Whole-mount prostate sections reveal differential endoglin expression in stromal, epithelial, and endothelial cells with the development of prostate cancer

Endoglin is a nonsignaling receptor for transforming growth factor that contributes to the action of this growth factor in diverse cell types. It may also exhibit a function of its own. Endoglin levels vary with disease states and is a marker of new blood vessels. We studied endoglin expression in whole-mount prostate sections from 64 patients with localized prostate cancer, assessing reactivity in the epithelium, the stroma, and blood vessels. Cells in normal/benign acini were negative but significantly immunoreactive (P<0.001) in both prostatic intraepithelial neoplasia (PIN; 52% of cases) and malignant areas (77% of cases). In tumors, this involved less than 25% of malignant cells in 59% of specimens. The endoglin-stained stroma was detected mainly in areas surrounding PIN acini and tumors. Endoglin antibodies detected more microvessels than von Willebrand Factor antibodies in all prostatic areas (P < 0.01). In addition, the number of microvessels increased with the development of cancer and correlated with Gleason score (P < 0.01). Changes in endoglin expression in PIN and malignant cells, the surrounding stroma, and related blood vessels, suggest that endoglin function may be altered in prostate cancer.