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Objective: This study sought to explore the clinical value of matrix metalloproteinases 12 ( MMP12 ) in multiple cancers, including lung adenocarcinoma (LUAD)., Methods: Using >10,000 samples, this retrospective study demonstrated the first pan-cancer analysis of MMP12 . The expression of MMP12 between cancer groups and their control groups was analyzed using Wilcoxon rank-sum tests. The clinical significance of MMP12 expression in multiple cancers was assessed using receiver operating characteristic curves, Kaplan-Meier curves, and univariate Cox analysis. A further LUAD-related analysis based on 4565 multi-center and in-house samples was performed to verify the findings regarding MMP12 in pan-cancer analysis partly., Results: MMP12 mRNA is highly expressed in 13 cancers compared to their controls, and the MMP12 protein level is elevated in some of these cancers (e.g., colon adenocarcinoma) ( P < .05). MMP12 expression makes it feasible to distinguish 21 cancer tissues from normal tissues (AUC = 0.86). A high MMP12 expression is a prognosis risk factor in eight cancers, such as adrenocortical carcinoma (hazard ratio >1, P < .05). The elevated MMP12 expression is also a prognosis protective factor in breast-invasive carcinoma and colon adenocarcinoma (hazard ratio <1, P < .05). Some pan-cancer findings regarding MMP12 are verified in LUAD-MMP12 expression is upregulated in LUAD at both the mRNA and protein levels ( P < .05), has the potential to distinguish LUAD with considerable accuracy (AUC = .91), and plays a risk prognosis factor for patients with the disease ( P < .05)., Conclusions: MMP12 is highly expressed in most cancers and may serve as a novel biomarker for the prediction and prognosis of numerous cancers., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The roles of cyclin-dependent kinase 6 (CDK6) in various cancers, including small cell lung carcinoma (SCLC), remain unclear. Here, 111,54 multi-center samples were investigated to determine the expression, clinical significance, and underlying mechanisms of CDK6 in 34 cancers. The area under the curve (AUC), Cox regression analysis, and the Kaplan-Meier curves were used to explore the clinical value of CDK6 in cancers. Gene set enrichment analysis and correlation analysis were performed to detect potential CDK6 mechanisms. CDK6 expression was essential in 24 cancer cell types. Abnormal CDK6 expression was observed in 14 cancer types (e.g., downregulated in breast invasive carcinoma; p < 0.05). CDK6 allowed six cancers to be distinguished from their controls (AUC > 0.750). CDK6 expression was a prognosis marker for 13 cancers (e.g., adrenocortical carcinoma; p < 0.05). CDK6 was correlated with several immune-related signaling pathways and the infiltration levels of certain immune cells (e.g., CD8 + T cells; p < 0.05). Downregulated CDK6 mRNA and protein levels were observed in SCLC (p < 0.05, SMD = - 0.90). CDK6 allowed the identification of SCLC status (AUC = 0.91) and predicted a favorable prognosis for SCLC patients (p < 0.05). CDK6 may be a novel biomarker for the prediction and prognosis of several cancers, including SCLC., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Worldwide, lung squamous cell carcinoma (LUSC) has wreaked havoc on humanity. Matrix metallopeptidase 12 ( MMP12 ) plays an essential role in a variety of cancers. This study aimed to reveal the expression, clinical significance, and potential molecular mechanisms of MMP12 in LUSC., Methods: There were 2,738 messenger RNA (mRNA) samples from several multicenter databases used to detect MMP12 expression in LUSC, and 125 tissue samples were validated by immunohistochemistry (IHC) experiments. Receiver operator characteristic (ROC) curves, Kaplan-Meier curves, and univariate and multivariate Cox regression analyses were used to assess the clinical value of MMP12 in LUSC. The potential molecular mechanisms of MMP12 were explored by gene enrichment analysis and immune correlation analysis. Furthermore, single-cell sequencing was used to determine the distribution of MMP12 in multiple tumor microenvironment cells., Results: MMP12 was significantly overexpressed at the mRNA level ( p  < 0.05, SMD = 3.13, 95% CI [2.51-3.75]), which was verified at the protein level ( p  < 0.001) by internal IHC experiments. MMP12 expression could be used to differentiate LUSC samples from normal samples, and overexpression of MMP12 itself implied a worse clinical prognosis and higher levels of immune cell infiltration in LUSC patients. MMP12 was involved in cancer development and progression through two immune-related signaling pathways. The high expression of MMP12 in LUSC might act as an antigen-presenting cell-associated tumor neoantigen and activate the body's immune response., Conclusions: MMP12 expression is upregulated in LUSC and high expression of MMP12 serves as a risk factor for LUSC patients. MMP12 may be involved in cancer development by participating in immune-related signaling pathways and elevating the level of immune cell infiltration., Competing Interests: Gang Chen is an Academic Editor for PeerJ., (©2023 Zhang et al.)

