Inhibition of AXL signaling in anti-metastatic therapy

An isolated soluble AXL variant polypeptide, wherein said polypeptide lacks the AXL transmembrane domain and has a set of amino acid substitution(s) of the wild-type AXL sequence (SEQ ID NO.1) selected from the group consisting of 1) Gly32Ser, Asp87Gly, Val92Ala, and Gly127Arg, 2) Glu26Gly, Val79Met, Val92Ala, and Gly127Glu, 3) Asn33Ser, Ser74Asn, Asp87Gly, and Val92Ala, 4) Ala72Val, Ile97Arg, and His116Arg, 5) Gln78Glu, 6) Ala72Val, 7) Gln86Arg, Ile90Val, and Val92Ala, 8) Ala72Val, and Val92Asp, 9) Asp65Asn, and Asp87Gly, 10) Asp87Gly, and Val92Ala, 11) Glu27Lys, His61Tyr, Ala72Val, Asp88Asn, Val92Ala, and Thr98Ala, 12) Val92Ala, Gln109Arg, 13) Thr44Ala, Ala72Val, Ile90Val, Thr105Met, and Glu129Lys, 14) Val92Gly, 15) Val92Ala, Val112Ala, Phe113Leu, and Thr118Ala, 16) Val92Ala, and Thr98Pro, 17) Glu27Gly, and Asp87Gly, 18) Thr38Ile, and Val92Ala, 19) Asp87Gly, 20) Thr23Met, and Val92Ala, 21) Ala72Val, and Phe113Leu, 22) Gln86Arg, Val92Ala, 23) Ala19Thr, Glu26Gly, Glu27Gly, and Val92Ala, 24) Ile90Met and Val92Ala, 25) Gly32Ser, and Asp87Gly, 26) Gly32Ser, and Val92Ala, 27) Gly32Ser, and Gly127Arg, 28) Asp87Gly, and Gly127Arg, 29) Val92Ala, and Gly127Arg, 30) Asp87Gly, Val92Ala, and Gly127Arg, 31) Gly32Ser, Val92Ala, and Gly127Arg, 32) Gly32Ser, Asp87Gly, and Gly127 Arg, 33) Gly32Ser, Asp87Gly, and Val92Ala and 34) Gly32Ser, Ala72Val, Asp87Gly, Val92Ala, and Gly127Arg.