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

Expression Profiles of Hypoxia-Related Genes of Cancers Originating from Anatomically Similar Locations Using TCGA Database Analysis

Background: Hypoxia is a well-recognized characteristic of the tumor microenvironment of solid cancers. This study aimed to analyze hypoxia-related genes shared by groups based on tumor location. Methods: A total of 9 hypoxia-related pathways from the Kyoto Encyclopedia of Genes and Genomes database or the Reactome database were selected, and 850 hypoxia-related genes were analyzed. Based on their anatomical locations, 14 tumor types were categorized into 6 groups. The group-specific genetic risk score was classified as high- or low-risk based on mRNA expression, and survival outcomes were evaluated. Results: The risk scores in the Female Reproductive group and the Lung group were internally and externally validated. In the Female Reproductive group, CDKN2A, FN1, and ITGA5 were identified as hub genes associated with poor prognosis, while IL2RB and LEF1 were associated with favorable prognosis. In the Lung group, ITGB1 and LDHA were associated with poor prognosis, and GLS2 was associated with favorable prognosis. Functional enrichment analysis showed that the Female Reproductive group was enriched in relation to cilia and skin, while the Lung group was enriched in relation to cytokines and defense. Conclusions: This analysis may lead to better understanding of the mechanisms of cancer progression and facilitate establishing new biomarkers for prognosis prediction.

Genetic polymorphisms of IL-10, IL-18 and IL12B are associated with risk of non-small cell lung cancer in a Chinese Han population

PURPOSE

IL-10, IL-18 and IL-12 are reported to participate in the inflammation process. The potential influences of IL-10, IL-18 and IL-12 polymorphisms on non-small cell lung cancer (NSCLC) risk were explored in this study.

METHODS

Six candidate SNPs from 500 NSCLC patients and 500 controls were genotyped. The correlation between the SNPs and NSCLC risk was evaluated by logistic regression analysis.

RESULTS

Comparisons of the allele and genotype frequencies showed that five SNPs were correlated with NSCLC risk. The minor allele 'G' of IL-18 rs5744256 and rs1834481 and IL-10 rs3021094 was correlated with a decreased risk of NSCLC (p < 0.05). In contrast, the minor allele 'T' of IL-18 rs5744224 and the minor allele 'G' of IL-12B rs3212227 were correlated with an increased risk of NSCLC (p < 0.05). By genetic model analysis, we found that rs5744256 and rs1834481 were associated with a decreased risk of NSCLC under dominant and log-additive models (p < 0.05). Rs3021094 was correlated with a decreased risk of NSCLC under all three models (p < 0.05). In contrast, rs5744224 was associated with an increased risk of NSCLC under the recessive model (p = 0.005), and rs3212227 was associated with an increased risk of NSCLC under all three models (p < 0.05). Finally, the GGA haplotype of rs5744256, rs1834481 and rs5744224 and the GT haplotype of rs3021094 and rs3790622 were associated with a decreased risk of NSCLC (p < 0.05).

CONCLUSION

Our results provided new candidate SNPs for the prediction and prevention of NSCLC.

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 COX2 -765G/C polymorphism and periodontitis in Chinese population: a meta-analysis

BACKGROUND

Studies had attempted to clarify the relation between COX2 -765G/C gene polymorphisms and periodontitis risk, but there has been no definite consensus to date. A meta-analysis was performed to further explore the relationship of COX2 -765G/C polymorphism on periodontitis risk among Chinese population.

METHODS

The databases of PubMed, Springer Link, Ovid, Chinese Wanfang Databases, Chinese National Knowledge Infrastructure (CNKI) and Chinese Biology Medicine were searched up to January 2017. The overall result and subgroup analysis results were combined using fixed-effect or random-effect based on the heterogeneity.

RESULTS

Finally, 7 case-control publications including 1399 periodontitis cases and 1663 controls were identified according to the inclusion criteria. In the total analyses, COX2 -765G/C polymorphism had nonsignificant association on periodontitis risk in all models. The subgroup analyses suggested a significantly increased risk of periodontitis in studies with population-based controls and a significantly decreased risk in studies with hospital-based controls.

