The expression of ligands and receptors of the EGF family was examined in the several histologic stages of human ovarian carcinogenesis. Primary and metastatic ovarian cystadenocarcinomas, ovarian carcinomas of low malignant potential (borderline tumors), benign ovarian cystadenomas and normal ovaries were compared for immunoperoxidase detection of the ligands Epidermal Frowth Factor (EGF), Transforming Growth Factor-Alpha (TGF-a), amphiregulin (AR), cripto, and the receptors Epidermal Growth Factor Receptor (EGFR) and c-erbB-2. This matrix analysis of these EGF family members indicated no specific pattern of ligand or receptor detection with a specific ovarian histologic category except in the case of AR and TGF-a. Amphiregulin immunostaining was detected almost exclusively in borderline tumors. TGF-a differed most from EGF in the borderline tumors, in which EGF was umiformly positive while TGF-a was least frequently positive. However, TGF-a immunoreactivity in the absence of coexpression of cripto or EGF appeared to be associated only with adenocarcinomas of high grade and stage. For example, all six of the stage I/II adenocarcinomas were immunoreactive for at least two of three of cripto, EGF, or TGF-a; in contrast, six of seven of the stage III carcinomas were immunopositive for only TGF-a. Cripto staining was more common in normal ovarian surface epithelium than in cystadenomas of cystadenocarcinomas. In respect to receptor detection, both EGFR and c- erbB-2 immunopositivity was high in all histologic categories, with the exception that EGFR was detected in only half of the cystadenomas. The preferential association of AR immunoreactivity in ovarian carcinomas of low malignant potentiall was confirmed using AR mRNA detection by the RT-PCR method. However, in addition, several well- differentiated adenocarcinomas of both serous and mucinous histology expressed AR mRNA. This suggests that AR, at the message level at least, correlates most closely with a high degree of epithelial differentiation, and not histologic category or biologic behavior. Using RT-PCR amplification techniques to semi-quantify mRNA, the expression of these EGF-related genes was also compared in three ovarian carcinoma cell lines and their normal counterpart, ovarian surface epithelial (OSE) cell strains. Although mRNA expression was not detected for any of these ligands or receptors in three OSE cell strains even when grown in the presence of serum, two carcinoma cell lines even when grown in serum-free medium concurrently and simultaneously expressed high levels of mRNA for TGF-a, EGFR, and erbB-2, which is consistent with an autocrine involvement of these three gene products in in vitro ovarian epithelial cell growth.
