An antigen capture assay for the measurement of serum clusterin concentrations

We have developed and validated a robust antigen capture assay for the meas urement of serum clusterin. Increased clusterin expression, and alterations in serum clusterin levels have been associated with a number of disease st ates. In particular, clusterin has been shown to be associated with tissue regression and apoptosis in the rat ventral prostate in response to androge n ablation or administration of anti-androgens. The object of this study wa s to determine if changes in human serum clusterin can be used as a diagnos tic or prognostic marker to monitor the response to hormonal therapy in pat ients with prostate cancer, and to determine if clusterin concentrations in crease with the progression towards androgen independence. The antigen capt ure assay was used for an extensive analysis of human serum clusterin conce ntration in fasting males, and to determine if there is any relationship be tween clusterin and age or cholesterol levels. The average clusterin level in serum is 101+/-42 mug/ml (n = 96). Then is no correlation to age or seru m cholesterol levels. Analysis of serum clusterin levels in patients with n ewly diagnosed prostate cancer (n = 5), hormone responsive tumors (n = 5). and hormone refractory disease (n = 5), demonstrates that no significant ch anges in serum clusterin levels accompany the progression of prostatic dise ase, or response to hormone therapy. (C) 2001 Elsevier Science B.V. All rig hts reserved.