FGF basic, also known as FGF-2 and HBGF-2, is a member of the FGF superfamily of mitogenic proteins which show 35-60% amino acid conservation. Human FGF acidic shares 54% amino acid (aa) sequence identity with FGF basic and 17%-_x001F_33% with other human FGFs. It shares 92%, 96%, 96%, and 96% aa sequence identity with bovine, mouse, porcine, and rat FGF acidic, respectively, andexhibits considerable species crossreactivity. Alternate splicing generates a truncated isoform of human FGF acidic that consists of the Nterminal 40% of themolecule and functions as a receptor antagonist. The effects of androgen and FGF-2 could be partly reversed with a specific anti-FGF-2 immunoglobulin G or by suramin, which inhibits binding of FGFs to their high affinity receptors. Additionally, bFGF is frequently used for a critical component of cell culture medium, e.g., human embryonic stem cell culture medium, serum-free culture systems.