Correlations between c-erbβ-2 oncogene amplification and the expression of its mRNA and protein in human breast carcinomas

Abstract

Nineteen human breast tumours were analysed for c-erbβ-2 gene amplification, the over-expression of its mRNA and the production of its protein residue by southern blot, northern blot and western blot techniques respectively. Protein expression was also assessed by immunohistochemistry on paraffin sections. c-erbβ-2 gene amplification was found in 6 of 19 (31%) tumours. Over-expression of c-erbβ-2 mRNA was found in 7 of 19 (37%) tumours. Expression of the 185 kd c-erbβ-2 protein product was detected in 3 of 19 (16%) tumours by western blotting and in 5 of 19 (26%) by immunohistochemistry. In only 4 tumours with an amplified c-erbβ-2 gene was there a clear association between all three parameters. In view of the conflicting reports in the literature concerning c-erbβ-2 gene amplification or protein over-expression (assessed by western blot or immunohistochemistry) and prognosis of breast cancer, studies in which these parameters are correlated individually with prognosis in the same group of patients are needed.