Update of The Recommendations for HER2 Status Determination in Breast Cancers : ASCO/CAP 2013 and GEFPICS 2014

International guidelines on HER2 determination in breast cancer have just been updated by the American Society of Clinical Oncology (ASCO) and College of American Pathologists (CAP), on the basis of more than 10 years practice, results of clinical trials and concordance studies. The “Groupe d’Etude des Facteurs Pronostiques et Immunohistochimiques dans le Cancer du Sein” (GEFPICS), a group of  pathologists experts in breast cancer, presents these guidelines, adapted to the French routine practice. These recommendations highlight the possible diagnosis issues facing HER2 status determination, such as intra-tumor heterogeneity, special histological subtypes and biomarker reevaluation during metastatic relapse [W]. Pre-analytical data and updated scoring criteria (especially for equivocal cases) are detailed, in order to optimize diagnosis and reduce the possibility of false negative results. In the era of personalized medicine, the quality of oncotheranostic biomarkers evaluation is a major element for pathologist, clinical practitioner and patient.