**2. DC-based vaccines**

Since cancer in fact develops and evolves in the presence of an intact immune system TAAs are by definition inadequately immunogenic. This results in a suboptimal T-cell activation, induction of immune tolerance and thus an ineffective immune reaction. Cancer vaccines are intended to break this immune tolerance. Strong presentation of antigen by antigenpresenting cells (APCs) is essential. Dendritic cells (DCs), which are the most powerful APCs, are known to be deficient in number and function in cancer patients. Activating APCs that are able to appropriately process and present the TAA is pivotal to activating an adaptive immune response and breaking peripheral tolerance.
