The observation that dendritic cells (DCs) charged with tumor-associated antigens (TAAs) is a potent strategy to elicit protective immunity in tumor-bearings hosts has prompted extensive testing of DCs as cellular adjuvant in cancer vaccines. To improve the clinical development of DC-based cancer vaccines, it may be beneficial to analyze preexistent immunity against TAAs in cancer patients because it may be easier to expand a memory pool of T cells compared to generating new immunity. Recent research shows that engineering DCs to synthesize tumor epitopes endogenously by transfecting DCs with mRNA-encoding TAAs are particular effective in stimulating robust T-responses in vitro and in vivo. In this chapter, we describe the methodology to analyze for survivin-specific T cells in breast cancer patients using human DCs engineered with survivin mRNA.