Ratios between VEGF ligands and receptors in tumor and stroma have impact on the outcome in resectable NSCLC.

Abstract

e22147 Background: In tumor angiogenesis there is a complex interplay between endothelial, stromal and tumor cells. Some key regulators of this process are the members of the vascular endothelial growth factor (VEGF) family of ligands and receptors and the neuropilins (NRP). This study analyzes the correlations between the expression of these angiogenic factors in tumor cells and tumor stroma, and their prognostic role in tissue samples from resected non-small cell lung cancer (NSCLC) patients. Methods: Representative tumor and stroma areas from FFPE tissue samples of 125 early-stage NSCLC patients were carefully micro-dissected. RNA isolated from the samples was retrotranscripted and preamplified. RTqPCR was performed using hydrolysis probes (TaqMan, Applied Biosystems) and relative quantification was calculated using GAPDH and CDKN1B as endogenous controls. Results were normalized against a human cDNA (Clontech) as a reference. All statistical analyses were considered significant at p<0.05. Results: Paired Wilcoxon test revealed differences between tumor and stroma gene expression for VEGFB (p<0.0001), VEGFC (p<0.0001), VEGFR-1 (p<0.0001), VEGFR-2 (p=0.020), VEGFR-3 (p< 0.0001), NRP-1 (p=0.001) and NRP-2 (p< 0.0001). Survival analyses showed that those patients with higher levels of the Ratio Stromal-VEGFA/ Tumoral-VEGFR-2 had worse time to progression (TTP) (median 26.23 months vs NR, p=0.013) and overall survival (OS) (median 29.50 months vs NR, p=0.001). Similarly, those patients with higher levels of the Ratio Stromal-VEGFC/Tumoral-VEGFR-3 had worse TTP (median 23.30 vs 70.53 months, p=0.015) and OS (median 37.20 months vs NR, p=0.023). Conclusions: Our results show significant differences in the expression of VEGF family members between tumor and stromal cells. This may indicate the importance of the tumor-stroma interaction when trying to understand the angiogenic process. Furthermore, the combination of the ligands expression in stroma and their receptors in tumor may have a prognostic value in NSCLC patients. Supported by grants PS09-01149 and RD06/0020/1024 from ISCIII.