Induction of squamous cell carcinoma in human bronchi transplanted into nude mice.

Segments of surgically resected human adult bronchi were xenotransplanted into the subcutaneous tissue of 35 BALB/c genetic background athymic nude mice with 3-methylcholanthrene placed in their lumina. Bronchial segments were removed 8 to 20 weeks after transplantation and preservation of the bronchial mucosa was confirmed in 26 segments. The most frequent change observed in the mucosa was goblet cell hyperplasia, followed by squamous metaplasia and dysplasia. Severe dysplasia or questionable squamous cell carcinoma in situ was noted at the site of the bronchial gland in a segment removed 8 weeks after transplantation, and invasive squamous cell carcinoma in a segment removed 15 weeks after transplantation. A difficulty in this work was the frequent earlier development of malignant tumors of mouse origin.