Carcinogenicity of 8-nitroquinoline in Sprague-Dawley rats.

8-Nitroquinoline was added to the semisynthetic diet of outbred Sprague-Dawley rats for 48 weeks. Squamous cell carcinomas of the upper digestive tract (tongue and esophagus), but especially of the forestomach, occurred among the higher concentration groups. Squamous cell carcinoma of the forestomach occurred in 3 of 11 (27.3%) rats in the 2500 ppm group and 7 of 35 (20.0%) rats in the 1000 ppm group. Three cases of lung adenoma were also observed in the 2500 ppm group. Results clearly indicate that 8-nitroquinoline is carcinogenic in rats when administered orally in a semisynthetic diet.