A) genotype variants compared to that of the controls. There was a significant increase in total IgE levels, eosinophil counts, and the levels of both IL-4 and IL-17A, while IL12B was significantly lower in patients compared to that of the controls. There was no significant difference in IL-10 levels between patients and controls.                                                                            

Conclusion

Our findings indicate that IL12B (+1188 A/C) and IL17A (−197G/A) might be associated with an increase in the susceptibility to dust mites’ allergic patients.

Interleukin 17 receptor A haplotype analysis in chronic spontaneous urticaria: A preliminary study

BACKGROUND

Chronic spontaneous urticaria (CSU) is a distressing skin disease. Family clustering and heterogeneity in the onset and progression indicate that susceptibility to CSU is a complex trait. In this study, we performed haplotype analysis for one of the key player gene, IL17RA, for CSU to test the association with disease susceptibility and severity.

METHODOLOGY

The study included 70 CSU patients and 30 healthy controls. The severity of the disease was evaluated by autologous serum skin test (ASST) and urticaria activity score (UAS). ASST test was done and quality of life was assessed using a questionnaire. Allelic discrimination analysis for rs4819554 and rs879577 was performed using real-time polymerase chain reaction technology.

RESULTS

Carriers of rs4819554*G were more prone to develop CSU than its counterpart (P = .039), while rs4819554*A allele displayed more severe phenotype in the form of more prolonged disease duration (P = .040), concurrent angioedema (P < .001), higher level of treatment (P < .001), and higher score of quality of life (P < .001). Additionally, homozygote patients with rs879577*CC were associated with angioedema (P < .001). Haplotype analysis revealed that cohorts with both rs4819554*A and rs879577*T conferred protection against developing CSU (OR = 0.07, 95% CI = 0.01-0.32, P = .001).

CONCLUSION

Our results showed that IL17RA gene polymorphisms might contribute to the increased susceptibility to CSU.

IL-17A and IL-17F orchestrate macrophages to promote lung cancer

PURPOSE

Previously, inflammation has been found to be associated with the development of lung cancer. Despite their well-characterized pro-inflammatory functions, the putative roles of interleukin-17 (IL-17) cytokine family members in tumorigenesis have remained controversial. While IL-17A exhibits both pro- and anti-tumor effects, IL-17F has been suggested to serve as a candidate for cancer therapy. Thus, we aimed at clarifying the involvement of IL-17A/F in lung cancer.

METHODS

IL-17 receptor expression in human and murine lung cancer cells was assessed using immunofluorescence. The effect of IL-17A/F stimulation on lung cancer cell viability (SRB assay) and metabolism (glucose consumption and lactate production) was evaluated under normoxic and hypoxic conditions. Characterization of IL-17A/F-stimulated macrophages was performed by flow cytometry and ELISA. The effect of conditioned media (CM) from IL-17A/F-stimulated macrophages was evaluated on lung cancer cell migration. The effect of CM-stimulated macrophages on lung tumor growth, proliferation and angiogenesis was evaluated in vivo using a chicken chorioallantoic membrane (CAM) assay.

RESULTS

No alterations in lung cancer cell viability or metabolism were observed upon direct stimulation with IL-17A/F. We found, however, that CM from IL-17A/F-stimulated macrophages promoted both murine and human lung cancer cell progression through an increased migration capacity in vitro and enhanced in vivo tumor growth, proliferation and angiogenesis. These findings were supported by an increased polarization of human macrophages towards a M2-like phenotype.

CONCLUSIONS

Our data indicate that IL-17A/F act through immune cell orchestration, i.e., of macrophages, to promote lung cancer cell growth and progression. In addition, our data provide a link between IL-17A/F activity and lung cancer cell-macrophage crosstalk.

