Objective: To determine the expression of vascular endothelial growth factor (VEGF) and its receptor in nasal inverted papillomas (NIP) and to clarify the function of VEGF in the establishment of NIPs.
Method: VEGF and its receptor, fetal liver kinase-1 (flk-1) expression were examined by immunohistochemistry using SP method in sections of NIPs from 11 patients and inferior turbinates from 6 patients with chronic simple rhinitis. An automatic image analyzer was used to detect the staining results. Gray scale, a half-quantitative parameter, was used to describe the expression of VEGF and flk-1.
Result: It showed that all the epithelium in NIPs, together with vascular and stroma adjacent to the epithelium, expressed different degree of VEGF. The VEGF expression in epithelium was significantly stronger in NIPs than that in inferior turbinates (P < 0.001). The expressions of both VEGF and flk-1 in vascular endothelium were more intense in NIPs than that in inferior turbinates (P < 0.001, P < 0.001). Flk-1 positive expression was observed in epithelium of NIPs but not in inferior turbinates.
Conclusion: The results suggest that VEGF participate in the growth of NIPs, part of which shows the characteristics of containing plenty of blood vessels and being bloody in operation. The enhanced expression of VEGF may also play a key role in the development of edematous stroma. The expression degree of VEGF in the epithelium may be identified as one of the parameters of judging the propensity of NIPs' malignant transformation.