FLT1 and acute myeloid leukemia: Sorafenib (Figure 2), a multi-kinase inhibitor with N,N-diphenyl urea structure that can inhibit the activity of c-RAF, b-RAF, c-KIT, FLT3, PDGFR-α/β, and VEGFR-1/2/3 is usually used in tumor treatment, especially in acute myeloid leukemia (AML) clinical trials [15,16].