VSGP/F-spondin: a new ovarian cancer marker.

The discovery of genes that are overexpressed in ovarian cancers provides valuable insight into ovarian cancer biology and will lead to the development of more effective treatment strategies for combating this disease. To identify genes exhibiting ovarian- and ovarian cancer-specific expression, we generated four subtracted cDNA libraries from primary and metastatic ovarian adenocarcinoma tissues. 3,400 cDNA clones from these libraries were analyzed by microarray for tissue distribution and tumor specificity using 32 pairs of fluorophore-labeled cDNA samples from a variety of normal tissues and ovarian tumor tissues. cDNA clones showing elevated expression in ovarian tumors were identified by DNA sequencing with comparison to public databases, and the most promising candidates were further analyzed by quantitative real-time polymerase chain reaction and Northern blot. This systematic approach led to the identification of a number of genes including vascular smooth muscle growth-promoting factor (VSGP/F-spondin), a secreted protein previously identified and cloned from bovine and human ovary. VSGP/F-spondin protein was observed in ovarian carcinomas but not in normal ovarian epithelium by immunohistochemistry with a VSGP/F-spondin antibody. The expression profile of VSGP/F-spondin identifies this molecule as a potential diagnostic marker or target for developing therapeutic strategies to treat ovarian carcinoma.