Prognostic Significance of New Immunohistochemistry Scoring of p53 Protein Expression in Cutaneous Squamous Cell Carcinoma of Mice

Abstract

This study was conducted to investigate the prognostic value and therapeutic response of treatment modalities on p53 protein expression and AgNOR index in squamous cell carcinoma (SCC). Furthermore, based on data, we proposed a new p53 immunohistochemistry (IHC) scoring system. Sixty albino mice were given 7,12-dimethylbenz[a]anthracine (DMBA) and 12-O-tetradecanoly Phorbol-13-acetate (TPA) to produce skin tumors. The retinoids were given after the development of tumors. p53 immunohistochemical and AgNOR staining was performed on the sections taken before and after the retinoid administration. p53 protein was expressed in 31 of the lesions (60.8%). AgNOR index was high in all 51 (100%) of the pretreated lesions. There was a marked decrease in the expression of p53 protein in 16/51 (31.4%) and AgNOR index in 36/51 (70.6%) in post-treated mice. There was no decrease in the expression of both markers in mice harboring malignant neoplasms. p53 IHC scores were 0, I, and II in epidermal hyperplasia, papilloma, and dysplasia, respectively, while they were II, III, IV, and V in SCC in situ, well-differentiated, moderately differentiated, and poorly differentiated SCCs, respectively. Alteration of p53 and AgNOR index occured during the development of SCC. The p53 IHC scores are directly related to the grades of malignancy. Both markers might be used as a supportive tool with routinely performed Hematoxylin and Eosin staining and may help in the diagnosis of SCC. The newly proposed p53 IHC scoring system will help histopathologists in making their differential diagnosis among benign, premalignant, and malignant lesions. It will also help the oncologists to assess the prognosis and effectiveness of their chemotherapy.