Polymorphisms in genes involved in the inflammatory response and interaction with NSAID use or smoking in relation to lung cancer risk in a prospective study

Common variants of pro-inflammatory gene IL1B and interactions with PPP1R13L and POLR1G in relation to lung cancer among Northeast Chinese

Lung cancer is a complex disease influenced by a variety of genetic and environmental factors. The cytokine interleukin 1 encoded by IL1B is an important mediator of the inflammatory response, and is involved in a variety of cellular activities. The effect of single nucleotide polymorphisms (SNP) at IL1B has been investigated in relation to cancer with inconsistent results. This Northeastern-Chinese case-control study involving 627 cases and 633 controls evaluated the role of three haplotype-tagging single nucleotide polymorphisms (htSNP) (rs1143633, rs3136558 and rs1143630) representing 95% of the common haplotype diversity across the IL1B gene and assessed interactions with IL1B, PPP1R13L, POLR1G and smoking duration in relation to lung cancer risk. The analyses of five genetic models showed associations with lung cancer risk for rs1143633 in the dominant model [adjusted-OR (95% CI) = 0.67 (0.52-0.85), P = 0.0012] and rs3136558 in the recessive model [adjusted-OR (95% CI) = 1.44 (1.05-1.98), P = 0.025]. Haplotype4 was associated with increased lung cancer risk [adjusted-OR (95% CI) = 1.55 (1.07-2.24), P = 0.021]. The variant G-allele of rs1143633 was protective in smoking sub-group of > 20 years. Using multifactor dimensionality reduction (MDR) analyses, we identified the three best candidate models of interactions and smoking-duration or IL1B rs1143633 as main effect. In conclusion, our findings suggest that IL1B SNP rs1143633 may associate with lower risk of lung cancer, confirming previously identified marker; IL1B SNP rs3136558 and haplotype4 consisting of IL1B htSNPs may associate with increasing risk of lung cancer; interactions of IL1B with POLR1G or PPP1R13L or smoking-duration, which is independent or combined, may involve in risk of lung cancer and lung squamous cell carcinoma.

Effects of Anesthesia and Anesthetic Techniques on Metastasis of Lung Cancers: A Narrative Review

Purpose

Tumor recurrence and metastasis are essential for the mortality and morbidity of cancer. Surgical resection of solid tumors is the conventional treatment approach for malignant tumors. However, even after undergoing radical surgery, certain patients develop local or distant metastasis, which may contribute to treatment failure. Anesthesia and anesthetic techniques are widely used in the perioperative period. Emerging evidence indicates that anesthetics influence tumor recurrence and metastasis. Therefore, the current review summarizes the effects of anesthesia and anesthetic techniques on tumor recurrence and lung metastasis.

Methods

Relevant literature was retrieved from the following databases: Medline/PubMed, CNKI and Wanfang. A total of 109 articles were selected and analyzed in this research.

Results

(1) A variety of intravenous anesthetics may affect metastasis or tumor growth, though the evidence is contradictory and inconsistent, and the clinical data are still inconclusive. (2) Volatile anesthetics have proinflammatory effects and may have direct and indirect effects on the survival of cancer cells. (3) Although the relevant clinical data are limited, there is strong evidence in vitro that local anesthetics have a protective effect on cancer recurrence. (4) No mode of anesthesia has been determined to be beneficial to patients with cancer, but clinical studies are currently recommended for anesthesia modality and composite use.

Conclusion

Available data suggest that anesthesia and anesthetic techniques might play an important role in tumor progression and lung metastasis, the understanding of which will help in designing more effective management of the tumor and attaining fewer side effects.

Interleukin polymorphisms and protein levels associated with lung cancer susceptibility and phenotypes

BACKGROUND

We conducted a comprehensive analysis to explore whether multiple interleukin (IL), IL-1β, IL-4, IL-6, IL-8 and IL-10, polymorphisms and IL proteins (IL-6, IL-10) relate to lung cancer (LC) susceptibility or clinical characteristics.

METHODS

We performed the standard meta-analysis procedures according to PRISMA. The odds ratio (OR) and mean difference (MD) were used for analysis.

RESULTS

We investigated 11 variants from 43 articles, and found that IL-1β rs16944 (p = 0.04) and IL-10 rs1800872 (p = 0.003) decreased while IL-10 rs1800896 (p = 0.007) increased LC risks. We also found that IL-1β rs1143627 decreased NSCLC risks (p = 0.03). The heterozygotes and homozygotes contributed differently. In addition, another 15 articles were involved to explore the relationship between IL proteins and LC. We found that LC patients accounted for higher serum IL-6 of 16.60 pg/mL (p < 0.00001) and higher serum IL-10 of 3.47 pg/mL (p = 0.02) than that of controls. Furthermore, IIIA-Ⅳ LC patients tended to have higher proportion of positive IL-6 staining in lung tumor tissue in contrast with IA-IIB patients by TNM stage (p = 0.0002).

CONCLUSIONS

Four variants from IL-1β and IL-10, and serum IL-6 and IL-10 levels are associated with LC risks.

Effect of Concurrent Chemoradiation With Celecoxib vs Concurrent Chemoradiation Alone on Survival Among Patients With Non-Small Cell Lung Cancer With and Without Cyclooxygenase 2 Genetic Variants: A Phase 2 Randomized Clinical Trial

IMPORTANCE

Treatment of locally advanced non-small cell lung cancer (NSCLC) remains challenging. The rationale of combining a cyclooxygenase 2 (COX-2) inhibitor with concurrent chemoradiation (CCRT) was based on results of preclinical research and prospective clinical studies; however, no randomized clinical trial has provided evidence of a direct comparison with CCRT alone.

OBJECTIVE

To determine the effect of combined selective COX-2 inhibition with standard CCRT on survival among patients with unresectable stage III NSCLC.

DESIGN, SETTING, AND PARTICIPANTS

A single-center, open-label, randomized phase 2 clinical trial was performed among 96 patients who had histologically and cytologically confirmed unresectable stage III NSCLC. Participants were enrolled from November 2011 to August 2015. Data were analyzed from February to October 2018.

INTERVENTION

Patients were randomized to receive thoracic radiation, 60 Gy, for 6 weeks concurrent with etoposide and cisplatin or the same regimen of CCRT combined with 200 mg of celecoxib, taken twice daily.

MAIN OUTCOMES AND MEASURES

The primary end point was overall survival. The secondary end points were the proportion of patients with treatment-related toxic effects, progression-free survival, and overall survival in subgroups with and without the COX-2 genotype.

RESULTS

A total of 100 patients were randomized. Following the exclusion of 4 outliers, 96 participants (96.0%) were analyzed (51 randomized to CCRT alone and 45 randomized to CCRT with celecoxib; mean [SD] age, 60.0 [8.3] years; 73.0 [76.0%] male). The median overall survival time was 32.8 (95% CI, 17.0-48.5) months in the group that received CCRT with celecoxib and 35.5 (95% CI, 25.8-45.2) months in the group that received CCRT alone (P = .88). Celecoxib with CCRT was well tolerated; the incidence of symptomatic radiation pneumonitis was 6.6% (95% CI, 1.4%-18.0%) in the group that received CCRT with celecoxib and 11.8% (95% CI, 4.4%-23.9%) in the group that received CCRT alone (P = .49). Among patients with the high-risk genotype, celecoxib plus CCRT was not associated with higher progression-free survival (hazard ratio, 0.36; 95% CI, 0.13-1.04; P = .05) or overall survival (hazard ratio, 0.50; 95% CI, 0.15-1.72; P = .26) compared with CCRT alone.

CONCLUSIONS AND RELEVANCE

In unresectable stage III NSCLC, adding celecoxib to concurrent chemoradiation did not improve survival. A smaller, not statistically significant proportion of patients in the CCRT with celecoxib group compared with the CCRT alone group developed symptomatic radiation pneumonitis. Among patients with the high-risk genotype, adding celecoxib to CCRT did not improve overall or progression-free survival.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01503385.

Effect of IL2RA and IL2RB gene polymorphisms on lung cancer risk

BACKGROUND

Inflammation is crucial for lung cancer development. Variants of multiple genes in inflammation pathways may lead to susceptibility to lung cancer. In the present study, we aimed to assess the influence of polymorphisms in inflammation-related genes (IL2RA and IL2RB) on lung cancer risk.

METHODS

A total of 507 patients with lung cancer and 503 healthy controls were genotyped for seven polymorphisms of IL2RA and IL2RB using the Agena MassARRAY platform. We evaluated the relationship of the genotypes with lung cancer susceptibility using odds ratio (OR), 95% confidence interval (95% CI) and chi square test.

