Polymorphism in the interleukin-17A promoter contributes to gastric cancer

IL-17 signaling protects against Helicobacter pylori-induced gastric cancer

Helicobacter pylori infection is the predominant risk factor for the development of gastric cancer. Risk is enhanced by specific H. pylori virulence factors, diet, and the inflammatory response. Chronic activation of T helper (Th) 1 and Th17 pathways contributes to prolonged inflammation; yet, higher expression of IL-17 receptor (IL-17RA) is a favorable prognostic marker for survival after gastric cancer diagnosis. The protective impact of IL-17RA signaling is not understood. To investigate if IL-17RA signaling protects during H. pylori-induced carcinogenesis, the transgenic InsGAStg/tg mouse, which is prone to H. pylori-induced gastric cancer, was utilized. InsGAStg/tg mice and InsGAStg/tgIl17ra-/- mice were infected with a cag type 4 secretion system (T4SS) positive H. pylori strain for up to 6 months. Six weeks post-infection, IL-17RA deficiency led to increased bacterial burden, increased gastritis, and development of lymphoid follicles. Increased inflammation was associated with heightened cellular proliferation and earlier loss of parietal and chief cells in InsGAStg/tgIl17ra-/- mice. Gastric cancers developed more frequently by 3- and 6-months post-infection in H. pylori-infected InsGAStg/tgIl17ra-/- mice compared to InsGAStg/tg mice. Chronic inflammation was exacerbated with IL-17RA deficiency, characterized by elevated Th1/Th17 cytokines, increased B cell infiltration, and enhanced IgA production, despite reduced expression of the polymeric immunoglobulin receptor. Further, paragastric lymph nodes of InsGAStg/tgIl17ra-/- mice were enlarged relative to controls and displayed altered gene expression profiles. Increased inflammation was accompanied by a significant increase in Cybb expression, which encodes NADPH oxidase 2, suggesting that increased oxidative damage may occur in the absence of IL-17RA. Further, there is increased phosphorylation of histone 2AX in IL-17RA deficient mice, indicating that the DNA damage response is highly activated. These data suggest that IL-17RA signaling activates a protective pathway to prevent excessive inflammation which otherwise can lead to increased oxidative stress, DNA damage, and drive gastric carcinogenesis after H. pylori infection.

Genetic and molecular biology of gastric cancer among Iranian patients: an update

Background

There is a declining trend of gastric cancer (GC) incidence in the world during recent years that is related to the development of novel diagnostic methods. However, there is still a high ratio of GC mortality among the Iranian population that can be associated with late diagnosis. Despite various reports about the novel diagnostic markers, there is not any general and standard diagnostic panel marker for Iranian GC patients. Therefore, it is required to determine an efficient and general panel of molecular markers for early detection.

Main body of the abstract

In the present review, we summarized all of the reported markers until now among Iranian GC patients to pave the way for the determination of a population-based diagnostic panel of markers. In this regard, we categorized these markers in different groups based on their involved processes to know which molecular process is more frequent during the GC progression among Iranians.

Conclusion

We observed that the non-coding RNAs are the main factors involved in GC tumorigenesis in this population.

Polymorphisms at the IL17A and IL17RA genes are associated with prognosis of papillary thyroid carcinoma

BACKGROUND

Interleukin (IL)-17A has a dual role in tumor immunity, promotes anti-tumor responses and facilitates angiogenesis by interacting with IL-17 receptor A (IL-17RA). Although IL-17A has been associated with the pathogenesis of papillary thyroid carcinoma (PTC), the nucleotide variability at the IL17A and IL17RA genes is still poorly characterized.

AIM

To assess the contribution of the IL17A (-197 G >A, rs2275913) and IL17RA (-947 A >G, rs4819554) single nucleotide polymorphisms (SNP) on the development and progression of PTC and on IL-17 plasma levels.

METHODS

We studied 188 PTC patients and 170 healthy controls. SNPs were identified using PCR-amplified DNA and restriction fragment length polymorphism (RFLP) techniques. Plasma levels of IL-17A was evaluated in 83 PTC patients using ELISA. Statistical analyses were performed to evaluate the associations between SNPs and clinicohistopathological features of PTC and IL-17A levels.

RESULTS

No significant difference was observed regarding the allele and genotype distributions of both SNPs between PTC patients and controls. The IL17A GA was associated with poor biochemical and structural incomplete response to therapy, whereas no influence over the IL-17A expression was observed. The IL17RA AG was significantly associated with small-sized tumors, initial tumor stage at diagnosis and better response to therapy.

CONCLUSIONS

The IL17A SNP may predict an aggressive manifestation of PTC, whereas the IL17RA SNP was associated with a more favorable clinical outcome.

Association of Helicobacter pylori Infection and Host Cytokine Gene Polymorphism with Gastric Cancer

The global cancer burden of new cases of various types rose with millions of death in 2018. Based on the data extracted by GLOBOCAN 2018, gastric cancer (GC) is the third leading cause of mortality related to cancer across the globe. Carcinogenic or oncogenic infections associated with Helicobacter pylori (Hp) are regarded as one of the essential risk factors for GC development. It contributes to the increased production of cytokines that cause inflammation prior to their growth in the host cells. Hp infections and specific types of polymorphisms within the host cells encoding cytokines are significant contributors to the host's increased susceptibility in terms of the development of GC. Against the backdrop of such an observation is that only a small portion of the cells infected can become malignant. The diversities are a consequence of the differences in the pathogenic pathway of the Hp, susceptibility of the host, environmental conditions, and interplay between these factors. It is evident that hosts carrying cytokine genes with high inflammatory levels and polymorphism tend to exhibit an increased risk of development of GC, with special emphasis being placed on the host cytokines gene polymorphisms.

