An isolated, heteroclitic WT1 peptide, wherein the isolated peptide comprises the amino acid sequence SGQAYMFPNAPYLPSCLES (SEQ ID No: 41) and has one or more point mutations in a primary or secondary anchor residue of an HLA class I or class II binding motif, or the isolated peptide has at least 83% sequence identity with the amino acid sequence SEQ ID NO:41, or the isolated peptide is 20-26 amino acids in length and comprises the amino acid sequence SGQAYMFPNAPYLPSCLES (SEQ ID NO:41), or the isolated peptide is 17 or 18 amino acids in length and comprises a fragment of the amino acid sequence SGQAYMFPNAPYLPSCLES (SEQ ID NO:41). The peptide may be for use in treating a WT1-expressing cancer in asubject.
