The prostate also surrounds the urethra, the canal through which urine passes out of the body. Scientists do not know all the prostate's functions. One of its main roles, though, is to squeeze fluid into the urethra as sperm move through during sexual climax. This fluid, which helps make up semen, energizes the sperm and makes the vaginal canal less acidic. One of the gland's main roles is to squeeze fluid into the urethra as sperm move through during sexual climax.
Prostate cancer develops from cells of the prostate gland.
Eventually the cancer cells may spread outside the gland to other parts of the body. Most prostate cancers grow very slowly. Autopsy studies show that many elderly men who died of other diseases also had a prostate cancer that neither they nor their doctor were aware of. But some prostate cancers can grow and spread quickly. The prostate gland is about the size of a walnut and is located in front of the rectum, behind the base of the penis, and under the bladder.