Serum c-erbB-2 protein is a useful marker for monitoring tumor recurrence of the breast.

C-erbB-2 oncogene protein (ErbB-2/HER-2) overexpression is a prognostic marker of breast carcinoma. The purpose of this study was to evaluate serum ErbB-2 for monitoring tumor recurrence of operable breast carcinoma patients. The subjects were 86 breast carcinoma patients with stage I-IIIB. Sera were collected at preoperative and postoperative periods from 1996 to 2000. The cutoff value was set at 5.4 ng/ml for preoperative patients and at 6.5 ng/ml for postoperative patients. Twenty-nine patients (34%) had higher preoperative serum ErbB-2 levels (>or=5.4 ng/ml). A higher preoperative serum ErbB-2 was associated with higher clinical stage, larger tumor size, nodal metastasis, higher histologic grade and lymphatic invasion, but not with vascular invasion, hormonal receptor status or other tumor markers, such as carcinoembryonic antigen (CEA) and carbohydrate antigen 15-3 (CA15-3). As of April 2005, 27 patients (31%) had recurrence and 18 (62%) of them had a higher preoperative serum ErbB-2. Seventeen patients died of tumor progression. The recurrence-free survival rates at 7 years after breast surgery were 84% in 57 patients with a normal preoperative serum ErbB-2 and 41% in 29 patients with a higher preoperative serum ErbB-2 (p < 0.0001). The overall survival rates at 7 years were 93% and 55% (p < 0.0001), respectively. A multivariate analysis revealed that preoperative serum ErbB-2 was an independent prognostic factor for recurrence-free survival and overall survival in breast carcinoma patients. The specificities and sensitivities of postoperative tumor markers (CEA, CA15-3 and ErbB-2) were 91%, 100% and 85%, and 40%, 30% and 70%, respectively. Serum ErbB-2 is a preoperative prognostic marker and may be useful for monitoring tumor recurrence of the breast.