A pathological study of spontaneous tumors in SPF Ktc : ICR mice

SPF Ktc : ICR 마우스의 자연발생 종양에 대한 병리학적 연구

The study was carried out to obtain the basic data for types, incidence and histopathological features of the spontaneous tumors of the specific pathogen free (SPF) Ktc : ICR mice bred in a barrier system in Technology Research Center, Korea Research Institute of Chemical Technology. One hundred of the mice consisted of 50 males and 50 females were examined for 18 months. 1. The overall incidence rate of spontaneous tumors was 51(51%) of 100 heads tested. The male mice showed slightly higher incidence(28%) than the female(23%), and the incidence rate and the number of affected organs were increased with the increasing age of mice. 2. The incidence rate of primary tumor was 59(59%) of 100 heads tested, consisted of 30 cases (50.8%) of benign tumors and 29 cases(49.2%) of malignant tumors. Among the malignant tumors twenty cases were metastasized to various organs. 3. In tumor incidence rates by systems and organs, the male mice showed the high incidence rate in the liver (18%), hematopoietic system (16% ) and lung (14%), while the female mice, in the hematopoietic system(18%), lung(12%), liver(8%) and uterus(8%). 4. The tumors showing the particularly low incidence rates (<1.0%) were rhabdomyosarcoma in the skeletal muscle, malignant schwannoma in the peripheral nerve, cortical adenoma in the adrenal gland, transitional cell carcinoma in the urinary bladder, tubular cell adenoma in the kidney and adenoma in the pituitary gland and harderian gland.