HER2
Gene Amplification
Clinical
Significance:
Recently
established guidelines from the American Society for Clinical Pathology (ASCP),
College of American Pathologists (CAP), Association for Molecular Pathology
(AMP), and/or the American Society of Clinical Oncology (ASCP) recommend HER2
FISH testing as a reflex to further clarify equivocal (2+) immunohistochemistry
(IHC) results and as routine testing in colorectal, gastroesophageal (GEJ), and
gastric cancers.
https://www.nccn.org/professionals/physician_gls/pdf/colon.pdf
https://www.nccn.org/professionals/physician_gls/pdf/gastric.pdf
https://www.nccn.org/professionals/physician_gls/pdf/esophageal.pdf
Specimen
Requirements and Collection:
Formalin fixed tissue containing a sufficient amount of tumor (generally
at least several mm of tumor tissue submitted in the tissue block).
Methodology:
Fluorescent in-situ hybridization (FISH) dual-probe assay
Forms:
Molecular pathology requisition form
Transport:
Send formalin-fixed, paraffin-embedded (FFPE) tissue and cell block
containing tumor at room temperature.
Also acceptable 2-unstained, 4-5 micron positively charged slides with 1
post H&E. Please include a surgical
pathology report
Unacceptable
specimen:
Specimens fixed in alternative fixatives or metal fixatives (ex. B-plus). Decalcified specimens.
Reference
Range:
HER2/CEP17 ratio
>= 2.0 = PRESENT = POSTIVE
HER2/CEP17 ratio
< 2.0 = ABSENT = NEGATIVE
Hoffmann M, Stoss O, Shi D, et al. Assessment of a HER2 scoring system
for gastric cancer: Results from a validation study. Histopathology 2008;52:797-5.80
CPT codes:
88377
Test
reported:
Results are reported within 7-10 days
