RAI1 Alternate Probe Identifies Additional Breast Cancer Cases as Amplified Following Equivocal HER2 Fluorescence In Situ Hybridization Testing Experience From a National Reference Laboratory

摘要

Context.-In 2013 the American Society of Clinical Oncology and College of American Pathologists updated the HER2 guidelines and changed the equivocal category for HER2 in situ hybridization testing to an average HER2 copy number of 4.0 to 5.9 with a HER2: CEP17 ratio of less than 2.0 and proposed retesting, with an option of using another control probe to avoid false- negative results. RAI1, located at band position 17p11.2, is a popular alternate probe locus for retesting equivocal changes.