Methodology: FISH

Clinical Significance:
This FISH assay detects most rearrangements involving the EWSR1 gene irrespective of translocation partner. Genetic approaches to identify rearrangements of the EWSR gene on chromosome 22q12, characteristic of over 90% of PNET/Ewing sarcomas, have become the method of choice for confirming this diagnosis. EWSR1 gene translocation can be identified in a number of different tumors including: 1) primitive neuroectodermal tumor (PNET/Ewing sarcoma) with t(11;22)(q24;q12) involving the EWSR1/Fli-1 as well as other EWSR1 variant translocations, 2) desmoplastic small round cell tumors (DSRCT) with t(11;22)(p13;q12) involving EWSR1/WT-1, 3) clear cell sarcoma (CCS), detecting t(12;22)(q13;q12) involving EWSR1/ATF1, and 4) extraskeletal myxoid chondrosarcomas (EMCs with t(9;22)(q22;q11-12) involving EWSR1/CHN. This assay is therefore of use when these tumors are being considered in a tumor differential. Probe type: Dual color breakapart

Organ: Soft Tissue

Disease State: Small, Blue, Round Cell Tumors

CPT Code(s): 88374. The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

Turnaround Time: Within 4-6 business days of receipt

Schedule: Monday - Friday

Specimen Requirements:
• Formalin-fixed, paraffin-embedded tissue block or cell block - OR - • Minimum of 5 unstained slide cut at 4µm for each test requested