The present invention provides compositions and methods of detecting prostate cancer in the body fluids or tissues of patients. Prostate cancer is detected by measuring the level of glypican-1 in a body fluid sample. In one embodiment prostate cancer is detected by contacting a body fluid sample with an anti-glypican-1 antibody, such as MIL-38. The invention includes kits for detection of prostate cancer in a body fluid sample, comprising an anti-glypican-1 antibody and glypican-1 standards.