The Non-synonymous rs763780 Single-Nucleotide Polymorphism in IL17F Gene Is Associated With Susceptibility to Tuberculosis and Advanced Disease Severity in Argentina

Th17 lymphocytes, that produce IL17A, IL17F, and IL22, play a crucial role during the immune response against Mycobacterium tuberculosis (Mtb) infection. Whereas, the contribution of IL17A in immunity to tuberculosis is usually accepted, the role of IL17F has been scarcely studied so far. The aim of this work was to evaluate the existence of a potential association of the non-synonymous variant rs763780 SNP of the IL17F gene with human tuberculosis. Accordingly, by comparing healthy donors (HD) and tuberculosis patients (TB) populations we demonstrated an association between the C allele of the SNP and the susceptibility to tuberculosis disease in Argentina. Furthermore, we found that peripheral blood mononuclear cells (PBMCs) from individuals with a more effective immune response against Mtb secreted the highest levels of IL17F when stimulated with a lysate of Mtb (Mtb-Ag). Besides, we evidenced that Mtb-Ag-stimulated PBMCs from HD carrying the C variant of the SNP displayed the lowest IFNG secretion, proliferation index, and SLAM expression as compared to TT carriers. Moreover, Mtb-Ag-stimulated PBMCs from TB carrying the C allele produced the lowest levels of IFNG, the highest level of IL17A, and the minimum proliferation indexes as compared to TT TB, suggesting a relationship between the C allele and tuberculosis severity. In fact, TB carrying the C allele presented a more severe disease, with the highest bacilli burden in sputum. Together, our findings identify the IL17F rs763780 SNP as a biomarker of tuberculosis susceptibility and advanced disease severity in Argentina, suggesting that IL17F could be a critical cytokine in tuberculosis immunity.

IL-17F expression correlates with clinicopathologic factors and biological markers in non-small cell lung cancer

Interleukin-17 F (IL-17F) is a pro-inflammatory cytokine that participate in inflammatory responses. Studies showed that IL-17F is likely involved in tumor development, but the biological function of IL-17F in non-small cell lung cancer (NSCLC) is unclear. The aim of this study was to explore the biological role of IL-17F in NSCLC and investigate its correlation with biological markers CD31, P53, Ki-67 and E-cadherin. Paraffin-embedded tumor tissues from 55 NSCLC patients were collected to detect proteins expression using immunohistochemistry (IHC). 12 normal lung tissues samples were used as control. IHC results showed that the expression of IL-17F in NSCLC cells (61.8%) was significantly higher compared with normal lung tissues (25.0%) (P <  0.05). The expression of IL-17F was positively associated with tumor differentiation and negatively associated with lymph node metastasis and TNM staging (P all < 0.05). Multivariate analysis showed that IL-17F expression was an independent factor associated with TNM staging (P <  0.01). Pearson's correlation analysis showed a negative correlation between IL-17F and CD31 expression and a positive correlation between IL-17F and E-cadherin expression (P all < 0.05). There was no relationship between IL-17 F and P53 or Ki-67 expression in NSCLC tissues (P >  0.05). These data suggest that IL-17 F may be considered as a potential marker for predicting the progression of NSCLC.

Comprehensive genomic and prognostic analysis of the IL‑17 family genes in lung cancer

