The expression of p63 in actinic keratoses, seborrheic keratosis, and cutaneous squamous cell carcinomas

BACKGROUND. p63 is a tumor suppressor that likely plays a role in the development of squamous cell carcinomas (SCCs) and possibly premalignant and benign skin tumors. Little data is available on its expression in these tumors. OBJECTIVE. To study the keratinocyte expression profile of p63 in 17 SCCs, 7 actinic keratoses, 2 Bowens tumors, and 7 seborrheic keratoses. METHODS. Skin tumors specimens were stained with an antibody to p63. Quantitative and qualitative data was collected on the staining. RESULTS. There was a statistically significant increase in p63 staining of SCCs when compared with normal. Seborrheic keratoses and actinic keratoses showed a trend towards increased expression in the basal layer compared with normal skin. The pattern of expression showed diffuse staining in SCCs. In actinic keratoses and seborrheic keratoses the pattern was most prominent in the basal layer. CONCLUSIONS. p63 expression is greater and different in SCCs when compared with normal skin, actinic keratoses, and seborrheic keratoses. Interestingly seborrheic keratoses and Bowens lesions showed expression that was mostly restricted to the basal layer, however significant diffuse staining was also noted. Our results support the notion that p63 plays a role in cell differentiation and tumorigenesis of skin tumors.