Tissue and serum c-erbB-2 and tissue EGFR in breast carcinoma: three years follow-up

Amplification of erbB-1 and c-erbB-2 genes has been shown in human breast cancer. Expression of these protooncogenes results in production of epidermal growth factor receptor (EGFR) and c-erbB-2. Both are transmembrane receptors with tyrosine kinase activity. Recent data have indicated that the external domain of c-erbB-2 is shed into the culture supernatant of certain breast cancer cell lines and sera of breast cancer patients. A body of literature has shown that the overexpression of these receptors in malignant tissue and c-erbB-2 when shed into serum is associated with bad prognosis. In the present work, tissue EGFR and c-erbB-2 were determined in the membrane fractions of histopathologically verified malignant and normal tissues from the same breast of 94 patients. These values were also determined in 48 tissue specimens of benign mastopathies. Serum c-erbB-2 was quantified in breast cancer patients (n = 105), patients with benign breast disease (n = 48) and 30 apparently healthy women as controls. Patients were followed up by determination of serum c-erbB-2 for one year and clinically for three years to detect any distant metastasis or recurrence. The levels of tissue and serum c-erbB-2 and Estrogen receptors were significantly higher in the carcinomas and sera of breast cancer patients than benign breast diseases or normal controls. Follow-up, although short, of pre-operative serum c-erbB-2 showed a prognostic value (P = 0.007) better than that of tumor size (P = 0.04), EGFR (P = 0.18), nodal involvement (P = 0.25) and tissue c-erbB-2 (P = 0.85). The shedding of soluble fragments of c-erbB-2 into the serum seems to be a characteristic of the potentially malignant cell. The EGFR mean level, however, was significantly lower in malignant tissues than benign and normal ones. A new definition of EGFR status was developed. Accordingly, the recurrence of the disease was more frequent among patients with negative EGFR. The present work did not reveal any correlation between tissue, serum c-erbB-2 or EGFR on one hand and age, menopausal status, stage, histological type and grade of carcinomas and nodal involvement on the other hand. The present work showed an inverse correlation between estrogen receptor level and level of EGFR in malignant tissues.