Lung Neutrophilic Recruitment and IL-8/IL-17A Tissue Expression in COVID-19

The new SARS-CoV-2 virus differs from the pandemic Influenza A virus H1N1 subtype (H1N1pmd09) how it induces a pro-inflammatory response in infected patients. This study aims to evaluate the involvement of SNPs and tissue expression of IL-17A and the neutrophils recruitment in post-mortem lung samples from patients who died of severe forms of COVID-19 comparing to those who died by H1N1pdm09. Twenty lung samples from patients SARS-CoV-2 infected (COVID-19 group) and 10 lung samples from adults who died from a severe respiratory H1N1pdm09 infection (H1N1 group) were tested. The tissue expression of IL-8/IL-17A was identified by immunohistochemistry, and hematoxylin and eosin (H&E) stain slides were used for neutrophil scoring. DNA was extracted from paraffin blocks, and genotyping was done in real time-PCR for two IL17A target polymorphisms. Tissue expression increasing of IL-8/IL-17A and a higher number of neutrophils were identified in samples from the H1N1 group compared to the COVID-19 group. The distribution of genotype frequencies in the IL17A gene was not statistically significant between groups. However, the G allele (GG and GA) of rs3819025 was correlated with higher tissue expression of IL-17A in the COVID-19 group. SARS-CoV-2 virus evokes an exacerbated response of the host’s immune system but differs from that observed in the H1N1pdm09 infection since the IL-8/IL-17A tissue expression, and lung neutrophilic recruitment may be decreased. In SNP rs3819025 (G/A), the G allele may be considered a risk allele in the patients who died for COVID-19.

Interleukin- 17agene Polymorphism, Serum Level and Its Tissue Expression in Iraqi Patients Gastric Lesions

BACKGROUND

T-helper 17 plays a novel role in inflammation in gastritis by producing IL-17A, IL-17A gene polymorphisms that might be responsible for disease susceptibility and development of different gastric lesions.

OBJECTIVE

The aims of study was to determine the association of IL-17A (G197A) genotype and allele frequency with disease phenotype and risk with different gastric lesions.

METHODS

Case controlled study involved 30 gastroduodenal ulcer, 30 chronic gastritis and 30 subjects as a control group with negative endoscopic findings. After genomic DNA extraction, IL-17A (G197A)ARMS-PCR genotyping were done for all cases. Serum IL-17A was measured using ELISA method and tissue expression was visualized using immunohistochemistry staining method.

RESULTS

The results showed that allele A was significantly frequent in gastroduodenal ulcer more than that in healthy control odd ratio= 4 (1.42-10.46), and none significantly with chronic gastritis p=0.071. Serum IL-17A was significantly higher in gastroduodenal ulcer (116.45±48.09 pg/ml), chronic gastritis (78.02±30.17pg/ml) and healthy control 19.36±9.28 pg/ml).However, the serum IL-17A level is not related to the allele pattern of each group. The tissue expression was expressed as dense granular cytoplasmic and membranous of inflammatory cells. Interestingly, the percentage of IL-17A protein expression was significantly higher in gastroduodenal ulcer (38.2±16.55%), chronic gastritis (30.89±14.02%) and normal mucosa (2.8±3.02%). Furthermore, patients with strong intensity of IL-17A stained mucosa were frequently carrier for mutant allele (68%).

CONCLUSION

IL-17A might predispose for aggressive inflammation of advanced lesions in stomach like ulcer.

Association of Foxp3 rs3761548 polymorphism with cytokines concentration in gastric adenocarcinoma patients

T regulatory cells (Tregs) and related-cytokines are effectively engaged in the process of tumor immune escape and functionally inhibit immune response against the tumor. This study aimed to investigate the association of Foxp3 gene single nucleotide polymorphism (SNP) (rs3761548) with serum IL-35, IL-10, and TGF-β levels in gastric adenocarcinoma (GA) patients. The blood samples were obtained from 150 GA patients and 166 control subjects. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was done to genotyping of Foxp3 gene polymorphism (rs3761548). The serum cytokines levels were measured using the ELISA method. According to genotyping, the AA, and AC genotypes and A allele demonstrated significantly greater risk of GA. Considering the Lauren classification, our results revealed a greater risk of GA progression in patients with AC + AA genotype compared to CC genotype. Moreover, significantly increased levels of IL-10, IL-35, and TGF-β were observed in GA patients compared to controls and also in diffuse-type compared to the intestinal type of GA patients. The IL-35, IL-10 concentrations in GA patients displayed significant differences between the participants with CC, AC and AA genotypes. Further analysis indicated the prognostic role of serum IL-35, IL-10, and TGF-β levels in GA patients. Our results confirmed that the Foxp3 polymorphism (rs3761548) could influence the predisposition to GA and the serum IL-10, IL-35, and TGF-β levels. Thus, this polymorphism might be involved in the GA progression through influencing Tregs function and the secretion of immunomodulatory cytokines.

Associations of the IL-17A rs2275913 and IL-17F rs763780 polymorphisms with the risk of digestive system neoplasms: A meta-analysis

OBJECTIVE

To clarify the associations between the IL-17A rs2275913 and IL-17F rs763780 polymorphisms and the risk of digestive system neoplasms.

METHODS

An internet search was used to identify relevant articles from CNKI, Wanfang, VIP, PubMed, EMBASE and Elsevier up to December 2017. The meta-analysis was performed using Stata 11.0 software.

RESULTS

Twenty-three studies were included. Among these, 21 studies with 6978 cases and 8000 controls were related to IL-17A rs2275913, while 18 studies that included 5073 cases and 6040 controls were related to IL-17F rs763780. The meta-analysis results demonstrated that the overall effects of the two polymorphisms were significantly different (P < 0.05) in the allele model, dominant model, recessive model and codominant model. Subgroup analysis showed that both polymorphisms were significantly associated with susceptibility to gastric cancer but not with hepatocellular carcinoma or colorectal cancer. In the ethnicity analysis, these two polymorphisms were associated with Asian populations but not with Caucasians. Similar results were observed in the hospital-based and population-based control subgroups.

