Serum c-erbB-2 protein in breast cancer patients

Measurements of c-erbB-2 protein were done in sera of 20 normal women, 22 benign breast disease patients and in respectively 43 and 51 samples from primary breast cancer patients obtained prior to and after surgical interventions. Mean value of serum c-erbB-2 in non-malignant women was insignificantly different from the value in the breast cancer group. Positivity rate of serum c-erbB-2 in the cancer group was 13.8 per cent. Increasing postoperative serum c-erbB-2 concentrations were in good association with severity, progressiveness and relapse of breast cancer independently of other variables such as age, menopausal status, tumor size, axillary node invasion, ER or PR status. Pretreatment serum c-erbB-2 positivity was inversely correlated to ER status but relation to other prognostic parameters of breast cancer was not found. Agreement between c-erbB-2 measured in serum by enzymeimmunoassay and in tissue by immunohistochemical assay was also found. Our data confirmed that in primary breast cancer patients, monitoring of circulating c-erbB-2 protein levels after operation are useful for detecting the recurrence and/or metastasis of the disease especially in ER positive breast cancer. Pretreatment serum c-erbB-2 concentrations do not have benefit for early diagnosis of the tumor.