Background: At present, studies on MircoRNA-22-3p (miR-22-3p) in lung adenocarcinoma use a single method, lack multi-center validation and multi-method validation, and there is no big data concept to predict and validate target genes., Objective: To investigate the expression, potential targets and clinicopathological significance of miR-22-3p in lung adenocarcinoma (LUAD) tissues., Methods: LUAD formalin-fixed paraffin-embedded (FFPE) tumors and adjacent normal lung tissues were collected for real-time quantitative polymerase chain reaction (RT-qPCR). Collect miR-22-3p in LUAD and non-cancer lung tissue from high-throughput datasets, standardized mean difference (SMD) and area under the curve (AUC) of the comprehensive receiver operating curve (summary receiver operating characteristic cure, sROC curve) were calculated. Cell function experiments on A549 cells transfected with LV-hsa-miR-22-3p. Target genes were predicted by the miRwalk2.0 website and the resulting target genes were subjected to Gene Ontology (GO) pathway enrichment analysis and constructed to protein-protein interaction network. Finally, the protein expression level of the key gene TP53 was validated by searching The Human Protein Atlas (THPA) database to incorporate TP53 immunohistochemical results in LUAD., Results: RT-qPCR result from 41 pairs of LUAD and adjacent lung tissues showed that miR-22-3p was downregulated in LUAD (AUC = 0.6597, p= 0.0128). Globally, a total of 838 LUADs and 494 non-cancerous lung tissues were included, and were finally combined into 14 platforms. Compared with noncancerous tissue, miR-22-3p expression level was significantly reduced in LUAD tissue (SMD =-0.32, AUC = 0.72l); cell function experiments showed that miR-22-3p has inhibitory effects on cell proliferation, migration and invasion, and has promotion effect on apoptosis. Moreover, target genes prediction, GO pathway enrichment analysis and PPI network exhibited TP53 as a key gene of target gene of miR-22-3p; at last, a total of 114 high-throughput datasets were included, including 3897 LUADs and 2993 non-cancerous lung tissues, and were finally combined into 37 platforms. Compared with noncancerous tissue, TP53 expression level was significantly increased in LUAD (SMD = 0.39, p< 0.01) and it was verified by the protein expression data from THPA., Conclusion: Overexpression of miR-22-3p may inhibit LUAD cell proliferation, migration and invasion through TP53, and promote cell apoptosis.

