Extra domain B variant of fibronectin (ED-B (also seen as EDB, ED-B FN))

The extra domain B (ED-B) variant of fibronectin is a specific alternative splice isoform of the ECM protein fibronectin, in which a 91-amino acid segment (the ED-B domain) is inserted into the fibronectin molecule via alternative splicing[2][5]. ED-B fibronectin is virtually absent from most adult tissues but is highly expressed during embryogenesis, tissue repair, and pathologically in newly formed blood vessels in tumors and some diseases, making it an "oncofetal" marker[4][5]. The ED-B domain alters the conformation and adhesive properties of fibronectin, contributing to enhanced cell adhesion and promoting angiogenesis by interacting with integrin receptors (notably αvβ3) on endothelial cells[3][5]. This expression pattern makes ED-B an attractive therapeutic target for imaging and selective delivery of drugs to tumor vasculature. Antibody-based therapies and imaging agents, such as L19 and L19-IL2, have been developed to exploit ED-B as a tumor-specific marker, underscoring its role as a target in cancer therapy and diagnosis[5][2][3].

Other names

ED-BExtra domain B (EDB)Oncofetal fibronectinED-B fibronectinEIIIB domainED-B-containing fibronectin

Antibody-binding to ED-B for selective delivery of therapeutic payloads (e.g., cytokines, radionuclides) to tumor vasculature - Blocking or interfering with FN-EDB interactions with integrins, which can inhibit angiogenesis