Test Overview
Test Methodology

Reverse transcription followed by Polymerase Chain Reaction (PCR) with detection by capillary electrophoresis.

Test Usage

Ewing sarcoma (ES) is a member of the "small round blue cell" tumor group, and must be differentiated from other morphologically similar tumors. ES is characterized by recurrent chromosomal rearrangements involving the EWSR1 gene. The great majority are the reciprocal translocation t(11;22)(q24;q12), which occurs in approximately 90% of ES cases. This translocation joins the EWSR1 gene on chromosome 22 and the FLI1 gene on chromosome 11, leading to expression of EWSR1/FLI1 fusion transcripts. Alternate translocations involving EWSR1 occur with lower frequency in ES. Of these, the t(21;22)(q22;q12) translocation is the most common, with an incidence of approximately 5-10%. This rearrangement leads to fusion of the EWSR1 and ERG genes, and is also characteristic of ES. This test qualitatively detects the EWSR1/FLI1 and EWSR1/ERG fusion transcripts in fresh/frozen or formalin-fixed paraffin embedded tissues. Testing can aid in the differential diagnosis of ES.

Reference Range *

Interpretive report provided. The specific fusion transcript type is reported with a positive test result.

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

Test Limitations

This test will detect the following forms of chimeric transcripts: EWSR1 exon 7/FLI1 exon 5, EWSR1 exon 7/FLI1 exon 6, EWSR1 exon 7/FLI1 exon 7, EWSR1 exon 7/FLI1 exon 8, EWSR1 exon 7/FLI1 exon 9, EWSR1 exon 7/ERG exon 6, EWSR1 exon 7/ERG exon 9. Other transcript forms or alternative EWSR1 fusion partners, which are not detected by this assay, have been described in a small percentage of Ewing sarcoma cases. Other methods such as fluoresence in situ hybridization (FISH) for EWSR1 rearrangement may detect EWSR1 translocations in these cases.

Test Details
Days Set Up
Monday - Thursday
Analytic Time

2 - 7 days

Soft Order Code
MiChart Code
EWSR1/FLI1 and EWSR1/ERG Translocations (Ewing Sarcoma) by PCR
  • EWS Chimeric Transcript Detection
  • ERG Chimeric Transcript Detection
  • FLI1 Chimeric Transcript Detection
  • EWS/FLI-1 Translocation
  • EWS/ERG Translocation
  • Ewing's Sarcoma
  • Ewing Sarcoma Translocation Detection
Molecular Diagnostics
Molecular Diagnostics
Specimen Requirements
Collection Instructions

A formalin-fixed, paraffin-embedded tissue block containing an area with a high percentage of neoplastic cells (for micro-/macro-dissection) is preferred. Unstained, UNBAKED slides (5-8, 10-micron slides; 10-15 if few neoplastic cells are present) 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.

Alternate Specimen
Previously extracted RNA may also be accepted.
Normal Volume
Formalin-fixed, paraffin-embedded tissue. Extracted RNA is also acceptable if extracted in a CLIA certified laboratory.
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.

CPT Code
81401 x2
Fee Code
NA077, NA078
Pro Fee CPT
NY State Approved