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

ABSTRACT 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.