The
protein c-erbB-2, also known as Her2/neu, is a prognostic
breast cancer marker assayed in tissue biopsies from women diagnosed with malignant
tumors. Present studies suggest that soluble fragments of the c-erbB-2 oncogene may be released from the cell surface and become detectable in patients with
carcinoma of the breast. Consequently, the purpose of this study was to assay the
c-erbB-2 protein in the saliva and serum of women with and without
carcinoma of the breast and to determine whether the
protein possesses any diagnostic value. To determine the diagnostic utility of this oncogene, the soluble form of the
c-erbB-2 protein was assayed in the saliva and serum using ELISA in three different groups of women. The three groups consisted of 57 healthy women, 41 women with benign breast lesions, and 30 women diagnosed with
breast cancer. To compare the relative diagnostic utility of the
c-erbB-2 protein, CA 15-3 was also measured. The CA 15-3 measurements served as a "gold standard" by which to compare the
c-erbB-2 protein's diagnostic effectiveness. We found
c-erbB-2 protein in the saliva and serum of all three groups of women. The salivary and serological levels of c-erbB-2 in the
cancer patients, however, were significantly higher (P < 0.001) than the salivary and serum levels of healthy controls and benign
tumor patients. Additionally, the
c-erbB-2 protein was found to be equal to or to surpass the ability of CA 15-3 to detect patients with
carcinoma. The results of the pilot study suggest that the
c-erbB-2 protein may have potential use in the initial detection and/or follow-up screening for the recurrence of
breast cancer in women.