CONCLUSIONS

The IL-17A rs2275913 and IL-17F rs763780 polymorphisms were associated with susceptibility to digestive system neoplasms.

Helicobacter pylori associated factors in the development of gastric cancer with special reference to the early-onset subtype

Nowadays, gastric cancer is one of the most common neoplasms and the fourth cause of cancer-related death on the world. Regarding the age at the diagnosis it is divided into early-onset gastric carcinoma (45 years or younger) and conventional gastric cancer (older than 45). Gastric carcinomas are rarely observed in young population and rely mostly on genetic factors, therefore provide the unique model to study genetic and environmental alternations. The latest research on early-onset gastric cancer are trying to explain molecular and genetic basis, because young patients are less exposed to environmental factors predisposing to cancer. In the general population, Helicobacter pylori, has been particularly associated with intestinal subtype of gastric cancers. The significant association of Helicobacter pylori infection in young patients with gastric cancers suggests that the bacterium has an etiologic role in both diffuse and intestinal subtypes of early-onset gastric cancers. In this paper we would like to ascertain the possible role of Helicobacter pylori infection in the development of gastric carcinoma in young patients. The review summarizes recent literature on early-onset gastric cancers with special reference to Helicobacter pylori infection.

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.

Association of interleukin-17A polymorphisms with the risk of colorectal cancer: A case-control study

BACKGROUND

Interleukin (IL)-17A is proinflammatory cytokine produced by Th17 cells, which play key, but sometimes inconsistent role in autoimmunity and cancer. Polymorphic variants in IL-17A gene were differentially associated with susceptibility to cancer, including colorectal cancer (CRC).

AIM

We investigated the association between six IL-17A gene variants (rs3819024, rs2275913, rs3819025, rs10484879, rs7747909, and rs3748067) with CRC susceptibility in Tunisians.

SUBJECTS AND METHODS

Retrospective case-control study. Study subjects comprised 293 patients with CRC, and 268 age-, gender-, and BMI-matched healthy controls. IL-17A genotyping was done by real-time PCR, with defined clusters.

RESULTS

Of the seven tested IL-17A tag-SNPs, minor allele frequency (MAF) of rs10484879 was significantly higher in CRC patients than control subjects. Heterozygous rs10484879 [OR (95% CI) = 2.63 (1.64-4.21)] was associated with higher risk, while carriage of heterozygous rs3748067 genotype was associated with reduced risk of CRC [OR (95% CI) = 0.56 (0.37-0.84)], respectively. Carriage of rs10484879 minor allele correlated with positive family history of CRC and other cancers (P = 0.002), CRC staging (P = 0.044), CRC treatment (P = 0.038), and with chemo body reaction (P = 0.001). Of the 7 IL-17A variants, 4 were in linkage disequilibrium, hence allowing for construction of 4-locus haplotypes. Varied linkage disequilibrium (LD) was noted between the even tested IL-17A variants, and further analysis was limited to only 4-locus (rs3819024-rs2275913- rs10484879-rs7747909). Haploview analysis identified the 4-locus IL-17A haplotypes AGTG (P < 0.011), and GATG (P = 0.036) to be positively associated with CRC, after controlling key covariates.

CONCLUSION

IL-17A rs10484879 SNP, and IL-17A haplotypes AGGTG and GAGTG constitute independent factors of CRC susceptibility. We propose that IL-17A may be a target for future CRC immunotherapy.

Association between IL-17A G197A polymorphism and gastric cancer risk: an updated meta-analysis based on 6,624 cases and 7,631 controls

Purpose

Previous studies investigating the association between interleukin-17A (IL-17A) G197A polymorphism and gastric cancer risk have provided inconsistent results. We, therefore, conducted this meta-analysis to clarify the association between IL-17A G197A polymorphism and gastric cancer risk.

Methods

We searched PubMed, Excerpta Medica Database, and CNKI databases to identify relevant studies up to June 10, 2017. A total of 16 case-control studies including 6,624 cases and 7,631 controls were identified.

Results

Overall, significant associations between IL-17A G197A polymorphism and gastric cancer risk were observed (A vs G: OR =1.24, 95% CI =1.14–1.36; AA vs GG: OR =1.63, 95% CI =1.35–1.96; GA vs GG: OR =1.12, 95% CI =1.01–1.25; AA+GA vs GG: OR =1.23, 95% CI =1.11–1.35; AA vs GA+GG: OR =1.54, 95% CI =1.27–1.87). Similar associations were also observed in Asian population (A vs G: OR =1.25, 95% CI =1.15–1.37; AA vs GG: OR =1.62, 95% CI =1.33–1.97; GA vs GG: OR =1.16, 95% CI =1.07–1.25; AA+GA vs GG: OR =1.24, 95% CI =1.15–1.33; AA vs GA+GG: OR =1.51, 95% CI =1.23–1.85), in Caucasian population (AA vs GA+GG: OR =2.19, 95% CI =1.40–3.44), and in the hospital-based controls’ subgroup (A vs G: OR =1.30, 95% CI =1.17–1.45; AA vs GG: OR =1.81, 95% CI =1.46–2.25; AA+GA vs GG: OR =1.27, 95% CI =1.12–1.43; AA vs GA+GG: OR =1.71, 95% CI =1.34–2.18).

Conclusions

The current meta-analysis suggests that IL-17A G197A polymorphism might enhance gastric cancer risk.

Could the inhibition of IL-17 or IL-18 be a potential therapeutic opportunity for gastric cancer?