The six members of the interleukin (IL)‑17 gene family (IL‑17A‑F) have been identified in various types of cancer. Although lung cancer is the leading cause of cancer‑related death worldwide and IL‑17A was found to play a critical role in lung cancer, there is little knowledge concerning the association between the other five members of the IL‑17 family and lung cancer. The genetic mutations and expression of IL‑17 family members were investigated using the Catalogue of Somatic Mutations in Cancer (COSMIC), Oncomine, and cBio Cancer Genomics Portal (cBioPortal) databases. Prognostic values and interaction networks of the members were assessed by the Kaplan‑Meier plotter, Search Tool for the Retrieval of Interacting Genes (STRING) database and FunRich software. The results found that, across 5,238 lung cancer patients in the cBioPortal, the results of IL‑17 family gene alteration frequencies and types showed that IL‑17A, IL‑25 and IL‑17F exhibited higher alteration frequencies (2, 2.1 and 1.9%, respectively), and gene amplification accounted for the majority of changes. IL‑17B, IL‑17C and IL‑17D exhibited lower alteration frequencies (0.8, 1.1 and 1.1%, respectively), and deep deletion accounted for the majority of changes. The rates of point mutations in IL‑17A through IL‑17F family genes in lung cancer were 0.66, 0.18, 0.13, 0.09, 0.27 and 0.44% in the COSMIC database. Within the Oncomine database, five datasets showed that IL‑17D was significantly decreased in lung cancer, while no dataset showed a significant difference in the expression of IL‑17A, IL‑17B, IL‑17C, IL‑25 or IL17‑F between lung cancer and normal controls. The frequencies of IL‑17A, IL‑17B and IL‑17C mRNA upregulation in lung squamous cell carcinoma were lower than those in lung adenocarcinoma (2.7, 1.9 and 2.1%, respectively), whereas the frequencies of IL‑17D, IL‑25 and IL‑17F mRNA upregulation were higher in lung squamous cell carcinoma than those in lung adenocarcinoma (3, 6 and 6%, respectively). IL‑17A and IL‑17B were unrelated to overall survival (p=0.11; P=0.17), whereas IL‑17C, IL‑17D, IL‑25 and IL‑17F influenced prognosis (P=0.0023, P=0.0059, P=0.039 and P=0.0017, respectively) according to the Kaplan‑Meier plotter. Moreover, the expression level of IL‑17C was the highest in lung tissues, and IL‑17 family genes mainly participate in the 'IFN‑γ pathway' according to the STRING database and Funrich software. In conclusion, we performed the first comprehensive investigation of the IL‑17 gene family in lung cancer, including gene mutation, mRNA expression levels, prognostic values and network pathways. Our results revealed that IL‑17 family gene mutation rates were in general low and that amplification and deep deletion were the main mutation type. The expression and function of IL‑17A and IL‑17B in lung cancer are still not fully elucidated and warrant research with larger sample sizes. IL‑17D was significantly decreased in lung cancer and was correlated with better OS. Studies of IL‑17C‑F in lung cancer are limited. Further experimental studies on the association between IL‑17D and lung cancer progression are needed to identify more effective therapeutic targets for lung cancer.

Interleukin-17A and -17F single nucleotide polymorphisms associate with susceptibility of asthma in Chinese Han population

Interleukin 17 (IL-17) plays important roles in the progression of asthma. Genetic variants in the Il-17 may influence the immunopathogenesis of many diseases. Many studies have investigated the relevance of IL-17 polymorphism with cancers or immune diseases, including asthma. In this study, single nucleotide polymorphisms (SNPs) of IL-17 were explored by PCR-RFLP and verified by sequencing method. The frequencies of genotypes and alleles were analyzed. Haplotypes were analyzed with the SHEsis online program. The relationship between the genotypes of SNPs and IgE level was also investigated. The False Discovery Rate (FDR) correction was performed (P-adjusted < 0.05). The frequencies of A allele, GA and (GA + AA) genotype of rs3748067 were significantly higher in asthma patients. As for rs763780, the C allele in patients was more frequent than healthy controls. In addition, we found C carriers (CT + CC) were significantly higher in asthma patients. We further found that the haplotype CT for IL-17F (rs763780/rs2397084) was associated with an increased susceptibility of asthma, but this association did not survive after FDR correction. The level of serum total IgE in mutant group (GA + AA) of rs3748067 was significantly higher than the wild genotype (GG) group and control group. These results suggested that IL-17 SNPs, but not haplotypes may be associated with the susceptibility of asthma in Chinese Han population from central China.

Genetic polymorphisms of IL-17A rs2275913, rs3748067 and IL-17F rs763780 in gastric cancer risk: evidence from 8124 cases and 9873 controls

