At POW 1, the hematoma within the interfragmentary gap of the in vivo experimental healing and non-union groups stained positively for TGF-β, FGF-b, PDGF and BMP 2/4, however, TGF-β and FGF-b staining of the hematoma in the non-union group appeared weaker than that of the healing group (Fig. 4A and Figure S1). Here, FGF2 is linked to hematoma.