RESULTS

We found that IL2RA rs12722498 was significantly associated with a decreased risk of lung cancer in dominant (p = 0.040, OR = 0.71, 95% CI = 0.51-0.98), additive (p = 0.016, OR = 0.68, 95% CI = 0.50-0.93) and allele (p = 0.019, OR = 0.69, 95% CI = 0.51-0.94) models. After stratification analysis, the results showed that IL2RA rs12569923 (non-smokers), IL2RA rs791588 (≤60 years old, non-drinkers, BMI < 24 kg/m²), IL2RA rs12722498 (≤60 years old, non-drinkers, BMI < 24 kg/m², female) and IL2RB rs2281089 (female, stage) significantly decreased the risk of lung cancer. Additionally, the haplotypes of rs12569923 and rs791588 in IL2RA had strong relationships with lung cancer in the subgroups of BMI < 24 kg/m², age ≤ 60 years old, non-smokers and non-drinkers.

CONCLUSION

Our results showed that the IL2RA and IL2RB polymorphisms were associated with lung cancer risk in the Chinese Han population, which suggests roles for IL2RA and IL2RB polymorphisms in lung cancer.

Association of Promoter Region Polymorphisms of IL-10 Gene with Susceptibility to Lung Cancer: Systematic Review and Meta-Analysis

Objective: Epidemiological studies have suggested that the promoter region polymorphisms of interleukin-10 (IL-10) gene may be associated with an increased risk of lung cancer. However, those studies results are controversial. Thus, a comprehensive meta-analysis was performed to evaluate the association of promoter region polymorphisms of IL-10 gene with susceptibility to lung cancer. Methods: a comprehensive search of PubMed, EMBASE, and CNKI databases was performed to find all eligible studies up to September 15, 2018. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of such association. Results: A total number of 19 case-control studies with 4084 cases and 6,131 controls were selected. The overall meta-analysis results showed that the -592A>C polymorphism was significantly associated with lung cancer risk under four genetic models, i.e., allele (CT vs. TT: OR= 1.17, 95% CI 1.01-1.35, p=0.02), homozygote (CC vs. AA: OR= 1.64, 95% CI 1.29-2.02, p≤0.001), heterozygote (CA vs. AA: OR= 1.26, 95% CI 1.06-1.50, p≤0.001), and dominant (CC+CA vs. AA: OR= 1.31, 95% CI 1.11-1.54, p=0.001). However, there was no significant association between -819T>C and -1082A>G polymorphisms of IL-10 and lung cancer risk. Similarly, subgroup analyses by ethnicity detected significant association between IL-10 -592A>C and lung cancer among Asians and Caucasians. Conclusions: Our meta-analysis suggests that the IL-10 -592A>C polymorphism might be risk factor for lung cancer, especially among Asian and Caucasians. In contrast, the IL-10 -819T>C and -1082A>G polymorphisms are not significantly associated with increased risk of lung cancer.

Association between rs20417 polymorphism in cyclooxygenase-2 and gastric cancer susceptibility: Evidence from15 case-control studies

OBJECTIVE

Previous studies have reported an association between cyclooxygenase-2 (COX-2) polymorphism and gastric cancer (GC) susceptibility, but their results are controversial. This meta-analysis was intended to evaluate the relationship between the COX-2 rs20417 polymorphism and GC susceptibility in different ethnic groups.

METHODS

We searched PubMed, EMBASE, Web of Knowledge, and the Chinese Biomedical Database (CBM) for relevant case-control studies published up to October 6, 2018, which reported an association between the COX-2 rs20417 polymorphism and gastric cancer risk. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of this association.

RESULTS

15 papers detailing case-control studies were included in the analysis, which included a total of 2848 GC cases and 4962 healthy controls. The meta-analysis results indicated that the COX-2 rs20417 polymorphism was associated with increased GC susceptibility under allele (G vs C: OR = 1.67, 95%CI = 1.19-2.35, P = .003), heterozygous (GG vs CG: OR = 1.44, 95%CI = 1.03-2.02, P = .034), dominant (GC+CC vs GG: OR = 1.66, 95%CI = 1.18-2.34, P = .004), homozygous (GG vs CC:OR = 2.20, 95%CI = 1.07-4.54, P = .033), and recessive models (CC vs GG+CG:OR = 2.05, 95%CI = 1.09-3.85, P = .025). An analysis of ethnic subgroups revealed that the COX-2 rs20417 polymorphism was significantly associated with GC susceptibility in Asians under all 5 models (G vs C: OR = 2.22, 95%CI = 1.66-2.96, P < .001; GG vs CC: OR = 4.29, 95%CI = 1.94-9.50, P < .001; GG vs CG: OR = 1.86, 95%CI = 1.34-2.58, P < .001; CC vs GG+CG: OR = 3.73, 95%CI = 1.92-7.24, P < .001; GC+CC vs GG: OR = 2.20, 95%CI = 1.65-2.93, P < .001). Helicobacter pylori positive patients suffered a high risk of GC, compared to H pylori negative patients under the dominant model (OR = 3.09, 95%CI = 1.80-5.32, P < .001).

CONCLUSION

This meta-analysis of 15 case-control studies provides strong evidence that the COX-2 rs20417 polymorphism increases the risk of GC susceptibility in general populations, especially in Asians. Helicobacter pylori positive patients and those with the COX-2 rs20417 polymorphism had a higher risk of developing GC.

Association between cyclooxygenase-2 (COX-2) 8473 T > C polymorphism and cancer risk: a meta-analysis and trial sequential analysis

Background

Numerous studies have investigated the relationship between COX-2 8473 T > C polymorphism and cancer susceptibility, however, the results remain controversial. Therefore, we carried out the present meta-analysis to obtain a more accurate assessment of this potential association.

Methods

In this meta-analysis, 79 case-control studies were included with a total of 38,634 cases and 55,206 controls. We searched all relevant articles published in PubMed, EMBASE, OVID, Web of Science, CNKI and Wanfang Data, till September 29, 2017. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the strength of the association. We performed subgroup analysis according to ethnicity, source of controls, genotyping method and cancer type. Moreover, Trial sequential analysis (TSA) was implemented to decrease the risk of type I error and estimate whether the current evidence of the results was sufficient and conclusive.

Results

Overall, our results indicated that 8473 T > C polymorphism was not associated with cancer susceptibility. However, stratified analysis showed that the polymorphism was associated with a statistically significant decreased risk for nasopharyngeal cancer and bladder cancer, but an increased risk for esophageal cancer and skin cancer. Interestingly, TSA demonstrated that the evidence of the result was sufficient in this study.

Conclusion

No significant association between COX-2 8473 T > C polymorphism and cancer risk was detected.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4753-3) contains supplementary material, which is available to authorized users.

COX-2 rs5275 and rs689466 polymorphism and risk of lung cancer: A PRISMA-compliant meta-analysis

BACKGROUND

Cyclooxygenase-2 (COX-2) is an inducible enzyme that mediates the synthesis of prostaglandin, which plays an important role in the inflammation response. The overexpression of COX-2 in lung cancer has been found in several studies, suggesting that COX-2 contributes to carcinogenesis. There are many previous case-control studies focused on the association between COX-2 polymorphism and lung cancer risk, however, the conclusion remained controversial.

OBJECTIVES

We performed this meta-analysis to evaluate the association between COX-2 rs5275 and rs689466 polymorphism and susceptibility to lung cancer.

METHODS

A systematic literature research was conducted on PubMed, Embase, Cochrane Library, OVID, Web of Science, and Google Scholar up to November 30, 2017. The quality of studies was assessed by Newcastle-Ottawa scale. We combined odds ratios (ORs) and 95% confidence intervals (CIs) in 5 different genetic models for evaluation under a fixed-effect model or random-effect model. Subgroup analysis was performed according to source of control, ethnicity, pathological types, and smoking status. Sensitivity analysis and publication bias were also conducted.

RESULTS

Eventually, 14 eligible studies were included in our meta-analysis. We found rs5275 gene polymorphism decreased the risk of lung cancer under heterozygote model (OR: 0.91, 95% CI: 0.84-0.98, P = .02). COX-2 rs689466 gene polymorphism was also related to a significantly reduced risk under allele (OR: 0.88, 95% CI: 0.82-0.95, P = .001), homozygote (OR: 0.81, 95% CI: 0.68-0.95, P = .01), heterozygote (OR: 0.81, 95% CI: 0.72-0.91, P < .001), and dominant model (OR: 0.81, 95% CI: 0.72-0.91, P < .001), except for recessive model. Subgroup analysis suggested a similar association in Asians, but not in Caucasians. Polymorphism of rs5275 was strongly associated with a reduced risk of lung adenocarcinoma according to stratified analysis by pathological types. Egger test identified no significant publication bias.

CONCLUSIONS

Our meta-analysis demonstrated that COX-2 rs5275 and rs689466 polymorphism significantly decrease the risk of lung cancer in Asians but not in Caucasians, indicating COX-2 could serve as a potential diagnostic marker for lung cancer.

