HEPSIN, A CELL-SURFACE SERINE-PROTEASE IDENTIFIED IN HEPATOMA-CELLS, IS OVEREXPRESSED IN OVARIAN-CANCER

Extracellular proteases mediate the digestion of neighboring extracell ular matrix components in initial tumor growth, allow shedding or desq uamation of tumor cells into the surrounding environment, provide the basis for invasion of basement membranes in target metastatic organs, and are required for release and activation of many growth and angioge nic factors, We identified overexpression of the serine protease hepsi n gene in ovarian carcinomas and investigated the expression of this g ene in 44 ovarian tumors (12 low malignant potential tumors and 32 car cinomas) and 10 normal ovaries, Quantitative PCR was used to determine the relative expression of hepsin compared to that of beta-tubulin, T he mRNA expression levels of hepsin were significantly elevated in 7 o f 12 low malignant potential tumors and in 27 of 32 carcinomas. On Nor thern blot analysis, the hepsin transcript was abundant in carcinoma b ut was almost never expressed in normal adult tissue, including normal ovary, Our results suggest that hepsin is frequently overexpressed in ovarian tumors and therefore may be a candidate protease in the invas ive process and growth capacity of ovarian tumor cells.