Specificity of HercepTest in Determining <i>HER-2</i>/<i>neu</i> Status of Breast Cancers Using the United States Food and Drug Administration–Approved Scoring System

Abstract

Our results indicate that the HercepTest kit, when used in accordance with the manufacturer's guidelines and the FDA-approved scoring system, results in a large proportion of breast cancers being categorized as positive for HER-2/neu protein expression and that many of these seem to be false-positives. Consideration of the level of staining of nonneoplastic epithelium resulted in improved specificity. The current FDA-approved scoring system for HercepTest results should be reevaluated before its widespread use in clinical practice.