Chronic inflammation is recognized as a key tumor-promoting factor in a number of epithelial cancers, including gastric cancer (GC). The production of pro-inflammatory cytokines in the tumor microenvironment by both the innate and the adaptive immune response can activate signaling pathways that are associated with increased cell survival and proliferation of cancer cells. Among the cytokines that have most commonly been linked to inflammation-associated cancers, are the Th17 cell-associated cytokines IL-17A, IL-23, IL-22, and the IL-1 family members IL-1β and IL-18. However, whether their contribution to inflammation-associated cancers is universal, or specific to individual types of cancers, remains to be elucidated. This review will explore our current understanding of the known roles of these cytokines in gastritis and discuss how their therapeutic inhibition may be useful for GC.

Gastric carcinoma in canines and humans, a review

Gastric carcinoma (GC) is the most common neoplasm in the stomach of dogs. Although incidence in the general population is reported to be low, breed-specific GC has a high incidence. Median age at presentation ranges from 8 to approximately 10 years. The disease is mostly located in the lesser curvature and antropyloric region of the stomach. Unfortunately, diagnosis is usually made when the disease is at an advanced stage and, therefore, prognosis is poor. Due to similarities in clinical presentation, diagnosis, histology and prognosis, canine GC may serve as a valuable model for human GC. Extensive pedigrees of canine gastric carcinoma cases could reveal insights for human gastric carcinoma. Putative species differences include the role of Helicobacter in pathogenesis, the wide array of genetic data and screening available for humans, and treatment protocols that are available for human GC.

Molecular alterations in gastric cancer with special reference to the early-onset subtype

Currently, gastric cancer (GC) is one of the most frequently diagnosed neoplasms, with a global burden of 723000 deaths in 2012. It is the third leading cause of cancer-related death worldwide. There are numerous possible factors that stimulate the pro-carcinogenic activity of important genes. These factors include genetic susceptibility expressed in a single-nucleotide polymorphism, various acquired mutations (chromosomal instability, microsatellite instability, somatic gene mutations, epigenetic alterations) and environmental circumstances (e.g., Helicobcter pylori infection, EBV infection, diet, and smoking). Most of the aforementioned pathways overlap, and authors agree that a clear-cut pathway for GC may not exist. Thus, the categorization of carcinogenic events is complicated. Lately, it has been claimed that research on early-onset gastric carcinoma (EOGC) and hereditary GC may contribute towards unravelling some part of the mystery of the GC molecular pattern because young patients are less exposed to environmental carcinogens and because carcinogenesis in this setting may be more dependent on genetic factors. The comparison of various aspects that differ and coexist in EOGCs and conventional GCs might enable scientists to: distinguish which features in the pathway of gastric carcinogenesis are modifiable, discover specific GC markers and identify a specific target. This review provides a summary of the data published thus far concerning the molecular characteristics of GC and highlights the outstanding features of EOGC.

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 IL-17A +197 G/A Polymorphism and Cancer Risk: A Meta-analysis

AIMS

The association between interleukin-17 (IL-17) gene polymorphism and cancer is controversial. Thus, we performed a meta-analysis to evaluate the correlation between this gene variant and cancer risk.

MATERIALS AND METHODS

We retrieved the available data from EMBASE and PUBMED through June, 2015, and evaluated the effect of the rs2273913 polymorphism in different ethnicities and cancer types. A meta-analysis was performed after data sorting.

RESULTS

Significant associations were confirmed among Asians by the allelic model (T allele vs. G allele, 95% confidence interval [95% CI] 1.304-2.120), homozygote comparison (AA vs. GG, 95% CI 1.073-1.615), and the recessive model (AA vs. AG/GG, 95% CI 1.128-1.778). We also demonstrated that rs2273913 confers a high risk of nongastrointestinal cancer based on the allelic model (T allele vs. G allele, 95% CI 2.288-3.442), homozygote comparison (AA vs. GG, 95% CI 1.312-1.925), and recessive model (AA vs. AG/GG, 95% CI 1.259-1.689).

CONCLUSIONS

Our present study indicates that the IL-17A +197 G/A/T polymorphism (rs2275913) is associated with the risk of cancer in Asian populations and nongastrointestinal cancers. Hence, rs2275913 might be useful as a diagnostic biomarker of cancer in these populations.

Association of interleukin-17 gene polymorphisms and Helicobacter pylori infection with gastric cancer susceptibility: a cumulative and comprehensive meta-analysis

BACKGROUND

The association between Interleukin-17(IL-17) gene polymorphisms and Helicobacter pylori (H. pylori) infection and gastric cancer susceptibility were inconsistent. We therefore performed a comprehensive meta-analysis about all three genetic polymorphisms of IL-17 to derive a more precise estimation.

METHODS

PubMed, Embase, CNKI and Wanfang databases were researched on the associations between IL-17A rs2275913G>A, rs3748067C>T and IL-17F rs763780 T>C and gastric cancer risk. Odds ratio (OR) with a 95% confidence interval (CI) was applied to assess the relationships. Publication bias, sensitivity and cumulative analysis was conducted to guarantee the strength of meta-analysis.

RESULTS

Overall, eleven related studies involving 4,478 cases and 5,612 controls were collected. Significantly increased risk between IL-17A rs2275913G>A polymorphism and gastric cancer were observed (A vs. G: OR = 1.22, 95% CI = 1.08-1.37, P<0.01, I(2) = 72.3%; AA vs. GG: OR = 1.55, 95% CI = 1.21-1.99, P<0.01, I(2) = 74.3%; GA + AA vs. GG: OR = 1.19, 95% CI = 1.05-1.39, P<0.01, I(2) = 48.2%; AA vs. GG + GA: OR = 1.50, 95% CI = 1.16-1.95, P<0.01, I(2) = 81.2%). For IL-17F rs3748067C>T and rs763780 T>C polymorphisms, only few significantly increased risk could be found in genetic models. Moreover, H. pylori infection also be proved to increase the risk of gastric cancer combined with rs3748067C>T mutation.

CONCLUSIONS

Our meta-analysis suggests that the three IL-17 polymorphisms were associated with a significantly increased risk of gastric cancer, especially in Chinese.

