Journal name: OncoTargets and Therapy Article Designation: Original Research Year: 2016 Volume: 9 OncoTargets and Therapy Dovepress Running head verso: Zheng et al Running head recto: ITGA5 and ITGB1 are prognostic in NSCLC open access to scientific and medical research DOI: http://dx.doi.org/10.2147/OTT.S91796 Open Access Full Text Article ORIGINAL RESEARCH Integrin and gene network analysis reveals that ITGA5 and ITGB1 are prognostic in non-small-cell lung cancer Weiqi Zheng Background: Integrin expression has been identified as a prognostic factor in non-small-cell Caihui Jiang lung cancer (NSCLC). This study was aimed at determining the predictive ability of integrins Ruifeng Li and associated genes identified within the molecular network. Patients and methods: A total of 959 patients with NSCLC from The Cancer Genome Atlas Department of Radiation Oncology, Guangqian Hospital, Quanzhou, Fujian, cohorts were enrolled in this study. The expression profile of integrins and related genes were People’s Republic of China obtained from The Cancer Genome Atlas RNAseq database. Clinicopathological characteristics, including age, sex, smoking history, stage, histological subtype, neoadjuvant therapy, radiation therapy, and overall survival (OS), were collected. Cox proportional hazards regression models as well as Kaplan–Meier curves were used to assess the relative factors. Results: In the univariate Cox regression model, ITGA1, ITGA5, ITGA6, ITGB1, ITGB4, and ITGA11 were predictive of NSCLC prognosis. After adjusting for clinical factors, ITGA5 (odds ratio =1.17, 95% confidence interval: 1.05–1.31) andITGB1 (odds ratio =1.31, 95% confidence interval: 1.10–1.55) remained statistically significant. In the gene cluster network analysis, PLAUR, ILK, SPP1, PXN, and CD9, all associated with ITGA5 and ITGB1, were identified as independent predictive factors of OS in NSCLC. Conclusion: A set of genes was identified as independent prognostic factors of OS in NSCLC through gene cluster analysis. This method may act as a tool to reveal more prognostic-associated genes in NSCLC. Keywords: integrin, prognosis, non-small-cell lung cancer, ITGA5, ITGB1 Introduction Lung cancer, particularly non-small-cell lung cancer (NSCLC), is one of the most com- mon malignancies and the most common cause of cancer-related mortality worldwide.1 The prognosis of patients with NSCLC, especially in an advanced stage, is generally poor where the 5-year survival rate is ,10%.2 Integrins are heterodimeric cell-surface adhesion receptors generally consisting of noncovalently linked alpha and beta subunits. A total of 18 alpha and eight beta subunits with different functions are currently known.3 Integrin family members participate in a variety of processes influencing the cell’s biological behavior, including cell adhesion, Correspondence: Ruifeng Li Department of Radiation Oncology, recognition, immune response, metastasis of tumor cells as well as embryogenesis, Guangqian Hospital, No 109, hemostasis, and tissue repair.4 Alterations in integrin expression levels can influence West Guangqian Road, Meishan cancer cell adhesion, polarity, and extracellular matrix assembly, which may result in Town, Quanzhou 362321, Fujian, People’s Republic of China tumor metastasis.5 Integrins can also interact with tyrosine kinase receptors, such as Tel +86 595 8657 2018 epidermal growth factor receptor (EGFR) and vascular EGFR (VEGFR), to promote Fax +86 595 8658 5153 Email [email protected] cancer cell proliferation, survival, and differentiation.6 EGFR mutations frequently submit your manuscript | www.dovepress.com OncoTargets and Therapy 2016:9 2317–2327 2317 Dovepress © 2016 Zheng et al. This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License (http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you http://dx.doi.org/10.2147/OTT.S91796 hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms (https://www.dovepress.com/terms.php). Zheng et al Dovepress occur in patients with lung cancer, and these patients have Survival curves were constructed using the Kaplan–Meier been found to benefit from tyrosine kinase inhibitor-targeted method, with log-rank tests used to assess differences therapy rather than first-line chemotherapy.7 between groups. Univariate and multivariate Cox propor- There was a report that discussed the integrin profile tional hazards models were used to analyze the relationship and prognosis in NSCLC;8 however, external validation between integrin network expression and OS of patients with and interactions of integrins within the network of