Associations of interleukin-6 gene polymorphisms with cancer risk: Evidence based on 49,408 cancer cases and 61,790 controls

Many molecular epidemiologic studies have shown that interleukin-6 (IL-6) polymorphisms are significantly associated with susceptibility for various cancers. However, the conclusions of these studies are inconsistent. The purpose of the present study was to explore the association between three common IL-6 loci (rs1800795, rs1800796, and rs1800797) and the risk for various cancers. We systematically searched the PubMed, Web of Science, Wanfang and China national knowledge infrastructure (CNKI) databases for relevant publications and obtained 108 eligible studies, involving 49,408 cancer patients and 61,790 cancer-free controls. Odds ratio (OR), 95% confidence interval (CI), and false positive reporting probability (FPRP) were used to evaluate cancer risk. All statistical analyses were performed using the R software meta package. We observed a non-significant association between rs1800795 and overall cancer risk, while rs1800797 was found to have a false positive association with overall risk of cancer. Subgroup analyses of rs1800797 also suggested non-significant association and rs1800795 played a protective role in liver cancer. Rs1800796 was found to be associated with overall cancer risk, particularly in Asian patients and those with prostate cancer. These findings provide evidence that IL-6 polymorphisms may affect cancer risk.

Factors Associated With Small Aggressive Non-Small Cell Lung Cancers in the National Lung Screening Trial: A Validation Study

Background

A small proportion of non-small cell lung cancers (NSCLCs) have been observed to spread to distant lymph nodes (N3) or metastasize (M1) or both, while the primary tumor is small (≤3 cm, T1). These small aggressive NSCLCs (SA-NSLSC) are important as they are clinically significant, may identify unique biologic pathways, and warrant aggressive follow-up and treatment. This study identifies factors associated with SA-NSCLC and attempts to validate a previous finding that women with a family history of lung cancer are at particularly elevated risk of SA-NSCLC.

Methods

This study used a case-case design within the National Cancer Institute's National Lung Screening Trial (NLST) cohort. Case patients and "control" patients were selected based on TNM staging parameters. Case patients (n = 64) had T1 NSCLCs that were N3 or M1 or both, while "control" patients (n = 206) had T2 or T3, N0 to N2, and M0 NSCLCs. Univariate and multivariable logistic regression were used to identify factors associated with SA-NSCLC.

Results

In bootstrap bias-corrected multivariable logistic regression models, small aggressive adenocarcinomas were associated with a positive history of emphysema (odds ratio [OR] = 5.15, 95% confidence interval [CI] = 1.63 to 23.00) and the interaction of female sex and a positive family history of lung cancer (OR = 6.55, 95% CI = 1.06 to 50.80).

Conclusions

Emphysema may play a role in early lung cancer progression. Females with a family history of lung cancer are at increased risk of having small aggressive lung adenocarcinomas. These results validate previous findings and encourage research on the role of female hormones interacting with family history and genetic factors in lung carcinogenesis and progression.

Genetic polymorphisms of IL-6 promoter in cancer susceptibility and prognosis: a meta-analysis

IL-6 is critical for tumorigenesis. However, previous studies on the association of IL-6 promoter polymorphisms with predisposition to different cancer types are somewhat contradictory. Therefore, we performed this meta-analysis regarding the relationship between IL-6 promoter single nucleotide polymorphisms and cancer susceptibility and prognosis. Up to April 2017, 97 original publications were identified covering three IL-6 promoter SNPs. Our results showed statistically significant association between IL-6 promoter and cancer risk and prognosis. Subgroup analysis indicated that rs1800795 was significantly associated with increased risk of cervical cancer, colorectal cancer, breast cancer, prostate cancer, lung cancer, glioma, non-Hodgkin’s lymphoma and Hodgkin’s lymphoma but not gastric cancer and multiple myeloma. Furthermore, rs1800796 was significantly associated with increased risk of lung cancer, prostate cancer and colorectal cancer but not gastric cancer. Additionally, rs1800797 was significantly association with breast cancer, non-Hodgkin’s lymphoma, B-cell lymphoma and diffuse large B-cell lymphoma but not gastric cancer. Simultaneously, rs1800795 and rs1800796 were associated with a significantly higher risk of cancer in Asia and Caucasian, rs1800797 was associated with a significantly risk of cancer in Caucasian but not in Asia. Furthermore, IL-6 promoter polymorphisms were significantly associated with the prognosis of cancer. Considering these promising results, IL-6 promoter including rs1800795, rs1800796 and rs1800797 may be a tumor marker for cancer therapy.

PPARG c.1347C>T polymorphism is associated with cancer susceptibility: from a case-control study to a meta-analysis

Recently, several studies suggested that PPARG c.1347C>T polymorphism was correlated with cancer risk. However, past results remained controversial. In this study, we performed a case-control study on the relationship of PPARG c.1347C>T polymorphism with risk of non-small cell lung cancer (NSCLC) and subsequently carried out a meta-analysis to further assess the association between PPARG c.1347C>T and overall cancer. In our case-control study, after adjusting by age, sex, body mass index (BMI), smoking and drinking, a tendency to increased NSCLC risk was noted (CT/TT vs. CC: adjusted OR, 1.21; 95% CI, 0.97–1.51; P = 0.097). In the meta-analysis, we found a significant association between PPARG c.1347C>T polymorphism and overall cancer risk (T vs. C: OR, 1.13; 95% CI, 1.03–1.23; P = 0.006; TT vs. CC: OR, 1.29; 95% CI, 1.07–1.56; P = 0.008, CT/TT vs. CC: OR, 1.11; 95% CI, 1.02–1.21; P = 0.014 and TT vs. CT/CC: OR, 1.26; 95% CI, 1.04–1.52; P = 0.016). In a subgroup analysis by ethnicity, evidence of significant association between PPARG c.1347C>T polymorphism and cancer risk was found among Asians and mixed populations. In a subgroup analysis by cancer type, PPARG c.1347C>T polymorphism was associated with risk of esophageal cancer and glioblastoma. In addition, in a subgroup analysis by origin of cancer cell, evidence of significant association between PPARG c.1347C>T polymorphism and cancer risk was also found among epithelial tumor. In conclusion, the findings indicate PPARG c.1347C>T polymorphism may increase the susceptibility of cancer.

Variability of the drug response to nonsteroidal anti-inflammatory drugs according to cyclooxygenase-2 genetic polymorphism

Purpose

Cyclooxygenase (COX) is the main pharmacodynamic target of nonsteroidal anti-inflammatory drugs (NSAIDs). We investigated the inhibitory effects on COX-2 after NSAIDs administration using a lipopolysaccharide (LPS)-derived COX-2 induction model in whole blood, according to the genotypes of COX-2 single-nucleotide polymorphisms (SNPs).

Patients and methods

Seven genotypes of COX-2 SNPs were selected from public databases and analyzed in 324 healthy subjects. Two genotypes showing a high percentage of variability were selected. A clinical trial examining pharmacodynamics according to the genotype of two SNPs (rs5275 and rs689466) was conducted. Twenty subjects were administered a single oral dose of 200 mg of celecoxib, and pharmacokinetic and pharmacodynamic analyses were performed.

Results

In the analysis of the pharmacokinetic parameters, significant differences in drug exposure were not investigated for each SNP genotype. The pharmacodynamic analysis revealed that the maximum effect of COX-2 inhibition was achieved at 2.0 hours for all genotypes of COX-2 SNPs after a single oral administration of 200 mg celecoxib. The inhibitory effects according to the genotype of COX-2 SNPs were investigated, and the area under the effect curve of the rs689466 GG genotype was significantly lower than that for the AA or AG genotype.

Conclusion

Our results demonstrated that inhibitory effects of celecoxib on COX-2 induction were different according to the genotype of COX-2 SNPs. In the present study, rs689466 is responsible for the variability of the response to celecoxib, suggesting that a subject with the GG genotype of rs689466 would be more responsive to celecoxib in terms of COX-2 inhibition.

Functional analysis of polymorphisms in the COX-2 gene and risk of lung cancer

The enzyme cyclooxygenase 2 (COX-2) is known to be involved in tumorigenesis and metastasis in certain types of cancer. Nevertheless, the prognostic value of COX-2 overexpression and its polymorphisms in patients with non-small cell lung cancer (NSCLC) have yet to be fully elucidated. The aim of the present study was to investigate the association between the three most commonly studied COX-2 gene polymorphisms (-1195 G/A, -765 G/C and 8473 T/C) with COX-2 expression and lung cancer risk in a Brazilian cohort. In the present hospital based, case-control retrospective study, 104 patients with NSCLC and 202 cancer free control subjects were genotyped for -1195 G/A, -765 G/C and 8473 T/C polymorphisms using allelic discrimination with a reverse transcription quantitative polymerase chain reaction method. COX-2 mRNA expression was analyzed in surgically resected tumors from 34 patients with NSCLC. The results revealed that COX-2 expression levels were higher in tumor tissue compared with normal lung tissue. However, this overexpression of COX-2 was not associated with the patient outcome, and furthermore, none of the analyzed polymorphisms were associated with the risk of developing lung cancer, COX-2 overexpression, or the overall survival of the patients with NSCLC. Taken together, the findings described in the present study do not support a major role for COX-2 polymorphisms and COX-2 overexpression in lung carcinogenesis within the Brazilian population.

