Changes in epidermal hydroxyproline and tyrosine accompanying induced epidermal carcinogenesis.

A marked and progressive decrease in epidermal hydroxyproline accompanied in duced epidermal carcinoma by methylcholanthrene in C3H mice. A decrease was also noted in the benzene-treated controls; but this was reversible, whereas the effect pro duced by the carcinogen was not. A progressive increase in epidermal tyrosine was ob served which was more marked in the carcinogen-treated animals than in the controls. Acid hydrolysates of the carcinogen-treated skins produced a darker, humin-like colora tion than did those of the controls. The possible origin of this is discussed. The results are interpreted in terms of the sensitivity of fibroblasts to methylcholanthrene.