Comparative assays for the HER-2/neu oncogene status in breast cancer.

Context: Tumor marker assays, especially those used to indicate the right therapy, should be standardized.

Objective: To analyze the current methods for the HER-2/neu (h2n) oncogene status by immunohistochemical (IHC) analysis, fluorescence in situ hybridization (FISH), and chromogenic in situ hybridization (CISH) and compare those results with the chromosome 17 copy number and the status of the topoisomerase II alpha (TPIIalpha) gene.

Design: We tested 50 infiltrating ductal breast carcinomas (pTNM status varied from pT1 N0 to pT4 N1) using the Food and Drug Administration (FDA)-approved methods HercepTest and Pathway for overexpression of h2n.