Immunohistochemical evaluation of HER-2/neu expression in infiltrating breast carcinoma: a study of reproducibility.

Objective: To determine interobserver and intraobserver reproducibility in the assessment of the HercepTest- and TAB250-immunostained slides.

Study Design: Three independent expert pathologists (two with and one without training in HercepTest assessment) evaluated the HercepTest and TAB250-immunostained slides of 108 infiltrating breast carcinomas with a triple-blind method. The evaluation was repeated, with the same method and sequence of view, after 60 days.