METHODS: The authors used quantitative
reverse transcriptase-polymerase chain reaction analysis and direct sequencing techniques for a retrospective study of
VEGF gene expression and K-ras gene status in
tumor tissue samples from 48 patients with
pancreatic carcinoma. Immunohistochemistry also was used to investigate
VEGF protein expression.
RESULTS: Thirty-one
tumors (64.6%) were evaluated with high
VEGF expression, and 17
tumors (35.4%) were evaluated with low
VEGF expression. Of the 48 primary pancreatic
tumors studied, 33
tumors (68.8%) contained mutations of the K-ras gene. There was a significant correlation between
VEGF expression and K-ras status. Twenty-five of 33
tumors (75.8%) with mutant K-ras genes showed high
VEGF expression, whereas only 6 of 15
tumors with the wild type K-ras (40.0%) showed high
VEGF expression (P = 0.038). The mean (+/- standard error)
VEGF conservation rate for the 33
tumors with mutant K-ras was 1.839 +/- 1.241, and that for the 15
tumors with wild type K-ras was 1.057 +/- 0.983 (P = 0.037). Furthermore, the median survival for patients with mutant K-ras was shorter than for those with wild type K-ras (10.6 months vs. 27.6 months, respectively; P = 0.026), whereas the median survival for patients with high
VEGF expression was shorter compared with that for patients with low
VEGF expression (9.5 months vs. 26.4 months, respectively; P = 0.002). Cox regression model analysis indicated that only the
VEGF status was a significant factor for prognosis (P = 0.024). Other variables, i.e., K-ras status, histopathologic
tumor grade,
tumor status, lymph node status, metastatic status, gender, and age at surgery, were not significant.
CONCLUSIONS: