The prostate is a walnut-sized male gland just below the bladder that surrounds the urethra (the tube that carries urine from the bladder). Its cells produce components of seminal fluid.
Male hormones cause the prostate to grow until adulthood. Sometimes, it continues growing benignly and can cause problems with urination. Cancer can develop if the size and shape of prostate gland cells begin to change. As men age their risk for prostate cancer increases. More than 65% of prostate cancers occur in men older than 65, according to the Prostate Cancer Foundation.