c-erbB-2 oncoprotein expression and amplification in pleomorphic adenoma and carcinoma ex pleomorphic adenoma: relationship to prognosis.

Abstract

The c-erbB-2 protooncogene has been shown to be overexpressed and/or amplified in carcinomas of the breast, ovary, pancreas, and other organs. Several studies of human breast carcinoma noted an association of c-erbB-2 overexpression and amplification with poor prognosis. Recent studies have demonstrated c-erbB-2 protein expression in a variety of salivary gland neoplasms, most notably pleomorphic adenoma (PA), carcinoma ex pleomorphic adenoma (CAexPA), and adenocarcinoma. In this study, we analyzed c-erbB-2 expression in 15 PAs and 13 CAexPAs, using immunohistochemistry. In addition, differential polymerase chain reaction was used to evaluate c-erbB-2 gene amplification in these tumors. Low-level c-erbB-2 immunoreactivity was detected in three of 15 PAs. Among the CAexPAs, low-, intermediate-, and high-level immunoreactivity was seen in two, three, and two cases, respectively. The only cases showing c-erbB-2 amplification were the two CAexPA cases with high-level immunoreactivity. Based on statistical analysis of the 10 CAexPA patients with known outcome, no significant association of prognosis with c-erbB-2 expression or amplification was apparent.