Immunohistochemical study of cyclooxygenase-2 and p53 expression in skin tumors

Overexpression of cyclooxygenase-2 (COX-2) has been demonstrated in various cancers, including experimentally promoted tumors, gastrointestinal cancers, breast tumors and skin tumors. The mechanism that controls COX-2 expression is not yet clear. Currently, it is reported that COX-2 expression is frequently associated with mutated p53 genes. The goal of this study was to evaluate the expression patterns of COX-2 and p53 in several skin tumors and their correlation. An immunohistochemical method was used to investigate the expression of COX-2 and p53 proteins on formalin-fixed, paraffin-embedded tissue specimens of squamous cell carcinomas (SCC), basal cell carcinomas (BCC), Bowen's disease (BD), actinic keratosis (AK) and porokeratosis. The expression of COX-2 increased in 50% (5/10) of SCC, 80% (8/10) of BCC, 40% (4/10) of BD, 50% (5/10) of AK, and 20% (2/10) of porokeratosis cases. The expression of p53 increased in 90% (9/10) of SCC, 70% (7/10) of BCC, 70% (7/10) of BD, 50% (5/10) of AK, and 40% (4/10) of porokeratosis cases. COX-2 positivity rates of the p53-positive skin tumors were 56%, 100%, 57%, 80% and 25% in SCC, BCC, BD, AK and porokeratosis, respectively. However, the correlation between p53 and COX-2 expression in skin tumors was not statistically significant (P > 0.05). Our results indicate that skin COX-2 and p53 may play roles in skin tumors, but that there is no apparent correlation between the two markers.