SERIAL SERUM C-ERBB-2 LEVELS IN PATIENTS WITH BREAST-CARCINOMA

BACKGROUND, Recently, the extracellular domain of the c-erbB-2 oncogen e product (HER-2/neu) has been reported to be elevated in the serum of one-fourth of patients with metastatic breast carcinoma. The role of serum c-erbB-2 as a tumor marker, however, is still poorly defined. Th e purpose of this study was to evaluate the utility of serial serum c- erbB-2 levels as a tumor marker in patients with metastatic breast car cinoma. METHODS, c-erbB-2 levels in the sera of patients with breast c arcinoma were determined by an enzyme immunoassay that detects the ext racellular domain of c-erbB-2. Serum c-erbB-2 levels were evaluated pr ior to treatment as well as throughout the course of treatment with se cond-line hormonal therapy employing either megestrol acetate or fadro zole, an experimental aromatase inhibitor. RESULTS, Fifty-eight of 300 patients (19.3%) had elevated pretreatment serum c-erbB-2 levels. Of these 58 patients with elevated pretreatment c-erbB-2, 48 had more tha n 1 visit which enabled us to quantitate serial c-erbB-2 levels throug hout the course of treatment. Of these 48 patients, 28 (58.3%) had ser ial c-erbB-2 values that correlated with the clinical course. CONCLUSI ONS, Serial serum c-erbB-2 levels did not show a high overall correlat ion with the clinical course in this group of patients with metastatic breast carcinoma treated with second-line hormonal therapy. (C) 1996 American Cancer Society.