Late somatic effects in syngeneic radiation chimaeras. III. Observations on animals repopulated with irradiated marrow.

Lethally-irradiated mice received a graft of bone-marrow cells obtained from intact syngeneic animals or from donors pre-irradiated with 200 or 400 rad. The numbers of haemopoietic cells injected were sufficient to give a high percentage of recipients which survived short-term bone-marrow failure. Epidemiological and pathological observations on long-term surviving animals showed an increased incidence of nephrosclerosis and of systemic or solid tumours following different relationships with the radiation dose given to the cells. These data are discussed within the framework of an experimental model system which might allow estimates of incidence of some neoplastic diseases according to cellular hypotheses of tumour induction.