We have developed and validated a robust
antigen capture assay for the measurement of serum
clusterin. Increased
clusterin expression, and alterations in serum
clusterin levels have been associated with a number of disease states. In particular,
clusterin has been shown to be associated with tissue regression and apoptosis in the rat ventral prostate in response to
androgen ablation or administration of anti-
androgens. The object of this study was to determine if changes in human serum
clusterin can be used as a diagnostic or prognostic marker to monitor the response to hormonal
therapy in patients with
prostate cancer, and to determine if
clusterin concentrations increase with the progression towards
androgen independence. The
antigen capture assay was used for an extensive analysis of human serum
clusterin concentration in fasting males, and to determine if there is any relationship between
clusterin and age or
cholesterol levels. The average
clusterin level in serum is 101+/-42 microg/ml (n=96). There is no correlation to age or serum
cholesterol levels. Analysis of serum
clusterin levels in patients with newly diagnosed
prostate cancer (n=5),
hormone responsive
tumors (n=5), and
hormone refractory disease (n=5), demonstrates that no significant changes in serum
clusterin levels accompany the progression of
prostatic disease, or response to
hormone therapy.