Interleukin-17 (IL-17) is a critical cytokine involved in inflammation-associated cancers. Single nucleotide polymorphisms (SNPs) might promote carcinogenesis. In this current meta-analysis, we investigated the association of IL-17A and IL-17F gene polymorphisms with gastric cancer (GC) risk. Eligible genetic association studies were retrieved from PubMed, Web of Science and Scopus database sources. Two reviewers independently assessed methodological quality and extracted data from eligible articles. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Quantitative data synthesis was conducted using comprehensive meta-analysis v2. Subgroup analysis and heterogeneity analysis were performed. Begg's funnel plot and Egger's regression tests were used to judge publication bias. In silico data analysis was executed to analyze the functional and structural impact of the SNPs. A total of 21 case-control studies for rs2275913 c.-197G > A (7660 patients and 9409 controls), 9 studies for rs3748067 c.*1249C > T (3378 patients and 4120 controls), and 14 studies for rs763780 c.482A > G (4481 patients and 5354 controls) were included. The pooled estimate revealed an association between IL-17A rs2275913 polymorphism and the risk of GC under all genetic models (A vs. G, OR 1.187, 95% CI 1.086-1.297, P < 0.001; GA vs. GG, OR 1.108, 95% CI 1.008-1.218, P = 0.033; AA vs. GG, OR 1.484, 95% CI 1.236-1.781, P < 0.001), while no evidence of association was found with IL-17A rs3748067 or IL-17F rs763780 polymorphisms. Our results showed that IL-17A promoter rs2275913 variant might represent a potential risk factor for gastric cancer susceptibility.

Genetic variants of immune-related genes IL17F and IL10 are associated with functional dyspepsia: A case-control study

BACKGROUND

Low-grade inflammation may play an important role in pathogenesis of functional dyspepsia (FD). Since cytokines may influence gastric mucosal inflammation, which is associated with FD, we evaluated singe nucleotide polymorphisms (SNPs) of pro-inflammatory IL17F and anti-inflammatory IL10 cytokine genes in patients with FD and healthy subjects (HS).

METHODS

Two hundred and thirty-seven consecutive patients with FD (Rome III) and 250 HS were genotyped for IL17F (rs2397084: A/G, rs763780: T/C) and IL10 (rs1800896: G/A, rs1800871: C/T) (PCR-RFLP).

RESULTS

Patients with FD [173 (73%) men, age 38.4±12 years] were comparable with HS [195 (78%) men, age 37.3±12 years] with respect to age and gender. Out of 237 patients, 26 (11%) had epigastric pain, 55 (23.2%) had post-prandial distress syndromes (EPS, PDS), and 156 (65.8%) had EPS-PDS overlap. Among 237 patients with FD, GG (variant) genotype of IL17F (rs2397084) was more common than HS [15 (6.3%) vs. 4 (1.6%), p=0.015, odds ratio (OR)=4.0, 95% confidence interval (CI)=1.3-12.3]. IL17F (rs763780) and IL10 (rs1800896) were comparable among patients and HS (p=0.56, 0.28), respectively. However, TT (variant) genotype of IL10 (rs1800871) was more common among patients than HS [39 (16.5%) vs. 32 (12.8%), p=0.06, OR=1.7, 95% CI=0.98-2.98]. SNPs of IL17F and IL10 (rs2397084, rs763780, rs1800896 and rs1800871) were comparable among patients among sub-types of FD (p=0.80 and 0.44).

CONCLUSION

SNPs of IL17F (rs2397084) and IL10 (rs1800871) genes are associated with FD.

Immune-related gene polymorphisms in pulmonary diseases

Between the DNA sequences of two randomly-selected human genomes, which consist of over 3 billion base pairs and twenty five thousand genes, there exists only 0.1% variation and 99.9% sequence identity. During the last couple of decades, extensive genome-wide studies have investigated the association between single-nucleotide polymorphisms (SNPs), the most common DNA variations, and susceptibility to various diseases. Because the immune system's primary function is to defend against myriad infectious agents and diseases, the large number of people who escape serious infectious diseases underscores the tremendous success of this system at this task. In fact, out of the third of the global human population infected with Mycobacterium tuberculosis during their lifetime, only a few people develop active disease, and a heavy chain smoker may inexplicably escape all symptoms of chronic obstructive pulmonary disease (COPD), lung cancer, and other smoke-associated lung diseases. This may be attributable to the genetic makeup of the individual(s), including their SNPs, which provide some resistance to the disease. Pattern recognition receptors (PRRs), transcription factors, cytokines and chemokines all play critical roles in orchestrating immune responses and their expression/activation is directly linked to human disease tolerance. Moreover, genetic variations present in the immune-response genes of various ethnicities may explain the huge differences in individual outcomes to various diseases and following exposure to infectious agents. The current review focuses on recent advances in our understanding of pulmonary diseases and the relationship of genetic variations in immune response genes to these conditions.

