[Expression of vascular endothelial growth factor and its receptors in endometrial carcinoma]

To study the expression of vascular endothelial growth factor (VEGF) and its receptors, the fms-like tyrosine-1 (flt-1) and kinase insert domain-containing receptor (KDR) in endometrial carcinoma and investigate the functions of VEGF and its receptors for endometrial carcinoma angiogenesis and its relation to the grade of tumor.

Immunocytochemistry and in situ hybridization technique were used to measure the level of VEGF, flt-1, KDR protein and mRNA in endometrial carcinoma tissue from 23 patients and endometrial samples from 6 normal menopausal women. A few endometrial carcinoma samples were homogenized for Western blot analysis. The blood vessel density was estimated by counting blood vessels stained with endothelial marker VIII factor.

The VEGF and its receptors were widely expressed in the cytoplasm of endothelial cells and tumor cells of endometrial carcinoma. The level of VEGF protein in endothelial cells and endometrial cancer cells of grade II and III tumor tissues was higher than that in grade I and normal menopausal endometrium (P < 0.05). VEGF mRNA did not show higher expression with the increase of tumor grade but its expression in normal tissue was lower than that in cancer (P < 0.05). The expression of flt-1 protein and mRNA in endothelial cells got higher in III than in grade II and I (P < 0.05), but invariable in cancer cells (P > 0.05), flt-1 expression in cancer was higher than that in normal menopausal endometrium either in endothelial cells or in cancer cells (P < 0.05). The expression of KDR protein in endothelial and cancer cell was high but did not alter with the increase of tumor grade (P > 0.05), the level of its mRNA was higher in cancer than that in normal tissue (P < 0.05). The microvascular density in grade III (48 +/- 12) was higher than that in grade II (26 +/- 16), grade I (27 +/- 14) and normal menopausal tissue (26 +/- 11, P < 0.05).

The expression pattern of VEGF, flt-1 and KDR protein and mRNA increased with the increase of tumor grade in endometrial carcinoma indicates that VEGF and its receptors contribute to the neovascularization of tumors and is one of the factors that relate to rapid tumor growth of endometrial carcinoma.