Immunohistochemical Expression of C-erb-B2 and Vimentin in Adenoid Cystic Carcinoma and Polymorphous Low-Grade Adenocarcinoma: A Comparative Study

BACKGROUND: The salivary glands tumors are relatively uncommon neoplasms of oral and maxillofacial region with an annual incidence of 2.2 to 2.5 cases per 100,000 in the United States. The aim of the present study was to assess the immunohistochemical expression of two genes, C-erb-B2 (also known as HER-2/neu) and vimentin, in adenoid cystic carcinoma and polymorphous low-grade adenocarcinoma to observe these tumor markers as predictors of grade and stage in salivary gland tumors. METHODS: Thirty consecutive cases, histologically diagnosed as epithelial salivary gland tumors, were included in the study. Fifteen cases were adenoid cystic carcinoma and the remaining cases were polymorphous low-grade adenocarcinoma. Immunohistochemical techniques were used to detect the expression of vimentin and Cerb-B2. RESULTS: We found that C-erb-B2 was expressed in all (100%) cases of adenoid cystic carcinoma and in 93.3% cases of polymorphous low-grade adenocarcinoma. Normal tissues did not show any staining pattern (p<0.001). The peak incidence of both neoplasms was observed between the fourth to sixth decades of life, males were affected more than females and the palate was the commonest affected site. There was no significant correlation between C-erb-B2 and vimentin expression with other factors except significant (p<0.05) positive correlation with gender. CONCLUSION: C-erb-B2 is expressed in both tumors compared with the controls suggesting its oncogenic potential. However, we did not find any significant association between C-erb-B2 or vimentin expression and the tumor grade or stage suggesting that these two may be important in oncogenesis but not in determining the tumor grade or stage.