抄録
Since January, 1958, a subline of C3H/He mice (Dr. Heston, N. I. H.) has been introduced at the Institute for Cancer Research, Osaka University Medical School. This strain has been continued by brother-sister mating and at the present, November, 1966, has reached the 37th generation. Old male mice develop spontaneous hepatomas as high as 34%, and females have a high incidence of spontaneous mammary tumors (92.5% for breeders, at 35.9 weeks in average and 78.8% for virgins at 46.1 weeks in average) . Detailed data of occurrence of the mammary tumor of this strain from 18th to 30th generations have been listed for comparison of related C3H sublines of mice such as C3H/He, C3H/HeNSa, C3H/An, and C3H/Bi. It has been proposed that this strain of mice has been established as a subline of C3H/He and that from now on we designate this strain of mice as C3H/HeOs.
