The Expression of Vascular Endothelial Growth Factor and Thrombospondin-1 in Wilms' Tumor / 대한비뇨기과학회지

ABSTRACT

PURPOSE: With the process of neoangiogenesis being linked to the growth and metastasis of various tumors, anticancer therapeutics with a basis in the suppression of neoangiogenesis has recently been receiving attention. In this study, we tried to clarify the immunoreactivities of vascular endothelial growth factor (VEGF), major angiogenic inducer and thrombospondin-1 (TSP-1), major angiogenic inhibitor in human Wilms' tumor and its clinicopathological significance. MATERAILS AND METHODS: Utilizing immunohistochemical staining, we assessed the immunoreactivities of VEGF and TSP-1 in archival tissues of 29 Wilms' tumors and 25 normal kidneys. Also, we assessed the relationship between expression of each factor and clinicopathological parameters in 29 cases of Wilms' tumors. RESULTS: Immunoreactivities of VEGF and TSP-1 were detected mainly in the cytoplasm of the tubular cells in normal kidneys. In Wilms' tumors, whereas VEGF was detected in the cytoplasm of the tumor cells and peritumoral stromal tissues, but TSP-1 only in the peritumoral stromal tissues. Immunohistochemical expression patterns of each factor were divided into two groups according to the area of immunoreactivity (negative OR =10%). VEGF immunoreactivity was detected in 25 (100%) normal kidneys and in 20 (69%) Wilms' tumors. However, TSP-1 immunoreactivity was detected in 24 (97%) normal kidneys and in 3 (10%) Wilms' tumors. Therefore, although no significant difference was observed between the expressions of VEGF and TSP-1 in normal kidney, the TSP-1 immunoreactivity was significantly lower than VEGF immunoreactivity in Wilms' tumors. A relatively higher rate of positive expression of TSP-1 was observed in the patients with no demonstrable lymph node metastasis. Also, as for the VEGF, maximal diameter of the tumor was larger in the positive expression group. However, it proved otherwise for TSP-1 as the negative expression group demonstrated tumors with larger maximal diameters. CONCLUSIONS: Our study demonstrated that the TSP-1 immunoreactivity was significantly lower than VEGF immunoreactivity in Wilms' tumors, and disease progression has a tendency to be found in the VEGF-positive cases and TSP-1 negative cases. We suggest that the growth and metastasis of Wilms' tumor may be influenced mainly by TSP-1 decrease rather than VEGF increase.