CONCLUSIONS

This meta-analysis indicated that COX2 -765G/C polymorphism had significantly affect on periodontitis risk among Chinese individuals, which should be confirmed by other ethnic groups.

Biological interaction of cigarette smoking on the association between genetic polymorphisms involved in inflammation and the risk of lung cancer: A case-control study in Japan

Chronic inflammation serves an important role in lung carcinogenesis, thus genetic polymorphisms involved in this pathway may affect the risk of lung cancer. The present case-control study focused on the association between lung cancer risk and genetic polymorphisms involved in inflammatory pathways. The study comprised 462 lung cancer cases and 379 controls from Japan. The roles of interleukin 8 (IL8) rs4073, nuclear factor kappa B (NFκB) rs28362491, cytochrome b-245, alpha polypeptide (CYBA) rs4673, NAD(P) H dehydrogenase, quinone 1 (NQO1) rs1800566, nitric oxide synthase 2 and inducible (NOS2) rs2297518 polymorphisms in lung carcinogenesis were investigated. An unconditional logistic model was used to estimate the odds ratio (OR) and 95% confidence interval (CI) for the association between the genetic polymorphisms and lung cancer risk. The multiplicative and additive [relative excess risk due to interaction, attributable proportion due to interaction (AP) and synergy index (SI)] interactions with cigarette smoking were also determined. A significant association was revealed between the TT genotype of NQO1 rs1800566 and an increased risk of lung cancer (OR=1.78; 95% CI=1.14-2.79). The additive interaction evaluations between CYBA rs4673 (AP=0.50, 95% CI=0.15-0.85; SI=2.66, 95% CI=1.01-6.99) and smoking were also statistically significant. NQO1 rs1800566 was significantly associated with lung cancer risk and smoking may influence the association between CYBA rs4673 and the risk of lung cancer. Additional studies with larger control and case populations are warranted in order to confirm the CYBA rs4673-smoking association suggested by the present study.

Proteomic-Based Approaches for the Study of Cytokines in Lung Cancer

Proteomic techniques are currently used to understand the biology of different human diseases, including studies of the cell signaling pathways implicated in cancer progression, which is important in knowing the roles of different proteins in tumor development. Due to its poor prognosis, proteomic approaches are focused on the identification of new biomarkers for the early diagnosis, prognosis, and targeted treatment of lung cancer. Cytokines are proteins involved in inflammatory processes and have been proposed as lung cancer biomarkers and therapeutic targets because it has been reported that some cytokines play important roles in tumor development, invasion, and metastasis. In this review, we aim to summarize the different proteomic techniques used to discover new lung cancer biomarkers and therapeutic targets. Several cytokines have been identified as important players in lung cancer using these techniques. We underline the most important cytokines that are useful as biomarkers and therapeutic targets. We also summarize some of the therapeutic strategies targeted for these cytokines in lung cancer.

Tumor necrosis factor-α (TNF-α)-308G/A promoter polymorphism in colorectal cancer in ethnic Kashmiri population - A case control study in a detailed perspective

Background

Inflammation constitutes one of the important components of colorectal cancer (CRC) pathogenesis. Tumor necrosis factor-α (TNF-α), a cytokine and an important inflammatory mediator plays a pivotal role in the malignant cellular proliferation, angiogenesis, tissue invasion and metastasis in CRC. The studies on association of various polymorphisms in human TNF-α gene including TNF-α-308G/A single nucleotide polymorphism (SNP) are limited, mixed and inconclusive.

Materials and methods

The aim of this study was to analyze the association of TNF-α-308G/A promoter SNP with colorectal cancer (CRC) susceptibility and development risk and also to evaluate the modifying effects of possible TNF-α-308G/A genotypes on different risk factors of CRC in ethnic population of Kashmir, India through a case–control setup. The genotype frequencies of TNF-α-308G/A promoter SNP were compared between 142 CRC patients and 184 individually matched healthy controls by using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) method. The associations between the TNF-α-308G/A SNP and CRC risk were examined through conditional logistic regression models adjusted for multiple possible confounding (third) variables. Further, the associations between this SNP and various clinico-pathological parameters, demographic variables and environmental factors within the case group subjects with regard to CRC risk were also evaluated.

