the invention relates to the use of polycomb group proteins as a tumour - associated antigens . polycomb group proteins are highly involved in body architecture development , haematopoiesis and cell cycle control . aberrant expression of polycomb proteins has been linked with haematological malignancies , mainly lymphomas . this invention relates to the use of these polycomb group proteins as antigens for cancer immunotherapy . immunological responses can be raised against these proteins and such responses are active against polycomb protein over - expressing tumour cells .