FLI1

Overview

FLI1 (Friend leukemia integration 1 transcription factor) is an ETS-family transcription factor. It is most prominently known as the C-terminal fusion partner in the EWSR1::FLI1 fusion oncogene, which defines the majority of Ewing sarcomas. The fusion protein acts as an aberrant transcription factor that rewires gene expression programs in the cell of origin.

Alterations observed in the corpus

  • EWSR1::FLI1 fusion expressed in heMSCs is sufficient to induce Ewing sarcoma–like transcriptome, BRCA1 dysregulation, DDR defect, and metastatic tumor formation; binds intronic CA microsatellites in stem cell context vs GGAA microsatellite enhancers in established Ewing lines PMID:25186949
  • EWSR1-FLI1 fusion in 101/112 Ewing sarcoma WGS discovery-cohort tumors; most common ETS-family fusion partner of EWSR1 and defining molecular event PMID:25223734
  • Recurrent ETS fusion in mCRPC (part of 56% ETS-fusion prevalence) PMID:26000489
  • Defines a rare ETS-fusion subtype (1%) in primary prostate cancer; three tumors had fusions involving more than one ETS gene, likely reflecting convergent clonal evolution PMID:26544944
  • FLI1 partner in EWSR1-FLI1 fusion identified in an odontogenic tumor reclassified as Ewing sarcoma (ES) with epithelial differentiation via NGS using MSK-IMPACT PMID:27442865
  • EWSR1–FLI1 fusion diagnostic of Ewing sarcoma (ES) in two pediatric patients in the PIPseq cohort; fusion detection by RNA-seq; one patient showed a poor-prognosis transcriptomic signature including high FLI1 expression PMID:28007021.
  • FLI1 fusions (e.g., EWSR1-FLI1) are the canonical oncogenic driver in Ewing sarcoma, reported in this cohort study PMID:28199314
  • EWSR1-FLI1 fusion detected in n=25 Ewing sarcoma (ES) cases within the MSK-IMPACT pan-cancer cohort of 10,336 patients PMID:28481359
  • FLI1 catalogued in the TCGA pan-cancer fusion atlas (9,624 samples, 33 cancer types) as an ETS-family fusion partner; EWSR1-FLI1 is the canonical Ewing sarcoma (SARC) fusion. PMID:29617662

Cancer types (linked)

  • Ewing sarcoma: defined by EWSR1::FLI1 (or variant EWSR1::ETS fusions) in ~85% of cases.

Co-occurrence and mutual exclusivity

Therapeutic relevance

Open questions

Sources

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This page was processed by wiki-cli on 2026-05-14. - PMID:28199314

This page was processed by wiki-cli on 2026-05-14. - PMID:28481359

This page was processed by wiki-cli on 2026-05-15. - PMID:29617662

This page was processed by wiki-cli on 2026-05-15.