Immunohistochemical analysis of Omi/HtrA2 expression in prostate cancer and benign prostatic hyperplasia†

To study the expression and significance of the serine protease Omi/HtrA2 in prostate cancer and benign prostatic hyperplasia. The expression of Omi/HtrA2 was assayed by means of immunohistochemical technique in 41 prostate cancer (Cap), 20 benign prostatic hyperplasia (BPH) and 10 normal prostate (NP) specimens. Omi/HtrA2 expression was positive in 30 (73.17%) prostate cancer specimens, and the positive rate of Omi/HtrA2 was lower in well differentiated than in poorly and moderately differentiated groups (P<0.05). By contrast, the cells in normal prostate and benign prostatic hyperplasia groups showed no or weak expression of Omi/HtrA2. Prostate cancer cells in vivo may need Omi/HtrA2 expression for apoptosis, and that Omi/HtrA2 expression might be involved in prostate cancer development.