IL-10 -1082A/G, -592C/A, and -819T/C polymorphisms in association with lung cancer susceptibility: a meta-analysis

Numerous studies have examined the association between interleukin-10 (IL-10 -1082A/G, -592C/A, and -819T/C) gene polymorphisms and risk of lung cancer, but these have revealed inconsistent results. The aim of this study was to clarify the relationship between these polymorphisms and the risk of lung cancer by performing a meta-analysis. The published literature concerning IL-10 polymorphisms and lung cancer risk were retrieved by systematically searching PubMed, Embase, Web of Science, China National Knowledge Infrastructure, WanFang, and Database of Chinese Scientific and Technical Periodicals (VIP) database. Statistical analysis was conducted with Stata 12.0 software. A total of ten published articles comprising of 19 studies were selected, including seven studies (1,960 controls and 1,321 cases) for IL-10 -1082A/G, seven studies (2,613 controls and 1,839 cases) for IL-10 -592C/A, and five studies (1,558 controls and 926 cases) for IL-10 -819T/C. This study found that the IL-10 -1082A/G and -592C/A polymorphisms were significantly associated with the risk of lung cancer in the overall analysis. When stratified by ethnicity, significantly increased risks were observed for IL-10 -1082A/G, -592C/A, and -819T/C polymorphisms in Asians (for -1082A/G, AA vs [AG + GG]: odds ratio [OR] =1.20, confidence interval [CI] =1.05–1.39, P<0.05; for C-592A, C vs A, OR =1.36, CI =1.20–1.53, P<0.05; CC vs AA, OR =1.85, CI =1.45–2.37, P<0.05; CC vs [CA + AA], OR =1.36, CI =1.15–1.61, P<0.05; for -819T/C, T vs C: OR =1.21, CI =1.06–1.38, P<0.05; TT vs CC, OR =1.54, CI =1.18–2.01, P<0.05; [TT + TC] vs CC, OR =1.51, CI =1.17–1.95, P<0.05). Moreover, the data indicated that there was a significant association between IL-10 -819T/C polymorphism and non-small-cell lung cancer risk. No significant publication bias was detected under the four genetic models (allele model, homozygous model, dominant model, and recessive model) in this meta-analysis. On the basis of these 19 studies, this study found that the IL-10 -1082A/G and -819T/C polymorphisms might have a significant association with risk of lung cancer in Asian populations.

Association Between COX-2 Polymorphisms and Lung Cancer Risk

BACKGROUND Multiple relevant risk factors for lung cancer have been reported in different populations, but results of previous studies were not consistent. Therefore, a meta-analysis is necessary to summarize these outcomes and reach a relatively comprehensive conclusion. MATERIAL AND METHODS STATA 12.0 software was used for all statistical of the relationship between COX-2 polymorphisms and lung cancer risk. Inter-study heterogeneity was examined with the Q statistic (significance level at P<0.1). The publication bias among studies in the meta-analysis was analyzed with Begg's funnel plot and Egger's test. Hardy-Weinberg equilibrium was tested in all controls of the studies. RESULTS COX-2 rs20417 polymorphism had a significant association with reduced risk of lung cancer under homozygous and recessive models, and similar results were observed in white and population-based subgroups under 2 and 3 contrasts, respectively. Additionally, rs2066826 polymorphism manifested a strong correlation with increased risk of lung cancer under 5 genetic models. CONCLUSIONS In COX-2 gene, rs20417 may have a certain relationship with reduced risk of lung cancer, while rs2066826 may increase the risk of lung cancer.

Circulating interleukin-6 and cancer: A meta-analysis using Mendelian randomization

Interleukin-6 (IL-6) plays a contributory role in the progression and severity of many forms of cancer; it however remains unclear whether the relevance between circulating IL-6 and cancer is causal. We therefore meta-analyzed published articles in this regard using IL-6 gene -174G/C variant as an instrument. Seventy-eight and six articles were eligible for the association of -174G/C variant with cancer and circulating IL-6, respectively. Overall analyses failed to identify any significance between -174G/C and cancer risk. In Asians, carriers of the -174CC genotype had an 1.95-fold increased cancer risk compared with the -174GG genotype carriers (P = 0.009). By cancer type, significance was only attained for liver cancer with the -174C allele conferring a reduced risk under allelic (odds ratio or OR = 0.74; P = 0.001), homozygous genotypic (OR = 0.59; P = 0.029) and dominant (OR = 0.67; P = 0.004) models. Carriers of the -174CC genotype (weighted mean difference or WMD = −4.23 pg/mL; P < 0.001) and -174C allele (WMD = −3.43 pg/mL; P < 0.001) had circulating IL-6 reduced significantly compared with the non-carriers. In further Mendelian randomization analysis, a reduction of 1 pg/mL in circulating IL-6 was significantly associated with an 12% reduced risk of liver cancer. Long-term genetically-reduced circulating IL-6 might be causally associated with a lower risk of liver cancer.

Interleukin-8 -251A/T gene polymorphism and lung cancer susceptibility: a meta-analysis

Many studies have examined the association between the interleukin-8 -251T/A (rs4073) gene polymorphism and lung cancer risk in various populations, but the results have been inconsistent. In this meta-analysis, PubMed was searched for case-control studies published through 01 December 2013. The data were extracted, and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. We assessed six published studies on the association between the interleukin-8 -251T/A polymorphism and lung cancer risk. The included studies yielded a total of 3265 lung cancer cases and 3607 controls. For the homozygous A/A and A allele carriers (T/A + A/A), the pooled ORs for all studies combining 3265 cases and 3607 controls were 1.03 (95% CI = 0.92-1.14; P = 0.235 for heterogeneity) and 1.07 (95% CI = 0.96-1.19; P = 0.245 for heterogeneity) when compared with the homozygous wild-type genotype (T/T). When the analysis was stratified by ethnicity, significant risks were found among Asians for both the A allele carriers and the homozygous A/A individuals. However, no significant associations were found in non-Asian populations using any of the genetic models. This meta-analysis suggests that the interleukin-8 -251A allele confer an increased risk for the development of lung cancer among Asians.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Intestinal PTGS2 mRNA levels, PTGS2 gene polymorphisms, and colorectal carcinogenesis

Background & Aims

Inflammation is a major risk factor for development of colorectal cancer (CRC). Prostaglandin synthase cyclooxygenase-2 (COX-2) encoded by the PTGS2 gene is the rate limiting enzyme in prostaglandin synthesis and therefore plays a distinct role as regulator of inflammation.

Methods

PTGS2 mRNA levels were determined in intestinal tissues from 85 intestinal adenoma cases, 115 CRC cases, and 17 healthy controls. The functional PTGS2 polymorphisms A-1195G (rs689466), G-765C (rs20417), T8473C (rs5275) were assessed in 200 CRC cases, 991 adenoma cases and 399 controls from the Norwegian KAM cohort.

Results

PTGS2 mRNA levels were higher in mild/moderate adenoma tissue compared to morphologically normal tissue from the same individual (P<0.0001) and (P<0.035) and compared to mucosa from healthy individuals (P<0.0039) and (P<0.0027), respectively. In CRC patients, PTGS2 mRNA levels were 8–9 times higher both in morphologically normal tissue and in cancer tissue, compared to healthy individuals (P<0.0001). PTGS2 A-1195G variant allele carriers were at reduced risk of CRC (odds ratio (OR) = 0.52, 95% confidence interval (95% CI): 0.28–0.99, P = 0.047). Homozygous carriers of the haplotype encompassing the A-1195G and G-765C wild type alleles and the T8473C variant allele (PTGS2 AGC) were at increased risk of CRC as compared to homozygous carriers of the PTGS2 AGT (A-1195G, G-765C, T8473C) haplotype (OR = 5.37, 95% CI: 1.40–20.5, P = 0.014). No association between the investigated polymorphisms and PTGS2 mRNA levels could be detected.

Conclusion

High intestinal PTGS2 mRNA level is an early event in colorectal cancer development as it occurs already in mild/moderate dysplasia. PTGS2 polymorphisms that have been associated with altered PTGS2 mRNA levels/COX-2 activity in some studies, although not the present study, were associated with colorectal cancer risk. Thus, both PTGS2 polymorphisms and PTGS2 mRNA levels may provide information regarding CRC risk.

