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Updated: Jan 10, 2026
Single-Molecule Imaging of EWS-FLI1 Condensates Assembling on DNA
Published on: September 8, 2021
A Novel FLI1 Monoclonal Antibody Which Recognizes EWS::FLI1 with High Affinity Is Useful for Detecting Ewing Sarcoma
Saravana P Selvanathan1, Olivia O Lansinger1, David V Allegakoen1
1Departments of Oncology and Pediatrics, Georgetown University, Washington, DC 20057, USA.
Background:
Ewing sarcoma (ES) is a rare tumor that affects children, adolescents, and young adults. ES is associated with high morbidity in all patients and high mortality for those who present with metastatic disease. A chromosomal translocation, either t(11;22)(q24;p12) or t(21;22)(q22;q12) leads to the fusion oncoproteins EWS::FLI1 or EWS::ERG in 95% of ES patients. We recognized a critical need for a stably sourced high-affinity antibody that recognizes EWS::FLI1 with maximal specificity. Understanding EWS::FLI1 protein complexes is a pivotal gap in ES knowledge that necessitates the development of antibodies capable of identifying native proteins in solution. Further, variable epitope sequencing of a monoclonal antibody enables the construction of degraders and nanobody identifiers.
Methods:
Monoclonal antibodies were produced following informed peptide synthesis, injection, and hybridoma creation. Hybridoma antibodies were validated for specificity and function.
Results:
Our results indicate that the FLI1 1.2 monoclonal antibody, which recognizes the EWS::FLI1 fusion oncoprotein, can be reliably applied to multiple molecular biology applications like immunoblot, immunoprecipitation, immunofluorescence, and immunohistochemistry. This FLI1 1.2 monoclonal antibody has a high affinity of 0.3 nM KD to EWS::FLI1. In terms of specificity, this antibody is highly specific to EWS::FLI1 and some cross reactivity with ERG.
Conclusions:
This reagent will provide the research community with valuable tools for further biochemical and genomic interrogation of the oncogenic activity of EWS::FLI1 in ES.
