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

ABSTRACT

BACKGROUND: 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. AIM: To verify whether p50 and cortactin are useful differentiation markers to distinguish between subungual KA and well-differentiated SCC. METHODS: 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. RESULTS: 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. CONCLUSION: p50 and cortactin might be useful makers to distinguish between KA and well-differentiated SCC.