Induction of malignant bone tumors in rats by 1-(2-hydroxyethyl)-1-nitrosourea

Forty male MRC-W rats were treated chronically with 1-(2-hydroxyethyl)-1-nitrosourea in drinking water (total dose, 330 mg/rat). Fifteen rats (38%) developed osteogenic osteosarcomas or chondrosarcomas of the lower vertebrae. This was the first time that an orally administered organic compound induced a high incidence of these tumors.