Background: The clinical value of pyroptosis-related genes (PRGs) in lung adenocarcinoma (LUAD) remains obscure., Objective: The study attempts to explore PRGs in LUAD, which will enable an understanding of LUAD from the perspective of PRGs., Methods: Lung adenocarcinoma patients were diagnosed using pathology, and their clinical information was collected from several public databases. A PRGs prognostic signature (PPS) for LUAD patients was established based on a multivariate Cox regression analysis. The differential expression of PRGs was identified using standardized mean differences in 6,958 samples. The area under the curve (AUC) was used to evaluate the predictive effects of the PPS to determine the survival rate of LUAD patients. Decision curve analysis was utilized to assess the clinical significance of the PPS in LUAD., Results: The PPS consists of five PRGs, namely CASP3, CASP9, GSDMB, NLRP1, and TNF. The prognostic effect of the PPS is evident in all the predicted one-, three-, and five-year survival rates (AUCs ≥ 0.58). The PPS represents an independent risk factor for the prognosis of LUAD patients (hazard ratio > 1; 95% confidence interval excluding 1). The PPS risk score can predict the prognosis of LUAD patients more accurately than PRGs of the PPS and multiple clinical parameters, such as age, tumor stage, and clinical stage. The decision curve analysis revealed that the nomogram based on the PPS and clinical parameters might result in better clinical decisions., Conclusion: The PPS makes it feasible to distinguish LUAD from non-LUAD. Thus, the underlying significance of the PPS in distinguishing LUAD from non-LUAD is promising., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: Little is known about the relationship between integrin subunit alpha V (ITGAV) and cancers, including small cell lung cancer (SCLC)., Methods: Using large sample size from multiple sources, the clinical roles of ITGAV expression in SCLC were explored using differential expression analysis, receiver operating characteristic curves, Kaplan-Meier curves, etc. RESULTS: Decreased mRNA (SMD = - 1.05) and increased protein levels of ITGAV were detected in SCLC (n = 865). Transcription factors-ZEB2, IK2F1, and EGR2-may regulate ITGAV expression in SCLC, as they had ChIP-Seq (chromatin immunoprecipitation followed by sequencing) peaks upstream of the transcription start site of ITGAV. ITGAV expression made it feasible to distinguish SCLC from non-SCLC (AUC = 0.88, sensitivity = 0.78, specificity = 0.84), and represented a risk role in the prognosis of SCLC (p < 0.05). ITGAV may play a role in cancers by influencing several immunity-related signaling pathways and immune cells. Further, the extensive pan-cancer analysis verified the differential expression of ITGAV and its clinical significance in multiple cancers., Conclusion: ITGAV served as a potential marker for prognosis and identification of cancers including SCLC., (© 2022. The Author(s).)

Background: Cyclin-dependent kinase inhibitor 2C (CDKN2C) was identified to participate in the occurrence and development of multiple cancers; however, its roles in small cell lung carcinoma (SCLC) remain unclear., Methods: Differential expression analysis of CDKN2C between SCLC and non-SCLC were performed based on 937 samples from multiple centers. The prognosis effects of CDKN2C in patients with SCLC were detected using both Kaplan-Meier curves and log-rank tests. Using receiver-operating characteristic curves, whether CDKN2C expression made it feasible to distinguish SCLC was determined. The potential mechanisms of CDKN2C in SCLC were investigated by gene ontology terms and signaling pathways (Kyoto Encyclopedia of Genes and Genomes). Based on 10,080 samples, a pan-cancer analysis was also performed to determine the roles of CDKN2C in multiple cancers., Results: For the first time, upregulated CDKN2C expression was detected in SCLC samples at both the mRNA and protein levels (p of Wilcoxon rank-sum test < 0.05; standardized mean difference = 2.86 [95% CI 2.20-3.52]). Transcription factor FOXA1 expression may positively regulate CDKN2C expression levels in SCLC. High CDKN2C expression levels were related to the poor prognosis of patients with SCLC (hazard ratio > 1, p < 0.05) and showed pronounced effects for distinguishing SCLC from non-SCLC (sensitivity, specificity, and area under the curve ≥ 0.95). CDKN2C expression may play a role in the development of SCLC by affecting the cell cycle. Furthermore, the first pan-cancer analysis revealed the differential expression of CDKN2C in 16 cancers (breast invasive carcinoma, etc.) and its independent prognostic significance in nine cancers (e.g., adrenocortical carcinoma). CDKN2C expression was related to the immune microenvironment, suggesting its potential usefulness as a prognostic marker in immunotherapy., Conclusions: This study identified upregulated CDKN2C expression and its clinical significance in SCLC and other multiple cancers, suggesting its potential usefulness as a biomarker in treating and differentiating cancers., (© 2022. The Author(s).)

