Prostate-specific antigen, or PSA, is a protein produced by the cells of the prostate gland, which is found only in men. This protein is primarily involved in the liquefaction of semen, helping sperm to swim more freely. PSA levels can be measured through a simple blood test, and they can provide important information about prostate health. Elevated levels of PSA in the blood may indicate various conditions, including prostate cancer, benign prostatic hyperplasia (BPH), or prostatitis. However, high PSA levels do not always mean cancer is present, so further testing is often needed to determine the cause. Regular screening can help in early detection and management of prostate-related issues.