Abstract:

Objective To investigate the expression of p73 protein in normal skins and lesions of benign and malignant epidermal tumors. Methods By immunohistochemical staining, the expression of p73, p53 and Ki67 was examined in 19 cases of seborrheic keratosis (SK), 16 basal cell carcinoma (BCC), 11 Bowen's disease (BD), 5 squamous cell carcinoma (SCC),as well as in 10 normal skin controls. Results In normal skin, p73 protein was found to distribute in the basal cells of the epidermis, basal cells in the outer root sheath of the hair follicles, and the germinative cells in the sebaceous glands. p73 was expressed strongly in the basal cell-like cells of BCC and SK lesions, and in the atypical cells of BD lesions, but weakly or even negatively in the tumor cells of SCC lesions and the squamous cell-like cells of SK lesions. There was significant difference in the expression of p73 among the SK, BD, BCC and SCC lesions (H=12.71,P<0.01); the strongest expression was found in the BCC lesions. Comparing all the tumors evaluated, significant difference was found in the expression of Ki67 antigen (H=14.12, P<0.01) but not in the expression of p53 (H=2.058, P<0.01). No correlation was observed between the p73 and p53 distribution or between the p73 and Ki67 expression. Conclusion The present study shows that p73 protein is likely to play an important role in epidermal differentiation.

Key words: Protein p73, Protein p53, Antigen Ki-67, Carcinoma, basal cell, Carcinoma, squamous cell, Bowen’s disease, Keratosis, seborrheic