Background: The roles and clinical values of synaptojanin 2 (SYNJ2) in lung squamous cell carcinoma (LUSC) remain unclear., Methods: A total of 2824 samples from multi-center were collected to identify the expression of SYNJ2 in LUSC by using Wilcoxon rank-sum test, t-test, and standardized mean difference (SMD), and 194 in-house samples were also included to validate SYNJ2 expression in LUSC. The clinical roles of SYNJ2 were investigated via receiver operating characteristic (ROC) curves, univariate Cox regression analysis, and Kaplan-Meier plots. The underlying mechanisms of SYNJ2 in LUSC were explored by gene set enrichment analysis and immune correlation analysis. Further, a pan-cancer analysis based on 10,238 sapiens was performed to promote the understating of the expression and clinical significance of SYNJ2 in multiple human cancers., Results: SYNJ2 was found to be significantly upregulated in LUSC at both mRNA and protein levels (p < 0.05, SMD = 0.89 [95% CI 0.34-1.45]) via public and in-house samples. Overexpressed SYNJ2 predicted poor prognosis for LUSC patients (hazard ratio = 2.38 [95% CI 1.42-3.98]). The cancer-promoting effect of SYNJ2 may be related to protein digestion and absorption and extracellular matrix-receptor interaction. SYNJ2 expression was closely related to immune cell infiltration, indicating its role in the immune response. Moreover, the distinct expression levels and essential clinical relevance of SYNJ2 in a series of cancers were initially revealed in this study., Conclusions: This study disclosed the clinical significance of SYNJ2 in LUSC and multiple cancers, demonstrating the novel and potential biomarker for predicting and treating cancers., (© 2022. The Author(s).)

Background: The role of HOXA family genes in the occurrence and progression of a variety of human cancers has been scatteredly reported. However, there is no systematic study on the differential expression, prognostic significance and potential molecular mechanism of HOXA4 and HOXA5 in LUAD., Methods: In-house immunohistochemistry (IHC), multi-center microarrays, RT-qPCR and RNA-seq data were incorporated for comprehensively evaluating the expression and prognostic value of HOXA4 and HOXA5 in LUAD. The mechanism of HOXA4 and HOXA5 in the formation and development of LUAD was analyzed from multiple aspects of immune correlations, upstream transcriptional regulation, functional states of single cells and co-expressed gene network. The functional roles of HOXA4 and HOXA5 in LUAD were validated by in vitro experiments., Results: As a result, in 3201 LUAD samples and 2494 non-cancer lung samples, HOXA4 and HOXA5 were significantly downexpressed (P < 0.05). The aberrant expression of HOXA5 was significantly correlated with the clinical progression of LUAD (P < 0.05). HOXA5 showed remarkable prognostic value for LUAD patients (P < 0.05). The expression of HOXA4 and HOXA5 in LUAD were negatively correlated with tumor purity and positively correlated with the infiltration of various immune cells such as B cells, T cells and macrophages. HOXA4 and HOXA5 overexpression had notable inhibitory effect on the proliferation, migration and invasion of LUAD cells., Conclusions: In conclusion, the identified downexpressed HOXA4 and HOXA5 had significant distinguishing ability for LUAD samples and affected the cellular functions of LUAD cells. The low expression of HOXA5 indicated worse overall survival of LUAD patients. Therefore, the two HOXA family genes especially HOXA5 may serve as potential biomarkers for LUAD., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Background: To explore the clinical significance of miR-125b-5p and its potential mechanisms in lung squamous cell carcinoma (LUSC). Materials and Methods: An integrated analysis of data from in-house quantitative real-time polymerase chain reaction (qRT-PCR), microRNA-sequencing, and microarray assays to appraise the expression level of miR-125b-5p in LUSC tissues compared to adjacent noncancerous controls. The authors identified the candidate targets of miR-125b-5p and conducted functional analysis using computational biology strategies from gene ontology, the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, disease ontology (DO), and protein-protein interaction (PPI) network analyses to investigate the prospective mechanisms. Results: According to qRT-PCR results, the expression level of miR-125b-5p was markedly decreased in LUSC tissues compared to noncancerous control tissues. Receiver operating characteristic and summary receiver operating characteristic analyses showed that miR-125b-5p had good specificity and sensitivity for distinguishing LUSC tissue from noncancerous lung tissue. The standard mean difference revealed that men and women with lower expression levels of miR-125b-5p may have a higher risk for LUSC. KEGG analysis and DO analysis intimated that target genes were evidently enriched in pyrimidine metabolism and pancreatic carcinoma. The PPI network of the top assembled KEGG pathway indicated that RRM2 , UMPS , UCK2 , and CTPS1 were regarded as crucial target genes for miR-125b-5p, and RRM2 was eventually deemed a key target. Conclusions: The authors' findings implicate a low expression level of miR-125b-5p in LUSC. A tumor-suppressive role of miR-125b-5p is proposed, based on its effects on LUSC tumor growth, clinical stage progression, and lymph node metastasis.

