Application of the AMeX method to the evaluation of HER-2 status in breast carcinomas: comparison with the results of HercepTest.

The recent development of the recombinant humanized monoclonal antibody against HER-2 oncoprotein requires a simple and accurate method for the evaluation of HER-2 status in patients with breast cancers. We here report that the evaluation of the HER-2 status is improved by the use of the acetone-methanol-xylene (AMeX) method. Compared with an ordinary test of HercepTest, 25 out of 63 cases (39.7%) were scored upwards by the AMeX method. In addition, the HER-2 gene amplification was easily estimated by fluorescence in situ hybridization (FISH) using the AMeX method. Thus, the AMeX method is likely to provide more improved data about the HER-2 status in breast carcinoma specimens.