Abstract: Objective To investigate the expression of bcl-2 and PCNA in mixed tumor of skin. Methods Bcl-2 and PCNA expression in 12 cases of mixed tumor of skin were studied using immunohistochemical S-P method and double-staining. Results Positive reactions of bcl-2 and PCNA were observed in all cases. PCNA staining was positive in tumor cells lining cystic and duct-like structures in tumor nests, but bcl-2 staining was positive in epitheloid tumor cells. Most tumor cells with bcl-2 were PCNA negative and vice versa. Conclusion Aberrant expression of bcl-2 and PCNA in mixed tumor of skin may play a role in tumorigenesis.

Key words: Mixed tumor of skin, Proto-oncogene proteins bcl-2, Proliferating cell nuclear antigen