This study is aimed at thoroughly exploring the expression status, clinical significance, and underlying molecular mechanism of miRNA-33a-5p in lung squamous cell carcinoma (LUSC). Here, we detected miRNA-33a-5p in 20 samples from patients with LUSCs and 20 matching non-LUSC specimens by in-house quantitative real-time PCR (RT-qPCR). Relationship between miRNA-33a-5p expression and clinicopathological traits was investigated from materials derived from miRNA sequencing and miRNA microarrays. A pool standard mean difference (SMD) and summary receiver operating characteristic curves (SROC) were calculated to evaluate the integrated expression value of miRNA-33a-5p in LUSC. Twelve online platforms were applied to select potential target genes of miRNA-33a-5p. The differentially expressed genes (DEGs) of LUSC and the candidate target genes of miRNA-33a-5p were overlapped to acquire a set of specific genes for further analyses of the Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and protein-protein interaction (PPI) network. miRNA-33a-5p overexpressed in LUSC was supported by 706 LUSC and 261 non-LUSC samples gathering from RT-qPCR, miRNA-seq, and public miRNA microarrays. The pooled SMD was 0.56 (95% CI: -0.01-1.05), and the area under the curve (AUC) of the SROC was 0.78 (95% CI: 0.74-0.82). A total of 240 genes were identified as potential target genes of miRNA-33a-5p for functional enrichment analyses; the results suggested that these target genes may participate in several vital biological processes that promote the proliferation and progression of LUSC. miRNA-33a-5p may play an essential role in the occurrence and development of LUSC by targeting hub genes (ETS1, EDNRB, CYR61, and LRRK2) derived from the PPI network. In summary, our results indicated that miRNA-33a-5p may contribute as a prospective therapeutic target in LUSC., Competing Interests: The authors declare there is no conflict of interest regarding the publication of this article., (Copyright © 2021 Xiang-Ming Wang et al.)

