Compositions and methods for diagnosis and treatment of cancer

A recombinant nucleic acid encoding a Fibronectin Extra Domain B (EDB) binding peptide, wherein said peptide comprises the amino acid sequence:

• (SEQ ID NO:
• 4)
• (Xaa)n1 Cys(Xaa)n2 Arg Ile/Val Arg Leu(Xaa)n3
• Cys(Xaa)n4 Cys(Xaa)n5 Cys (Xaa)n6 Cys(Xaa)n7
• Cys(Xaa)n8,
• wherein
• the Cys residues form a cystine knot structure,
• each Xaa is independently any amino acid, and n1, n2, n3, n4, n5, n6, n7, and n8 are the respective numbers of amino acids, wherein
• n1 is 0 to 4,
• n2 is 3 to 10,
• n3 is 0 to 3,
• n4 is 3 to 7,
• n5 is 2 to 6,
• n6 is 1 to 3,
• n7 is 3 to 7, and
• n8 is 0 to 4, and
• each amino acid Xaa and the number of amino acids n1, n2, n3, n4, n5, n6, n7 and n8 are selected such that a cystine knot structure can form between the Cys residues;
• and wherein the recombinant nucleic acid is in the form of a vector or RNA.