to test the feasibility of employing a combined lung adenoma / skin papilloma assay for broader detection of chemical carcinogenesis than that realized with either bioassay done separately , four strains of mice , sencar , balb / c , a / j , and icr - swiss , were administered carcinogens either by the oral or intraperitoneal ( ip ) routes . the carcinogens administered were ethyl carbamate ( ec ) , benzo(a)pyrene [ b(a)p ] , n-[4-(5-nitro-2-furyl)thiazolyl]formamide ( fanft ) , and acrylamide ( acr ) . 
 starting 2 weeks later , 1 to 5 micrograms ( depending on strain ) of 12-o - tetradecanoylphorbol-13-acetate ( tpa ) in 0.2 ml acetone / mouse was applied three times weekly to the shaved back for 20 weeks . 
 all strains displayed increases in the yield of lung adenomas in response to ec at 32 weeks . 
 b(a)p increased lung adenomas in only the sencar and a / j strain . 
 only the sencar and icr - swiss mice gave positive responses in the skin . 
 in the sencar mice , positive response was seen with all four chemicals , however , fanft gave an inconsistent response . 
 the icr - swiss mice responded with an increased skin papilloma yield only to ec . in a separate experiment involving only sencar mice , 
 animals were treated with a single oral dose of diethylnitrosamine ( den ) followed by triweekly application of 1.0 microgram tpa . 
 this treatment resulted in 51/57 animals developing lung adenomas vs. 5/57 in the control animals . 
 no treatment - related skin tumors resulted with den . 
 histopathologically confirmed lesions indicate that the spectrum of chemicals detected in the sencar mouse may be broadened using a combined bioassay that examines both lung and skin responses.imagesfigure 1.figure 2.figure 3.figure 4.figure 5 .