Mice obtained from a commercial supplier were found to have a very high incidence of lung tumors, whereas the progeny of the same mice bred in this laboratory in stainless steel cages had a low incidence. The use by the animal supplier of creosoted wooden cages for breeding was the suspected cause for the high tumor incidence in the parent mice.
Creosote applied to the skin of mice led to a high incidence of both skin and lung tumors. Mice reared in creosoted wooden boxes and also painted with creosote had a higher lung tumor incidence than mice reared in metal cages and painted with creosote.
In a second experiment it was shown that quantities of creosote too small to cause skin tumors were nevertheless effective in giving rise to lung adenomas.
This was supported in part by grants from the Alexander and Margaret Stewart Trust Fund and from the American Cancer Society.
A preliminary report of this work was presented at the Annual Meeting of the American Association for Cancer Research, April, 1958.