Association between SNPs at IL-17A and IL-17F and susceptibility to accelerated silicosis

The association between single nucleotide polymorphisms (SNPs) in the interleukin (IL)-17 gene and silicosis has been evaluated in different populations. The aim of the present study was to analyze the association between SNPs at IL-17A (−832A/G) and IL-17F (+7488A/G) and susceptibility to accelerated silicosis in the Iranian Kurdish population. We studied 48 patients with accelerated silicosis and 62 controls. Genomic DNA was isolated using the “salting out” method. PCR-RFLP was performed for all SNPs typing. The frequencies of A/A, A/G, and G/G genotypes at IL-17A (−832A/G) were 4 (8.33%), 23 (47.92%), and 21 (43.75%) in patients and 5 (8.06%), 35 (56.45%), and 22 (35.48%) in controls, respectively. The frequencies of A and G alleles at IL-17 (−832A/G) were 31 (32.29%) and 65 (67.71%) in patients, and 45 (36.29%) and 79 (63.71%) in the controls, respectively. The frequencies of A/A, A/G, and G/G genotypes at IL-17F (+7488A/G) were 1 (2.08%), 47 (97.92%), and 0 (0%) in patients, and 11 (17.74%), 51 (82.26%), and 0 (0%) in the controls, respectively. The frequencies of A and G alleles at IL-17F (+7488A/G) were 49 (51.04%) and 47 (48.96%) in patients, and 73 (58.87%) and 51 (41.13%) in the controls, respectively. IL-17F (+7488A/G) genotype was more frequent among the cases compared with controls (97.92% vs. 82.26%). The frequency of the IL-17F (+7488A/G) genotype was significantly greater in patients with accelerated silicosis (odds ratio = 10.13 95%; confidence interval = 1.2–81.5; p = 0.008). The IL-17F (+7488A/G) genotype revealed a significantly increased risk of accelerated silicosis ( p < 0.05). The IL-17F (+7488 G) allele was associated with an increased risk of accelerated silicosis, but in the case of the IL-17A (−832A/G) polymorphism, a significant association was not observed.

The Role of Interleukin-17 in Lung Cancer

Tumour-associated inflammation is a hallmark of malignant carcinomas, and lung cancer is a typical inflammation-associated carcinoma. Interleukin-17 (IL-17) is an important inflammatory cytokine that plays an important role in chronic inflammatory and autoimmune diseases and in inflammation-associated tumours. Numerous studies have shown that IL-17 directly or indirectly promotes tumour angiogenesis and cell proliferation and that it inhibits apoptosis via the activation of inflammatory signalling pathways. Therefore, IL-17 contributes to the metastasis and progression of lung cancer. Research advances with respect to the role of IL-17 in lung cancer will be presented as a review in this paper.

Emerging roles of T helper 17 and regulatory T cells in lung cancer progression and metastasis

Lung cancer is a leading cause of cancer-related deaths worldwide. Lung cancer risk factors, including smoking and exposure to environmental carcinogens, have been linked to chronic inflammation. An integral feature of inflammation is the activation, expansion and infiltration of diverse immune cell types, including CD4⁺ T cells. Within this T cell subset are immunosuppressive regulatory T (Treg) cells and pro-inflammatory T helper 17 (Th17) cells that act in a fine balance to regulate appropriate adaptive immune responses.In the context of lung cancer, evidence suggests that Tregs promote metastasis and metastatic tumor foci development. Additionally, Th17 cells have been shown to be an integral component of the inflammatory milieu in the tumor microenvironment, and potentially involved in promoting distinct lung tumor phenotypes. Studies have shown that the composition of Tregs and Th17 cells are altered in the tumor microenvironment, and that these two CD4⁺ T cell subsets play active roles in promoting lung cancer progression and metastasis.We review current knowledge on the influence of Treg and Th17 cells on lung cancer tumorigenesis, progression, metastasis and prognosis. Furthermore, we discuss the potential biological and clinical implications of the balance among Treg/Th17 cells in the context of the lung tumor microenvironment and highlight the potential prognostic function and relationship to metastasis in lung cancer.