Results

The association between the TNF-α-308G/A SNP and the modulation of risk of CRC was not found to be significant (p value = 0.156). The effect of less common TNF-α-308A allele on the risk of colorectal cancer was also not found to be significant (p value = 0.175). The variant genotype (AA) was nonexistent in the study population. Further, we found no significant effect modulation of CRC risk by wild and heterozygous TNF-α-308G/A SNP genotypes in presence of different possible risk factors (p > 0.05). We also found no significant association of TNF-α-308G/A SNP with the subsets of various characteristics of the case group subjects under study (p > 0.05).

Conclusions

This study indicates that there is no significant association between the TNF-α-308G/A promoter SNP and the risk of developing CRC in ethnic Kashmiri population. However, in order to substantiate our findings, this study needs to be replicated with bigger sample size and should involve other ethnically defined populations with high CRC risk.

Significant impact of IL-6 -174G/C but inverse relation with -634 C/G polymorphism in patients with non-small cell lung cancer in Kashmiri population

To study the possible role of proinflammatory interleukin 6 -174 G>C (rs 1800795) and -634 C>G (rs 1800796) polymorphism in the pathogenesis of non-small cell lung cancer (NSCLC). A total of 190 NSCLC patients and 200 healthy controls were evaluated for polymorphic analysis of -174 G/C and -634 C/G by PCR-RFLP followed by DNA sequencing. A significant association was observed in the genotypic and allelic distribution of IL-6 -174 G/C in the NSCLC group as compared to control group [OR = 2.7 (1.77-4.11), p < 0.0001]. Smokers with the -174C allele were found to be significantly associated with NSCLC (p = 0.01), while 634C/G SNP showed an inverse relation [OR-0.4, p < 0.0001]. The present investigation revealed a significant association of the IL6 -174 G/C gene promoter polymorphism with NSCLC, and thus, the IL-6 -174G/C genotype can be considered as one of the biological markers in the etiology of NSCLC.

Lack of association between a functional polymorphism (rs1800796) in the interleukin-6 gene promoter and lung cancer

Background

A number of studies have examined the association between interleukin-6 (IL-6) rs1800796 polymorphism and risk of lung cancer but revealed inconsistent results. The aim of this study was to clarify the association between IL-6 rs1800796 polymorphism and risk of lung cancer.

Methods

Literature databases including PubMed, Embase and CNKI were searched up to January 2014. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) under co-dominant model, dominant model and recessive model were estimated using random-effects model.

Results

A total of seven studies, including 2691 lung cancer cases and 3067 controls, were included in the meta-analysis. The results suggested that IL-6 rs1800796 polymorphism was not associated with risk of lung cancer under homogeneous co-dominant model (OR = 1.06, 95%CI = 0.73-1.54), heterogeneous co-dominant model (OR = 1.24, 95%CI = 0.96-1.60), dominant model (OR = 1.23, 95%CI = 0.95-1.58) and recessive model (OR = 0.96, 95%CI = 0.70-1.32). The association was still not significant in either never-smokers (OR = 1.19, 95%CI = 0.95-1.48) or ever-smokers (OR = 1.73, 95%CI = 0.89-3.36).

