Are There More HER2 FISH in the Sea? An Institution's Experience in Identifying HER2 Positivity Using Fluorescent In Situ Hybridization in Patients with HER2 Negative Immunohistochemistry.

Autor: Suydam C; Department of Surgery, Eisenhower Army Medical Center, Fort Gordon, GA, USA. Camille.r.suydam.mil@health.mil., Chibane F; Department of Surgery, Medical College of Georgia at Augusta Health, Augusta, GA, USA., Brown N; Department of Surgery, Medical College of Georgia at Augusta Health, Augusta, GA, USA., Schlafly M; Department of Surgery, Medical College of Georgia at Augusta Health, Augusta, GA, USA., Arnold AH; Department of Surgery, Medical College of Georgia at Augusta Health, Augusta, GA, USA., Ghleilib I; Department of Pathology, Medical College of Georgia at Augusta Health, Augusta, GA, USA., Easley M; Department of Surgery, Medical College of Georgia at Augusta Health, Augusta, GA, USA., White J; Department of Pathology, Medical College of Georgia at Augusta Health, Augusta, GA, USA.
Jazyk: angličtina
Zdroj: Annals of surgical oncology [Ann Surg Oncol] 2024 Jan; Vol. 31 (1), pp. 376-381. Date of Electronic Publication: 2023 Nov 07.
DOI: 10.1245/s10434-023-14439-7
Abstrakt: Background: Approximately 20% of breast cancers express HER2-positive receptors in the USA. HER2 receptor immunohistochemistry (IHC) staining with equivocal (2+) results commonly undergoes fluorescence in-situ hybridization (FISH) for further classification. Current guidelines do not recommend routine FISH testing in IHC-negative (0 or 1+) cases. This study investigates an institution that performs both IHC and FISH testing on all cases to identify the true HER2-positive rate.
Patients and Methods: A retrospective chart review from 2015 to 2021 was conducted at an institution where both HER2 IHC and FISH testing were performed at the time of diagnosis for all invasive breast cancers. The rate of true HER2-positive patients was determined, and patient and tumor characteristics were further explored.
Results: A total of 1835 invasive breast cancer cases were primarily treated at this institution. A total of 289 cases were HER2 positive on IHC and FISH testing (15.7%). An additional 38 cases were identified as HER2 negative on IHC, but reclassified as HER2 positive on reflex FISH testing. Total HER2 positive cases increased from 289 (15.7%) to 327 cases (17.8%) with reflex FISH testing.
Conclusions: The additional HER2-positive cases after completing FISH testing on IHC-negative tumors suggests there may be a role for routine FISH testing in addition to standard IHC staining to determine HER2 status for breast cancer. The ethical, prognostic and even  benefits of a correct diagnosis outweigh the added expense of FISH testing.
(© 2023. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)
Databáze: MEDLINE
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