RESUMO
OBJECTIVE: To investigate the roles of angiogenesis, thrombospondin-1 (TSP-1) and transforming growth factor-ß1 (TGF-ß1) in invasive and noninvasive prolactinoma. METHODS: TSP-1 and TGF-ß1 protein were examined using immunohistochemistry and Western blotting in 81 prolactinomas. Angiogenesis was assessed by measuring microvessel density via CD34 immunostaining. RESULTS: Microvessel density was significantly higher in invasive prolactinomas than in noninvasive prolactinomas. Immunohistochemistry demonstrated that significantly fewer invasive prolactinomas were positive for TSP-1 compared with noninvasive prolactinomas (17.9% versus 50.0%, respectively), and significantly higher numbers of invasive prolactinomas were positive for TGF-ß1 compared with noninvasive prolactinomas (82.1% versus 42.9%, respectively). Microvessel density was significantly lower in TSP-1-positive prolactinomas than in TSP-1-negative prolactinomas, and significantly higher in TGF-ß1-positive prolactinomas than in TGF-ß1-negative prolactinomas. CONCLUSIONS: These results suggest a close relationship between angiogenesis and tumour invasiveness in prolactinoma. TSP-1 and TGF-ß1 may play important roles in the progression of prolactinoma, by affecting angiogenesis.