RUNX family transcription factor 2 (RUNX2) overexpression has been found in various human malignancies. However, the expression levels of RUNX2 mRNA and protein in lung adenocarcinoma (LUAD) were not investigated. This study aims to thoroughly analysis the expression level and potential mechanisms of RUNX2 mRNA in LUAD. We applied in-house immunohistochemistry, high-throughput RNA-sequencing, and gene microarrays to comprehensively investigate the expression level of RUNX2 in LUAD. A pool standard mean difference (SMD) and summary receiver operating characteristic curves (SROC) were calculated to assess the integrated expression value of RUNX2 in LUAD. The hazard ratios (HRs) were integrated to evaluate the overall prognostic effect of RUNX2 on the LUAD patients. The differentially expressed genes (DEGs) of LUAD, the potential target genes of RUNX2, and its co-expressed genes were overlapped to obtain a set of specific genes for GO and KEGG enrichment analyses. RUNX2 overexpression in LUAD was validated using a large number of cases (2 418 LUAD and 1 574 non-tumor lung samples). The pooled SMD was 0.85 (95 % CI: 0.64-1.05) and the area under the curve (AUC) of the SROC was 0.86 (95 %CI: 0.83-0.89). The integrated HR was 1.20 [1.04-1.38], indicating that increased expression of RUNX2 was an independent risk factor for the poor survival of the LUAD patients. RUNX2 and its transcriptionally regulates potential target genes may promote cell proliferation and drug resistance of LUAD by modulating the cell cycle and MAPK signaling pathways. RUNX2 can provide new research directions for targeted drug therapy and drug resistance for LUAD treatment., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This study aimed to investigate the clinicopathological significance and prospective molecular mechanism of RUNX family transcription factor 2 (RUNX2) in lung squamous cell carcinoma (LUSC). The authors used immunohistochemistry (IHC), RNA-seq, and microarray data from multi-platforms to conduct a comprehensive analysis of the clinicopathological significance and molecular mechanism of RUNX2 in the occurrence and development of LUSC. RUNX2 expression was significantly higher in 16 LUSC tissues than in paired non-cancerous tissues detected by IHC ( P  < 0.05). RNA-seq data from the combination of TCGA and genotype-tissue expression (GTEx) revealed significantly higher expression of RUNX2 in 502 LUSC samples than in 476 non-cancer samples. The expression of RUNX2 protein was also significantly higher in pathologic T3-T4 than in T1-T2 samples ( P  = 0.031). The pooled standardised mean difference (SMD) for RUNX2 was 0.87 (95% CI, 0.58-1.16), including 29 microarrays from GEO and one from ArrayExpress. The co-expression network of RUNX2 revealed complicated connections between RUNX2 and 45 co-expressed genes, which were significantly clustered in pathways including ECM-receptor interaction, focal adhesion, protein digestion and absorption, human papillomavirus infection and PI3K-Akt signalling pathway. Overexpression of RUNX2 plays an essential role in the clinical progression of LUSC.

Lung squamous cell carcinoma (LUSC) is the main pathological type of pulmonary malignant tumors; at present, less than 10% of patients with advanced metastatic LUSC live for more than 5 years. We previously reported that low expression of miRNA-126-3p is associated with the occurrence and progression of lung adenocarcinoma (LUAD). Here, we examined expression of miRNA-126-3p in 23 samples from patients with LUSCs and 23 normal control specimens by quantitative real-time PCR (RT-qPCR). Associations between miRNA-126-3p expression and clinical features were studied from materials derived from Gene Expression Omnibus (GEO) chips and The Cancer Genome Atlas (TCGA) database. Twelve online platforms were used to identify candidate target genes of miRNA-126-3p. Further analyses of the Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and protein-protein interaction (PPI) network were performed on the target genes. GEO microarray analysis, TCGA data mining, RT-qPCR, and integration analysis consistently reported low expression of miRNA-126-3p in LUSC. A total of 42 genes were identified as potential target genes of miRNA-126-3p from online platforms, GEO microarrays, and the TCGA database. GO and KEGG analyses demonstrated that the target genes are involved in several biological processes that promote the progression of LUSC. SOX2, E2F2, and E2F3 were selected as hub genes from the PPI network for further analysis. In summary, our results suggest that the low expression of miRNA-126-3p may play a role in promoting the development of LUSC and miRNA-126-3p may be a biomarker for LUSC early diagnosis and prognosis., (© 2020 The Authors. Published by FEBS Press and John Wiley & Sons Ltd.)

Aim of Study: There were many reports published on the relationship between glutathione S-transferase T1 (GSTT1) null/presence gene polymorphism and the risk of lung cancer in these years. In previous, we conducted a meta-analysis to evaluate the relationship between GSTT1 null/presence gene polymorphism and the risk of lung cancer. This study was conducted to update it., Materials and Methods: The association studies were identified from PubMed and Cochrane Library on March 1, 2016., Results: Sixty-three reports were recruited into this meta-analysis for the association of null genotype of GSTT1 with lung cancer susceptibility, consisting of 21,220 patients with lung cancer and 21,496 controls. There was a marked association between GSTT1 null genotype and lung cancer risk in overall populations and in Asians (overall populations: Odds ratio [OR] = 1.17, 95% confidence interval [95% CI]: 1.07-1.28, P = 0.006; Asians: OR = 1.41, 95% CI: 1.23-1.62, P < 0.00001). However, GSTT1 null genotype was not associated with the risk of lung cancer in Caucasians, Brazilian population, and Africans., Conclusion: GSTT1 null genotype is associated with the lung cancer risk in overall populations and in Asians.

