PROGNOSTIC-SIGNIFICANCE OF SERUM C-ERBB-2 PROTEIN IN BREAST-CANCER PATIENTS

The tissue expression of c-erbB-2 protein in breast cancer is a marker of poor prognosis in a number of studies. More recently it has also b een suggested that c-erbB-2 expression may predict response to systemi c therapy in patients with advanced breast cancer. The measurement of c-erbB-2 protein in the serum of breast cancer patients has now been r eported, but the significance of this finding is not clear. In this st udy an ELISA assay was used to measure c-erbB-2 in the sera of 23 norm al controls, 46 benign breast disease patients, and 119 breast cancer patients. Elevated serum c-erbB-2 protein levels were detected in 13% (3/23) of normal controls, 15% (7/46) of benign disease patients, 15% (7/46) of Stage I/II patients, 26% (9/35) of Stage III patients, and 2 1% (8/38) of Stage IV patients. The tissue expression of the c-erbB-2 protein showed no association with detection of the serum c-erbB-2 pro tein (p = 0.31). In the 67 Stage III and IV patients who had assessabl e disease the presence of the c-erbB-2 protein in the serum bore no re lationship to response to hormonal therapy (p = 0.71). Serum detection of the c-erbB-2 protein in Stage I/II patents predicted for a worseni ng of both survival outcome (p = 0.002) and disease free interval (p = 0.002). A worse outcome was also seen for the Stage III patients (p = 0.04) and Stage IV patients, although the latter did not reach statis tical significance (p = 0.27). This study found that the presence of c -erbB-2 in the serum of breast cancer patients was of prognostic signi ficance for all stages of disease.