RESUMEN
BACKGROUND: p53 is a nucleoprotein encoded by a tumor suppressor gene. It's mutations are implicated in the genesis of a wide variety of malignant neoplasia including skin cancers. OBJECTIVE: To study the expression of the p53 protein in cutaneous squamous cell carcinoma (SCCs) and evaluate the relationships between this expression and sites, varying degrees of differentiation and amounts of apoptotic cells. METHOD: Sixty-seven tissue samples of SCCs from Songklanagarind Hospital obtained from January 1991 to December 1996 were examined by immunohistochemistry using polyclonal anti p53-CM1. (Novocastra Laboratories, Newcastle, England, dilution 1:700) RESULT: p53 Immunoreactivity was demonstrated in 26.87 per cent of SCCs. This was observed in 15/51 of sun-exposed cases and 3/16 of sun-protected cases (p = 0.401). The more differentiated the tumor, the less p53 staining was observed (p = 0.043). There was no association between p53 positivity and the amounts of apoptotic cells. CONCLUSION: The p53 expression is not related to the sun exposure. It does not represent a commitment to apoptosis. However, it may indicate the differentiation and/or proliferative status of the tumor cells.