Test Overview
Test Methodology

Reverse Transcription Polymerase Chain Reaction (PCR) with capillary electrophoresis

Test Usage

Greater than 90% of clear cell sarcomas harbor the reciprocal chromosomal translocation t(12;22)(q13;q12). This rearrangement joins the EWSR1 and ATF1 genes and leads to expression of EWSR1/ATF1 fusion transcripts. This test detects three EWSR1/ATF1 fusion transcript types: Type 1 (EWSR1 exon 8/ATF1 exon 4), Type 2 (EWSR1 exon 7/ATF1 exon 5), and Type 3 (EWSR1 exon 10/ATF1 exon 5) which collectively account for almost all t(12;22)-bearing clear cell sarcoma cases. Testing for EWSR1/ATF1 fusion is a useful diagnostic adjunct in the differential diagnosis of clear cell sarcoma, since malignant melanoma is not associated with this chimeric transcript.

Reference Range *

Interpretive report provided.

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

Test Limitations

This assay is designed to detect only types 1, 2, and 3 EWSR1/ATF1 fusion transcripts (which collectively account for approximately 90-95% of clear cell sarcoma cases). A negative result does not rule out the presence of transcript at a level below the sensitivity of detection, or a rare EWSR1/ATF1 transcript variant that is not evaluated by this test, such as type 4 (EWSR1 exon 7/ATF1 exon 7). Rare cases of clear cell sarcoma with EWSR1/CREB1 fusions are also not detected by this test.

Test Details
Days Set Up
Monday - Thursday
Analytic Time

2 - 7 days

Soft Order Code
MiChart Code
EWSR1/ATF1 Translocation (Clear Cell Sarcoma) by PCR
  • CCS
  • t(12;22)(q13;q12) Translocation Detection
  • Clear Cell 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
Fee Code
Pro Fee CPT
NY State Approved