Free prostate-specific antigen is used clinically to screen for prostate cancer. Free prostate-specific antigen is a single-chain glycoprotein secreted by the prostate gland, which can be found in the epithelial cells of the prostate gland, and is specific enough to be used to assess the condition of the prostate. Normal serum levels of prostate-specific antigen are extremely low, and it is often present in both free and bound forms and is used to identify prostate inflammation or prostate cancer. If there is inflammation of the prostate gland, it will be slightly higher than the normal value, but if its value is greatly increased, it may indicate prostate cancer, and you need to go to the hospital as soon as possible for further examination of the prostate gland. Therefore, men can have regular medical checkups to screen for prostate-specific antibodies to avoid prostate cancer.