Tumorigenesis in F1 offspring mice following paternal 12.5 cGy 252Cf fission neutron irradiation.

Experiments were conducted to determine whether following genetic damage at germ cell stages induced by paternal exposure to 252Cf fission neutron could lead to tumorigenesis in the offspring. Seven-week-old C3H/HeNCrj male mice were irradiated with 252Cf fission neutrons, at doses of 0 and 12.5 cGy and were mated with nine-week-old C57BL/6NCrj females two weeks after the exposure. Three weeks later, it was found that the proportion of abnormal sperm in the 12.5 cGy-irradiated males was higher than that of 0 cGy-irradiated group. Embryo lethality among the F1 offspring was also found to be higher in the 12.5 cGy group than in the 0 cGy group, while the incidence of liver tumors among the F1 offspring increased in males only. These results suggest that the paternal 12. 5 cGy radiation exposure may have caused genetic transmission of liver tumor-associated traits, which is in line with findings that show steep increase in incidence of tumorigenesis in B6C3F1.