A polypeptide comprising the sequence of SEQ. ID NO. 2, 3, 4, 7 or 8. The polypeptide may have the sequence of an immunogenic fragment thereof comprising at least eight amino acids, wherein the immunogenic fragment is not one of SEQ. ID NOS. 6 or 11 to 16. The polypeptide may have a sequence having at least 80% sequence identity to the aforementioned polypeptide or immunogenic fragment. The polypeptide is less than 100 amino acids in length and does not comprise the sequence of any of SEQ. ID NOS. 10, 46, 56, 57 or 59 to 62 and does not consist of the sequence of SEQ ID NO. 58. The polypeptide is useful in the treatment or prophylaxis of cancer.