Effects of sorafenib on RAF1 expression in HHUA-SP- and -MP-derived tumors in mice. Immunofluorescence staining of RAF1 and VM in HHUA-SP- and -MP-derived tumors in mice treated orally with or without sorafenib for 2 weeks (A) or 4 weeks (B). DAPI was used for nuclear staining. Note that sorafenib decreased the expression of RAF1 in SP-derived tumors compared with the vehicle control after 4 weeks, which is consistent with the results shown in Fig. 5C. Scale bar, 200 μm.