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Test Code GPNMB Glycoprotein Non-Metastatic Melanoma Protein B (GPNMB), Technical Component Only


Ordering Guidance


This test includes only technical performance of the stain (no pathologist interpretation is performed). If diagnostic consultation by a pathologist is required order PATHC / Pathology Consultation.



Shipping Instructions


Attach the green "Attention Pathology" address label (T498) and the pink Immunostain Technical Only label included in the kit to the outside of the transport container.



Specimen Required


Specimen Type: Tissue

Supplies: Immunostain Technical Only Envelope (T693)

Container/Tube: Immunostain Technical Only Envelope

Submit:

Formalin-fixed, paraffin-embedded tissue block

OR

2 Unstained, positively charged glass slides (25- x 75- x 1-mm) per test ordered; sections 4-microns thick


Useful For

Screening kidney tumors for genetic alterations

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
IHTOI IHC Initial, Tech Only No No
IHTOA IHC Additional, Tech Only No No

Testing Algorithm

For the initial technical component only immunohistochemical (IHC) stain performed, the appropriate bill-only test ID will be reflexed and charged (IHTOI). For each additional technical component only IHC stain performed, an additional bill-only test ID will be reflexed and charged (IHTOA).

Method Name

Immunohistochemistry (IHC)

Reporting Name

GPNMB IHC, Tech Only

Specimen Type

TECHONLY

Specimen Stability Information

Specimen Type Temperature Time
TECHONLY Ambient (preferred)
  Refrigerated 

Interpretation

This test does not include pathologist interpretation, only technical performance of the stain. If interpretation is required, order PATHC / Pathology Consultation for a full diagnostic evaluation or second opinion of the case.

 

The positive and negative controls are verified as showing appropriate immunoreactivity.

 

Interpretation of this test should be performed in the context of the patient's clinical history and other diagnostic tests by a qualified pathologist.

Clinical Reference

1. Tekin B, Folpe AL, Dasari S, et al. TFE3-rearranged ossifying fibromyxoid tumors are uniquely negative for glycoprotein non-metastatic melanoma protein B: A study of 13 TFE3-rearranged mesenchymal tumors. Hum Pathol. 2025;157:105768

2. Alesi N, Asrani K, Lotan TL, Henske EP. The Spectrum of Renal "TFEopathies": Flipping the mTOR Switch in Renal Tumorigenesis. Physiology (Bethesda). 2024;39(6):347-359

3. Li H, Argani P, Halper-Stromberg E, et al. Positive GPNMB immunostaining differentiates renal cell carcinoma with fibromyomatous stroma associated with TSC1/2/MTOR alterations from others. Am J Surg Pathol. 2023;47(11):1267-1273

4. Salles DC, Asrani K, Woo J, et al. GPNMB expression identifies TSC1/2/mTOR-associated and MiT family translocation-driven renal neoplasms. J Pathol. 2022;257(2):158-171

Day(s) Performed

Monday through Friday

Report Available

1 to 3 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

88342-TC, primary

88341-TC, if additional IHC

LOINC Code Information

Result ID Test Result Name Result LOINC Value
623082 GPNMB IHC, Tech Only No LOINC Needed