To date, tumor-specific cellular therapy has been successful primarily when well-defined viral associated antigens can be defined and targeted. Multiple potential tumor-associated antigens have been identified but development of targeted cellular therapy has been limited by inability to generate sufficient, HLA-restricted T cells, and in the case of patients who have had prior allogeneic SCT, donor T cell senescence has limited ability to expand tumor-specific T cells [20] . This technical advance is important since it permits generation of CTLs against multiple tumorassociated antigens and therefore may reduce the risk of tumor escape; it is likely that multiple antigens will need to be targeted for maximal efficacy. Furthermore, the ability to generate CTLs with multiple specificities markedly increases the efficiency of this approach and eliminates the need for specific polymorphic HLA-restriction. It will be of interest to see if activation by this method can reverse functional tolerance or senescence in patients with primary disease or after allogeneic stem cell transplantation.