GENETICS OF NEOPLASIA 



249 



mice and selecting for mammary gland tumors. Since that time many inbred strains 

 of mice have been developed, but most of the early ones were developed for studies on 

 cancer. Systems of matings are discussed by Drs. Green and Doolittle and will not be 

 mentioned, other than to point out that brother x sister and parent x offspring 

 matings have been used almost exclusively. Nor will definitions of an inbred strain, 

 or substrain, be given here since these have been published by the Committee on 

 Standardized Nomenclature. 220 



The introduction of these inbred strains constituted probably the greatest advance 

 in all cancer research. Genetically suitable material for the study of a wide variety 

 of neoplasms is now available. Table 50 lists these neoplasms in the mouse along with 



Table 50 

 Some suggested inbred strains for studies of neoplasms 



Neoplasm 



Strains 



Incidence of neoplasm 



References 



Mammary gland tumors C3H 

 A 



DBA 

 RIII 

 BALB/c 



CC57BR \ 

 CC57W J 



Almost 100 per cent in $$ 



High in breeding $$, low in virgin $$ 



High in breeding $$ 



High in breeding $$ 



Incidence low, but high following intro- 

 duction of mammary tumor agent 



Do not develop spontaneous mammary 

 tumors; 55 per cent after introduction 

 of mammary-tumor agent 



220 

 220 

 220 

 220 



Pulmonary tumors 



A 



SWR 

 BALB/c 

 BL 



90 per cent in mice living to 18 months 

 80 per cent in mice living to 18 months 

 26 per cent in ?$, 29 per cent in <$<$ 

 26 per cent in mice of all ages 



557 

 764 

 1073 

 814 



Hepatomas 



C3H 



C3Hf 



C3He 



85 per cent in males 14 months old 

 72 per cent in males 14 months old 

 78 per cent in males 14 months old 

 91 - 



per cent in breeding £3; 59 per cent 

 m virgin $$; 30 per cent in breeding 

 ??; and 38 per cent in force-bred $$ 



572 

 572 

 572 



Leukemia and other reti- C58 

 cular-cell neoplasms AKR 



C57L 



High leukemia 



High leukemia 



Hodgkins-like lesion, reticular-cell neo- 

 plasm Type B, approximately 25 per 

 cent at 18 months 



767 

 767 



Papilloma and carcinoma HR 

 of skin 



Papillomas occurred in all mice both 

 haired and hairless painted with 

 methylcholanthrene and the carcino- 

 matous transformation occurred in 

 most of the animals 



Most susceptible of 5 strains tested with 

 methylcholanthrene 



