Serum cathepsin D and its density in men with prostate cancer as new predictors of disease progression.

We examined whether serum levels of cathepsin D (CatD) and its density (CatD-D), which was determined by dividing the serum levels of CatD by the prostate volume, could be used as predictors of the progression and prognosis in patients with prostate cancer. Serum levels of CatD in 40 healthy controls, 70 patients with benign prostatic hypertrophy (BPH) and 80 patients with prostate cancer were measured by a sandwich enzyme immunoassay, and prostate volume was measured using transrectal ultrasonography. The mean levels of CatD and CatD-D in patients with prostate cancer were significantly higher than those in healthy controls and patients with BPH. Furthermore, the CatD and CatD-D levels in prostate cancer patients with metastasis were significantly elevated compared with those in patients without metastasis. Among patients who underwent radical prostatectomy, the levels of CatD and CatD-D in patients with pathologically organ-confined disease were significantly lower than in those with extraprostatic disease. However, the elevated levels of CatD and CatD-D were not significantly associated with the cause-specific survival in prostate cancer patients. These findings suggest that the elevation of CatD or CatD-D could be used as new predictors of disease progression, but not prognosis, in patients with prostate cancer.