The IL-17A G-197A and IL-17F 7488T/C polymorphisms are associated with increased risk of cancer in Asians: a meta-analysis

Background

Interleukin-17 (IL-17) is a family of emerged pro-inflammatory cytokines. The IL-17A and IL-17F are two important members of IL-17 family. Previous studies have shown that the functional IL-17A G-197A and IL-17F 7488T/C polymorphisms may contribute to susceptibility to cancer but the results were inconclusive. This meta-analysis was performed to determine the exact association between IL-17 polymorphisms and cancer risk.

Methods

Online databases were searched to identify eligible case–control studies. Pooled odds ratios (ORs) and confidence intervals (CIs) were calculated by fixed-effect models or random-effect models. Publication bias was detected by Egger’s test and Begg’s test.

Results

Nine eligible case–control studies of IL-17A G-197A and seven studies of IL-17F 7488T/C, including 3,181 cases and 4,005 controls, were identified. Pooled analysis suggested the variant IL-17A-197A allele was associated with increased risk cancer (GA/AA vs GG, OR =1.27, 95% CI: 1.15, 1.41, P_{heterogeneity} =0.374; and A vs G, OR =1.30, 95% CI: 1.17, 1.45, P_{heterogeneity} =0.021). For IL-17F 7488T/C, the homozygote 7488CC genotype significantly increased risk of cancer (CC vs TC/TT, OR =1.36, 95% CI: 0.97, 1.91, P_{heterogeneity} =0.875; and CC vs TT, OR =1.39, 95% CI: 1.03, 1.88, P_{heterogeneity} =0.979), especially for gastric cancer.

Conclusion

The variant IL-17A-197A allele and IL-17F 7488CC genotype were associated with increased risk of cancer, especially for gastric cancer.

IL17A gene polymorphism, serum IL17 and total IgE in Egyptian population with chronic HCV and hepatocellular carcinoma

BACKGROUND

Chronic infections with HCV (CHC) induce a chronic inflammation which can lead to liver fibrosis and subsequently cirrhosis. A recent study suggests a role of IL-17 polymorphism and serum IL17 in hepatitis B related HCC. These data indicate that the IL-17 G-197A polymorphism may be a good indicator for susceptibility to cancer development.

AIM

To investigate the role of the IL17A gene polymorphism, serum IL17 and total IgE in Egyptian population with chronic infections with HCV and HCC.

SUBJECTS AND METHODS

This study was carried out on 40 patients with chronic HCV, 35 patients with hepatocellular carcinoma and 20 healthy persons as control. All subjects were submitted to History taking, clinical examination, abdominal ultrasound, laboratory tests including CBC, liver function tests, alpha fetoprotien, determination of IL17gene polymorphisms by PCR-RFLP, IL17 by ELISA and IgE by immunonephelometric assay.

RESULTS

In reference to AA genotype, the frequencies of GG, GA+GG genotypes in the cases with HCC were significantly different from that of the controls (p=0.012, 0.011) and carry 6.12,4.9 respectively fold increase for HCC risk and that of chronic HCV without HCC (p=0.005, 0.004) respectively. However, there was no significant difference in allele frequency in the studied groups (p=0.095). Cases with HCC significantly have higher levels of serum IL17 and IgE than both healthy control and chronic HCV. In conclusion, the present study showed the GG, GG+GA genotypes of IL17A gene is a risk factor for HCC development may be through increased IL17 and IgE and further studies with larger sample size and different populations are recommended.

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 associations between interleukin-17 gene polymorphisms and risk of gastric cancer

BACKGROUND

Previous studies have indicated that single nucleotide polymorphisms (SNPs) of the interleukin-17 (IL-17) gene are associated with an increased risk of gastric cancer. However, the findings were inconsistent.

MATERIALS AND METHODS

To provide a more reliable estimation of the association between SNPs in the IL-17 gene and the susceptibility to gastric cancer, we searched PubMed, CNKI, and Wan Fang databases and selected finally six studies covering 2,366 cases and 3,205 controls to perform a meta-analysis.

RESULTS

Statistical analyses showed that an rs2275913 polymorphism within the IL-17A gene was significantly associated with an increased risk of gastric cancer using a generalized odds ratio (ORG, a model-free approach). Moreover, we also found that the 'A' allele carriers of IL-17A rs2275913 had a significant link with clinicopathological features. However, no significant positive signals were observed in the association analysis of the rs3748067 and rs763780 polymorphisms with the risk of gastric cancer in IL-17A and IL-17F, respectively.

CONCLUSIONS

Despite some limitations, the present meta-analysis provided a more precise estimation of the relationship between the IL-17 gene SNPs and gastric cancer risk compared with individual studies.

Interleukin-17A gene polymorphism is associated with susceptibility to gastric cancer

We conducted a study to investigate the role of three common SNPs in the IL-17A and IL-17F genes (rs2275913G>A, rs3748067C>T and rs763780T>C) in the development of gastric cancer, and their interaction with H.pylori infection. A total of 326 patients with gastric cancer and 326 control subjects were consecutively recruited between May 2012 and May 2014. Genotyping of IL-17A rs2275913G>A and rs3748067C>T and IL-17F rs763780T>C was performed in a 384-well plate format on the Sequenom MassARRAY platform. By logistic regression analysis, individuals carrying the GA and AA genotypes of IL-17 rs2275913G>A were significantly associated with an increased risk of gastric cancer when compared with GG genotype, and the adjusted Ors (95% CI) were 1.46 (1.03-2.06) for GA genotype and 2.57 (1.51-4.43) for AA genotype. We observed that the GA+AA genotype of rs2275913 was associated with an increased risk of gastric cancer among H.pylori infection subjects (OR=2.21, 95% CI=1.29-3.79). In conclusion, we found that there was a significant association between L-17A rs2275913G>A polymorphism and increased gastric cancer risk, especially in H.pylori infection subjects.

