PMID- 31647316 OWN - NLM STAT- MEDLINE DCOM- 20200731 LR - 20200731 IS - 1543-2165 (Electronic) IS - 0003-9985 (Linking) VI - 144 IP - 5 DP - 2020 May TI - Impact of the 2018 American Society of Clinical Oncology/College of American Pathologists HER2 Guideline Updates on HER2 Assessment in Breast Cancer With Equivocal HER2 Immunohistochemistry Results With Focus on Cases With HER2/CEP17 Ratio <2.0 and Average HER2 Copy Number >/=4.0 and <6.0. PG - 597-601 LID - 10.5858/arpa.2019-0307-OA [doi] AB - CONTEXT.-: The American Society of Clinical Oncology/College of American Pathologists HER2 testing guideline in breast cancer was updated in 2018 to address issues on interpretation of uncommon results using dual-probe in situ hybridization according to the 2013 guideline. OBJECTIVE.-: To assess impact of the 2018 guideline on breast cancer with equivocal HER2 immunohistochemistry results. DESIGN.-: We retrospectively reviewed HER2 fluorescence in situ hybridization (FISH) data (HER2/CEP17 ratio and average HER2 copy number per cell) of HER2 immunohistochemistry-equivocal (2+ or 1+ to 2+) breast cancers at our center between January 2014 and May 2018 and compared HER2 FISH results according to 2013 and 2018 guidelines. RESULTS.-: A total of 1666 HER2 FISH results from 1421 patients with equivocal HER2 immunohistochemistry were reviewed. Based on the 2013 guideline, HER2 FISH results were amplified in 346 cases (20.8%), equivocal in 242 (14.5%), and nonamplified in 1078 (64.7%). Using the 2018 guideline, 258 cases (16%) were reclassified, including 242 previously equivocal test results (15%) and 16 previously positive results (1%) reclassified as negative. The subset of 2013 HER2-equivocal and 2018 HER2-nonamplified cases with HER2/CEP17 ratio lower than 2.0 and average HER2 copy number 4.0 or higher and lower than 6.0 showed higher incidence of micropapillary morphology compared with HER2-amplified cases. Despite most patients in this group not receiving HER2-targeted treatment, 96% had no evidence of disease at follow-up. CONCLUSIONS.-: The 2018 guideline eliminated HER2 FISH-equivocal cases by reclassifying HER2-equivocal cases and cases with nonclassical amplification without HER2 overexpression as HER2 negative. As a consequence, we observed a considerable increase in HER2 FISH-negative cases and a slight decrease in HER2 FISH-positive cases. FAU - Hoda, Raza S AU - Hoda RS AD - From the Departments of Pathology (Drs Hoda, Brogi, Xu, Ross, and Wen and Ms Ventura), Medicine (Drs Dang, Robson, and Norton), and Surgery (Dr Morrow), Memorial Sloan Kettering Cancer Center, New York, New York. FAU - Brogi, Edi AU - Brogi E AD - From the Departments of Pathology (Drs Hoda, Brogi, Xu, Ross, and Wen and Ms Ventura), Medicine (Drs Dang, Robson, and Norton), and Surgery (Dr Morrow), Memorial Sloan Kettering Cancer Center, New York, New York. FAU - Xu, Jin AU - Xu J AD - From the Departments of Pathology (Drs Hoda, Brogi, Xu, Ross, and Wen and Ms Ventura), Medicine (Drs Dang, Robson, and Norton), and Surgery (Dr Morrow), Memorial Sloan Kettering Cancer Center, New York, New York. FAU - Ventura, Katia AU - Ventura K AD - From the Departments of Pathology (Drs Hoda, Brogi, Xu, Ross, and Wen and Ms Ventura), Medicine (Drs Dang, Robson, and Norton), and Surgery (Dr Morrow), Memorial Sloan Kettering Cancer Center, New York, New York. FAU - Ross, Dara S AU - Ross DS AD - From the Departments of Pathology (Drs Hoda, Brogi, Xu, Ross, and Wen and Ms Ventura), Medicine (Drs Dang, Robson, and Norton), and Surgery (Dr Morrow), Memorial Sloan Kettering Cancer Center, New York, New York. FAU - Dang, Chau AU - Dang C AD - From the Departments of Pathology (Drs Hoda, Brogi, Xu, Ross, and Wen and Ms Ventura), Medicine (Drs Dang, Robson, and Norton), and Surgery (Dr Morrow), Memorial Sloan Kettering Cancer Center, New York, New York. FAU - Robson, Mark AU - Robson M AD - From the Departments of Pathology (Drs Hoda, Brogi, Xu, Ross, and Wen and Ms Ventura), Medicine (Drs Dang, Robson, and Norton), and Surgery (Dr Morrow), Memorial Sloan Kettering Cancer Center, New York, New York. FAU - Norton, Larry AU - Norton L AD - From the Departments of Pathology (Drs Hoda, Brogi, Xu, Ross, and Wen and Ms Ventura), Medicine (Drs Dang, Robson, and Norton), and Surgery (Dr Morrow), Memorial Sloan Kettering Cancer Center, New York, New York. FAU - Morrow, Monica AU - Morrow M AD - From the Departments of Pathology (Drs Hoda, Brogi, Xu, Ross, and Wen and Ms Ventura), Medicine (Drs Dang, Robson, and Norton), and Surgery (Dr Morrow), Memorial Sloan Kettering Cancer Center, New York, New York. FAU - Wen, Hannah Y AU - Wen HY AD - From the Departments of Pathology (Drs Hoda, Brogi, Xu, Ross, and Wen and Ms Ventura), Medicine (Drs Dang, Robson, and Norton), and Surgery (Dr Morrow), Memorial Sloan Kettering Cancer Center, New York, New York. LA - eng PT - Journal Article PT - Research Support, N.I.H., Extramural DEP - 20191024 PL - United States TA - Arch Pathol Lab Med JT - Archives of pathology & laboratory medicine JID - 7607091 RN - 0 (Biomarkers, Tumor) RN - EC 2.7.10.1 (ERBB2 protein, human) RN - EC 2.7.10.1 (Receptor, ErbB-2) SB - IM MH - Adult MH - Aged MH - Aged, 80 and over MH - American Medical Association MH - Biomarkers, Tumor/*genetics/metabolism MH - Breast Neoplasms/classification/*genetics/metabolism/pathology MH - Centromere/genetics MH - Chromosomes, Human, Pair 17/genetics MH - Cohort Studies MH - *DNA Copy Number Variations MH - Female MH - Guidelines as Topic MH - Humans MH - Immunohistochemistry MH - In Situ Hybridization, Fluorescence MH - Medical Oncology MH - Middle Aged MH - Pathologists MH - Receptor, ErbB-2/*genetics/metabolism MH - Retrospective Studies MH - United States EDAT- 2019/10/28 06:00 MHDA- 2020/08/01 06:00 CRDT- 2019/10/25 06:00 PHST- 2019/10/28 06:00 [pubmed] PHST- 2020/08/01 06:00 [medline] PHST- 2019/10/25 06:00 [entrez] AID - 10.5858/arpa.2019-0307-OA [doi] PST - ppublish SO - Arch Pathol Lab Med. 2020 May;144(5):597-601. doi: 10.5858/arpa.2019-0307-OA. Epub 2019 Oct 24.