Quantitation by competitive PCR assay of vascular endothelial growth factor in non-small cell lung carcinomas

The vascular endothelial growth factor (VEGF) is known to be one of the mos t important angiogenic factors under both physiological and pathological co nditions. The VEGF overexpression by a wide spectrum of neoplastic diseases has suggested an important role of this cytokine in tumor-neovascularizati on. A method is described for quantification by reverse transcription-polym erase chain reaction (RT-PCR) of VEGF mRNA in non-small cell lung cancer ti ssues (NSCLC). The method entails addition to the sample of competitor DNA molecules that share the same primer recognition sites as the amplified tar get, but which can be easily distinguished by gel electrophoresis because o f their different lengths (competitive PCR). We analyzed the VEGF mRNA expr ession level in 34 cases of lung tumor tissues compared to the respective a djacent normal tissues. In 4 out of 34 (11.7%) analyzed couples there was n o VEGF mRNA expression, in 8 out of 34 (23.5%) only normal parenchymal tiss ue was positive for VEGF mRNA expression; in the remaining 22 cases (64.7%) both normal and tumor tissues showed PCR products for VEGF. In 17 out of t hese 22 couples (77.2%) a higher number of VEGF mRNA molecules were present in tumor specimens than in the normal counterpart. According to these resu lts, the competitive PCR-method seems to provide a useful tool for the quan titate VEGF expression in order to identify its role in the development of lung cancer.