The nuclear factor kappa B p50 subunit and cortactin as markers to distinguish between keratoacanthoma and well-differentiated squamous cell carcinoma

Abstract

Distinguishing keratoacanthoma (KA) from well-differentiated squamous cell carcinoma (SCC) is sometimes difficult. Recent evidence indicates that the nuclear factor kappa B p50 subunit (p50) and cortactin might be useful to distinguish between these two conditions. To verify whether p50 and cortactin are useful differentiation markers to distinguish between subungual KA and well-differentiated SCC. Immunohistochemistry using p50, cortactin and Ki-67 was performed on 20 patients with KA and 20 patients with facial well-differentiated SC. Ki-67 staining was also evaluated and scored. Both p50 and cortactin had higher levels of expression in KA than in SCC. Both were localized to the basal-cell layer of KA, whereas they were scattered without polarity throughout the SCC lesions. Although the Ki-67 index was not significantly different between KA and SCC, the staining pattern also showed loss of polarity in SCC. p50 and cortactin might be useful makers to distinguish between KA and well-differentiated SCC.