Abstract: Objective：To detect the expression of Smad7 in the lesions of seborrheic keratosis, actinic keratosis, and basal cell carcinoma. Methods：The levels of Smad7 in the lesions of seborrheic keratosis, actinic keratosis, basal cell carcinoma and normal controls (30 lesions in each group), were detected by immunohistochemical staining. Results：Smad7 was positive in 23 seborrheic keratosis lesions, 23 actinic keratosis lesions and 28 basal cell carcinoma lesions. The positivity rates of Smad7 cells were 31.0±23.0%, 32.7±26.3% and 62.6±32.1% respectively, which were all higher than that in the controls (6.7±5.0%). Conclusions：Smad7 may play a role in the pathogenesis of seborrheic keratosis, actinic keratosis and basal cell carcinoma.

Key words: seborrheic keratosis, actinic keratosis, basal cell carcinoma, Smad7, immunohistochemistry