In contrast to 2 weeks of treatment, 4 weeks of sorafenib significantly reduced tumor weight and volume (Fig. 4D and Additional file 4: Fig. S4A), together with decreased staining intensity of MDR1 (Fig. 4E and Additional file 4: Fig. S4B) and Ki67 (Fig. 4F and Additional file 4: Fig. S4C), in HHUA-SP-derived tumors. This evidence concerns the gene ABCB1 and neoplasm.