Extra Domain B of fibronectin (EDB)

The Extra Domain B (EDB) of fibronectin, also known as the EIIIB splice variant domain, is a 91-amino acid type III repeat that is inserted into the fibronectin molecule via alternative splicing of the pre-mRNA [1.1.1, 1.2.1]. It is considered an oncofetal antigen because it is abundantly expressed during embryonic development and in various pathological states—such as solid tumors, chronic inflammation, and tissue repair—while remaining virtually undetectable in healthy adult tissues [1.3.2, 1.5.5]. In the context of cancer, EDB is prominently deposited in the tumor stroma and around newly formed blood vessels, where it plays a critical role in promoting tumor cell adhesion, migration, and angiogenesis [1.1.1, 1.3.4]. Due to its highly restricted expression pattern and accessibility within the extracellular matrix, EDB has become a major target for vascular targeting and stroma-directed therapies [1.2.1, 1.5.2]. Therapeutic approaches include the use of high-affinity antibodies, such as the L19 fragment, to deliver cytotoxic drugs, cytokines, or radioisotopes specifically to the tumor microenvironment [1.5.2, 1.5.4]. Additionally, EDB serves as a valuable diagnostic and prognostic biomarker for imaging tumor neovascularization and monitoring therapeutic response [1.2.2, 1.3.4].

Other names

EIIIB splice variant domain of fibronectinED-B fibronectinEDB-FNOncofetal fibronectinExtra type III domain BEIIIB exon

Targeted delivery of therapeutic payloads (cytotoxins, cytokines, or radionuclides) to the tumor microenvironment and neovasculature; inhibition of angiogenesis and tumor cell invasion by disrupting extracellular matrix-cell interactions.