string: …et al, 1999; Weigert et al, 2002), insulin-like growth factor 1 (IGF-1) (Brink et al, 1999; Haddad et al, 2003), basic fibroblast growth factor (bFGF) (Peng et al, 2001), vascular endothelial growth factor (VEGF) (Otani et al, 1998; Tamarat et al, 2002) and angiopoietin 2 (Otani et al, 2001).