Leo Lin 1 , Deepika Sirohi 1 , Joshua F Coleman 1 , H Evin Gulbahce 1 Show Affiliations »
Abstract
OBJECTIVES: To review impact of the ASCO/CAP 2018 update on HER2 testing. METHODS: HER2 fluorescence in situ hybridization (FISH) test requests from primary and metastatic breast cancers between August 2018 and January 2019 were included. FISH results requiring a changed algorithm under the new guidelines (groups 2, 3, and 4) were identified and HER2:CEN17 ratios, average HER2, CEN17 signals/cell, and HER2 immunohistochemistry (IHC) results were recorded. RESULTS: Of the HER2 FISH cases 176/812(21.7%) fell within groups 2, 3, or 4; 0/12, 1/12, and 2/152 cases were positive (3+) by IHC, and 1/12, 2/12, and 6/152 cases were positive after targeted scoring from groups 2, 3, and 4, respectively. Following 2018 updates, 8.3%, 25%, and 5.3% of the groups 2, 3, and 4 were positive, respectively. CONCLUSIONS: Groups 2, 3, and 4 constituted over 20% of HER2 FISH tests in a reference laboratory. The 2018 ASCO/CAP update significantly decreased the HER2 positivity rate. © American Society for Clinical Pathology, 2019. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
OBJECTIVES: To review impact of the ASCO/CAP 2018 update on HER2 testing. METHODS: HER2 fluorescence in situ hybridization (FISH) test requests from primary and metastatic breast cancers between August 2018 and January 2019 were included. FISH results requiring a changed algorithm under the new guidelines (groups 2, 3, and 4) were identified and HER2:CEN17 ratios, average HER2, CEN17 signals/cell, and HER2 immunohistochemistry (IHC) results were recorded. RESULTS: Of the HER2 FISH cases 176/812(21.7%) fell within groups 2, 3, or 4; 0/12, 1/12, and 2/152 cases were positive (3+) by IHC, and 1/12, 2/12, and 6/152 cases were positive after targeted scoring from groups 2, 3, and 4, respectively. Following 2018 updates, 8.3%, 25%, and 5.3% of the groups 2, 3, and 4 were positive, respectively. CONCLUSIONS: Groups 2, 3, and 4 constituted over 20% of HER2 FISH tests in a reference laboratory. The 2018 ASCO/CAP update significantly decreased the HER2 positivity rate. © American Society for Clinical Pathology, 2019. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Entities: Disease
Keywords:
Breast cancer; FISH; HER2
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Year: 2019
PMID： 31172196 DOI： 10.1093/ajcp/aqz061
Source DB: PubMed Journal: Am J Clin Pathol ISSN： 0002-9173 Impact factor: 2.493