The prostate is a gland of the male reproductive system. The function of the prostate is to produce fluid that is one of the constituents in semen, together with fluid from seminal vesicles and sperm from the testis. The prostate is composed of secretory glands and a specific smooth muscle rich fibromuscular stroma. Transcriptome analysis shows that 71% (n=14228) of all human proteins (n=20162) are expressed in the prostate and 129 of these genes show an elevated expression in the prostate compared to other tissue types.