Immunotherapies Towards Tumor Initiating Cells and Cancer Stem Cells

Active immunotherapy of cancer is a promising treatment modality by inducing long lived tumor reactive im- mune effector cells. Several vaccine trials have indicated that its effectiveness is probably best when the tumor burden is low. An attractive population of cells to target by this approach may be tumor initiating cells (TICs). Recent research sug- gests that such types of cells may be precursors to cancer possibly giving rise to metastatic disease. Although more work is being done to characterize appropriate phenotypic and functional markers, this population of cells would make an ideal target for active immunotherapy in high risk patients, so as to achieve remission over much longer periods of time. This review gives an overview of the potential of immunotherapy and how it may target TICs as a potential treatment option for cancer patients.