HER2/neu expression in adenoid cystic carcinoma of salivary gland origin:: an immunohistochemical study

Background: Adenoid cystic carcinoma (ACC) is a malignant tumor of salivary gland origin, which is characterized by a high rate of local recurrence and distant hematogenous metastasis. Despite aggressive surgical treatment and radiotherapy, the patient's long-term prognosis is dismal. Prompted by recent studies on the amplification of the oncogene HER2/neu in salivary gland tumors, we analyzed the immunohistochemical overexpression of HER2/neu in salivary glands ACC. If the tumor exhibits overexpression of HER2/neu, then treating it with the anti-HER2/neu therapeutic agent, Herceptin (Trastuzumab, Genentech, CA), could be considered. Methods: The study comprised of 32 samples of formalin-fixed, paraffin-embedded specimens. All laboratory procedures and scoring criteria were performed according to currently approved FDA methods. Results: HER2/neu overexpression was found in only five (16%) cases. Four cases (13%) scored 1+ and one case (3%) scored 2+. Conclusions: The low prevalence of HER2/neu overexpression in ACC limits the clinical utility of Herceptin therapy for salivary gland ACC.