Polymorphisms in arachidonic acid metabolism-related genes and the risk and prognosis of colorectal cancer

Cyclooxygenase-2 (COX-2), 12-lipoxygenase (12-LOX) and phospholipaseA2 (PLA2) played important roles in the modulation of apoptosis, angiogenesis, carcinogenesis and invasion of colorectal cancer (CRC). The polymorphisms in COX-2, 12-LOX and PLA2 may affect their roles. Therefore, we investigated if COX-2 -1195G > A, 12-LOX 261Arg > Gln and PLA2 c.349 + 191A > G polymorphisms were associated with risk and prognosis of CRC as well as possible interactions with the environmental factors on the risk of CRC in Northeast of China. A case-control study with 451 cases and 631 controls were carried out, a cohort with 386 patients were followed up. Genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Compared with the 261Arg/Arg genotype, 12-LOX 261Arg/Gln genotype and 261Arg/Gln + Gln/Gln genotypes reduced the risk of rectal cancer by 33% (adjusted OR = 0.67, 95% CI 0.47-0.97, p = 0.03) and 32% (adjusted OR = 0.68, 95% CI 0.49-0.96, p = 0.03), respectively. The adjusted HR for the association between 12-LOX 261Gln/Gln genotype and overall survival in patients with CRC was 1.68 (95% CI 1.06-2.68, p = 0.03). There was also evidence of an interaction between the PLA2 c.349 + 191 A > G genotypes and the overnight food consumption (adjusted ORi = 1.92, 95% CI 1.14-3.25, P(interaction) = 0.01). These observations indicate that 12-LOX 261Arg > Gln polymorphism may affect risk of rectal cancer, and it may be a potential predictive marker for prognosis of CRC.

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

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

Lack of association between -174G>C and -634C>G polymorphisms in interleukin-6 promoter region and lung cancer risk: a meta-analysis

Evidence suggested that the -174G>C and -634C>G polymorphisms in interleukin-6 (IL6) promoter region may modulate risk of lung cancer; however, the conclusion was still inconclusive. Therefore, we performed this meta-analysis to determine the association between IL6 -174G>C and -634C>G polymorphisms and lung cancer risk. The association strength was measured by odds ratios (ORs) and 95% confidence intervals (CI). Egger's test and Begg's test were performed to detect potential publication bias. By searching PubMed, EMBASE and China National Knowledge Infrastructure, we included 16 eligible studies in this meta-analysis, involving 6,202 lung cancer cases and 7,067 controls. Five studies about -174G>C polymorphism and 11 studies about -634C>G polymorphism were analyzed. By pooling eligible studies, we found no significant association of -174G>C with lung cancer risk (C vs. G: OR = 1.029; 95% CI, 0.957-1.106; heterogeneity, P = 0.478) and no statistic association of -634C > G with lung cancer susceptibility (G vs. C: OR = 1.050; 95% CI, 0.893-1.235; Heterogeneity, P < 0.001). No significant publication bias was observed. In conclusion, we found that -634C>G and -174G>C polymorphisms in IL6 promoter region were not associated with lung cancer risk.

Interleukin-6 -634C/G polymorphism is associated with lung cancer risk: a meta-analysis

Several studies have examined the associations of polymorphisms in interleukin-6 (IL6) with lung cancer (LC) risk. However, the results were conflicting. Thus, a meta-analysis was conducted to determine the relationship between IL6 polymorphisms and LC risk. Databases including PubMed, EMBASE, Wanfang, and China National Knowledge Infrastructure (CNKI) were searched. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. Thirteen studies were included in this meta-analysis. Overall, a significant association between IL6 -634C/G polymorphism and LC susceptibility was observed for GG + CG vs. CC (OR = 1.33, 95% CI 1.20-1.47, P < 0.00001). This polymorphism was also significantly associated with LC risk in Asians (OR = 1.33, 95% CI 1.20-1.47, P < 0.00001), female patients (OR = 1.30, 95% CI 1.11-1.52, P = 0.0009), male patients (OR = 1.25, 95% CI 1.03-1.52, P = 0.02), non-small cell lung cancer patients (OR = 1.21, 95% CI 1.03-1.41, P = 0.02), small cell lung cancer patients (OR = 1.91, 95% CI 1.23-2.97, P = 0.004), smokers (OR = 1.42, 95% CI 1.21-1.65, P < 0.0001), and non-smokers (OR = 1.32, 95% CI 1.13-1.53, P = 0.0003), respectively. No significant result was found for IL6 -174C/G polymorphism. This meta-analysis suggested that IL6 -634C/G polymorphism was a risk factor for LC.

The interleukin 10 -819C/T polymorphism and cancer risk: a HuGE review and meta-analysis of 73 studies including 15,942 cases and 22,336 controls

The aim of the present work was to perform a meta-analysis to evaluate the association between the interleukin 10 (IL-10) -819C/T (rs1800871) polymorphism and cancer risk. A total of 73 studies, including 15,942 cancer cases and 22,336 controls, were identified in this meta-analysis. The odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using the random-effects model. Overall, no significant association was identified between the IL-10 -819C/T polymorphism and cancer risk. In the subgroup analyses, the T allele and TT genotype were associated with a moderately reduced cancer risk in the Asian population (T allele vs. C allele: OR=0.93, 95%CI: 0.87, 0.99; TT vs. CC: OR=0.86, 95%CI: 0.76, 0.98; TT vs. CT/CC: OR=0.90, 95%CI: 0.82, 0.98). Individuals who were homozygous for the T allele (TT) were found to be associated with significantly reduced gastric cancer risk in the Asian population. The heterozygous variant (CT) and the dominant model (TT/CT vs. CC) were associated with an increased risk for cervical and ovarian cancer. However, the IL-10 -819C/T polymorphism was not significantly associated with breast cancer, colorectal cancer, lung cancer, hepatocellular carcinoma, prostate cancer, lymphoma, or melanoma. The depressed cancer risk of the TT genotype occurred in the studies of hospital-based case-control studies and the studies recruited less than 500 subjects, but no statistically significant results were found in the stratified analyses using genotyping method. The results suggest that the IL-10 -819TT genotype may be a protective factor for cancer in Asians, especially gastric cancer. In contrast, the CT genotype and the dominant model could be risk factors for cervical and ovarian cancer. The importance of stratifying by ethnicity, cancer type, study design, and sample size needs to be standardized in future studies, together with considering the association between the IL-10 -819C/T polymorphism and cancer risk. Furthermore, the linkage of -819C/T with other polymorphisms of the IL-10 gene may help explain the variability in findings.

Interactions between diet, lifestyle and IL10, IL1B, and PTGS2/COX-2 gene polymorphisms in relation to risk of colorectal cancer in a prospective Danish case-cohort study

Background & Aims

Diet contributes to colorectal cancer development and may be potentially modified. We wanted to identify the biological mechanisms underlying colorectal carcinogenesis by assessment of diet-gene interactions.

Methods

The polymorphisms IL10 C-592A (rs1800872), C-rs3024505-T, IL1b C-3737T (rs4848306), G-1464C (rs1143623), T-31C (rs1143627) and PTGS2 (encoding COX-2) A-1195G (rs689466), G-765C (rs20417), and T8473C (rs5275) were assessed in relation to risk of colorectal cancer (CRC) and interaction with diet (red meat, fish, fibre, cereals, fruit and vegetables) and lifestyle (non-steroid-anti-inflammatory drug use and smoking status) was assessed in a nested case-cohort study of nine hundred and seventy CRC cases and 1789 randomly selected participants from a prospective study of 57,053 persons.

Results

IL1b C-3737T, G-1464C and PTGS2 T8473C variant genotypes were associated with risk of CRC compared to the homozygous wildtype genotype (IRR=0.81, 95%CI: 0.68-0.97, p=0.02, and IRR=1.22, 95%CI: 1.04-1.44, p=0.02, IRR=0.75, 95%CI: 0.57-0.99, p=0.04, respectively). Interactions were found between diet and IL10 rs3024505 (P-value for interaction (P_int); meat=0.04, fish=0.007, fibre=0.0008, vegetables=0.0005), C-592A (P_int; fibre=0.025), IL1b C-3737T (P_int; vegetables=0.030, NSAID use=0.040) and PTGS2 genotypes G-765C (P_int; meat=0.006, fibre=0.0003, fruit 0.004), and T8473C (P_int; meat 0.049, fruit=0.03) and A-1195G (P_int; meat 0.038, fibre 0.040, fruit=0.059, vegetables=0.025, and current smoking=0.046).

Conclusions

Genetically determined low COX-2 and high IL-1β activity were associated with increased risk of CRC in this northern Caucasian cohort. Furthermore, interactions were found between IL10, IL1b, and PTGS2 and diet and lifestyle factors in relation to CRC. The present study demonstrates that gene-environment interactions may identify genes and environmental factors involved in colorectal carcinogenesis.

A meta-analysis of PTGS1 and PTGS2 polymorphisms and NSAID intake on the risk of developing cancer

Background

Several studies have investigated whether the polymorphisms in the prostaglandin endoperoxide synthase 1 (PTGS1) and PTGS2 genes and nonsteroidal anti-inflammatory drug (NSAID) use are associated with cancer risk; however, those studies have produced mixed results. Therefore, we performed a meta-analysis to evaluate the association between the PTGS1 and PTGS2 polymorphisms and the effect of NSAID use on the risk of developing cancer.

Methods

We conducted a comprehensive search in PubMed through March 2012. The odds ratios (ORs) with the corresponding 95% confidence intervals (CIs) were calculated using the fixed-effect model or the random-effect model.

