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  • 254M-1 - FLI-1 (MRQ-1) Mouse Monoclonal Antibody

254M-1 Sigma-Aldrich

FLI-1 (MRQ-1) Mouse Monoclonal Antibody

  •  NACRES NA.41



Related Categories Alphabetical Index, Antibodies, Cell Marque Antibodies, FK-FO, Primary Antibodies,
conjugate   unconjugated
clone   MRQ-1, monoclonal
biological source   mouse
application(s)   immunohistochemistry (formalin-fixed, paraffin-embedded sections): 1:25-1:100
species reactivity   human
form   buffered aqueous solution
shipped in   wet ice
storage temp.   2-8°C
packaging   vial of 0.1 mL concentrate (254M-14)
  vial of 0.5 mL concentrate (254M-15)
  bottle of 1.0 mL predilute (254M-17)
  vial of 1.0 mL concentrate (254M-16)
  bottle of 7.0 mL predilute (254M-18)
antibody form   culture supernatant
isotype   IgG2b
Quality Level   100
antibody product type   primary antibodies
description   For In Vitro Diagnostic Use in Select Regions (See Chart)
mfr. no.   Cell Marque
concentration   1.0-10.0 μg/mL (predilute)
  40-400 μg/mL (concentrate)
control   pnet
visualization   nuclear


General description

Ewing sarcoma/peripheral primitive neuroectodermal tumor (ES/PNET) is a rare primary tumor of the bone/soft tissue that resembles other undifferentiated tumors. The differential diagnosis of undifferentiated tumors of the soft tissue includes blastemal Wilms tumor, rhabdoid tumor, neuroblastoma, lymphoma, clear cell sarcoma, small cell carcinoma, synovial sarcoma (SS), neuroblastoma, desmoplastic small round cell tumor (DSRCT), and ES/PNET. It is important to correctly classify these tumors for appropriate treatment. The most common primitive renal tumor, Wilms tumor, responds well to a standard regimen of multiagent chemotherapy, whereas renal ES/PNET tends to be a high-stage, aggressive neoplasm that requires more extensive therapy .

The FLI-1 gene and FLI-1 protein are best known for their critical role in the pathogenesis of ES/PNET. More than 85% of ES/PNET are characterized by the translocation t(11;22)(q24;q12) that results in the fusion of the ews gene on chromosome 22 to the FLI-1 gene on chromosome 11. FLI-1 is a member of the ETS (erythroblastosis virus-associated transforming sequences) family of DNA-binding transcription factors and is involved in cellular proliferation and tumorigenesis. FLI-1 is normally expressed in endothelial cells and in hematopoietic cells, including T lymphocytes. The immunohistochemical detection of FLI-1 protein has been shown in two recent studies to be valuable in the discrimination of ES/PNET from most of its potential mimics, with the notable exception of lymphoblastic lymphoma.

The FLI-1 gene has also recently been shown to play an important role in the embryologic development of blood vessels. Expression of FLI-1 protein in adult endothelial cells in all types of blood vessels (arterial, venous, and lymphatic) has previously been shown both in our previous work and in that of Nilsson et al.

Folpe et al. found FLI-1 to be a highly sensitive (92%) and, with regards to the cases evaluated in this study, specific (100%) marker of both benign and malignant vascular tumors. The “absolute specificity” of FLI-1 is of course lower, given its expression in ES/PNET and lymphomas. FLI-1 expression appears to be the first reliable nuclear marker of endothelial differentiation. In particular, Folpe et al. found that FLI-1 reliably distinguished epithelioid forms of angiosarcoma from two important mimics, epithelioid sarcoma and carcinoma.

Assoc. products: WT-1, CD99, Synaptophysin, Chromogranin A, CK AE1/AE3

Physical form

Solution in Tris Buffer, pH 7.3-7.7, with 1% BSA and <0.1% Sodium Azide

Legal Information

Cell Marque is a trademark of Sigma-Aldrich Co. LLC







FLI-1 Positive Control Slides, Product No. 254S, are available for immunohistochemistry (formalin-fixed, paraffin-embedded sections).

Preparation Note

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Other Notes

For Technical Service please contact: 800-665-7284 or email: service@cellmarque.com

Safety & Documentation

Safety Information

NONH for all modes of transport
WGK Germany 
Flash Point(F) 
Not applicable
Flash Point(C) 
Not applicable


Certificate of Analysis (COA)

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Protocols & Articles


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254S FLI-1 Positive Control Slides, suitable for immunohistochemistry (formalin-fixed, paraffin-embedded sections) 

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