Six-Transmembrane Epithelial Antigen of the Prostate as an Immunotherapeutic Target for Renal Cell and Bladder Cancer

Purpose: T-cell based immunotherapy for renal cell and bladder cancer is one of the most promising therapeutic approaches. STEAP is a novel cell surface protein that is over expressed in various cancers, including renal cell and bladder cancer. Recently we induced STEAP specific helper T lymphocytes that recognize the naturally processed STEAP peptide epitopes STEAP102-116 and STEAP192-206 arising from STEAP expressing tumor cells. Thus, STEAP may be a useful tumor associated antigen for designing T-cell based immunotherapy. We determined whether STEAP could induce anti-cellular immune responses to urological cancer.Materials and Methods: We selected 2 previously described STEAP derived epitope peptides, STEAP102-116 and STEAP192-206, and examined their ability to elicit helper T-lymphocyte responses by in vitro vaccination of CD4 T lymphocytes from healthy individuals and patients with cancer.Results: STEAP peptides induced helper T-lymphocyte responses using lymphocytes from healthy individuals that dir...