Circulating Her-2/Neu Extracellular Domain in Breast Cancer Patients-Correlation with Prognosis and Clinicopathological Parameters Including Steroid Receptor, Her-2/Neu Receptor Coexpression

摘要

HER-2eu extracellular domain (ECD) can be detected in blood as a soluble circulating protein. The aim of this study was to analyze the relationship between HER-2eu extracellular domain in the serum and the prognosis in breast cancer patients. We also correlated HER-2eu ECD with various clinicopathological factors including steroid receptor, HER-2eu receptor coexpression. The serum from seventy nine patients with invasive breast cancer and twenty individuals without malignancy was analyzed using the enzyme-linked immune adsorbent assay method. The cut-off value was estimated by the ROC curve analysis (15.86 mu g/L). HER-2eu ECD values in the serum of patients with breast cancer were significantly higher than in control subjects. Circulating HER-2eu ECD was significantly associated with the histological grade of tumors and the status of axillary lymph nodes. Negative correlation was observed between HER-2eu ECD in the serum and estrogen receptor positivity. When we analyzed HER-2eu ECD in relation with coexpression of steroid receptor and HER-2eu receptor in tissue, statistically higher values were found in the subgroup of patients with steroid receptor negative, HER-2eu negative tumors than in the other subgroups. HER-2eu ECD was not an independent factor in the univariate and multivariate analysis. However, elevated HER-2eu ECD levels were found in patients with breast cancer possessing more aggressive phenotype.