Axl, also known as Ufo and Ark, is a widely expressed 140 kDa glycoprotein in the TAM receptor tyrosine kinase family. Axl binds the vitamin K-dependent protein Gas6 which triggers tyrosine autophosphorylation of the Axl cytoplasmic domain. Axl functions in dampening the immune response, regulating cytokine secretion, clearing apoptotic cells and debris, and maintaining cell survival. Axl is highly expressed in solid cancers and promotes in vivo tumorigenesis and tumor cell invasiveness. It also functions as a cellular entry receptor for Gas6-opsonized lentiviruses. Axl contributes to cell survival, migration, invasion, metastasis and chemosensitivity justify further investigation of Axl as novel therapeutic targets in cancer. The receptor tyrosine kinase AXL is thought to play a role in metastasis. The soluble AXL receptor as a therapeutic candidate agent for treatment of metastatic ovarian cancer. GAS6/AXL targeting as an effective strategy for inhibition of metastatic tumor progression in vivo.