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Test ID MTAP Methylthioadenosine Phosphorylase (MTAP) Immunostain, Tech 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 pathology address label and the pink Immunostain Technical Only label included in the kit to the outside of the transport container.

Specimen Required

Supplies: Immunostain Technical Only Envelope (T693)

Specimen Type: Tissue

Container/Tube: Immunostain Technical Only Envelope

Preferred: 2 unstained positively charged glass slide (25- x 75- x 1-mm) per test ordered; sections 4-microns thick.

Acceptable: Formalin-fixed, paraffin-embedded (FFPE) tissue block

Useful For

Aiding in the diagnosis of malignant mesothelioma

Reflex Tests

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

Method Name

Immunohistochemistry (IHC)

Reporting Name

MTAP IHC, Tech Only

Specimen Type


Specimen Stability Information

Specimen Type Temperature Time Special Container
TECHONLY Ambient (preferred)

Clinical Information

Methylthioadenosine phosphorylase (MTAP) is a 9p21.3 related protein involved in purine metabolism that plays a role in salvage of adenosine and methionine and is expressed in mesothelial cells. Deletion of the 9p21.3 chromosome region and loss of MTAP (or BCRA1 associated protein 1: BAP1) protein expression is a reliable marker for malignant mesothelioma diagnosis.


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 and documentation is retained at Mayo Clinic Rochester. If a control tissue is not included on the slide, a scanned image of the relevant quality control tissue is available upon request; call 855-516-8404.


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. Berg K, Dacic S, Miller C, et al: Utility of methylthioadenosine phosphorylase compared With BAP1 immunohistochemistry, and CDKN2A and NF2 fluorescence in situ hybridization in separating reactive mesothelian proliferations from epithelioid malignant mesotheliomas. Arch Pathol Lab Med. 2018;1-5

2. Hida T, Hamasaki M, Matsumoto S, et al: Immunohistochemical detection of MTAP and BAP1 protein loss for mesothelioma diagnosis: Comparison with 9p21 FISH and BAP1 immunohistochemistry. Lung Cancer. 2017;104(12):98-105

3. Su C, Chang Y, Chan Y, et al: MTAP is an independent prognosis marker and the concordant loss of MTAP and p16 expression predicts short survival in non-small cell lung cancer patients. EJSO. 2014;40(6):1143-1150

4. Watanabe F, Takao M, Inoue K, et al: Immunohistochemical diagnosis of methylthiodenosine phosphorylase (MTAP) deficiency in non-small cell lung carcinoma. Lung Cancer. 2009; 63(4): 39-44

Day(s) Performed

Monday through Friday 

Report Available

1 to 3 days

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

Test ID Test Order Name Order LOINC Value
MTAP MTAP IHC, Tech Only Order only;no result


Result ID Test Result Name Result LOINC Value
605178 MTAP IHC, Tech Only Bill only; no result
Mayo Clinic Laboratories | IHC Catalog Additional Information: