The FNDC3B antibody targets the Fibronectin type III domain-containing protein 3B (FNDC3B), a transmembrane or secreted protein characterized by multiple fibronectin III (FN3) domains. FNDC3B is implicated in cellular adhesion, migration, and signaling, though its precise biological functions remain under investigation. Research highlights its potential role in cancer progression, particularly in metastasis and drug resistance. For instance, FNDC3B overexpression has been linked to enhanced invasiveness in hepatocellular carcinoma and breast cancer, possibly through interactions with signaling pathways like TGF-β or via modulation of extracellular matrix dynamics. Additionally, FNDC3B may regulate protein stability through partnerships with deubiquitinating enzymes such as USP15. Antibodies against FNDC3B are essential tools for detecting its expression patterns in tissues or cell lines via techniques like Western blotting, immunohistochemistry, or immunofluorescence. These antibodies aid in studying its subcellular localization, post-translational modifications, and interactions with binding partners. Emerging evidence also suggests FNDC3B involvement in non-cancer contexts, including neural development and lipid metabolism, broadening its research relevance. Commercial FNDC3B antibodies are typically validated for specificity using knockout controls or siRNA-mediated silencing. Despite progress, further studies are needed to fully elucidate its molecular mechanisms and therapeutic potential.