Tumor promotion by abrasion induced epidermal hyperplasia in the skin of mice.

Regenerative epidermal hyperplasia produced by repeated abrasion every 21 days of the skin of female mice after initiation with 7, 12-dimethylbenz(a)anthracene results in the appearance of epidermal tumors. Full thickness wounds, approximately 2 cm in length, made every 14 days in mouse skin initiated with 7, 12-dimethylbenz(a)anthracene also results in the appearance of epidermal tumors adjacent to the wound edge. Repeated abrasion or wounding of normal female mouse skin does not result in the appearance of epidermal tumors. Repeated plucking of initiated mouse skin, which produces a milder epidermal hyperplasia than abrasion, does not result in the appearance of tumors. The data demonstrate that regenerative epidermal hyperplasia, of a sufficient intensity, can act as a tumor promoter.