Association of IL-17 polymorphisms with gastric cancer risk in Asian populations

AIM: To investigate associations between the IL-17 rs2275913 G>A and rs763780 T>C polymorphisms and susceptibility to gastric cancer in Asian populations.

METHODS: We reviewed studies published up to 2014 on IL-17 polymorphisms with gastric cancer susceptibility systematically. Relevant articles were identified in the MEDLINE, Science Citation Index, Cochrane Library, PubMed, EMBASE, CINAHL and Current Contents Index databases. We used version 12.0 STATA statistical software to evaluate the statistical data. Two reviewers abstracted the data independently. Odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated.

RESULTS: Seven independent, case-control studies were chosen for the meta-analysis, which included 3210 gastric cancer patients and 3889 healthy controls. The overall estimation showed a positive association between the IL-17 rs2275913 G>A polymorphism and the occurrence of gastric cancer for five genetic models (all P < 0.05) and similar results were observed for the IL-17 rs763780 T>C variation with four genetic models (all P < 0.05), but not for the dominant model (P > 0.05). Subgroup analysis by country revealed that the rs2275913 G>A and rs763780 T>C polymorphisms may be the main risk factor for gastric cancer in Chinese and Japanese populations.

CONCLUSION: The IL-17 gene may be significantly correlated with gastric cancer risk in Asian populations, especially those carrying the rs2275913 G>A and rs763780 T>C polymorphisms.

Effect of three common IL-17 single nucleotide polymorphisms on the risk of developing gastric cancer

A 1:1 matched case-control study was conducted to analyze the association between three common interleukin (IL)-17A and IL-17F single nucleotide polymorphisms (SNPs) and the risk of developing gastric cancer. Genotyping of SNPs rs2275913, rs763780 and rs3748067 within the IL-17 gene were detected by performing polymerase chain reaction-restriction fragment length polymorphism analysis. Gastric cancer patients were more likely to be cigarette smokers, alcohol drinkers and have a family history of cancer in their first-degree relatives. Patients carrying the rs763780 polymorphism were correlated with a significant increased risk of gastric cancer in codominant, dominant and recessive models. Additionally, individuals with the rs763780 polymorphism were correlated with a markedly increased risk of gastric cancer among alcohol drinkers in codominant, dominant and recessive models. Furthermore, a significant correlation was identified between the rs763780 polymorphism and the consumption of alcohol. However, no association was identified between rs2275913 and rs3748067 polymorphisms and the risk of developing gastric cancer. Thus, the present study reported that the rs763780 polymorphism may be associated with risk of developing gastric cancer in the population studied, particularly in alcohol drinkers.

Association of IL-17A and IL-17F polymorphisms with gastric cancer risk in Asians: a meta-analysis

Increasing number of studies focused on the association of IL-17A rs2275913 and IL-17F rs763780 polymorphisms with gastric cancer (GC) risk. However, the results were inconsistent. To elucidate the exact association, we performed the present meta-analysis. Databases including PubMed, Web of knowledge and Chinese National Knowledge Infrastructure (CNKI) were systematically searched for potentially eligible literatures. Odds ratios (OR) and their 95% confidence interval (CI) were used to evaluate the strength of association. Eight studies for IL-17A rs2275913 (3345 cases and 4427 controls) and five studies for IL-17F rs763780 (1784 cases and 2592 controls) were finally included. The results indicated that individuals with AA genotype of IL-17A rs2275913 polymorphism were associated with increased GC risk compared with wild-type GG (OR=1.61, 95% CI=1.17-2.23, P=0.004); A allele was significantly associated with increased GC risk compared with G allele (OR=1.22, 95% CI=1.06-1.41, P=0.007). IL-17F rs763780 polymorphism was also significantly associated with increased GC risk (CC vs. CT: OR=1.40, 95% CI=1.04-1.88, P=0.025; CT vs. TT: OR=1.35, 95% CI=1.16-1.58, P<0.001; C allele vs. T allele: OR=1.30, 95% CI=1.15-1.47, P<0.001). In summary, IL-17A rs2275913 A/G polymorphism and IL-17F rs763780 C/T polymorphism might be associated with increased GC risk in Asians. Further large-scale studies are still required to confirm the results of this meta-analysis.

Lack of Association of the Polymorphisms IL-17A (-197G/A) and IL-17F (+7488A/G) with Multibacillary Leprosy in Mexican Patients

Background. Leprosy is a chronic infectious disease caused by the intracellular acid-fast bacilli Mycobacterium leprae; it has been determined that genetic factors of the host play an important role in the disease susceptibility. Thus, in this case-control study, we evaluated the possible association between the IL-17A G-197A (rs227593) and IL-17F A7488G (His161Arg, rs763780) gene SNPs and susceptibility to leprosy disease in Mexican population. Methods. Seventy-five leprosy patients and sixty-nine control subjects were included. Both SNPs were genotyped with the polymerase chain reaction-restriction fragment length polymorphism technique. Results. We found nonsignificant differences in genotype and allele frequencies related to IL-17A G-197A (rs227593) and IL-17F A7488G (His161Arg, rs763780) gene SNPs in MB as well as subclinical forms of leprosy disease versus healthy individuals. Conclusions. Since the sample size is not large enough, it is difficult to sustain an association of susceptibility to leprosy with genotypes or allele frequencies of IL-17A G-197A (rs227593) and IL-17F A7488G (His161Arg, rs763780), suggesting that IL-17 polymorphisms have no significant role in the genetic susceptibility to development of this disease in the Mexican Mestizo population.

