Expression of c-erbB-2 in Human Pancreatic Adenocarcinomas

Abstract

The c-erbB-2 (neu) gene encodes a transmembrane phosphoglycoprotein (p¹⁸⁵^erbB-2) which resembles a growth factor receptor-like molecule closely related to the epidermal growth factor receptor. Overexpression of c-erbB-2 induces cell transformation in vitro. Poorer survival rates and elevated recurrance rates following treatment have been shown in patients whose breast adenocarcinomas demonstrate increased c-erbB-2 expression. Using immunoprecipitation and immunoperoxidase staining, we surveyed human cell lines for p¹⁸⁵^erbB-2. Cell lines from most tumor types (e.g. lymphomas, neuroblastomas, melanomas) demonstrated negligible p¹⁸⁵^erbB-2; however, 3 of 6 pancreatic cell lines overexpressed c-erbB-2. Southern blot analysis revealed that c-erbB-2 was amplified in two of these cell lines and was both rearranged and amplified in one of them. Based on these findings, we examined tissue sections from archival specimens of primary human pancreatic adenocarcinomas. A substantial proportion of specimens had increased p¹⁸⁵^erbB-2, as judged by increased immunostaining of the tumor cells. In such pancreatic tumors pi85 erbB-2 _may contribute to the malignant phenotype and could provide a target for immunodiagnostic or immunotherapeutic strategies.