Expression of vascular endothelial growth factor and its receptors VEGFR-1 and 2 in gastrointestinal stromal tumors,leiomyomas and schwannomas

AIM： To investigate the role of vascular endothelial growth factor （VEGF/and its receptors VEGFR-1 and 2 in the growth and differentiation of gastrointestinal strornal tumors （GISTs）. METHODS： Thirty-three GISTs, 15 leiomyomas and 6 schwannomas were examined by immunohistochemistry in this study. RESULTS： VEGF protein was expressed in the cytoplasm of tumor cells, and VEGFRol and 2 were expressed both in the cytoplasm and on the membrane of all tumors. Irnrnunohistochernical staining revealed that 26 GISTs （78.8%）, 9 leiornyornas （60.0%） and 3 schwannornas （50.0%/were positive for VEGF; 24 GISTs （72.7%/, 12 leiornyornas （80.0%） and 4 schwannornas （66.7%） were positive for VEGFR-1; 30 GISTs （90.9%/, 5 leiornyornas （33.3%/and 4 schwannornas （66.7%） were positive for VEGFR-2. VEGFR-2 expression was statistically different between GISTs and leiomyomas （P 〈 0.0001）. However, there was no correlation between the expression of VEGF pathway componenets and the clinical risk categories. CONCLUSION： Our results suggest that the VEGF pathway may play an important role in the differentiation of GISTs, leiomyomas and schwannomas.