The prostate gland is a walnut-sized organ found only in men that encircles the urethra (urine passage) below the urinary bladder. It secretes fluid that is an important component of semen. Prostate cancer is a disease of the prostate gland where malignant tumours cells invade normal prostate tissue and spread to other organs. It is second leading cause of cancer death in men and it is mainly found in men above the age of 50 years.