Expression of proliferation-associated proteins (proliferating cell nuclear antigen and Ki-67 antigen) in Bowen's disease.

Abstract

Bowen's disease and invasive squamous cell carcinoma arising in Bowen's disease (Bowen's carcinoma) were investigated immunohistochemically with regard to their expression of proliferating cell nuclear antigen (PCNA) and the Ki-67 antigen. Both proliferation-associated proteins were found in all layers of the tumours, and were present in nuclei of any size and shape. The nucleoli lacked PCNA immunoreactivity, but they expressed the Ki-67 antigen. The PCNA labelling index was 36.9 +/- 12.6% in Bowen's disease (n = 16), and 40.7 +/- 11.0% in Bowen's carcinoma (n = 3). The Ki-67 antigen labelling index was 43.6 +/- 16.7% in Bowen's disease (n = 16), and 51.7 +/- 11.6% in Bowen's carcinoma (n = 3). Dyskeratotic cells were positive for PCNA and the Ki-67 antigen, suggesting that these cells are not in a post-mitotic state. We conclude that in dyskeratotic cells of Bowen's disease the cell cycle is interrupted by nuclear disorganization.