Ki-67 and p53 expression in cutaneous Bowen's disease: an immunohistochemical study of fixed-embedded tissue sections

The monoclonal Ki-67-specific MIB-1 and p53 protein-specific DO-1 antibodies were used to identify proliferating cell fractions on microwave-pretreated paraffin sections of 7 cutaneous Bowen's disease specimens. A high Ki-67 score was characteristic of all cases examined, and significant p53-positivity was seen in 4 cases. In the peritumoral, histologically normal epidermis, Ki-67- and p53-positive cells were frequently present, in one case with very high scores (89% as well as 82%, respectively). These findings indicate an increase in the proliferative activity of the Bowen cells (high Ki-67 score) and that p53 mutations are frequently found in this disease. The p53 expression was not related to the Ki-67 score. The expression of Ki-67 and p53 in morphologically normal epidermal cells is also discussed. The histologically normal epidermal cells expressing p53 and Ki-67 antigens may correspond to pre-malignant clones.