[Role of Interleukin 17 in Lung Carcinogenesis and Lung Cancer Progression]

白介素-17（interleukin 17, IL-17）是一个重要的炎症因子，参与介导了机体的抗感染免疫及自身免疫性疾病相关的病理性炎症；此外，IL-17还与多种炎症相关的肿瘤有着密切联系。吸烟是导致肺癌的重要危险因素之一，而吸烟等因素所致的肺部慢性炎症反应伴有IL-17过表达，提示IL-17可能与肺癌的发生存在潜在联系；同时，IL-17还通过多种机制影响肺癌进展，本文对这一领域的相关研究进展进行了综述。

Single-Nucleotide Polymorphisms of IL-17 Gene Are Associated with Asthma Susceptibility in an Asian Population

BACKGROUND

The aim of this study was to examine the associations between the single-nucleotide polymorphisms (SNPs) of interleukin-17 (IL-17), including rs763780 (7488A/G), rs2275913 (-197G/A), and rs8193036 (-737C/T), and asthma susceptibility in an Asian population.

MATERIAL/METHODS

From Oct 2013 to Dec 2014, 125 asthma patients enrolled in our hospital were selected as the case group. Another 132 healthy controls undergoing physical examinations in our hospital were enrolled as the control group. The genotype frequencies of IL-17 rs763780, rs2275913 and rs8193036 SNPs were detected using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Comprehensive Meta-analysis 2.0 (CMA 2.0) software was applied for meta-analysis.

RESULTS

Our results demonstrated that asthma patients presented with higher frequencies of GA genotype in rs2275913 and TT genotype in rs8193036 of IL-17 than healthy controls (both P<0.001). The genotype frequencies of IL-17 rs763780 between the asthma patients and healthy controls exhibited no significant differences (P>0.05). The comparisons on the rs2275913 and rs8193036 frequencies between the asthma patients and healthy controls were statistically significant in both allele and addictive models (all P<0.05). The frequency of IL-17 rs763780 between the asthma patients and healthy controls were statistically different in allele models (P<0.05), but not in addictive models (P>0.05). The overall results of our case-control study were further confirmed by meta-analysis.

CONCLUSIONS

Our results revealed that, in an Asian population, IL-17 rs763780, rs2275913, and rs8193036 SNPs may be associated with asthma susceptibility, and GA genotype in rs2275913 and TT genotype in rs8193036 of IL-17 may contribute to increased risk of asthma in Asians.

Role of IL-17A rs2275913 and IL-17F rs763780 polymorphisms in risk of cancer development: an updated meta-analysis

Single nucleotide polymorphisms (SNPs) in the interleukin-17 (IL-17) gene have been shown to be correlated with susceptibility to cancer. However, various studies report different results of this association. The aim of the present work was to clarify the effects of IL-17A G197A (rs2275913) and IL-17F T7488C (rs763780) polymorphisms on cancer risk. We performed systematic searches of the PubMed and CNKI databases to obtain relevant publications. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the association of rs2275913 and rs763780 polymorphisms with cancer risk. Data were extracted from the selected studies, and statistical analysis was conducted using the STATA software. Our results indicated that rs2275913 and rs763780 polymorphisms significantly increase cancer risk, especially in gastric cancers. Subgroup analysis suggested the existence of a significant correlation between rs763780 polymorphism and cancer susceptibility in Caucasian populations. This updated meta-analysis confirms that rs2275913 and rs763780 polymorphisms are highly associated with increased risk for multiple forms of cancer.

Association between the interleukin-17A -197G>A (rs2275913) polymorphism and risk of digestive cancer

