335 The Impact of 2013 ASCO/CAP Guidelines on the Breast Cancer Her2/Neu FISH Results. (11th January 2018)

• Record Type: Journal Article
• Authors: Zhang, Songlin; Wang, Xiaohong
• Is Part Of: American journal of clinical pathology. Volume 149(2018)Supplement 1
• Page Start: S144
• Page End: S144
• Publication Date: 2018-01-11
• Subjects: Diagnosis, Laboratory -- Periodicals; Pathology -- Periodicals; 616.07
• DOI: 10.1093/ajcp/aqx127.334
• Languages: English
• ISSNs: 0002-9173

Abstract

Abstract: Objectives: The 2013 American Society of Clinical. Oncology/College of American Pathologists (ASCO/CAP) Her2/neu fluorescence in situ hybridization (FISH) interpretation guidelines had several changes compared to the 2007 ASCO/CAP guidelines. Few studies showed a significant increasing Her2/neu equivocal FISH cases compared with the 2007 guidelines. We routinely perform Her2/neu immunohistochemistry and reflex with HER2/neu FISH on the IHC 2+ cases. Here we summarize our HER2/neu results after adapting the 2013 ASCO/CAP guidelines. Methods: All Her2/neu FISH results were retrospectively reviewed and recorded for the Her2/neu signal/cell, CEP17 signal/cell, and the Her2/neu to CEP17 ratio. The results were interpreted into positive, equivocal, and negative based on both the 2013 and 2007 ASCO/CAP guidelines. Results: There were 116 reflex Her2/neu FISH tests during the study period. Using the 2007 ASCO/CAP guidelines, 12 cases were positive, no case was equivocal, and 104 cases were negative. Using the 2013 ASCO/CAP guidelines, 12 cases were positive, six cases were equivocal, and 98 cases were negative. There was a significant increase in Her2/neu FISH equivocal cases (6/116 vs 0/116; P = .01) using the 2013 ASCO/CAP guidelines. Conclusion: Our data support the early observation that the 2013 ASCO/CAP guidelines significantly increase the equivocal Her2/neu FISH cases, and additional retesting, such as retesting on different specimens or retesting with a different probe than CEP17, on these equivocal FISH cases are required. The 2013 ASCO/CAP guidelines can potentially lead to more patients being eligible for trastuzumab therapy.