Tumorigenesis at a predetermined oral site after one intraperitoneal injection of N-nitroso-N-methylurea

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Science  11 Jun 1982:
Vol. 216, Issue 4551, pp. 1235-1237
DOI: 10.1126/science.7079755


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.