Antibody array profiling reveals serumTSP-I as a marker to distinguish benign from malignant prostatic disease

BACKGROUND. Blood protein markers that provide more accurate or earlier diagnosis of prostate cancer should have a positive impact on prostate cancer treatment and management. METHODS. Serum samples from control subjects and patients with benign or malignant prostatic disease were analyzed on antibody arrays targeting multiple candidate prostate cancer markers and detected with two-color, rolling-circle amplification (TC-RCA). The measurements of certain antibodies were validated using immunoblots, immunoprecipitation/mass spectrometry, and sandwich immunoassays. RESULTS. Several potential disease-associated protein alterations were uncovered. The most significant was thrombospondin-1, which was strongly elevated in patients with benign prostatic disease and repressed in patients with prostate cancer. Thrombospondin-1 levels did not correlate with prostate-specific antigen (PSA) levels and differentiated benign from malignant disease with 79% sensitivity and 81% specificity. CONCLUSIONS. The measurement of thrombospondin-1 could be used to assist the decision to obtain a biopsy in men with suspected prostate cancer, which could lead to a reduction in the number of unnecessary prostatic biopsies.