An active polypeptide comprising the amino acid sequence of SEQ ID NO: 3, or having at least 50%, preferably 70%, more preferably 90% identity with the amino acid sequence of SEQ ID NO: 3, or fragments thereof having at least 21 contiguous amino acids, or peptides having at least 50%, preferably 70%, more preferably 90% identity with the amino acid sequence of the fragments, provided that the polypeptide is not SEQ ID NO: 2. A method for inhibiting cancer and/or tumour growth comprising administering to a subject in need thereof an effective amount of the active polypeptide.