Stains & molecular markers
FLI1
Copyright: 2003-2021, PathologyOutlines.com, Inc.
PubMed Search: FLI1
FLI1
Author: Lauren N. Stuart, M.D., M.B.A.
Topic Completed: 1 June 2013
Minor changes: 7 December 2020
Copyright: 2003-2021, PathologyOutlines.com, Inc.
PubMed Search: FLI1
Table of Contents
Definition / general | Uses by pathologists | Microscopic (histologic) images | Positive staining - normal | Positive staining - disease | Negative stainingCite this page: Stuart L. FLI1. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/stainsfli1.html. Accessed January 16th, 2021.
Definition / general
- Protein is member of ETS family of DNA binding transcription factors; gene is fli-1, on #11q24
- Also called Friend leukaemia integration-1
- Involved in cellular proliferation, tumorigenesis and embryologic development of blood vessels
- Interpretation: call positive if nuclear staining of 10% of tumor cells (usually is > 50%) and positive internal controls of endothelial cells and small lymphocytes (Am J Surg Pathol 2001;25:1061)
- Note: other vascular tumor markers (CD31, CD34 and von Willebrand factor) are membranous or cytoplasmic stains
- Note: cytoplasmic staining is present in breast epithelium (benign / malignant) and cutaneous eccrine glands
Uses by pathologists
- Diagnosis of Ewing sarcoma (sensitive and specific marker)
- 90% of Ewing sarcoma / primitive neuroectodermal (PNET) tumors have t(11;22)(q24;q12), which results in fusion of EWS to FLI1
- Distinguish Ewing sarcoma / PNET of kidney (positive) from blastema predominant Wilms tumor (negative)
- Distinguish Ewing sarcoma / PNET (positive) from small cell osteosarcoma or mesenchymal chondrosarcoma (negative, Appl Immunohistochem Mol Morphol 2011;19:233)
- Sensitive and specific for vascular tumors versus sarcomas, carcinomas or melanomas (Am J Surg Pathol 2001;25:1061)
Microscopic (histologic) images
Images hosted on other servers:
D: normal kidney
D: normal spleen and lymph node
Ewing sarcoma / PNET
Maxilla: desmoplastic small round cell tumor
Various tumour types
Merkel cell carcinoma (negative)
Positive staining - normal
- Endothelial cells, T cells and small lymphocytes
Positive staining - disease
- Ewing sarcoma / PNET, vascular tumors
- Variable for desmoplastic small round cell tumor, lymphoma (Appl Immunohistochem Mol Morphol 2009;17:409), melanoma (Histol Histopathol 2008;23:1309), Merkel cell carcinoma (J Clin Pathol 2007;60:694)
Negative staining
- Muscle, nerve and fibroblasts
- Blastema predominant Wilms tumor
- Carcinoma and nonvascular sarcoma
