657 Tissue expression and serum levels of HER-2/NEU in patients with breast cancer

Abstract

The extracellular domain of the HER-2/ neu (c-erbB-2) oncogene protein can be found in soluble form in the sera of patients with breast cancer. We have analyzed serum levels of soluble HER-2/ neu in 42 patients prior to any therapy and put it into relation to the overexpression and amplification of HER-2/ neu in the primary tumor after surgical excision and to data obtained by patho histological staging. In addition, we have investigated the sera of 62 patients with stage IV breast cancer. We have further compared the possible prognostic value of serum HER-2/ neu to two other Known serological tumor markers CEA and CA15–3 in both patient groups. We have observed an elevated serum HER-2/ neu level (>20U/I) in 6/42 (14.2%) preoperative patients, out of whom those with HER2/ neu tissue expression/amplification showed elevated serum, levels in 42.8%. In contrast, 8.5% of patients without HER-2/ neu expression/amplification in the primary tumor presented with elevated serum levels. There was a significant difference in soluble HER-2/ neu serum concentrations between patients with tumors of different size (p neu . In patients with stage IV disease, 27 out of 62 (43,5%) had elevated soluble HER-2/ neu serum levels. A highly signiticant correlation of serum concentrations of HER-2/ neu with CA15–3 (p neu levels at diagnosis defines a small subgroup of breast cancer patients with a relatively advanced stage of disease. Its strong correlation with tumor load in patients with stage II disease and the high prevalence in patients with stage IV disease make it a promising tool for the assessment of disease activity and biologic behaviour in breast-cancer.