Induction of Carcinoma and Papilloma of the Tracheobronchial Mucosa of the Syrian Hamster by Intratracheal Instillation of Benzo[α]-pyrene

Abstract

The effect of benzo[a]pyrene on the tracheobronchial mucosa of Syrian hamsters was studied. The carcinogen was administered by intratracheal instillation either as 1) a suspension in an aqueous solution of polyoxyethylene sorbitan monostearate (Tween 60) or 2) a solution in olive oil. Repeated intratracheal instillation of benzo[a]pyrene suspended in Tween 60 induced papillomas and carcinomas of the trachea, main-stem bronchi, and bronchioles. The mucosa of the tracheobronchial tree revealed, in addition to the tumors, a variety of atypical epithelial alterations. It is not known whether these changes might have progressed to tumors, had the hamsters lived longer. Histologically some of the carcinomas resembled the squamous-cell bronchogenic carcinoma of man. Neoplastic lesions were not induced in animals that received benzo[a]-pyrene in olive oil. The tumor-promoting action of Tweens and their ability to increase the permeability of mucous membranes may account for the successful induction of cancer with benzo[a]pyrene in Tween 60.