Conclusion

The present meta-analysis suggested that there was no association between IL-6 rs1800796 polymorphism and lung cancer, which was independent of smoking status.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1060061508127855

Interleukin 6 -174G>C polymorphism and cancer risk: meta-analysis reveals a site dependent differential influence in Ancestral North Indians

In our earlier studies, single nucleotide polymorphisms (SNPs) associated with anti-inflammatory cytokines were found to influence risk for breast cancer in western Indian women. Analysis of Interleukin 6 (IL-6) -174G>C polymorphism in this cohort (patients = 182; controls = 236) suggested a protective role for IL-6 -174C allele associated with the lower expression of the cytokine (OR = 0.54; 95% CI 0.32-0.89, dominant model). Together these observations suggested that in comparison to Caucasians, inflammation associated-cytokine gene polymorphisms may have higher influence on risk for cancer in this population. To examine this possibility we analyzed data assessing influence of Interleukin 6 (IL-6) -174G>C polymorphism on risk for various cancers. Overall, there was a marginally higher risk for rare allele homozygotes compared to wild type homozygotes (OR = 1.07; 95% CI 1.00-1.15). Increased risks for genitourinary cancers and for skin cancer were also indicated. The ethnicity based analysis indicated a protective effect of the minor allele in Ancestral North Indians (OR = 0.73; 95% CI 0.55-0.97). Site by ethnicity analysis once again revealed a significant protection against breast cancer (OR = 0.51; 95% CI = 0.37-0.70; dominant model) but an opposite influence on the risk of genitourinary malignancies (OR = 2.51; 95% CI 1.59-3.96; recessive model) in this population alone. The observations imply that contribution of IL-6 to inflammation or effector immunity may depend on the site of malignancy. Assessment of available data in relation to prognosis in breast cancer patients also revealed trends that are compatible with the observations of the meta-analysis. Thus, IL-6 -174G>C polymorphism clearly represents a potential modulator of risk for malignant disorders with ethnicity and site dependent trends. The results also support the possibility of higher influence of inflammation related cytokine gene polymorphisms on the risk for cancers in Ancestral North Indians.

Association between TNF-α gene 308G>A polymorphism and lung cancer risk: a meta-analysis

Many studies have investigated the association between tumor necrosis factor alpha (TNF-α) gene 308G/A polymorphism and lung cancer risk, but the results were inconsistent. We thus comprehensively searched the PubMed, EMBASE, and BIOSIS Previews databases and extracted data from all eligible articles to estimate the association between TNF-α gene 308G/A polymorphism and lung cancer risk. The pooled odds ratio (OR) with 95 % confidence intervals (CIs) were calculated. Twelve case-control studies in 11 articles involving 2,436 cases and 2,573 controls were included in the meta-analysis to assess the association between TNF-α gene 308G>A polymorphism and susceptibility to lung cancer. Overall, TNF-α gene 308G>A polymorphism was significantly associated with an increased risk of lung cancer for A vs. G (OR = 1.13, 95 % CI 1.00 ~ 1.27, P = 0.04). Subgroup analysis by ethnicity showed that there was a significant association between TNF-α gene 308G>A polymorphism and increased risk of lung cancer in Asians, but not in Caucasians. In subgroup analysis by tumor type, there were significant associations between TNF-α gene 308G>A polymorphism and increased risk of lung cancer in small cell lung cancer (SCLC) for AA+AG vs. GG, in non-small cell lung cancer (NSCLC) for A vs. G, AA vs. GG, and AA+AG vs. GG. No association between the genotypes and different stages of lung cancer was detected. The meta-analysis suggests that TNF-α gene 308G>A polymorphism is associated with an increased risk of lung cancer, particularly among Asians, both for SCLC and NSCLC, considering tumor type.

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-10-1082 gene polymorphism is associated with papillary thyroid cancer

