Test Details
Methodology
Immunohistochemistry (IHC)
Result Turnaround Time
2 - 4 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
Equivocal results by IHC should be reflexed to HER2 FISH to determine overall status. HER-2/neu overexpression is a predictor of response to certain breast cancer therapies, including targeted immunotherapies.1-3 A positive IHC result (3+) or an equivocal result with ISH amplification provides eligibility for trastuzumab (HERCEPTIN®) and trastuzumab emtansine (KADCYLA®) therapies. This test can also be used to qualify patients as HER2-low (1+ IHC or 2+/ISH-) or HER2-ultralow (any staining of the membrane in greater than 0 and less than or equal to 10% of invasive tumor cells) for fam-trastuzumab-deruxtecan-nxki (ENHERTU®) eligibility determination.
Special Instructions
Fixation time and fixative used must be indicated on the test request form. Please direct any questions regarding this test to oncology customer service at 800-345-4363.
Limitations
Use of fixatives other than 10% neutral-buffered formalin or fixation times less than six hours or more than 72 hours may not yield reliable results. Decalcification procedures may negatively affect antigenicity and DNA quality.
Specimen Requirements
Specimen
Formalin-fixed, paraffin-embedded (FFPE) tumor
Volume
One paraffin block or five unstained, positively-charged tissue slides cut at 4 to 5 microns and dried for one hour at 60°C
Container
Paraffin block transport pouch or slide mailer
Collection Instructions
Specimen should be fixed in 10% neutral-buffered formalin. Time from tissue acquisition to fixation should be as short as possible. Fixation time should be between six and 72 hours according to ASCO/CAP guidelines.
Storage Instructions
Maintain specimen at room temperature.
Causes for Rejection
Tumor other than breast tumor
References
Modi S, Jacot W, Yamashita T, Petukhova MN, Agafonov SV, Itkin GP. Trastuzumab Deruxtecan in Previously Treated HER2-Low Advanced Breast Cancer. N Engl J Med. 2022 Jul 7;387(1):9-20. PubMed 35665782
PATHWAY anti-HER-2/neu (4B5) Rabbit Monoclonal Primary Antibody [package insert]. Roche Diagnostics; Jan 29, 2025.
Wolff AC, Hammond MEH, Allison KH, et al. Human Epidermal Growth Factor Receptor 2 Testing in Breast Cancer: American Society of Clinical Oncology/College of American Pathologists Clinical Practice Guideline Focused Update. J Clin Oncol. 2018 Jul 10;36(20):2105-2122. PubMed 29846122
Footnotes
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 480376 | HER-2/neu Oncoprot, Paraffin | 480449 | HER-2/neu (C-erbB-2) | 18474-7 | ||
| 480376 | HER-2/neu Oncoprot, Paraffin | 480458 | Scoring Guide | 19147-8 | ||
| 480376 | HER-2/neu Oncoprot, Paraffin | 480381 | Comment | 77202-0 | ||
| 480376 | HER-2/neu Oncoprot, Paraffin | 483256 | Fixation Time | N/A | ||
| 480376 | HER-2/neu Oncoprot, Paraffin | 483257 | Fixative | N/A | ||
| 480376 | HER-2/neu Oncoprot, Paraffin | 480233 | Director Review | 69426-5 | ||
| Order Code | 480376 | |||||
| Order Code Name | HER-2/neu Oncoprot, Paraffin | |||||
| Order Loinc | ||||||
| Result Code | 480449 | |||||
| Result Code Name | HER-2/neu (C-erbB-2) | |||||
| UofM | ||||||
| Result LOINC | 18474-7 | |||||
| Order Code | 480376 | |||||
| Order Code Name | HER-2/neu Oncoprot, Paraffin | |||||
| Order Loinc | ||||||
| Result Code | 480458 | |||||
| Result Code Name | Scoring Guide | |||||
| UofM | ||||||
| Result LOINC | 19147-8 | |||||
| Order Code | 480376 | |||||
| Order Code Name | HER-2/neu Oncoprot, Paraffin | |||||
| Order Loinc | ||||||
| Result Code | 480381 | |||||
| Result Code Name | Comment | |||||
| UofM | ||||||
| Result LOINC | 77202-0 | |||||
| Order Code | 480376 | |||||
| Order Code Name | HER-2/neu Oncoprot, Paraffin | |||||
| Order Loinc | ||||||
| Result Code | 483256 | |||||
| Result Code Name | Fixation Time | |||||
| UofM | ||||||
| Result LOINC | N/A | |||||
| Order Code | 480376 | |||||
| Order Code Name | HER-2/neu Oncoprot, Paraffin | |||||
| Order Loinc | ||||||
| Result Code | 483257 | |||||
| Result Code Name | Fixative | |||||
| UofM | ||||||
| Result LOINC | N/A | |||||
| Order Code | 480376 | |||||
| Order Code Name | HER-2/neu Oncoprot, Paraffin | |||||
| Order Loinc | ||||||
| Result Code | 480233 | |||||
| Result Code Name | Director Review | |||||
| UofM | ||||||
| Result LOINC | 69426-5 |