Genetics of gastric cancer

Gastric cancer remains highly prevalent and accounts for a notable proportion of global cancer mortality. This cancer is also associated with poor survival rates. Understanding the genetic basis of gastric cancer will offer insights into its pathogenesis, help identify new biomarkers and novel treatment targets, aid prognostication and could be central to developing individualized treatment strategies in the future. An inherited component contributes to <3% of gastric cancers; the majority of genetic changes associated with gastric cancer are acquired. Over the past few decades, advances in technology and high-throughput analysis have improved understanding of the molecular aspects of the pathogenesis of gastric cancer. These aspects are multifaceted and heterogeneous and represent a wide spectrum of several key genetic influences, such as chromosomal instability, microsatellite instability, changes in microRNA profile, somatic gene mutations or functional single nucleotide polymorphisms. These genetic aspects of the pathogenesis of gastric cancer will be addressed in this Review.

Interleukin-23A is associated with tumor growth in Helicobacter-pylori-related human gastric cancer

Background

Interleukin (IL)-23 is one of the newly identified inflammatory cytokines, and inflammation is also known to be related to the development of gastric cancer (GC). The role of IL-23 in gastric cancer, however, is largely unknown. In the present study, we investigated the expression and possible role of IL-23A in human GC.

Methods

The expression of IL-23A and IL-17A in human GC tissues was determined by immunohistochemistry, and the relationship between IL-23A expression and clinical characteristics of GC was investigated. The serum concentration of IL-23A and IL-17A was also tested by ELISA. The source and role of IL-23A in GC were studied in vitro by Flowcytometry, MTS (Owen’s reagent) assay and Western blot.

Results

IL-23A, IL-23 receptor (IL-23R) and IL-17A were all overexpressed in human GC tissues, and the level of IL-23A was well correlated with IL-17A in GC tissues as well as in patient’s serum. Macrophages and GC cells were the main source of IL-23A secretion upon stimulation of H. pylori lysate. Furthermore, we found that IL-23A promoted proliferation of GC cell lines via IL-17A/IL-17 receptor antagonist (IL-17RA) /nuclear factor-κB (NF-κB) signaling.

Conclusions

The high expression of IL-23A is associated with GC. IL-23A can promoted GC cells growth by inducing the secretion of IL-17A in tumor microenvironment. Our results suggest that the serum concentration of IL-23A is a good biomarker of poor clinical prognosis in GC patients.

Interleukin-17 gene polymorphisms contribute to cancer risk

Epidemiological studies have suggested that interleukin-17 (IL-17) polymorphisms are associated with cancer risk. However, the results of these studies are inconsistent. Therefore, we performed a meta-analysis to obtain a precise conclusion. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association of the IL-17A rs2275913G>A and IL-17F rs763780T>C polymorphisms with cancer risk. Publication bias and sensitivity analyses were performed to ensure the statistical power. Overall, 10 relevant case-control studies involving 4,516 cases and 5,645 controls were included. The pooled ORs with 95% CIs indicated that the IL-17A rs2275913G>A polymorphism was significantly associated with increased cancer risk (for A versus G: OR = 1.28, 95% CI: 1.16–1.41, P < 0.001, I² = 61.1%; for GA versus GG: OR = 1.12, 95% CI: 1.02–1.23, P = 0.015, I² = 27.8%; for AA versus GG: OR = 1.71, 95% CI: 1.38–2.41, P < 0.001, I² = 69.6%; for GA + AA versus GG: OR = 1.23, 95% CI: 1.13–1.34, P < 0.001, I² = 6.4%; for AA versus GG + GA: OR = 1.62, 95% CI: 1.27–2.07, P < 0.001, I² = 81.4%). Succeeding analysis of HWE and stratified analysis of gastric cancer and the Asian (and Chinese) population revealed similar results. The IL-17F rs763780T>C polymorphism was also significantly associated with gastric cancer development. Overall, the present meta-analysis suggests that IL-17 polymorphisms increase the risk of developing cancer, particularly gastric cancer, in the Asian (and Chinese) population.

IL-17A G197A and C1249T polymorphisms in gastric carcinogenesis

Interleukin 17A (IL-17A) is a critical cytokine involved in inflammatory diseases and inflammation-associated cancers. Increasing case-control studies have implicated crucial roles of IL-17A single nucleotide polymorphisms (G197A and C1249T) in gastric carcinogenesis, but providing inconclusive findings. The present study is aimed to estimate the association of IL-17A G197A and C1249T polymorphisms with gastric cancer risk by pooling all available publications. A comprehensive literature search in PubMed, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang databases was performed for eligible publications from their inception up to May 5, 2014. The pooled odds ratios (ORs) with corresponding 95 % confidence intervals (CIs) were calculated to estimate the effect of IL-17A polymorphisms on gastric carcinogenesis. Stratified analysis by ethnicity, Helicobacter pylori (H. pylori) infection, and smoking status were also conducted. All analyses were performed by using the Stata 12.0 software. There were five case-control studies with 2,774 cases and 3,162 controls and two case-control studies with 620 cases and 1,123 controls on the susceptibility of IL-17A G197A and C1249T polymorphisms to gastric cancer, respectively. Significant association was observed between IL-17A G197A polymorphism and gastric cancer risk, particularly among Asians. The status of H. pylori infection and smoking did not influence this association. In addition, the IL-17A C1249T polymorphism did not confer a risk effect on gastric carcinogenesis. The pooled results were not materially altered by sensitivity analysis. We firstly show that the polymorphism of IL-17A G197A but not C1249T is a risk factor for gastric cancer.

Interleukin 17A rs3819024 A>G polymorphism is associated with an increased risk of gastric cardia adenocarcinoma in a Chinese population

Gastric cardia adenocarcinoma (GCA) is one of the most common malignant tumors. In addition to environmental risk factors, genetic factors might play an important role in GCA carcinogenesis. To evaluate the association between polymorphisms in the interleukin 17A (IL17A) gene on the development of GCA, we conducted a hospital-based case-control study. A total of 243 GCA cases and 476 controls were recruited and their genotypes were determined using a custom-by-design 48-Plex SNPscan™ Kit. IL17A rs3819024 A > G polymorphism was found to be associated with the increased risk of GCA. When the IL17A rs3819024 AA homozygote genotype was used as the reference group, the AG genotype was associated with a significantly increased risk of GCA (AG versus AA: adjusted OR = 1.53, 95% CI = 1.05-2.23, p = 0.026). However, there was no significant association between five other SNPs and GCA. Stratified analyses indicated that a significantly increased risk of GCA associated with the IL17A rs3819024 A > G polymorphism was evident among male patients, patients who drank alcohol or those who never smoked. These findings indicated that functional polymorphism IL17A rs3819024 A > G might contribute to GCA susceptibility. Future larger studies with more rigorous study designs are required to confirm the current findings.

