Overexpression of HER-2 in ovarian carcinomas

The transmembrane receptor encoded by the HER-2 cellular oncogene is amplif ied in several types of human carcinomas and provides an attractive therape utic target. Shown by immunohistology, <25% of newly diagnosed ovarian carc inomas express the HER-2 protein. However, now we report that this protein was expressed in all 20 tumor cell lines derived from stage III and IV ovar ian cancers as well as in tumor cells harvested from patients with malignan t ascites and in tumor samples taken at a second surgery, suggesting that c ells with excess expression may have a selective growth advantage. HER-2-po sitive ovarian carcinoma cells were shown to be sensitive to antibody-depen dent cellular cytotoxicity, and their in vitro proliferation was inhibited by anti-HER-2 MAb Herceptin. We postulate, therefore, that therapy which ta rgets HER-2 may be more efficacious in patients with ovarian carcinoma than indicated by the commonly low expression of HER-2 in tumors removed at the time of primary surgery.