Cancer induction in subcutaneously implanted bronchial autograft of a dog by 3-methylcholanthrene

An experimental cancer induction in subcutaneously autoimplanted bronchial grafts in dogs was studied. After successful bronchial autografting, 3-methylcholanthrene or 3,4-benzo[a]pyrene suspended in sterile saline solution containing 1% carboxymethylcellulose was injected into the lumen. Twenty-eight weeks after this treatment, an invasive squamous cell carcinoma with concomitantly existing atypical squamous metaplasia was found in one dog by histological examination. Squamous cell metaplasia was also observed in two other dogs at 24th experimental week. Cytological examination revealed the findings corresponding to these epithelial changes. Remaining 15 dogs are still living and under observation.