IMMUNOGENETICS OF TUMOURS IN CHIMERAS 16$ 



of the experimental mouse sarcomas, particularly those induced 

 by polycyclic hydrocarbons, grow progressively at the site of 

 the primary tumour formation, or at the site of transplantation, 

 but only a few produce metastasis. Hence, attempts to study 

 experimentally factors involved in the formation of tumour 

 metastasis in mice have been very limited. Experiments on trans- 

 plantation of tumours in various combinations of radiation 

 chimeras seem to have furnished a new system, for the experi- 

 mental analysis of this phenomenon. All sarcomas used in our 

 experiments were of the " non-metastatic " type, i.e. they did not 

 form progressive metastasis when grafted either subcutaneously 

 or intramuscularly in normal, non-irradiated mice. However, 

 when these tumours were grafted to radiation chimeras, a 

 regular appearance of metastasis was observed in the inguinal, 

 brachial, and axillary lymph nodes. The results, summarized in 

 Tables II and III, show that sarcoma Cio, of C3H origin, developed 



Table II 



Tumour metastasis produced in radiation chimeras by sarcomas Cio 



AND MCiM 



