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Division
of Chest Medicine (AY, PCY, CJY), Department of Internal Medicine; Division
of Cardiovascular Medicine (WJC), Department of Internal Medicine; Division
of Cardiovascular Surgery (FYL), Department of Surgery; and Department of
Laboratory Medicine (SHK, KTL), National Taiwan University Hospital, Taiwan
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A reliable quantitative method for measuring gene product expression
is important in investigating the relationship between growth factors
and tumor biological 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 quantitative polymerase chain reaction (PCR) method, ie,
real-time quantitative reverse transcription-PCR (RTQ RT-PCR). The samples
consisted of 46 squamous cell carcinomas, 50 adenocarcinomas, and 8 undifferentiated
cell carcinomas. In 17 cases, the results obtained were compared with
those obtained using quantitative competitive RT-PCR (QC RT-PCR). Using
RTQ RT-PCR, VEGF mRNA expression was detected and quantified in all 104
(100%) lung cancer samples and their normal counterparts. VEGF mRNA expression
in the lung cancer tissue was significantly higher than in the normal
counterparts (95% CI: 0.575 ~ 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 mRNA expression was higher in nonsquamous
cell carcinoma (p = 0.02), and higher in tumor with hilar or mediastinal
lymph node metastasis (p = 0.024). QC 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 for VEGF mRNA expression
were higher in the tumor in 13 (76%) cases. Comparison of the values of
the VEGF mRNA expression quantified using RTQ RT-PCR or 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 counterpart
(r = 0.53, p = 0.027). Agreement between the results for
the relative expression of VEGF mRNA expression in cancer and normal tissue
obtained using these two methods was seen in 14/16 cases (88%). We conclude
that RTQ RT-PCR is as accurate as QC RT-PCR and is more sensitive than
QC RT-PCR in detecting and quantifying VEGF mRNA expression in lung cancer
and normal tissues, and both methods reveal that the VEGF mRNA expression
is higher in lung cancer tissue than in healthy lung tissue.
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