IL-17A (-197G/A) and IL-17F (7488T/C) gene polymorphisms and cancer risk in Asian population: a meta-analysis

Interleukin (IL)-17 has been shown to play an important role in the pathogenesis of inflammation and cancer. The IL-17A (-197G/A) and IL-17F (7488T/C) polymorphisms have been extensively investigated with cancer risk, but individually published results have been inconclusive. The aim of this study was to clarify the effects of the IL-17A (-197G/A) and IL-17F (7488T/C) polymorphisms on cancer risk in Asian populations. Relevant studies were identified by searching databases extensively. The association between the IL-17A (-197G/A) and IL-17F (7488T/C) polymorphisms and cancer risk was assessed by odds ratios (ORs) together with their 95% confidence intervals (CIs). A total of 12 articles with adequate information satisfied our inclusion criteria; these included 12 studies, with 4,540 cases and 5,875 controls, of IL-17A (-197G/A) polymorphism and seven studies, with 1,960 cases and 3,226 controls, of IL-17F (7488T/C) polymorphism. In the overall analysis, the IL-17A (-197G/A) polymorphism was significantly associated with increased cancer risk (P<0.05), for all genetic models. However, there was no statistically significant association between IL-17F (7488T/C) and cancer risk (P>0.05), for any genetic models. Furthermore, stratification by cancer type revealed a significant correlation between the IL-17A (-197G/A) polymorphism and cancer risk for all cancer types. When stratified by source of controls, a significant correlation was observed between the IL-17A (-197G/A) polymorphism and cancer risk in the population-based control subgroup but not in hospital-based control subgroup. In conclusion, our meta-analysis provides evidence that the IL-17A (-197G/A) polymorphism might be associated with cancer risk, while no evidence suggested a significant association between IL-17F (7488T/C) polymorphism and cancer risk.

Interleukin-8 and interleukin-17 for cancer

Pro-inflammatory cytokines have been associated with chronic inflammation and inflammatory diseases. Increased levels of interleukins (ILs) have been associated with inflammatory disease exacerbation. ILs levels have been observed to be associated with advance stage cancer for several types of cancer and a poor prognostic maker for malignant disease. Moreover; increased levels of cytokines induce tumorigenesis. There are several paradigms such as the hepatocellular carcinoma induced from chronic inflammation of an underlying hepatitis. In the current review, we will focus on IL-8 and -17. These two ILs as in the case of others, induce neo-angiogenesis through activation of the vascular endothelial growth (VEGF) factor pathway. Additionally, they enhance the activity of matrix metalloproteinase-2 and -9 (MMP-2,-9) which in turn increase the metastatic activity of the underlying malignancy. Inhibition of cytokine production could be a potential treatment both for chronic inflammatory diseases and tumor modulation. Local microenvironment modulation could be applied in surgery resected patients as in the case of lung cancer in order to enhance the local immune activity.

Interleukin-17 and type 17 helper T cells in cancer management and research

Since their recent discovery, T helper 17 (Th17) cells have been frequently detected in the tumor microenvironment of many malignancies, but their clinical implications remain largely unknown. Interleukin-17 (IL-17) detection is commonly related with poor outcomes in colorectal cancers, yet its presence is associated with antitumor responses in ovarian carcinomas. Numerous experimental models illustrate the divergent roles of Th17 cells in tumor immunity, which appears to be mainly dependent on the tumor context (type, location, and stage of cancer). It is recognized that IL-17 is produced by a variety of cell types and that Th17 cells are endowed with a unique functional plasticity. Therefore, when trying to elucidate potential immune biomarkers and immunotargets, it is extremely important to make a clear dissociation between strategies targeting Th17 versus its hallmark cytokine, IL-17. In this review, we will summarize the data regarding the detection of IL-17 and Th17 in human cancers, consider the experimental evidence on their respective roles in antitumor activity, and discuss the potential of IL-17 as an immune target for therapeutic interventions.

Effect of interleukin-17A and interleukin-17F gene polymorphisms on the risk of gastric cancer in a Chinese population

We selected six tagged single-nucleotide polymorphisms (SNPs) in the IL-17A and IL-17F genes, and evaluated the relationship between the six common SNPs and H. pylori infection, tobacco smoking and subsites of gastric cancer in gastric cancer patients. Genotyping of IL-17A (rs2275913, rs3748067 and rs3819025) and IL-17A (rs763780, rs9382084, and rs12203582) was performed in a 384-well plate format on the MassARRAY® platform. An unconditional multiple logistical regression model was performed to determine the association between IL-17A and IL-17F genetic variations and gastric cancer risk. Unconditional logistic regression analysis showed that subjects carrying the rs2275913AA and rs3748067 TT genotypes were 1.70 and 3.45 times more likely to develop gastric cancer. Furthermore, rs2275913 and rs3748067 genetic variants significantly interacted with H. pylori infection on the risk of gastric cancer. The interaction between rs3748067 and rs9382084 genetic variants and tobacco smoking trend was significant. In addition, rs2275913, rs3748067 and rs9382084 genetic variants were only associated with non-cardia gastric cancer. The findings suggest that the rs2275913, rs3748067 and rs9382084 polymorphisms increase the risk of gastric cancer, and they interact with H. pylori infection, tobacco smoking and subsites of gastric cancer. These findings could be helpful in identifying individuals at increased risk for developing gastric cancer.