IMMUNOTHERAPY OF COLORECTAL-CANCER

Research and clinical interest in the therapy of cancer and in adjuvant therapy for preventing cancer recurrence involve the application of sophisticated immunological techniques to the recognition and destruction of tumour targets. The current status of immunotherapy for advanced colorectal cancer includes modifications of monoclonal antibodies that recognise surface glycoproteins of colorectal cancer cells in a relatively specific fashion. These have been used successfully for imaging studies and in preclinical therapeutic trials. Attempts are under way to find the optimum radioisotope for antibody labelling in order to maximise therapeutic efficacy while maintaining low toxicity. Chemical and molecular modifications of antibody molecules are directed at improving their therapeutic efficacy while reducing their immunogenicity. The advent of genetic engineering techniques has now enabled the production of cytotoxic lymphocytes that are independent of histocompatibility restrictions. Such cells possess engineered tumour antigen specificity that endows them with the ability to recognise and be activated by tumour cells bearing the antigen of interest. Transgenic tumour cell vaccines composed of irradiated tumour cells secreting selected cytokines may be useful in the adjuvant therapy of colorectal cancer and may complement approaches using transgenic effector lymphocytes. Finally, the extension of genetic engineering techniques to produce tumour cells expressing high concentrations of optimally presented immunodominant peptides of their tumour antigens and/or accessory molecules involved in effector cell triggering is likely to lead to effective vaccines for solid tumours in the near future.