Fibroblast growth factor-4 (FGF-4) plays an important physiologically role in the self-renewal of human embryonic stem cells (PMID 21990129). It also promotes stem cell proliferation and may aid in differentiation. Xeno-free Recombinant Human FGF-4 is expressed in human 293 cells as a monomeric glycoprotein with an apparent molecular mass of 17 and 27 kDa.