RAF1 and fibrosarcoma: The Raf/MEK/ERK signalling pathway (Raf = rapidly accelerated fibrosarcoma, MEK = MAPK/ERK kinase, ERK = extracellular signal–regulated kinases) is recognized as the mitogen-activated protein kinase (MAPK) cascade comprising guanosine-nucleotide-binding protein RAS (GTPase) which stimulates Raf-family proteins including A-Raf, b-Raf and c-Raf/Raf1 [6].