Aim of Study: The conclusions on the association between glutathione S-transferase P1 (GSTP1) gene polymorphism and lung cancer risk are still debated. This meta-analysis was performed to update the association between GSTP1 and the risk of lung cancer., Materials and Methods: The association investigations were identified from PubMed and Cochrane Library, and eligible studies were included and synthesized using meta-analysis method., Results: Fifty reports were included into this meta-analysis for the association of GSTP1 A/G gene polymorphism and lung cancer susceptibility. The association between GSTPI G allele/GG genotype and lung cancer risk was found in this meta-analysis (G allele: odds ratio [OR] = 1.08, 95% confidence interval [CI]: 1.02-1.14, P = 0.006; GG genotype: OR = 1.09, 95% CI: 1.00-1.18, P = 0.04). However, the AA genotype was not associated with the susceptibility of lung cancer., Conclusion: GSTP1 G allele/GG genotype is associated with the lung cancer susceptibility., Competing Interests: None

Lung cancer is becoming the leading cause of cancer death worldwide with highest morbidity and mortality, and knowing the pathogenesis and signaling pathway is very important and advances in the diagnosis and treatment of the disease are urgently needed. Gene polymorphism was reported to be associated with the lung cancer risk. We reviewed the potential signaling pathway of hypoxia-inducible factor in lung cancer and conducted a meta-analysis to explore its gene polymorphism with lung cancer risk. In the meta-analysis, hypoxia-inducible factor-1α (HIF-1α) G1790A A allele, AA genotype and GG genotype were associated with lung cancer risk (A allele: OR = 2.31, 95% CI: 1.77-3.02, p < 0.00001; AA genotype: OR = 4.52, 95% CI: 2.31-8.83, p < 0.0001; GG genotype: OR = 0.45, 95% CI: 0.33-0.63, p < 0.00001). Furthermore, HIF-1α C1772 TT genotype and CC genotype were associated with lung cancer risk, but the T allele was not. In conclusion, HIF-1α G1790A A allele, AA genotype and GG genotype, HIF-1α C1772 TT genotype and CC genotype were associated with lung cancer risk. However, more studies should be performed to confirm it.

Epidermal growth factor receptor (EGFR) is a member of the tyrosine kinase receptor family, which is thought to be involved in the development of cancer, as the EGFR gene is often amplified, and/or mutated in cancer cells. Lung cancer remains one of the most major causes of morbidity and mortality worldwide, accounting for more deaths than any other cancer cause. Gene polymorphism factor has been reported to be an important factor which increases the susceptibility of lung cancer. There lacks a well-documented diagnostic approach for the lung cancer risk, and the etiology of lung cancer is not clear. The current systematic review was performed to explore the association of EGFR gene polymorphism with lung cancer risk. In this review, association of EGFR 181946C > T, 8227G > A gene polymorphism with lung cancer was found, and EGFR Short genotype of cytosine adenine repeat number polymorphism was significantly associated with an increased risk of lung cancer.

