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Test 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.


Secondary ID

621064

Useful For

Identification of breast and urinary cancer, among others

Method Name

Immunohistochemistry (IHC)

Reporting Name

TROP2, SemiQuant IHC, Manual

Specimen Type

Special

Specimen 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 days

Specimen Retention Time

Until reported

Performing 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