integrins NSCLC in TCGA cohort. A two-sided P-value ,0.05 was were not determined. The Cancer Genome Atlas (TCGA) considered statistically significant. Odds ratios with 95% database has been developed in recent years using a large confidence intervals (CIs) were calculated. amount of NSCLC RNAseq data as well as detailed clinical data, and this has made bioinformatic data mining conve- Results nient and reliable.9 This study was aimed at determining the Clinical factors in TCGA cohorts prognostic ability of integrins and associated genes identi- A total of 959 patients with NSCLC, including 576 men and fied through the molecular network using TCGA database 383 women, from TCGA cohort were enrolled in the current analysis in NSCLC. study. The median age of the cohort was 67. There were 485 patients diagnosed with adenocarcinoma and 474 patients Materials and methods diagnosed with squamous cell carcinoma (SCC). Detailed Patients clinicopathological data are shown in Table 1. The median Expression data of integrins and their associated genes and OS in this cohort was 16.7 months. relative clinical data of patients with NSCLC were available in TCGA database provided on the website of the Cancer ITGA5 and ITGB1 expressions were Genomics Browser of the University of California Santa independent prognostic factors for OS in Cruz (https://genome-cancer.ucsc.edu/). Thirty members of TCGA cohort the integrin family were included in our study (Table S1). In univariate Cox regression analysis, ITGA1, ITGA5, ITGA6, There were 1,092 patients with NSCLC enrolled in TCGA ITGB1, ITGB4, and ITGA11 were significantly associated database (updated on February 24, 2015) according to the with OS in patients with NSCLC (all P,0.05, Table 2). parameters defined in a previous study.10 Patients without fully In multivariate models, after adjusting for age, sex, stage, characterized tumors, deficient overall survival (OS) data, histological subtype, smoking history, neoadjuvant therapy or incomplete RNAseq information were excluded from the history, and radiation therapy history, ITGA5 (HR =1.17, 95% study. Clinicopathological characteristics, including age, sex, CI: 1.05–1.31) and ITGB1 (HR =1.31, 95% CI: 1.10–1.55) histology, TNM stage, American Joint Committee on Cancer were independent predictors of prognosis (all P,0.01, stage, smoking status, and history of neoadjuvant and radiation Table 2). therapy, were collected. Information on integrin family genes We then divided TCGA cohort according to the histological was also obtained from TCGA RNAseq database. Networks of subtype. In TCGA NSCLC cohort, large-cell carcinoma data integrin genes, which were independent prognostic predictors were not available; therefore, we analyzed only two subgroups of NSCLC, were obtained from the cBioPortal website (http:// of adenocarcinoma and SCC. In 485 patients with adenocarci- www.cbioportal.org/public-portal/cgds_r.jsp). Network filters noma, ITGA5 (HR =1.316, 95% CI: 1.135–1.525) and ITGB1 were set as “in the same complex” or “interacted with each (HR =1.788, 95% CI: 1.399–2.286) were associated with OS in other”, and threshold was set as .12% changes. univariate analysis. However, in multivariate analysis, ITGA6 This study is based on publicly available data from TCGA (HR =1.208, 95% CI: 1.014–1.439) was found to be the unique, database and did not involve interaction with human subjects independent prognostic factor. Also, ITGA5 (HR =1.142, or the use of personal identifying information. The study was 95% CI: 1.005–1.299) and ITGB1 (HR =1.231, 95% CI: approved by the Institutional Review Board of Guangqian 1.006–1.507) were prognostic factors of 474 patients with SCC Hospital, Quanzhou, Fujian, People’s Republic of China. with univariate analysis. After adjusting for clinical factors and other integrin family members, ITGA3 (HR =1.182, 95% CI: Statistical analysis 1.002–1.394) was the only prognostic factor (Table 3). OS was defined as time from the date of diagnosis to the date Further studies of integrin and lymph node metastasis of death or the last follow-up. Patients without an event of and distant metastasis were conducted with Spearman’s cor- death were recorded as censored at the time of last follow-up. relation analysis. ITGA3, ITGB5, ITGB6, and ITGB8 were The R project (3.1.3) was used to perform statistical analysis. associated with lymph node staging of SCC. ITGB1 was the 2318 submit your manuscript | www.dovepress.com OncoTargets and Therapy 2016:9 Dovepress Dovepress ITGA5 and ITGB1 are prognostic in NSCLC Table 1 Clinical characteristics