Abstract

It has become clear that mutation and subsequent accumulation of nuclear p53 protein is an almost universal step in the development of human cancers. We have immunohistochemically studied p53 expression in 112 benign and malignant epidermal neoplasms using monoclonal anti-p53 protein antibody DO7. p53 immunoreactivity was not detected in any benign epidermal tumors including verrucae vulgaris, seborrheic keratoses, and keratoacanthomas. In contrast, positive staining was observed in 5/13 (38%) of squamous cell carcinomas, 2/10 (20%) of basal cell carcinomas, 14/32 (44%) of Bowen's disease, as well as 8/13 (62%) of solar keratoses. p53 expression was absent in all 10 cases of extramammary Paget's disease thus far examined. The results suggest that the mutation of p53 gene and an abnormal expression of nuclear p53 protein may be a common event in malignant and premalignant epidermal neoplasms.