Extracellular proteases mediate the digestion of neighboring extracellular matrix components in initial tumor growth, allow desquamation of tumor cells into the surrounding environment, provide the basis for invasion of basement membranes in targeted metastatic organs and are required for release and activation of many growth and angiogenic factors. The TMPRSS2 gene encodes a 492 amino acid multimeric serine protease, which is mainly expressed in the mouse prostate and kidney, and is also expressed in the human small intestine, prostate, colon, stomach and salivary gland. TMPRSS2 contains several domains, including a serine protease domain of the S1 family, a scavenger receptor cysteine-rich domain of group A, an LDL receptor class A domain and a transmembrane domain. TMPRSS2 is expressed as a full length form and a cleaved protease domain and its expression is increased by androgenic hormones. TMPRSS2 is also expressed in prostate carcinoma, suggesting that it may play a role in prostate carcinogenesis.
