Expression of epidermal growth factor receptor in plutonium-239-induced lung neoplasms in dogs

The expression of epidermal growth factor receptor (EGF-R) was examined in canine lung tumors and in proliferative epithelial foci induced by plutonium-239 to determine if EGF-R was associated with specific neoplastic phenotypes or putative preneoplastic lesions. Seventeen (47%) of 36 canine lung tumors expressed EGF-R. Of these 17 tumors, three tumors hybridized with an erb-B RNA probe, which identified activated cell oncogenes. The expression of EGF-R was not correlated with tumor etiology, e.g., spontaneous versus radiation induced, but did correlate with specific histologic phenotypes. Nineteen (15%) of 127 proliferative epithelial foci in the canine lungs also expressed EGF-R. The phenotypic specificity demonstrated for EGF-R in canine lung tumors parallels that previously shown in human lung tumors. This finding, in addition to the identification of EGF-R in nonneoplastic proliferative lung lesions, indicates that radiation-induced lung tumors in the dog may be a useful animal model to investigate the role of EGF-R in lung carcinogenesis.