Results

The database search generated 13 studies that met the inclusion criteria. For PTGS1 rs3842787, NSAID users homozygous for the major allele (CC) had a significantly decreased cancer risk compared with non-NSAID users (OR = 0.73, 95% CI = 0.59–0.89). For PTGS2 rs5275 and rs20417, there were no significant differences between the gene polymorphism and NSAID use on cancer risk among the 8 and 7 studies, respectively. However, in the stratified analysis by the type of cancer or ethnicity population, NSAID users homozygous for the major allele (TT) in rs5275 demonstrated significantly decreased cancer risk compared with non-NSAID users in cancer type not involving colorectal adenoma (OR = 0.70, 95% CI = 0.59–0.83) and among the USA population (OR = 0.67, 95% CI = 0.56–0.82). NSAID users homozygous for the major allele (GG) in rs20417 displayed a significantly decreased cancer risk than non-NSAID users among the US population (OR = 0.72, 95% CI = 0.58–0.88). For the PTGS2 rs689466 and rs2745557 SNPs, there were no significant differences.

Conclusion

This meta-analysis suggests that the associations between PTGS polymorphisms and NSAID use on cancer risk may differ with regard to the type of cancer and nationality.

Polymorphisms in genes related to inflammation, NSAID use, and the risk of prostate cancer among Danish men

The etiology of prostate cancer (PC) remains mostly unknown, but increasing evidence suggests that chronic inflammation in the prostate is associated with an increased risk of PC. Epidemiological studies have suggested that use of nonsteroidal anti-inflammatory drugs (NSAIDs) may protect against PC. Inborn variations in genes involved in the inflammatory response may modulate the risk of PC and interact with NSAIDs. The aims of this study were 1) to evaluate whether polymorphisms and haplotypes of the inflammation-related genes COX-2, Il1B, NFKB1, and PPARG are associated with risk of PC; 2) to investigate gene-environment interactions between polymorphisms and NSAID use; and 3) to examine whether the studied polymorphisms were associated with the aggressiveness of PC. The study population consisted of 370 cases of PC and 370 risk-set matched (age) controls nested within the prospective Danish "Diet, Cancer, and Health" cohort. Carriers of the variant deletion allele of NFKB1 -94ins/delATTG had a tendency toward a reduced risk of PC (incidence rate ratio (IRR), 0.73; 95% confidence interval (CI) 0.52-1.04). A lowered risk for PC was also found for carriers of variant allele NFKB1 -94ins/delATTG among non-users of NSAIDs (IRR 0.68; 95% CI 0.47-0.99), for non-aggressive disease (IRR 0.64; 95% CI 0.42-0.99), and among men with a body mass index above 30 kg/m(2) (IRR 0.56; 95% CI 0.27-1.16), although the latter estimate was based on small numbers. A similar pattern was seen for the variant C allele of the COX-2 +8473T→C polymorphism. No apparent association with PC was observed for the other studied polymorphisms. Our study did not indicate that chronic inflammation is a major risk factor for aggressive PC.

Current evidences on IL1B polymorphisms and lung cancer susceptibility: a meta-analysis

Interleukin 1, beta (IL1B) plays a key role in mediating acute and chronic inflammation, which is further correlated with lung carcinogenesis. Several polymorphisms on IL1B gene have been identified, and a series of epidemiological studies have examined the association between IL1B polymorphisms and lung cancer risk. However, these findings are inconclusive. To derive a precise estimation of the relationship, a meta-analysis was performed. We summarized 12 eligible publications on three commonly studied IL1B polymorphisms (i.e., -31 T/C, -511 T/C, and +3954 C/T) by searching electronic databases. Combined odds ratio (OR) with 95% confidence interval (CI) was calculated to assess the strength of association between them. Heterogeneity and publication bias were also assessed. We observed a significant association between IL1B polymorphisms and lung cancer. For -31T/C, the overall OR (95% CI) of TT/TC versus CC was 1.23 (1.06-1.43). For +3954 C/T, the overall OR (95% CI) of CC versus TT and CC versus CT/TT were 0.92 (0.86-0.99) and 0.92 (0.86-0.99), respectively. In conclusion, this meta-analysis suggests that the IL1B -31 T/C and +3954 C/T polymorphisms are associated with lung cancer risk. However, larger number of samples and studies with homogeneous lung cancer patients are needed to confirm these findings.

An association between the PTGS2 rs5275 polymorphism and colorectal cancer risk in families with inherited non-syndromic predisposition

Recently our group completed a genome-wide linkage study investigating Australian and Spanish families with inherited risk of colorectal cancer (CRC). A minor linkage peak from that study located on chromosome 1 correlates with the location of a known CRC risk-modifying gene, prostaglandin synthase (PTGS2). PTGS2 encodes the inducible prostaglandin synthase enzyme cyclooxygenase-2 (COX-2). Prostaglandins are implicated in the initiation of carcinogenesis and progression of tumours. Sequencing of PTGS2 in a small subset of affected individuals identified a high frequency of the minor C allele of single nucleotide polymorphism rs5275. We then genotyped the rs5275 polymorphism in 183 affected and 223 unaffected individuals from our CRC predisposed families. Tests for association in the presence of linkage were made using family-based association tests. The C allele was found to be significantly associated (P<0.01) with diagnosis of hereditary non-syndromic CRC (P=0.0094, dominant model) and an earlier age of diagnosis (P=0.0089, heterozygous-advantage model). Interestingly, by stratifying the age of diagnosis data, we observed a speculative gender-discordant effect. Relative to other groups, female CC carriers were diagnosed less when young, but by 60 years of age were the most at risk group. Conversely, CT carriers of both genders showed a consistently earlier diagnosis relative to TT carriers. Our results suggest potential differential age-and gender-dependent efficacies of chemopreventative COX-2 inhibitors in the context of non-syndromic colorectal cancer.

The interleukin-10 promoter polymorphism rs1800872 (-592C>A), contributes to cancer susceptibility: meta-analysis of 16,785 cases and 19,713 controls

Interleukin-10 (IL-10) is a multifunctional cytokine which participates in the development and progression of various malignant tumors. To date, a number of case–control studies were conducted to detect the association between IL-10-592C>A polymorphism and cancer risk in humans. However, the results of these studies on the association remain conflicting. In an effort to solve this controversy, we performed a meta-analysis based on 70 case–control studies from 65 articles, including 16 785 cancer cases and 19 713 controls. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. The overall results suggested that the variant homozygote genotype AA of the IL-10-592C>A polymorphism was associated with a moderately decreased risk of all cancer types (OR = 0.90, 95% CI = 0.83–0.98 for homozygote comparison, OR = 0.92, 95% CI = 0.86–0.98 for recessive model). In the stratified analyses, the risk remained for studies of smoking-related cancer, Asian populations and hospital-based studies. These results suggested that the IL-10-592C>A polymorphism might contribute to the cancer susceptibility, especially in smoking-related cancer, Asians and hospital-based studies. Further studies are needed to confirm the relationship.

Genetic susceptibility to lung cancer--light at the end of the tunnel?

Lung cancer is one of the most common and deadliest cancers in the world. The major socio-environmental risk factor involved in the development of lung cancer is cigarette smoking. Additionally, there are multiple genetic factors, which may also play a role in lung cancer risk. Early work focused on the presence of relatively prevalent but low-penetrance alterations in candidate genes leading to increased risk of lung cancer. Development of new technologies such as genomic profiling and genome-wide association studies has been helpful in the detection of new genetic variants likely involved in lung cancer risk. In this review, we discuss the role of multiple genetic variants and review their putative role in the risk of lung cancer. Identifying genetic biomarkers and patterns of genetic risk may be useful in the earlier detection and treatment of lung cancer patients.

Mechanistic aspects of COX-2 expression in colorectal neoplasia

The cyclooxygenase-2 (COX-2) enzyme catalyzes the rate-limiting step of prostaglandin formation in pathogenic states and a large amount of evidence has demonstrated constitutive COX-2 expression to be a contributing factor promoting colorectal cancer (CRC). Various genetic, epigenetic, and inflammatory pathways have been identified to be involved in the etiology and development of CRC. Alteration in these pathways can influence COX-2 expression at multiple stages of colon carcinogenesis allowing for elevated prostanoid biosynthesis to occur in the tumor microenvironment. In normal cells, COX-2 expression levels are potently regulated at the post-transcriptional level through various RNA sequence elements present within the mRNA 3' untranslated region (3'UTR). A conserved AU-rich element (ARE) functions to target COX-2 mRNA for rapid decay and translational inhibition through association with various RNA-binding proteins to influence the fate of COX-2 mRNA. Specific microRNAs (miRNAs) bind regions within the COX-2 3'UTR and control COX-2 expression. In this chapter, we discuss novel insights in the mechanisms of altered post-transcriptional regulation of COX-2 in CRC and how this knowledge may be used to develop novel strategies for cancer prevention and treatment.

Genetic variation in innate immunity and inflammation pathways associated with lung cancer risk

BACKGROUND

Pulmonary inflammation may contribute to lung cancer etiology. The authors conducted a broad evaluation of the association of single nucleotide polymorphisms (SNPs) in innate immunity and inflammation pathways with lung cancer risk and conducted comparisons with a lung cancer genome-wide association study (GWAS).