Interleukin-17A (IL-17A) is a multifunctional cytokine which plays a crucial role in the initiation and progression of cancer. To date, several studies have investigated associations between IL-17A -197G>A (rs2275913) polymorphism and digestive cancer risk, but the results remain conflicting. We here aimed to confirm the role of this single nucleotide polymorphism (SNP) in susceptibility to digestive cancer through a systemic review and meta-analysis. Ten eligible case-control studies were identified by searching electronic databases, involving 3,087 cases and 3,815 controls. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were used to estimate the strength of the association. The results of overall analyses indicated that the variant A allele was associated with an increased risk of digestive cancer (AA vs GG: OR=1.51, 95%CI=1.18-1.93; AA vs GG+GA: OR=1.45, 95%CI=1.12-1.87; A vs G: OR=1.21, 95%CI=1.05-1.39). In subgroup analysis stratified by specific cancer type, elevated risk among studies of gastric cancer was found (AA vs GG: OR=1.68, 95%CI=1.24-2.28; AA vs GG+GA: OR=1.62, 95%CI=1.16-2.26; A vs G: OR=1.23, 95%CI=1.04-1.46). According to ethnicity, there was evidence in the Asian populations for an association between this polymorphism and cancer risk (GA vs GG: OR=1.19, 95%CI=1.05-1.36; AA vs GG: OR=1.56, 95%CI=1.15-2.12; AA+GA vs GG: OR=1.28, 95%CI=1.13- 1.44; AA vs GG+GA: OR=1.42, 95%CI=1.01-2.00; A vs G: OR=1.24, 95%CI=1.08-1.44), while in the Caucasian populations an association was found in the recessive model (AA vs GG+GA: OR=1.62, 95%CI=1.17-2.24). In conclusion, the results of this meta-analysis suggest that the IL-17A -197G>A polymorphism contributes to an increased risk of human digestive cancer, both in the Asian and Caucasian populations and especially for gastric cancer.

Meta analysis of association of the IL-17F rs763780T>C gene polymorphism with cancer risk

PURPOSE

To investigate the association of IL-17F rs763780T>C with cancer risk.

MATERIALS AND METHODS

We searched the Cochrane Central Library, PubMed, MEDLINE, EMBASE, CNKI (China National Knowledge Infrastructure) and WangFang databases until May 2014 for a meta-analysis conducted using RevMan 5.2 software.

RESULTS

A total of ten papers were included into this meta analysis, involving 3, 336 cases and 4, 217 healthy people. There were no significant differences on association of IL-17F rs763780T>C polymorphism with cancer risk except in the CC vs TT genetic model. Although the the risk in the gastric cancer group is higher than that in control group, there were no significant differences on the association of IL-17F rs763780T>C polymorphism with other cancers.

CONCLUSIONS

Our meta analysis reveal the IL-17A rs763780T>C gene polymorphism is involved in risk of gastric cancer but not other tumor types.

Association between six genetic variants of IL-17A and IL-17F and cervical cancer risk: a case-control study

We conducted a case-control study to estimate association between six common single nucleotide polymorphisms (SNPs) and risk of cervical cancer and evaluate the interaction between IL-17 gene polymorphisms and environmental factors in cervical cancer patients. This study included 264 consecutive primary cervical cancer patients and 264 age-matched controls. The genotypes of IL-17A rs2275913, rs3748067, and rs3819025 and IL-17A rs763780, rs9382084, and rs1266828 were analyzed using polymerase chain reaction-restriction fragment length of polymorphism (PCR-RFLP) assay. By logistic regression analysis, we found that individuals with AA genotype of rs2275913 were correlated with increased risk of cervical cancer when compared with GG genotype, and the odds ratio (OR) (95 % confidence interval (CI)) for AA genotype was 2.34 (1.24-4.49). By stratified analysis, individuals with AA genotype of rs2275913 were significantly associated with increased risk of cervical cancer in HPV-16- or HPV-18-infected patients when compared with GG genotype, and the OR (95 % CI) was 4.11 (1.14-22.33). In this case-control study, we suggest that rs2275913 may play an important role in the development of cervical cancer, especially in HPV-16- or HPV-18-infected patients.

