C-ERBB-2 AMPLIFICATION AND OVEREXPRESSION IN BREAST-CANCER - EVALUATION AND COMPARISON OF SOUTHERN BLOT, SLOT BLOT, ELISA AND IMMUNOHISTOCHEMISTRY

The oncogene c-erbB-2 has been shown to be amplified in 17-30% of brea st cancers, with similar levels of overexpression of the oncogene prod uct p185, a transmembrane growth factor receptor glycoprotein. Amplifi cation of c-erbB-2 is now generally considered to be a significant pro gnostic indicator in patients with breast cancer. A series of 74 conse cutive breast carcinomas were analysed for c-erbB-2 amplification and p185 overexpression. The procedures of Southern blotting and slot blot were used for the analysis of oncogene amplification, while immunoper oxidase (IPOX) staining and enzyme-linked immunosorbent assay (ELISA) were used for the analysis of p185 overexpression. Detection of c-erbB -2 oncogene amplification by both the conventional Southern blotting t echnique and by the slot blot technique showed complete accord, with t he amplified c-erbB-2 oncogene being detected in 14 of the 74 patients (18.9%). The c-erbB-2 oncoprotein, as measured by IPOX and ELISA, was found to be overexpressed in 21% and 19% of patients, respectively. C omparison was made between the results attained by all four methods, a nd further comparison of the techniques was made from the point of vie w of ease of use, expense and ease of introduction into routine diagno stic laboratories. Immunocytochemistry in combination with slot blotti ng procedures were considered to be the most cost effective methods fo r evaluation of overexpression and amplification in routine pathology laboratories.