METHODS

In total, 378 patients with lung cancer (cases) and a group of 450 controls from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial were included. A proprietary oligonucleotide pool assay was used to genotype 1429 SNPs. Odds ratios and 95% confidence intervals were estimated for each SNP, and P values for trend (P(trend) ) were calculated. For statistically significant SNPs (P(trend) < .05), the results were replicated with genotyped or imputed SNPs in the GWAS, and P values were adjusted for multiple testing.

RESULTS

In the PLCO analysis, a significant association was observed between lung cancer and 81 SNPs located in 44 genes (P(trend) < .05). Of these 81 SNPS, there was evidence for confirmation in the GWAS for 10 SNPs. However, after adjusting for multiple comparisons, the only SNP that retained a significant association with lung cancer in the replication phase was reference SNP rs4648127 (nuclear factor of kappa light polypeptide gene enhancer of B-cells 1 [NFKB1]) (multiple testing-adjusted P(trend) = .02). The cytosine-thymine (CT)/TT genotype of NFKB1 was associated with reduced odds of lung cancer in the PLCO study (odds ratio, 0.56; 95% confidence interval, 0.37-0.86) and the in the GWAS (odds ratio, 0.79; 95% confidence interval, 0.69-0.90).

CONCLUSIONS

A significant association was observed between a variant in the NFKB1 gene and the risk of lung cancer. The current findings add to evidence implicating inflammation and immunity in lung cancer etiology.

Genetic epidemiology of cigarette smoke-induced lung disease

Chronic obstructive pulmonary disease (COPD) and lung cancer represent two diseases that share a strong risk factor in smoking, and COPD increases risk of lung cancer even after adjusting for the effects of smoking. These diseases not only occur jointly within an individual but also there is evidence of shared occurrence within families. Understanding the genetic contributions to these diseases, both individually and jointly, is needed to identify the highest risk group for screening and targeted prevention, as well as aiding in the development of targeted treatments. The chromosomal regions that have been identified as being associated either jointly or independently with lung cancer, COPD, nicotine addiction, and lung function are presented. Studies jointly measuring genetic variation in lung cancer and COPD have been limited by the lack of detailed COPD diagnosis and severity data in lung cancer populations, the lack of lung cancer-specific phenotypes (histology and tumor markers) in COPD populations, and the lack of inclusion of minorities. African Americans, who smoke fewer cigarettes per day and have different linkage disequilibrium and disease patterns than whites, and Asians, also with different patterns of exposure to lung carcinogens and linkage patterns, will provide invaluable information to better understand shared and independent genetic contributions to lung cancer and COPD to more fully define the highest risk group of individuals who will most benefit from screening and to develop molecular signatures to aid in targeted treatment and prevention efforts.

Single nucleotide polymorphisms in IL1B and the risk of acute coronary syndrome: a Danish case-cohort study

Background

Interleukin-1B (IL-1B) is a key pro-inflammatory cytokine that has been associated with the development of atherosclerosis and myocardial infarction. However, the prospective associations between functional single nucleotide polymorphisms (SNPs) in IL1B and incident acute coronary syndrome (ACS) have not been thoroughly investigated. The aims of this study were to examine the associations between individual SNPs in and SNP haplotypes of the promoter region of IL1B and incident ACS in a prospective study. Furthermore, we wanted to explore potential interactions with other risk factors for ACS on an additive scale.

Methodology/Principal Findings

The present study was based on the Danish prospective study Diet, Cancer and Health comprising more than 57 000 participants aged 50–64 at baseline. During a median follow-up of 7.2 years we identified 989 cases of incident ACS (755 men and 234 women). All cases were validated by review of medical records, and information on covariates was collected by study technicians. The study was conducted according to a case-cohort study design including ACS cases and a sex-stratified sub cohort of 1663 participants drawn randomly from the entire cohort. Weighted Cox proportional hazard models with age as time axis were used in the statistical analyses. Individual IL1B SNPs, SNP haplotypes, or haplotype combinations were not significantly associated with incident ACS, and, likewise, we found no evidence of interaction on an additive scale between IL1B haplotypes and risk factors, respectively.

Conclusions/Significance

Genetic variation in the promoter region of IL1B may not be associated with incident ACS in men or women above the age of 50 years.

Interaction between interleukin-10 (IL-10) polymorphisms and dietary fibre in relation to risk of colorectal cancer in a Danish case-cohort study

Background

More than 50% of the colorectal cancer (CRC) etiology has been attributed to diet. Established or suspected dietary factors modifying risk of CRC are red meat, cereals, fish, and fibre. Diet and lifestyle may be linked to cancer through inflammation. Interleukin-10 (IL-10) is an anti-inflammatory cytokine. We wanted to test if dietary factors and IL10 polymorphisms interact in relation to colorectal carcinogenesis.

Methods

The functional IL10 polymorphism C-592A (rs1800872) and the marker rs3024505 were assessed in relation to diet and lifestyle in a nested case-cohort study of 378 CRC cases and 775 randomly selected participants from a prospective study of 57,053 persons. Genotyping data on the IL10 polymorphism C-592A, smoking and non-steroidal anti-inflammatory drugs (NSAID) was retrieved from Vogel et al. (Mutat Res, 2007; 624:88). Incidence rate ratios (IRR) and 95% Confidence Interval (95% CI) were calculated.

Results

No associations were found between the IL10 rs3024505 polymorphism and risk of CRC. There was interaction between rs3024505 and dietary fibre (P-value for interaction = 0.01). IL10 rs3024505 homozygous wildtype carriers were at 27% reduced risk of CRC per 10 g fibre per day (95% CI: 0.60-0.88) whereas variant carriers had no risk reduction by fibre intake. Also, interaction between IL10 C-592A and intake of fibre was found (P-value for interaction = 0.02). Among those eating <17.0 grams of fibre per day, carriers of an C-592A variant allele had a statistically significantly higher risk of colorectal cancer compared to homozygous wildtypes. No significant differences in colorectal cancer risk were observed between the reference group (CC and <17.0 g/day) and carriers of one C-592A variant allele eating 17.0 or more grams of dietary fibre per day. This suggests that the increased risk due to carrying the variant allele can be overcome by higher fibre intake. No interactions between IL10 polymorphisms and dietary meat, cereal, or fish intake, or between IL10 rs3024505 and smoking or NSAID use were found.

Conclusions

In this northern Caucasian cohort we found interaction between IL10 and dietary fibre in CRC carcinogenesis. High intake of fibre seems to protect against CRC among individuals with IL10 related genetic susceptibility to CRC. This finding should be evaluated in other prospective and population-based cohorts with different ethnic groups.

Multistage analysis of variants in the inflammation pathway and lung cancer risk in smokers

BACKGROUND

Tobacco-induced lung cancer is characterized by a deregulated inflammatory microenvironment. Variants in multiple genes in inflammation pathways may contribute to risk of lung cancer.

METHODS

We therefore conducted a three-stage comprehensive pathway analysis (discovery, replication, and meta-analysis) of inflammation gene variants in ever-smoking lung cancer cases and controls. A discovery set (1,096 cases and 727 controls) and an independent and nonoverlapping internal replication set (1,154 cases and 1,137 controls) were derived from an ongoing case-control study. For discovery, we used an iSelect BeadChip to interrogate a comprehensive panel of 11,737 inflammation pathway single-nucleotide polymorphisms (SNP) and selected nominally significant (P < 0.05) SNPs for internal replication.

RESULTS

There were six SNPs that achieved statistical significance (P < 0.05) in the internal replication data set with concordant risk estimates for former smokers and five concordant and replicated SNPs in current smokers. Replicated hits were further tested in a subsequent meta-analysis using external data derived from two published genome-wide association studies (GWAS) and a case-control study. Two of these variants (a BCL2L14 SNP in former smokers and an SNP in IL2RB in current smokers) were further validated. In risk score analyses, there was a 26% increase in risk with each additional adverse allele when we combined the genotyped SNP and the most significant imputed SNP in IL2RB in current smokers and a 36% similar increase in risk for former smokers associated with genotyped and imputed BCL2L14 SNPs. CONCLUSIONS/IMPACT: Before they can be applied for risk prediction efforts, these SNPs should be subject to further external replication and more extensive fine mapping studies.

Epigenetic deregulation of the COX pathway in cancer

Inflammation is a major cause of cancer and may condition its progression. The deregulation of the cyclooxygenase (COX) pathway is implicated in several pathophysiological processes, including inflammation and cancer. Although, its targeting with nonsteroidal antiinflammatory drugs (NSAIDs) and COX-2 selective inhibitors has been investigated for years with promising results at both preventive and therapeutic levels, undesirable side effects and the limited understanding of the regulation and functionalities of the COX pathway compromise a more extensive application of these drugs. Epigenetics is bringing additional levels of complexity to the understanding of basic biological and pathological processes. The deregulation of signaling and biosynthetic pathways by epigenetic mechanisms may account for new molecular targets in cancer therapeutics. Genes of the COX pathway are seldom mutated in neoplastic cells, but a large proportion of them show aberrant expression in different types of cancer. A growing body of evidence indicates that epigenetic alterations play a critical role in the deregulation of the genes of the COX pathway. This review summarizes the current knowledge on the contribution of epigenetic processes to the deregulation of the COX pathway in cancer, getting insights into how these alterations may be relevant for the clinical management of patients.

