Reliability assessment of soluble c-erbB-2 concentrations in the saliva of healthy women and men

Background. The protein c-erbB-2, also known as Her2/neu, is a prognostic breast cancer marker assayed in tissue biopsy specimens from women diagnosed with malignant tumors. Current studies suggest that soluble fragments of the c-erbB-2 oncogene may be released from the cell surface and become detectable in patients with a carcinoma Of the breast. Consequently, the purpose of this study is to assay soluble c-erbB-2 protein in the saliva of healthy men and women to determine the reliability of the assay. Methods. To determine the diagnostic utility of this oncogene, we assayed the soluble form of the c-erbB-2 protein in the saliva with an enzyme-linked immunosorbent assay. The study population consisted of 10 healthy women and 9 healthy men who were serially sampled for saliva 3 times a day for a 5-day period. Saliva was collected from each subject at 9 AM, 4 PM, and 9 PM during the 5-day period. Results. We found the presence of c-erbB-2 protein in the saliva of both groups of subjects. The salivary levels of c-erbB-2 were not significantly different when compared for gender differences. Likewise, the results suggest that sampling during various rimes of the day for salivary c-erbB-2 levels has no effect on marker concentration. Reliability analyses showed that supervised salivary collections were more reliable than unsupervised collections. Conclusions. The results of this pilot study suggest that the assay for salivary c-erbB-2 protein is reliable and might have potential use in the initial detection and follow-up screening for the recurrence of breast cancer in both men and women.