Tumorigenesis at a predetermined oral site after one intraperitoneal injection of N-nitroso-N-methylurea.
Tumors in the soft tissues of the oral cavity of rats developed at predetermined sites as a result of a combination of an intraperitoneal injection of a direct-acting carcinogen. N-nitro-N-methylurea, and a continuous irritation of the buccal mucosa by a stainless steel wire. The incidence of histologically malignant tumors was significantly higher in the irritated area than in any other area of the body. These results constitute evidence for a carcinogenic mechanism whereby the cells that develop into tumors may require the promotional effect of a nonspecific, nonmutagenic stimulus.
D000818:Animals; D002455:Cell Division; D003043:Cocarcinogenesis; D007274:Injections, Intraperitoneal; D007509:Irritants; D008297:Male; D008770:Methylnitrosourea / Q000008:administration & dosage*; D009062:Mouth Neoplasms / Q000139:chemically induced*; D009374:Neoplasms, Experimental / Q000139:chemically induced; D009607:Nitrosourea Compounds / Q000008:administration & dosage*; D051381:Rats
D007509:Irritants; D009607:Nitrosourea Compounds; D008770:Methylnitrosourea