Correlation of total VEGF mRNA and protein expression with histologic type, tumor angiogenesis, patient survival and timing of relapse in non-small-cell lung cancer

We have quantified the expression of all 4 isoforms of vascular endothelial growth factor (VEGF) mRNA in nonsmall-cell lung cancer (NSCLC) using a new kinetic quantitative PCR method, real-time quantitative (RTQ) RT-PCR, and investigated the association between VEGF expression at the mRNA and protei n levels and the clinicopathologic variables, tumor angiogenesis, patient s urvival and timing of relapse. Surgical tumor specimens from 72 NCSLC patie nts (37 squamous-cell carcinomas, 35 adenocarcinomas) were examined. Twenty -eight patients had stage I, 10 stage II and 34 stage IIIA or IIIB disease. Total VEGF mRNA (all 4 iso forms) was quantified by RTQ RT-PCR, while VEGF protein expression and microvessel number in tumors were assessed immunohi stochemically. VEGF mRNA was detected in all 72 tumor samples at significan tly higher levels than in adjacent normal tissue. Tumoral VEGF mRNA levels correlated strongly with the VEGF protein staining score and microvessel co unt. Adenocarcinomas showed significantly higher VEGF mRNA expression and a higher protein staining score than squamous-cell carcinomas. High tumoral VEGF mRNA expression was associated with advanced (IIIA or IIIB) tumor stag e, lymph node metastasis, high tumoral microvessel counts, short patient su rvival (< 24 months) and early relapse (< 12 months), while a high VEGF pro tein staining score was associated with high tumoral microvessel counts, sh ort patient survival and early relapse. Patients with high tumoral levels o f both VEGF mRNA and protein had significantly shorter survival and earlier relapse. In multivariate analysis, the VEGF protein staining score and nod al status were the most important independent predictors of survival and re currence. We conclude that RTQ RT-PCR is a sensitive method for detecting a nd quantifying VEGF mRNA expression in NSCLC and that the expression levels of total VEGF mRNA and protein in NSCLC are strongly associated with histo logic type, tumor angiogenesis, survival and timing of relapse. High VEGF e xpression in adenocarcinomas may contribute to their greater metastatic pot ential. Int. J. Cancer (Pred. Oncol.) 89:475-483, 2000. (C) 2000 Wiley-Liss , Inc.