Immunoelectron microscopical identification of the c-erbB-2 oncoprotein in patients with laryngeal squamous cell carcinoma

Summary roxidase-antiperoxidase (PAP) method was used for localization of the c-erbB-2 oncoprotein at the electron microscopical level in 15 patients with laryngeal squamous cell carcinoma. It was found that c-erbB-2 oncoprotein was present in 7 of 15 samples. Electron microscopical examination revealed expression of the c-erbB-2 oncoprotein both on the membrane of individual cells and in the cytoplasm. In 5 of the 7 cases of positive labeling, it was observed only on the plasma membrane of cells whereas in 2 cases, there was also cytoplasmic staining. Reaction product was associated with endoplasmic reticulum, and the nuclear envelope and was scattered throughout the cytoplasm on ribosomes. Control incubations using normal rabbit serum instead of the primary antibody showed no labeling. A significant correlation between c-erbB-2 oncoprotein and pathological characteristics such as nodal status and histological grade was not found.