Owing to the intense effort of numerous investigators, the number of tumour antigens potentially of use for clinical immunotherapy continues to increase. At the same time, further strategies employed by tumour cells to avoid destruction by the immune system are being uncovered. A combined onslaught to target tumour cells and prevent their "escape" will be required for successful immunotherapy. Progress in this area was the subject of a meeting supported by the European Cancer Research Consortium "EUCAPS", which was held in London in February 2000. This conference was the second of a series, the first of which was summarised previously in this journal [Pawelec G et al. (1999) Cancer Immunol Immunother 48: 214].