The relationship between glutathione S-transferase T1 (GSTT1) null/presence gene polymorphism and the risk of lung cancer from the published reports are still conflicting. This study was conducted to evaluate the relationship between GSTT1 null/presence gene polymorphism and the risk of lung cancer using meta-analysis method. The association studies were identified from PubMed, and Cochrane Library on July 1, 2012, and eligible investigations were included and synthesized using meta-analysis method. 51 reports were recruited into this meta-analysis for the association of null genotype of GSTT1 with lung cancer susceptibility, consisting of 15,140 patients with lung cancer and 16,662 controls. There was a marked association between GSTT1 null genotype and lung cancer risk in overall populations (OR = 1.15, 95 % CI 1.04-1.27, P = 0.007). Furthermore, GSTT1 null genotype was associated with the lung cancer risk in Asians (OR = 1.47, 95 % CI 1.23-1.76, P < 0.0001). However, GSTT1 null genotype was not associated with the risk of lung cancer in Caucasians, Brazilian population and Africans. In conclusion, GSTT1 null genotype is associated with the lung cancer in overall populations and in Asians.

The conclusions of the published reports on the relationship between glutathione S-transferase P1 (GSTP1) A/G gene polymorphism and the histological types of lung cancer are still debated. GSTP1 is one of the important mutant sites reported at present. This meta-analysis was performed to evaluate the association between GSTP1 and histological types of lung cancer. The association investigations were identified from PubMed and Cochrane Library, and eligible studies were included and synthesized using meta-analysis method. Seventeen reports were included into this meta-analysis for the association of GSTP1 A/G gene polymorphism and histological types of lung cancer. The G allele and GG genotype were not associated with the susceptibility of risk of squamous cell carcinomas, adenocarcinomas, small cell carcinoma, non-small cell carcinoma or large cell carcinoma. However, in the sub-group analysis, there was an association between G allele/GG genotype with the risk of squamous cell carcinomas in East-Asians and GG genotype was associated with the risk of small cell carcinoma in Caucasians. In conclusion, GSTP1 A/G gene polymorphism is not associated with the susceptibility of squamous cell carcinomas, adenocarcinomas, small cell carcinoma, non-small cell carcinoma or large cell carcinoma.

The conclusions of the published reports on the relationship between glutathione S-transferase P1 (GSTP1) gene polymorphism and the risk of lung cancer are still debated. GSTP1 is one of the important mutant sites reported at present. This meta-analysis was performed to evaluate the association between GSTP1 and the risk of lung cancer. The association investigations were identified from PubMed and Cochrane Library, and eligible studies were included and synthesized using meta-analysis method. Forty-four reports were included into this meta-analysis for the association of GSTP1 A/G gene polymorphism and lung cancer susceptibility, consisting of 12,363 patients with lung cancer and 13,948 controls. The association between GSTPI G allele and lung cancer risk was found in this meta-analysis (OR 1.08, 95 % CI 1.02-1.15, P = 0.01). However, the GG genotype and AA genotype were not associated with the susceptibility of lung cancer. Furthermore, there was no association between GSTP1 A/G gene polymorphism and the risk of lung cancer in Caucasians, and East-Asians. In conclusion, GSTP1 G allele is associated with the lung cancer susceptibility. However, more studies on the relationship between GSTP1 A/G gene polymorphism and the risk of lung cancer should be performed in the future.

Objective: The conclusions of published reports on the relationship between the glutathione S-transferase M3 (GSTM3) A/B gene polymorphism and the risk of lung cancer are still debated. This meta-analysis was performed to evaluate the association between GSTM3 and the risk of lung cancer., Methods: Association investigations were identified from PubMed, Embase, and Cochrane Library, and eligible studies were included and synthesized using a meta-analysis method., Results: Eight reports were included into this meta-analysis for the association of GSTM3 A/B gene polymorphism and lung cancer susceptibility, covering 1,854 patients with lung cancer and 1,926 controls. No association between the GSTM3 A/B gene polymorphism and lung cancer was found in this meta-analysis (B allele: OR = 1.25, 95% CI: 0.89-1.76, P = 0.20; BB genotype: OR = 1.53, 95% CI: 0.71-3.32, P = 0.28; AA genotype: OR = 0.85, 95% CI: 0.59-1.23, P = 0.39)., Conclusions: The GSTM3 A/B gene polymorphism is not associated with lung cancer susceptibility. However, more studies on the relationship between GSTM3 A/B gene polymorphism and the risk of lung cancer should be performed in the future.