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

Angiopoietin-1 and angiopoietin-2 are antagonist angiogenic factors acting via the same receptor Tie-2. Their role in prostate carcinoma (PCa) is not known.

Using immunohistochemistry, localization of angiopoietin-1, angiopoietin-2 and their receptor Tie-2 was studied in normal human prostate and PCa.

Few epithelial cells of normal prostate expressed angiopoietin-1 and Tie-2 but not angiopoietin-2. Normal prostate blood vessels were negative. In PCa, intraductal grown tumor cells showed angiopoietin-1 but not angiopoietin-2. Blood vessels close to the ducts and some apical tumor cells expressed angiopoietin-1 and Tie-2. In glandular PCa, most of the tumor and intraglandular stromal cells were positive for both angiopoietin-1 and angiopoietin-2. Angiopoietin-1 and angiopoietin-2 were also found in tumor capillaries. Additionally, angiopoietin-2 was expressed in smooth muscle cells of intratumoral blood vessels which also exhibited Tie-2.

The results presented indicate a role of angiopoietin-Tie-2 system, particularly of angiopoietin-2 in the vascularization of PCa.