The prostate, found only in men, is a walnut-sized gland located in front of the rectum, at the outlet of the bladder. It contains gland cells that produce some of the seminal fluid, which protects and nourishes sperm cells in semen. Just behind the prostate gland are the seminal vesicles that produce most of the fluid for semen. The prostate surrounds the first part of the urethra, the tube that carries urine and semen through the penis.
Male hormones stimulate the prostate gland to develop in the fetus.
The prostate continues to grow as a man reaches adulthood. It will continue to grow or at least is maintained after it reaches normal size throughout the life of a man as long as male hormones are produced. If male hormones are removed, the prostate gland will not fully develop or will shrink. The medical term for a cancer that starts in glandular cells is adenocarcinoma. Because other types of prostate cancer are so rare, if you have prostate cancer, it is almost certain to be adenocarcinoma.