Single nucleotide polymorphisms as susceptibility, prognostic, and therapeutic markers of nonsmall cell lung cancer

Lung cancer is a major public health problem throughout the world. Among the most frequent cancer types (prostate, breast, colorectal, stomach, lung), lung cancer is the leading cause of cancer-related deaths worldwide. Among the two major subtypes of small cell lung cancer and nonsmall cell lung cancer (NSCLC), 85% of tumors belong to the NSCLC histological types. Small cell lung cancer is associated with the shortest survival time. Although tobacco smoking has been recognized as the major risk factor for lung cancer, there is a great interindividual and interethnic difference in risk of developing lung cancer given exposure to similar environmental and lifestyle factors. This may indicate that in addition to chemical and environmental factors, genetic variations in the genome may contribute to risk modification. A common type of genetic variation in the genome, known as single nucleotide polymorphism, has been found to be associated with susceptibility to lung cancer. Interestingly, many of these polymorphisms are found in the genes that regulate major pathways of carcinogen metabolism (cytochrome P450 genes), detoxification (glutathione S-transferases), adduct removal (DNA repair genes), cell growth/apoptosis (TP53/MDM2), the immune system (cytokines/chemokines), and membrane receptors (nicotinic acetylcholine and dopaminergic receptors). Some of these polymorphisms have been shown to alter the level of mRNA, and protein structure and function. In addition to being susceptibility markers, several of these polymorphisms are emerging to be important for response to chemotherapy/radiotherapy and survival of patients. Therefore, it is hypothesized that single nucleotide polymorphisms will be valuable genetic markers in individual-based prognosis and therapy in future. Here we will review some of the most important single nucleotide polymorphisms in the metabolic pathways that may modulate susceptibility, prognosis, and therapy in NSCLC.

Meta-analysis of association between cytokine gene polymorphisms and lung cancer risk

The aim of this study was to evaluate the association between various cytokine gene polymorphisms and lung cancer (LC) susceptibility. We searched Pubmed, Elsevier Science Direct, China National Knowledge Infrastructure database, Chinese Biomedical database, Google scholar. Totally, 20 studies involving 6,467 cases and 8,320 controls were included in the meta-analysis. The effects of eight polymorphisms, i.e. TNF-α 308G/A, IL-6 174G/C, IL-1β 31T/C, IL-1β 511C/T, COX-2 8473T/C, IL-10 1082G/A, IL-10 819C/T, and IL-10 592C/A were evaluated. The combined odds ratio (OR) with 95% confidence interval (95% CI) was calculated to estimate the strength of the association in a fixed or random effect model. Heterogeneity and publication bias were also assessed. We found a significant association between IL-10 polymorphism and LC. For IL-10 1082G/A, the overall ORs (95% CI) of the G versus A, GG versus AA, and GG/GA versus AA were 2.35 (1.16-4.76), 2.07 (1.16-3.70) and 3.17 (1.31-7.68), respectively. For IL-10 819C/T, the pooled ORs (95% CI) of the C versus T and CC versus TT were 1.27 (1.01-1.58) and 2.27 (1.32-3.89). For IL-10 592C/A, the comparison of subjects in the CC or CC/CA genotype versus AA homozygotes showed significant results (OR = 2.00, 95% CI: 1.24-3.23; OR = 1.80, 95% CI: 1.28-2.54). But, other gene polymorphisms did not reach statistical associations. IL-10 1082G/A, 819C/T and 592C/A polymorphisms might be risk factors for LC. TNF-α 308G/A, IL-6 174G/C, IL-1β 31T/C, IL-1β 511C/T, COX-2 8473T/C polymorphisms were not detected to be related to the risk for LC. Due to the limitation of the number of the studies, we should take the conclusion with caution. While, further studies are necessary for more precise association.

Genetic variations in multiple myeloma I: effect on risk of multiple myeloma

Few risk factors have been established for the plasma cell disorder multiple myeloma, but some of these like African American ethnicity and a family history of B-cell lymphoproliferative diseases suggest a genetic component for the disease. Genetic variation represents the genetic basis of variability in a population. The complex interplay between environment and genes for the development of cancer may therefore be influenced by genetic variations. A genetic variation may change the function of the gene, and if the genetic variation is associated with the risk of disease, that particular gene may be involved in the pathogenesis of disease. Genes of interest are genes involved in the normal development and function of the plasma cell and genes that protect us against exposures from the environment, for example, genes involved in the metabolism of xenobiotics, metabolism of folate and methionine, as well as genes involved in inflammation and DNA repair. Identification of genes with potential influence on cancer risk may help us to establish relevant laboratory studies on exposure and dose-response assessment and may help us to test the hypothesis in epidemiological studies. Knowledge of individual at high risk of cancer may offer promising insight for the prevention of cancer.

Cyclooxygenase-2 polymorphisms and pancreatic cancer susceptibility

OBJECTIVES

DNA sequence variants in the cyclooxygenase-2 (COX-2) gene may lead to altered COX-2 production and/or activity, resulting in interindividual differences in susceptibility to pancreatic cancer. To test this hypothesis, we investigated the relationship between polymorphisms in the COX-2 gene and the risk of pancreatic cancer in a European population.

METHODS

The COX-2 genotypes for 7 single-nucleotide polymorphisms (rs2745557, rs5277, rs2066826, rs4648261, rs4648262, rs2206593, and rs5275) were determined in 162 pancreatic cancer patients and 170 control subjects without cancer who were matched for age and sex. Data analysis was by conditional logistic regression analysis, adjusting for age, sex, and smoking.

RESULTS

Two haplotypes (GGAGGGT and GCGGGGT for rs2745557, rs5277, rs2066826, rs4648261, rs4648262, rs2206593, rs5275, respectively) were more frequent among the patients compared with control subjects (P < 0.024), although no individually statistically significant associations for the 7 single-nucleotide polymorphisms studied were detected.

CONCLUSIONS

Our findings suggest the individual polymorphisms we studied in the COX-2 gene are not associated with risk of pancreatic cancer. However, the finding of a modest association with 2 haplotypes might be consistent with a small effect, which could be also seen at the genotype level had more samples been available.

A common single-nucleotide polymorphism in cyclooxygenase-2 disrupts microRNA-mediated regulation

Elevated expression of the prostaglandin synthase cyclooxygenase-2 (COX-2) is commonly observed in many chronic inflammatory diseases and cancer. However, the mechanisms allowing for pathogenic COX-2 overexpression are largely unknown. The gene for COX-2 (PTGS2) carries a common single-nucleotide polymorphism (SNP) at position 8473 (T8473C), in exon 10 that is associated with diseases in which COX-2 overexpression is a contributing factor. We demonstrate that the T8473C SNP resides within a region that targets COX-2 mRNA for degradation through microRNA-mediated regulation. miR-542-3p was identified to bind transcripts derived from the 8473T allele and promote mRNA decay. By contrast, the presence of the variant 8473C allele interfered with miR-542-3p binding, allowing for mRNA stabilization, and this effect was rescued using a mutated miR-542-3p at the respective 8473 site. Colon cancer cells and tissue displayed COX-2 mRNA levels that were dependent on T8473C allele dosage, and allele-specific expression of COX-2 was observed to be a contributing factor promoting COX-2 overexpression. These findings provide a novel molecular explanation underlying disease susceptibility associated with COX-2 T8473C SNP, and identify it as a potential marker for identifying cancer patients best served through selective COX-2 inhibition.

The Cox-2 -1195 G > A polymorphism and cancer risk: a meta-analysis of 25 case-control studies

Cyclooxygenase 2 (Cox-2, a rate-limiting enzyme in the conversion of arachidonic acid to prostanoids) has been implicated in several physiological and pathological processes, and it has been reported that polymorphisms in the regulatory region of Cox-2 might influence its expression, contributing to the interindividual susceptibility to cancer. However, results from published studies on the association between the Cox-2 -1195G > A polymorphism and the risk of cancer are conflicting. We performed a meta-analysis based on 25 case-control studies, including a total of 9482 cancer cases and 12 206 controls to derive a more precise estimation of the association and its possible influence on cancer risk. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. The overall results indicated that the variant genotypes moderately increased risk of cancer (AA/AG versus GG, OR = 1.15, 95% CI: 1.02-1.31). In the stratified analysis for the -1195G > A polymorphism, a proximate association was observed in Asian populations (AA/AG versus GG, OR = 1.28, 95% CI: 1.12-1.46), but no significant association except for oesophageal cancer and 'others' was found when stratified by cancer type. In conclusion, our meta-analysis indicates that -1195G > A of Cox-2 is a low penetration risk factor for cancer.