EWSR1 rearrangements were first identified in Ewing sarcoma, but EWSR1-rearranged neoplasms now includes many tumour subtypes.
EWSR1 gene is located in chromosome 22q12.
Here is a compilation of tumors associated with EWSR1 rearrangement. This includes latest updates from the WHO 2020 5th edition of soft tissue and bone tumors.
TUMORS ASSOCIATED WITH EWSR1-REARRANGEMENT
- Ewings sarcoma
- Desmoplastic small round cell tumor (DSRCT)
- Extraskeletal myxoid chondrosarcoma (EMC)
- Angiomatoid fibrous histiocytoma (AFH)
- Clear cell sarcoma (CCS)
- Primary pulmonary myxoid sarcoma (PPMS)
- Salivary gland hyalinizing clear cell carcinomas
- Undifferentiated round cell sarcomas with EWSR-non ETS fusion- NEW ENTITY
- EWSR1 – SMAD3 fibroblastic tumor PROVISIONAL ENTITY
- Myxoid liposarcoma (MLPS)
- Clear cell sarcoma of the gastrointestinal tract (CCSGT)
AN EASY WAY TO REMEMBER
Common EWSR1 fusion transcripts associated with Ewing’s sarcoma.
- t(11;22)(q24;q12)of FLI1-EWSR1 genes
- t(21;22)(q12q12)of ERG-EWSR1 genes
2.Desmoplastic small round cell tumor (DSRCT)
- Has pathogenic balanced translocation t(11;22)(p13;q12) of the EWSR1 gene to the Wilms tumor (WT1 gene)
3.Extraskeletal myxoid chondrosarcoma (EMC)
- t(9;22)(q22-31;q11-12): CHN-EWS fusion gene, is consistent marker for extraskeletal myxoid chondrosarcoma
4.Angiomatoid fibrous histIocytoma (AFH)
- t(12;22)(q13;q12) creating ATF1-EWSR1 gene
- t(2;22)(q33;q12) creating CREB1-EWSR1 gene
However, the most common rearrangement in angiomatoid fibrous histoocytoma is t(12;16)(q13;p11) creating ATF1-FUS fusion.
5.Clear cell sarcoma (CCS)
- t(12;22)(q13;q12): ATF1 and EWSR1
6.Primary pulmonary myxoid sarcoma (PPMS)
- EWSR1 rearrangement is seen in 85% cases. Fusion partner is usually ATF1 same as AFH and CSS.
7.Salivary gland hyalinizing clear cell carcinomas
- > 80% of cases have EWSR1-ATF1 fusion
Both have distinct morphologic features.- CHECK BELOW
- EWSR1-SMAD1 fusion
HERE IS A QUICK SUMMARY
10.Myxoid liposarcoma (MLPS)
- t(12;22)(q13;p11) – EWSR1-DDIT3 -rare
Most common translocation associated with t(12;16)(q13;p11) – FUS-DDIT3 is seen in 90%
11.Clear cell sarcoma of the gastrointestinal tract (CCSGT)
- EWSR1-CREB fusion
- EWSR1-YY1 appears to be uncommon
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Ref: WHO 5th edition soft tissue and bone tumors 2020