In a retrospective analysis of the adjuvant trastuzumab trial N9831 recently published in the Journal, Perez et al . ( 1 ) compared the frequency of HER2-positive status as was determined by the US Food and Drug Administration (FDA) criteria for eligibility for the trial with post hoc criteria proposed by the 2007 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP)...
