Tumor heterogeneity as a rationale for a multi-epitope approach in an autologous renal cell cancer tumor vaccine.

PURPOSE: An autologous tumor vaccine already used successfully in the immune therapy of renal cell carcinoma was investigated in detail. The evaluation of potential tumor markers should allow for the assessment of potency according to pharmaceutical regulations. METHODS: A panel of 36 tumor-associated antigens and cellular marker proteins was characterized in a total of 133 tumor cell lysates by methods such as ELISA, Western blots, and topological proteomics. The induction of tumor-associated antigen-specific antibodies was demonstrated by immunization in mice. RESULTS: Tumor heterogeneity was demonstrated: none of the tumor-associated antigens investigated were detectable in each tumor lysate. In parallel, the coincidental presence of potential danger signals was shown for HSP-60 and HSP-70. The presence of both antigen and danger signal allowed a successful induction of an immune response in a murine model. CONCLUSION: The verified tumor heterogeneity indicates the need for a multi-epitope approach for the successful immunotherapy in renal cell carcinoma.