FISH for Ewings Sarcoma

Test Mnemonic


CPT Codes

  • 88377 - QTY (1)


  • Ewing Sarcoma Gene (22q12) translocation
  • Fluorescence in Situ Hybridization for Ewings Sarc


  • LSI 22q12

Performing Laboratory

Cleveland Clinic Laboratories

Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
2 slidesSlide (s), unstainedClean container AmbientOne formalin-fixed, paraffin embedded block containing representative tissue OR unstained 4 μm tissue sections on electrostatically charged slides containing representative tumor. Tissue must be fixed in formalin NOT B5 or PREFER fixative


Environmental Condition Description
AmbientSlides/Blocks stable at ambient temperatures.

Days Performed

5 days per week

Turnaround Time

5 - 7 days


Name Description
Fluorescent In-Situ Hybridization (FISH) 

Clinical Info

Interphase FISH analysis utilizing a dual color, break-apart rearrangement probe for the EWSR1 gene at 22q12.2. Rearrangements involving the EWSR1 gene are observed in various soft tissue tumors, including Ewing sarcoma and desmoplastic small round cell tumor. The translocation partner gene cannot be identified in this assay. If no cells are available for analysis, no analysis charges will be incurred.