The proliferative properties of tumor cells differentially correlate with the host immune responses in anogenital Bowen's disease

Bowen's disease is a squamous cell carcinoma in situ that rarely invades into the underlying dermis. In order to evaluate the relationship between the cytological properties of the tumor cells and the host immune response, we have examined the expression of p53 and proliferating cell nuclear antigen (PCNA), and the number of mitotic cells, clumping cells, koilocytes, Langerhans cells (LCs) and dermal lymphoid cell infiltration in 18 cases of anogenital Bowen's disease. When compared with normal anogenital skins (n= 10), a statistically significant number of p53-positive cells, PCNA-positive cells, mitotic cells, clumping cells, koilocytes and dermal lymphoid cells was observed in the cases of Bowen's disease. Importantly, there existed a very strong correlation between the number of PCNA-positive tumor cells and the number of infiltrated dermal lymphoid cells. Moreover, the number of mitotic cells significantly correlated with the number of intratumoral LCs. The in situ hybridization technique for human papilloma virus (HPV) demonstrated that the HPV-infected Bowen's disease showed a similar histological and immunohistological pattern as the HPV-non-infected counterparts, except for increased koilocyte formation and decreased p53 positivity. The present data suggest that the proliferative activity of Bowen's disease significantly correlates with the host immune reaction, and that the host immune system may differentially recognize the different cytological properties of tumor cells in the Bowen's disease.