The etiopathogenesis of thyroid cancer has not been clearly elucidated although the role of chronical inflammation and the imbalance between pro- and anti-inflammatory cytokines may play a role in the etiology. The aim of the present study was to investigate whether cytokine gene polymorphisms are associated with papillary thyroid cancer (PTC), and to evaluate the relationship between genotypes and clinical/laboratory manifestation of PTC. Tumor necrosis factorα (TNFα) G-308A (rs 1800629), interleukin-6 (IL-6) G-174C (rs 1800795) and IL-10 A-1082G (rs 1800896) single nucleotide polymorphisms in DNA from peripheral blood leukocytes of 190 patients with thyroid cancer and 216 healthy controls were investigated by real-time PCR combined with melting curve analysis. There was no notable risk for PTC afflicted by TNFα-308 and IL-6-174 alone. However, IL-10-1082 G allele frequency were higher among PTC patients than healthy controls (p=0.009). The patients with IL-10-1082 GG geotype have twofold increased risk of developing thyroid cancer according to AA genotype (OR 2.07, 95% CI 1.21-3.55). In addition, the concomitant presence of IL-10-1082 G allele (GG+AG genotypes) together with IL-6 -174 GG genotype has a nearly twofold increased risk for thyroid cancer (OR 1.75 with 95% CI 1.00-3.05, p=0.049). We suggest that IL-10-1082 G allele is associated with an increased risk of PTC. The polymorphism of IL-10 gene can improve our knowledge about the pathogenesis of PTC, and could provide to estimate people at the increased risk for PTC.

Tumor necrosis factor-a polymorphisms and colorectal cancer risk: a meta-analysis

BACKGROUND AND OBJECTIVES

Tumor necrosis factor-alpha (TNF-a) was related to inflammation and involved in the development of colorectal cancer. Polymorphisms located in TNF-a promoter region, such as 308G/A and 238G/A, could affect the risk of various types of cancer by regulating TNF-a production. In this study, a meta-analysis was performed to investigate the association between common polymorphisms of TNF-a promoter region and colorectal cancer susceptibility.

METHODS

Searching of several databases was performed for all publications on the association between TNF-a polymorphisms and colorectal cancer. Summary odds ratios (ORs) with their 95% confidence intervals (95% CIs) were calculated using random-effects models. Stratified analyses based on ethnicity and control population source were also conducted.

RESULTS

Overall, TNF-a 308A polymorphism showed a significant association with increased risk of colorectal cancer in worldwide populations under homozygote comparison [AA vs. GG, OR (95% CI) = 1.46 (1.07-1.97)] other than heterozygote comparison [AG vs. GG, OR (95% CI) = 1.05 (0.93-1.19)]. TNF-a 238A was not associated with colorectal cancer risk under homozygote or heterozygote comparisons. In stratified analysis, significant association was observed only in Western populations [AA vs. GG, OR (95% CI) = 1.39 (1.01-1.91)] other than in Eastern populations under homozygote comparison. No significant difference was observed between population-based subgroup and hospital-based subgroup.

CONCLUSIONS

TNF-a 308A was moderately associated with an increased risk of colorectal cancer in Western populations, and TNF-a 238A polymorphism was not significantly associated with colorectal cancer risk.

A systemic assessment of the association between tumor necrosis factor alpha 308 G/A polymorphism and risk of cervical cancer

Tumor necrosis factor alpha (TNF-α) is a multifunctional cytokine which plays an important role in the human immune response against various pathogens, and there may be a relationship between TNF-α 308 G/A polymorphism and cervical cancer risk. We performed a meta-analysis to get a systemic assessment of the association between TNF-α 308 G/A polymorphism and cervical cancer risk. Electronic searches of PubMed, Embase, and Web of Science were performed for all publications on the association between TNF-α 308 G/A polymorphism and cervical cancer risk through October 26, 2012. The pooled odds ratios (ORs) with their 95 % confidence interval (95 % CIs) were calculated to assess the association. Fifteen studies with a total of 3,743 cervical cancer cases and 4,096 controls were finally included into the meta-analysis. Overall, TNF-α 308 G/A polymorphism was significantly associated with increased risk of cervical cancer under three main genetic comparison models (A vs. G, OR 1.20, 95 % CI 1.02-1.42, P=0.03; AA vs. GG, OR 1.31, 95 % CI 1.00-1.72, P=0.048; AA vs. GG/GA, OR 1.30, 95 % CI 1.00-1.71, P=0.05). Subgroup analysis by ethnicity further showed that there was a significant association between TNF-α 308 G/A polymorphism and increased risk of cervical cancer in Asians (AA vs. GG, OR 1.83, 95 % CI 1.05-3.20, P=0.034; AA vs. GG/GA, OR 1.84, 95 % CI 1.05-3.22, P=0.032). The meta-analysis suggests that TNF-α 308 G/A polymorphism is associated with increased risk of cervical cancer, and TNF-α 308 G/A mutant allele A is a risk factor of cervical cancer.

