Elevated Expression of Inhibin α in Prostate Cancer

ABSTRACTPurpose: Less than 50% of men who undergo radical prostatectomy for prostate cancer are cured of disease. We evaluate tumor expression of inhibin α, a putative tumor suppressor, and the related protein, follistatin, to determine whether expression correlated with failure to be cured by surgery.Materials and Methods: Tissues were selected from an archival collection of 379 prostatectomy specimens from men with followup of at least 5 years after surgery. Since previous studies showed that such men with only Gleason grade 3 cancer had a greater than 95% chance of no biochemical recurrence (increase in serum prostate specific antigen), our investigation was confined to 174 men with 2% or greater grade 4/5 cancer. These men had an intermediate rate of failure, providing an opportunity to analyze the potential contribution of inhibin α or follistatin to progression. Intensity of immunohistochemical labeling for inhibin α and follistatin in each cancer was compared with that in normal glands within the s...