Cortactin and phosphorylated cortactin tyr421 and tyr466 expression in supraglottic laryngeal carcinomas and lymph node metastases

Abstract

Background: The most important adverse prognostic factor for laryngeal squamous cell carcinoma (LSCC) is the presence of cervical lymph node metastases. The supraglottic area of the larynx is richly supplied with lymphatics, and 25%-75% of supraglottic carcinomas metastasize in neck lymph nodes. Cortactin is a multidomain protein related to actin cytoskeleton regulation, podosome and lamellipodia formation, integrin signaling, axon guidance and extracellular matrix degradation. Cortactin is involved in metastasis formation because of its role in cell mobility. The present study focused mainly on the role of cortactin and phosphorylated cortactin (residues tyr421 and tyr466) expression and subcellular localization in primary supraglottic LSCCs and their cervical lymph node metastases. Methods: The immunohistochemical expression of cortactin, p-Y466-cortactin and p-Y421-cortactin was assessed in 38 primary supraglottic LSCCs and 10 lymph node metastases. The statistical approach included bootstrapping analysis. Results: Despite a significantly higher expression of cortactin in carcinoma cells than in adjacent normal laryngeal mucosa, no associations emerged between prognosis and the expression of cortactin or its isoforms in supraglottic LSCC. Statistical analysis found cortactin expression higher in less-differentiated LSCCs (p = 0.03). A significant direct correlation was found between cortactin and p-Y466-cortactin levels (p = 0.031), and between p-Y466-cortactin and p-Y421-cortactin levels (p = 0.001). Conclusions: Cortactin expression in carcinoma cells and its known involvement in the EGFR pathway suggest a role for this protein as a target for LSCC therapy. Further prospective studies are needed to investigate the potential of cortactin, p-Y466-cortactin and p-Y421-cortactin expression as markers of response to treatment (particularly EGFR-directed agents) in LSCC.