The expression of the c-erbB-2 receptor protein in glandular salivary secretions

Abstract
As the maintenance medium of the oral cavity, saliva is secreted from exocrine glands that include the parotid, submandibular, sublingual, and minor salivary glands. Considering that saliva is a fluid suffused with protein, it is possible that the solubilized by-products of oncogenic expression may be present in saliva. Recent studies suggest the presence of solubilized extracellular domain portion of the c-erbB-2 protein in serum, nipple aspirates, and saliva. As a consequence, the purpose of this study was to determine the presence and concentration of c-erbB-2 in major salivary gland secretions. Fifteen healthy women had serum, stimulated whole (SWS), parotid (SP), and submandibular/sublingual (SS) salivary secretions collected. The specimens were analyzed for c-erbB-2 using enzyme linked immunosorbent assays (ELISAs). Western blots using c-erbB-2 were also performed on these specimens. The ELISAs revealed the presence of c-erbB-2 in SWS (24.50 Units/ml), SP (19.66 Units/ml), SS (15.59 Units/ml) and serum (1472.15 Units/ml). Western blots confirmed the presence of these 185 kDa proteins. These results suggest that the protein, c-erbB-2, is present in relatively equal amounts in both SP and SS glandular secretions. Elevated glandular salivary c-erbB-2 concentrations could be useful as a preliminary, non-invasive test in clinical decision making when diagnosing salivary gland carcinomas. Additionally, this marker may have utility in distinguishing between oral lesions that are benign, pre-malignant and malignant in the oral cavity. Further research is required to determine if these findings have clinical utility.