Dermal oncogenicity study of 2-ethylhexyl acrylate by epicutaneous application in male C3H/HeJ mice

A carcinogenicity bioassay of 2-ethylhexyl acrylate (2-EHA) was conducted by applying 25 microliters 86.5%, 21%, or 2.5% 2-EHA in acetone three times a week to the clipped dorsal skin of male C3H/HeJ mice (80 per group) over their lifetime. Another group was treated with a 43% 2-EHA solution for 24 weeks and thereafter observed for lifetime (stop-test). An untreated group and a group that received only the diluent acetone served as controls. Treatment-related changes in the skin indicative of irritation (scaling, scabbing, hyperkeratosis, hyperplasia) were found in all 2-EHA-treated groups. These lesions were reversible in the 43% group immediately after treatment was stopped, and in the 2.5% group after the 11th week of treatment. Only in the 86.5% and 21% test groups showing chronic irritative skin damage was there a high incidence of nepolastic skin lesions (papillomas, carcinomas, and melanomas) with no dose dependency. In contrast, no skin tumors were found in the control groups, in the group treated with 2.5% 2-EHA for lifetime or in the group treated with 43% 2-EHA for about 6 months and observed for lifetime.