Quantification of VEGF mRNA expression in non-small cell lung cancer usinga real-time quantitative reverse transcription-PCR assay and a comparison with quantitative competitive reverse transcription-PCR

A reliable quantitative method for measuring gene product expression is imp ortant in investigating the relationship between growth factors and tumor b iological behavior. In this study, we quantified the expression of vascular endothelial growth factor (VEGF) mRNA in 104 paired samples of lung cancer tissue and the surrounding nontumorous lung tissue using a new kinetic qua ntitative polymerase chain reaction (PCR) method, ie, real-time quantitativ e reverse transcription-PCR (RTQ RT-PCR). The samples consisted of 46 squam ous cell carcinomas, 50 adenocarcinomas, and 8 undifferentiated cell carcin omas. In 17 cases, the results obtained were compared with those obtained u sing quantitative competitive RT-PCR (QC RT-PCR). Using RTQ RT-PCR, VEGF mR NA expression was detected and quantified in all 104 (100%) lung cancer sam ples and their normal counterparts. VEGF mRNA expression in the lung cancer tissue was significantly higher than in the normal counterparts (95% CI: 0 .575 similar to 1.727, p < 0.001; paired t test). In 68 (65.4%) cases, VEGF mRNA expression was higher in the cancer tissue than normal tissue. VEGF m RNA expression was higher in nonsquamous cell carcinoma lo = 0.02), and hig her in tumor with hilar or mediastinal lymph node metastasis (p = 0.024). Q C RT-PCR was able to detect and quantify VEGF mRNA expression in 15/17 (88% ) lung cancer samples and 12/17 (70.6%) normal tissue samples. The values f or VEGF mRNA expression were higher in the tumor in 13 (76%) cases. Compari son of the values of the VEGF mRNA expression quantified using RTQ RT-PCR o r QC RT-PCR showed a good correlation between results obtained using these two methods, both in cancer tissue (r = 0.68, p = 0.0025) and normal counte rpart (r = 0.53, p = 0.027). Agreement between the results for the relative expression of VEGF mRNA expression in cancer and normal tissue obtained us ing these two methods was seen in 14/16 cases (88%). We conclude that RTQ R T-PCR is as accurate as QC RT-PCR and is more sensitive than QC RT-PCR in d etecting and quantifying VEGF mRNA expression in lung cancer and normal tis sues, and both methods reveal that the VEGF mRNA expression is higher in lu ng cancer tissue than in healthy lung tissue.