Lysyl Oxidase Expression in Adenoid Cystic Carcinoma and Pleomorphic Adenoma

Objectives: Lysyl oxidase (LOX) oxidizes lysine residues in extracellular collagen and elastin. LOX increases the strength of the extracellular matrix and plays an important role in tumor development and metastasis. It has been reported that increased LOX protein and RNA are found in head and neck squamous cell carcinoma. Moreover some studies regard LOX as a prognostic marker of oral and oropharyngeal squamous cell carcinoma. However there has not been any report on LOX expression or its potential role in salivary gland tumors. Adenoid cystic carcinoma (ACC) is rare malignant tumor of salivary gland. Histologic feature of ACC is very unique. Perineural invasion and metastasis are often seen in microscopic examination. The purpose of this study is to examine the expression intensity of monoclonal antibody to LOX on ACC and pleomorphic adenoma (PA), and to evaluate the difference between those tumors.
Methods: We investigated LOX expression in 39 cases of ACC in salivary gland and compared it to those of PA using immunohistochemical staining method.
Results: Whereas ACC revealed more cases that showing high staining intensities for LOX, PA showed low staining intensities. Significantly increased LOX expression was found in the cases of ACC when compared to those of PA (P = 0.000).
Conclusions: Lysyl oxidase expression is increased in ACC than in PA.