Adoptive immunotherapy involves the transfer of immune effectors with antitumour activity into the tumour bearing host. Early approaches such as lymphokine activator killer (LAK) cells and tumour infiltrating lymphocytes (TILs) have yielded occasional clinical responses. More recently, attempts to stimulate and/or select antigen-specific T-cells in vitro have demonstrated that tumour-specific adoptive immunotherapy is possible. These approaches require complicated and time consuming in vitro stimulation procedures. Therefore, genetic modification of bulk T-cell populations is an attempt to create a large population of T-cells with a single specificity. In addition to work being done to develop the most potent effector, other studies are working on improving T-cell trafficking to tumours and interfering with the tumour-induced immunosuppression that can impair in vivo T-cell activity.