Interleukin-17A and interleukin-17F gene polymorphisms and hepatitis B virus-related hepatocellular carcinoma risk in a Chinese population

Interleukin (IL)-17A and IL-17F are inflammatory cytokines, which play a critical function in inflammation. Genetic variations in the IL-17A and IL-17F genes may be associated with a risk of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC), which is a typical inflammation-related cancer. However, their relationship with HBV-related HCC has not been thoroughly investigated. We conducted a case-control study including 155 patients with HBV-related HCC and 171 healthy controls to assess the association between IL-17A rs4711998, IL-17A rs2275913, and IL-17F rs763780 polymorphisms and risk of HCC. Genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing. There were no significant differences in the genotype and allele frequencies of IL-17A rs4711998, IL-17A rs2275913, and IL-17F rs763780 polymorphisms between the HBV-related HCC patients and healthy controls. However, our results revealed a statistically significant association between the ACA haplotype and increased HCC risk [odds ratio (OR) 1.820, 95 % confidence interval (CI) 1.181-2.624, P = 0.013]. In contrast, the GCG haplotype was associated with a significantly decreased risk of HBV-related HCC (OR 0.454, 95 % CI 0.112-0.898, P = 0.035). Our results suggest that IL-17A rs4711998, IL-17A rs2275913, and IL-17F rs763780 polymorphisms do not contribute to HBV-related HCC susceptibility independently. However, the ACA and GCG haplotypes in the IL-17 gene might be a risk factor and a protective marker, respectively, for HBV-related HCC in a Chinese population.

The effect of proinflammatory cytokines on IL-17RA expression in NSCLC

Interleukin-17 receptor (IL-17RA) is essential for proinflammatory cytokine IL-17-mediated pathogenesis of various tumors. IL-17RA is upregulated by some proinflammatory cytokines such as IL-21 and IL-15 and downregulated by IL-2, while the effect of IL-1β, IL-6, IL-8, TNF-α on IL-17RA expression in non-small cell lung caner (NSCLC) remains unknown. Our findings revealed that IL-17RA mRNA was increased in NSCLC tissues compared with the corresponding peritumor tissues (P = 0.0039) and high expression of IL-17RA protein in human NSCLC tissues was significantly associated with histological subtype, primary tumor size and clinical stages (P = 0.033, 0.033 and 0.011, respectively). IL-17RA mRNA expression was positively related to IL-1β, IL-6, IL-8, TNF-α mRNA expression (P = 0.013, 0.0001, 0.002 and 0.010 respectively) in NSCLC tissues. Furthermore, IL-1β, IL-6, IL-8, TNF-α upregulated IL-17RA mRNA and protein in A549 and H460 cells (all P < 0.05). It is suggested that IL-1β, IL-6, IL-8, TNF-α promoted IL-17RA expression in NSCLC and they may involve in IL-17RA signaling in NSCLC.

Role of IL-17F T7488C polymorphism in carcinogenesis: a meta-analysis

Previous case-control studies on the association of interleukin-17F (IL-17F) T7488C polymorphism and cancer risk have yielded conflicting and inconclusive findings. We performed a meta-analysis by pooling all currently available data to acquire a more precise estimation of the association. A comprehensive literature screening from the PubMed, Embase, Web of Science, and Wanfang databases was performed for eligible publications without language restrictions. The pooled odds ratios (ORs) with corresponding 95 % confidence intervals (95 % CIs) were calculated. According to the inclusion criteria, a total of nine case-control studies with 3,034 cases and 3,694 controls were included. Overall, the pooled ORs showed that IL-17F T7488C polymorphism was associated with neither increased nor decreased risk of cancer. However, the IL-17F T7488C polymorphism exerted risk effect on cancer in population-based case-control studies when stratifying analysis by source of controls (C vs T OR = 1.24, 95 % CI, 1.10-1.40, pooled OR (POR) < 0.001; TC vs TT OR = 1.28, 95 % CI, 1.11-1.48, POR = 0.001; CC + TC vs TT OR = 1.29, 95 % CI, 1.12-1.48, POR < 0.001). Additionally, the variant genotypes of IL-17F T7488C could alter the risk of gastric cancer under the following comparisons (C vs T OR = 1.29, 95 % CI, 1.13-1.47, POR < 0.001; TC vs TT OR = 1.35, 95 % CI, 1.14-1.60, POR < 0.001; CC + TC vs TT OR = 1.35, 95 % CI, 1.15-1.58, POR < 0.001). Sensitivity analysis by sequential omission of single study did not materially alter the pooled findings. The present meta-analysis suggests that the IL-17F T7488C polymorphism may modify the risk of cancer, particularly gastric cancer. However, the precise association needs to be elucidated by more individual studies with sufficient statistical power.