Positive test controls include: Rat liver. Immunogen sequence: MGLIWLLLLS LLEPGWPAAG PGARLRRDAG GRGGVYEHLG GAPRRRKLYC ATKYHLQLHP SGRVNGSLEN SAYSILEITA VEVGIVAIRG LFSGRYLAMN. Fibroblast growth factors (FGFs) can stimulate the proliferation of mesenchymal,