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HelpTest Code TROP2 Trophoblast Antigen 2 (TROP2) Immunostain, Semi-Quantitative Immunohistochemistry, Manual
Shipping Instructions
Attach the green "Attention Pathology" address label (T498) to the outside of the transport container before putting into the courier mailer.
Necessary Information
A pathology/diagnostic report and a brief history are required.
Specimen Required
Specimen Type: Tissue
Supplies: Pathology Packaging Kit (T554)
Collection Instructions: Formalin-fixed, paraffin-embedded tissue block; or 3 unstained glass, positively-charged slides with 4-microns formalin-fixed, paraffin-embedded tissue
Additional Information: One slide will be stained with hematoxylin and eosin and returned.
Useful For
Identification of breast and urinary cancer, among others
Method Name
Immunohistochemistry (IHC)
Reporting Name
TROP2, SemiQuant IHC, ManualSpecimen Type
SpecialSpecimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Special | Ambient (preferred) | ||
| Refrigerated | |||
Reject Due To
| Wet/frozen tissue Decalcified paraffin embedded tissue Cytology smears Non-formalin fixed tissue Nonparaffin embedded tissue Noncharged slides ProbeOn slides |
Reject |
Clinical Information
Trophoblast antigen 2 (TROP2) is overexpressed in many tissues and cancers, including breast and urinary cancer among others. An antibody drug conjugate, sacituzumab govitecan, targets the cell surface protein TROP2. Tumors with high expression of TROP2 are more likely to respond to targeted drug therapy.
Reference Values
An interpretive report will be provided.
Interpretation
Trophoblast antigen 2 is a membrane protein and immunohistochemical positivity is characterized by a membrane pattern of staining. Results are reported as percent positive cells and intensity of staining.
This result should be interpreted in the appropriate clinical context.
Cautions
This test has been validated for nondecalcified paraffin-embedded tissue specimens fixed in 10% neutral-buffered formalin. Recommended fixation time is between 6 and 48 hours. This assay has not been validated on tissues subjected to the decalcification process or use of alternative fixatives for bone and bone marrow specimens or cell blocks.
Age of a cut paraffin section can affect immunoreactivity. Stability thresholds vary widely among published literature and are antigen dependent. Best practice is for paraffin sections to be cut within 6 weeks.
Clinical Reference
1. Shvartsu A, Bonavida B. Trop2 and its overexpression in cancers: regulation and clinical/therapeutic implications. Genes Cancer. 2015;6(3-4):84-105
2. Bardia A, Mayer I, Diamond J, et al. Efficacy and safety of anti-Trop-2 antibody drug conjugate sacituzumab govitecan (IMMU-132) in heavily pretreated patients with metastatic triple-negative breast cancer. J Clin Oncol. 2017;35:2141-2148
3. Lenart S, Lenart P, Smarda J, Remsik J, Souce K, Benes P. Trop2: Jack of all trades, master of none. Cancers. (Basel). 2020;12(11):3328. doi:10.3390/cancers12113328
Method Description
Immunohistochemistry on sections of paraffin-embedded tissue.(Unpublished Mayo method)
Day(s) Performed
Monday through Friday
Report Available
5 to 7 daysSpecimen Retention Time
Until reportedPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
88360
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TROP2 | TROP2, SemiQuant IHC, Manual | 105178-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 621065 | Interpretation | 59465-5 |
| 621624 | Participated in the Interpretation | No LOINC Needed |
| 621625 | Report electronically signed by | 19139-5 |
| 621626 | Material Received | 81178-6 |
| 621627 | Disclaimer | 62364-5 |
| 621628 | Case Number | 80398-1 |