 In a study from 1991, lung precancerous and cancerous lesions were induced in Wistar rats by one intrabronchial injection of 3-MC.After 30 days, atypical hyperplasia of bronchiolar epithelium, adenoid hyperplasia or adenomas, and squamous cell carcinoma occurred in 15 (88.2%), 12 (70.6%) and 3 (17.7%) out of 17 rats respectively.After 60 days, the incidences were 15/18 (83.3%), 4/17 (23.5%) and 7/18 (38.9%).