[Tumors in CBA line mice caused by 1,2-dimethylhydrazine]

Female CBA mice were treated weekly with subcutaneous injections of 1,2-dimethyl-hydrazine (8 mg/Kg b. w.) for 38--40 weeks. All animals but one developed tumors, mainly of the uterus, and region and intestine. Uterine tumors were most likely endometrial sarcomas, although myometrial and vascular components were also present. Large tumors of the anal region were squamous cell or baso-squamous carcinomata, while small growths were sebaceous adenomas or basal-cell tumors. 1.2-dimethylhydrazine appears to be a more multipotent carcinogen for mice than for the rat. Uterine sarcomas are of special interest in view of their rarity in mice.