Association between the NBS1 Glu185Gln polymorphism and lung cancer risk: a systemic review and meta-analysis

Nijmegen Breakage Syndrome protein 1 (NBS1) is one of the most important DNA repair proteins playing important roles in maintaining the genomic stability of NDA. Previous studies regarding the association between NBS1 8360G>C (Glu185Gln) polymorphism and lung cancer reported conflicting results. To derive a more precise estimation of this association, a systemic review and meta-analysis was performed. We performed a meta-analysis using eligible case-control studies to summarize the data on the association between the NBS1 Glu185Gln polymorphism and lung cancer risk. Odds ratios (ORs) with corresponding 95 % confidence intervals (95 %CIs) were pooled to assess the association between NBS1 Glu185Gln polymorphism and lung cancer risk. Six case-control studies with a total of 2,348 lung cancer cases and 2,401 controls without canner were included into the meta-analysis. Overall, there was an association between NBS1 Glu185Gln polymorphism and lung cancer risk under the dominant comparison model (fixed-effects OR GluGln/GlnGln vs. GluGlu = 1.21, 95 % CI 1.07-1.37, P = 0.002, I (2) = 8.1 %). Subgroup analysis by race suggested a significant association between NBS1 Glu185Gln polymorphism and lung cancer risk in Asians (fixed-effects OR GluGlnGlnGln vs. GluGlu = 1.22, 95 % CI 1.06-1.41, P = 0.005) but not in Caucasians (fixed-effects OR GluGlnGlnGln vs. GluGlu = 1.17, 95 % CI 0.91-1.50, P = 0.220). This meta-analysis supports that there is an association between NBS1 Glu185Gln polymorphism and lung cancer risk. More studies are needed to further verify this association.

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.

Synergistic association of PTGS2 and CYP2E1 genetic polymorphisms with lung cancer risk in northeastern Chinese

BACKGROUND

Lung cancer is the most common cause of cancer-related deaths worldwide. The aim of this study was to investigate the association of five extensively-studied polymorphisms in PTGS2 (rs689466, rs5275, rs20417) and CYP2E1 (rs2031920, rs6413432) genes with lung cancer risk in a large northeastern Chinese population.

METHODOLOGY/PRINCIPAL FINDINGS

This is a hospital-based case-control study involving 684 patients with lung cancer and 604 cancer-free controls. Genotyping was performed using the PCR-LDR method. Data were analyzed using Haplo.stats and MDR programs. There were significant differences between patients and controls in allele/genotype distributions of rs5275 (P = 0.002/0.003) and rs6413432 (P = 0.037/0.044), as well as in genotype distributions of rs689466 (P = 0.02). The risk for lung cancer associated with the rs5275-C mutant allele was decreased by 60% (95% CI [confidence interval]: 0.21-0.74; P = 0.004) under the recessive model. Carriers of rs689466-G mutant allele had a 28% (95% CI: 0.57-0.92; P = 0.008) reduced risk of developing lung cancer relative to the AA genotype carriers. In haplotype analysis, haplotype G-C-C-T (in order of rs689466, rs5275, rs2031920 and rs6413432) decreased the odds of lung cancer by 28% (95% CI: 0.51-0.93; P = 0.019) after adjusting for confounding factors, whereas haplotype A-T-T-T had 1.49-fold (95% CI: 1.21-1.79; P = 0.012) increased risk for lung cancer. Using MDR method, the overall best model including rs5275, rs689466 and rs6413432 polymorphisms was identified with a maximal testing accuracy of 66.1% and a maximal cross-validation consistency of 10 out of 10 (P = 0.003).

CONCLUSIONS/SIGNIFICANCE

Our findings demonstrated a potentially synergistic association of PTGS2 and CYP2E1 polymorphisms with the underlying cause of lung cancer in northeastern Chinese.