[The skin allograft reduces the incidence of mammary cancer in Co60-irradiated female mice].

Skin allografts were performed in 51 BALB/c female mice by means of an easy technique devised by the authors. The skin for the allografts was taken from C57BL/6 male mice. All the mice were homozygotic.

Active immunization against spontaneous tumors in mice.

The incidence of spontaneous tumors was studied in a group of 136 female mice and in another group of 138 females after a sublethal dose of total body irradiation. Of the nonirradiated mice 10.2% developed mammary tumors, and 8% developed lung tumors.

Evidence of oncogenic cofactors in radiation-induced tumors in mice.

Five groups of 587 inbred female mice (WHC) were studied to determine the incidence of tumors as affected by irradiation of different areas. A dose of 400 rad of 60Co was given to all the groups. One group of 166 mice was total body irradiated, another group of 90 mice was irradiated in the upper-third portion of the body, another group of 93 mice was irradiated in the lower two-thirds of the body, and another group of 90 mice was half body irradiated on the right side.