Comparison of Methylcholanthrene Hyperplastic Epidermis with Benign Hyperplastic Epidermis in Healing Wounds*

It is h igh ly desirable to be able to recognize lesions l ikely to develop into cancer. One reason for so m u c h difference of op in ion is that the p rob lem has not been clarified by exper imenta l work on animals . A major research project in the Barnard Free Skin and Cancer Hosp i ta l is the in tegra t ion of changes that occur in ep ide rma l me thy lcho lan th rene carcinogenesis of mice. Ep idermis , r endered hyperplastic by methylcholanthrene , will, after a sufficient n u m b e r of properly spaced paint ings in the r ight concentrat ion, give rise to s q u a m o u s cell carcinomas in a fairly h igh percentage of cases. Consequen t ly it may be assumed that it has been r ende red more surely precancerous than any lesion natural ly occurr ing in the h u m a n body. T h e other de s ide r a tum is to create for compar i son another epide rma l hyperplasia of equal thickness in mice which is not precancerous. This can easily be done by excising small pieces of skin and by selecting the regenerating epithel ial edges. Since these exper imenta l condit ions afford ample oppor tun i ty for the compar ison of precancerous and regenerat ive ( b e n i g n ) ep idermal hyperplasia, an intensive search has been c o m m e n c e d for differences be tween them. W e th ink that in this way we are likely to be able to detect in the hyperplasia the essential precancerous modificat ions.