Epithelial Proliferative Lesions in the Nasal Cavities of c-Ha-ras Transgenic Mice

Abstract

In a study to collect background data using c-Ha-ras transgenic mice (rasH2 mice), epithelial proliferative lesions were observed in the nasal cavities of the animals with or without administration of a single intraperitoneal dose of N-methyl-N-nitrosourea (MNU). These proliferative lesions occurred most frequently in the ventral meatus of the incisive papilla (nasal cavity in the specimen). Most of the proliferative lesions were a polypoid or papillary form consisting mainly of an epithelium resembling a squamous epithelium. In addition, administration of MNU tended to increase the incidence of proliferative lesions. Therefore, in carcinogenicity studies using rasH2 mice, we may come across epithelial proliferative lesions in the nasal cavity.