Abstract 374: VEGFR2/KDR polymorphisms and gene copy gain with outcome in non-small cell lung cancer

Abstract

Abstract Background. The VEGF receptor 2 (VEGFR2) is the predominant mediator of VEGF-stimulated endothelial cell function. Recently, VEGFR2/KDR copy number gain and mutation, and VEGF copy number gain, have been described in lung adenocarcinoma tumor specimens. To better characterize the molecular changes of these two genes in non-small cell lung carcinoma (NSCLC), we investigated their abnormalities in NSCLC tumor tissue specimens and correlated with patients clinico-pathological characteristics. Methods. We extracted DNA from microdissected tissue obtained from 200 surgically resected NSCLCs. KDR single nucleotide polymorphism (SNP) 889G/A (rs2305948), SNP 1416A/T (rs1870377) and SNP −37A/G (rs2219471) were genotyped by PCR-based sequencing. KDR and VEGF copy number were examined by quantitative (q)-PCR. Protein expressions of VEGF and VEGFR2, and CD34 for microvascular density (MVD) analysis were studied by immunohistochemistry. SNP genotypes, genes copy number and protein expression were correlated with NSCLC clinico-pathological features, including overall survival (OS) and recurrence-free survival (RFS). Results. KDR 1416 AT/TT genotypes had significantly improved OS (HR = 0.56, 95% CI 0.33 to 0.96, P = 0.035) compared with KDR 1416 AA in all NSCLC patients in the multivariate analysis with adjustment of histology and tumor stage. In lung adenocarcinomas, KDR 1416 AT/TT genotypes and KDR −37AG/GG were associated with a favorable OS (HR = 0.43, 95% CI 0.20 to 0.92, P = 0.029; HR = 0.47, 95% CI 0.23 to 0.96, P = 0.039, respectively). Strikingly, KDR −37 AG/GG genotypes predicted a superior OS compared with KDR −37 AA genotype in the NSCLC patients treated with adjuvant therapy (HR = 2.45, 95% CI 1.06 to 5.66, P = 0.036). No genotype in KDR SNPs was associated with RFS in NSCLC patients. Gene copy gain of KDR and VEGF were detected respectively in 34/91 (37.4%) and 2/91 (2.2%) NSCLC tumors. Gene copy gain of KDR was associated with a poor overall survival in NSCLC patients (HR= 2.96, 95% CI 1.41 to 6.24, P = 0.004). Furthermore, tumors with gene copy gain of KDR showed significantly higher cytoplasmic (P = 0.013) and membrane (P = 0.009) VEGFR2 protein expression, lower cytoplasmic VEGF expression (P = 0.044), and higher MVD (P = 0.018) and larger vessel areas (P = 0.033) compared with tumors lacking KDR gene copy gain. Conclusion. Our findings suggest an association between KDR SNP genotypes and survival in NSCLC patients receiving adjuvant therapy. KDR copy number gain was frequently identified in NSCLC and was associated with worse survival in NSCLC patients. (Supported by grant US DoD W81XWH-07-1-0306). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 374.