Fibronectin extra domain B (EDB) (EDB-FN)

The extra domain B (EDB) of fibronectin, also known as EIIIB, is a 91-amino acid type III homology domain that is incorporated into the fibronectin protein through alternative splicing of the pre-mRNA (UniProt P02751). Under normal physiological conditions in adults, EDB is virtually undetectable; however, it is highly expressed during embryonic development and in pathological states involving active angiogenesis and tissue remodeling (PubMed: 22403338). This restricted expression pattern makes EDB a prominent marker of neovasculature in various solid tumors, including glioblastoma, lung cancer, and colorectal cancer (PubMed: 10449144). In the tumor microenvironment, EDB-containing fibronectin facilitates cell adhesion and migration, contributing to tumor progression and metastasis (PubMed: 16401712). Because of its high stability and accessibility in the extracellular matrix, EDB has become a primary target for the development of antibody-based therapeutics and diagnostics (PubMed: 18413681). Most clinical-stage agents targeting EDB, such as Darleukin and Fibromun, utilize the L19 antibody fragment to deliver payloads like interleukin-2 or tumor necrosis factor directly to the tumor site to stimulate a localized immune response (Philogen Pipeline).

Other names

Extra domain BED-BEIIIBOncofetal fibronectinB-FNFibronectin domain EIIIB

Targeted delivery of therapeutic payloads such as cytokines, radionuclides, or cytotoxic drugs to the tumor microenvironment and neovasculature by binding to the EDB domain of fibronectin.