The expression of angiopoietins and their receptor Tie-2 in human prostatecarcinoma

Background: Angiopoietin- 1 and angiopoietin-2 are antagonist angiogenic fa ctors acting via the same receptor Tie-2. Their role in prostate carcinoma (PCa) is not known. Material and methods: Using immunohistochemistry, local ization of angiopoietin-1, angiopoietin-2 and their receptor Tie-2 was stud ied in normal human prostate and PCa. Results: Few epithelial cells of norm al prostate expressed angiopoietin-1 and Tie-2 brit not angiopoietin-2 Norm al prostate blood vessels were negative. In PCa, intraductal grown tumor ce lls showed angiopoietin-1 but not angiopoietin-2. Blood vessels close to th e ducts and some apical tumor cells expressed angiopoietin-1 and Tie-2. In glandular PCa, most of the tumor and intraglandular stromal cells were posi tive for both angiopoietin-1 and angiopoietin-2. Angiopoietin-1 and angiopo ietin-2 were also found in tumor capillaries. Additionally, angiopoietin-2 was expressed in smooth muscle cells of intratumoral blood vessels which al so exhibited Tie-2. Conclusions: The results presented indicate a role of a ngiopoietin-Tie-2 system, particularly of angiopoietin-2 in the vasculariza tion of PCa.