Test Overview

Test Methodology

Fluorescence In Situ Hybridization (FISH)

Test Usage

This test detects amplification of the MDM2 gene region (12q15) via fluorescence in situ hybridization (FISH) in formalin-fixed, paraffin-embedded tissue specimens. FISH is performed using Vysis (Abbott Molecular, Inc.) probes to the MDM2 locus (12q15) and the chromosome 12 centromere (CEP12). MDM2 amplification is present in most cases of atypical lipomatous tumor/well-differentiated liposarcoma and most cases of dedifferentiated liposarcoma. MDM2 amplification is not seen in benign lipomatous tumors. Testing for MDM2 amplification may aid in the diagnosis and classification of these tumors.

Reference Range*

Interpretive report provided.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

Amplification may not be detected if sufficient liposarcomatous tissue is not present within the submitted block. Selection of the appropriate block may be problematic given the histologic similarity between atypical lipomatous tumor/well-differentiated liposarcoma and adjacent benign adipose tissue.

Test Details

Days Test Performed

Monday - Thursday

Analytic Time

3 - 10 days

Soft Order Code


MiChart Code

MDM2 Amplification by FISH



Chromosome 12 centromere (CEP12)

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Molecular Diagnostics

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Specimen Requirements

Offsite Collection Instructions

A formalin-fixed, paraffin-embedded tissue block containing sufficient neoplastic cells is preferred. Unstained slides (3, 4-micron slides) with associated H&E stained slide are also acceptable. Decalcified tissue or other fixatives will be accepted and the assay attempted, however these may result in failed testing due to degraded nucleic acid. Both blocks and slides should be stored at room temperature.

Normal Volume

Formalin-fixed, paraffin-embedded tissue

Additional Information

By ordering this test the clinician acknowledges that informed consent has been obtained from the patient as required by applicable state or federal laws and the ordering clinician has authorization from the patient permitting MLabs to report the test results to the ordering clinician. Test includes pathologist interpretation of results billed as a separate additional charge. This test is not available without interpretation.

Billing Information

Fee Codes

CPT Code


New York State Approved


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