Sorafenib reduces tumour mass in OS xenografts in SCID mice. Histological sections derived from sorafenib untreated (a) and treated (b) xenografts stained with Hematoxylin and Eosin show massive necrosis and reduced cellularity. Sorafenib reduces blood vessel number. 40× magnification on Masson's trichromic staining of sorafenib untreated (c) and treated (d) xenografts. Sorafenib reduces lung OS foci. Pictures show representative examples (10× magnification) of OS foci in lung sections of untreated (e) and sorafenib-treated mice (f).