DETECTION OF C-ERBB-2 RELATED PROTEIN IN SERA FROM BREAST-CANCER PATIENTS - RELATIONSHIP TO ERBB2 GENE AMPLIFICATION AND C-ERBB-2 PROTEIN OVEREXPRESSION IN TUMOR

The level of a c-erbB-2 related protein was determined in sera from 16 8 breast carcinoma patients, 12 females with benign breast disease, an d 66 female controls using an ELISA (enzyme linked immunosorbent assay ) kit. Elevated c-erbB-2 related protein level was detected in one of 13 preoperative sera (8%), two of 62 postoperative sera from patients without recurrent disease (3%), and 55 of 93 sera collected at recurre nt disease (59%), Elevated serum levels were detected significantly mo re often in patients with distant metastases than in patients with rec urrent disease restricted to locoregional areas (68% versus 19%). Pres ence of elevated serum level was associated with ERBB2 gene amplificat ion and c-erbB-2 protein overexpression in tumour. None of the patient s who had normal ERBB2 gene copy number in tumour had elevated serum l evels, Although the usefulness in postoperative prediction of the pres ence of micrometastases is somewhat questionable, the results suggest c-erbB-2 related protein to represent a novel tumour marker in serum a nd other body fluids from breast cancer patients at the time of diagno sis and during treatment monitoring.