Expression of SART3 Tumor‐rejection Antigen in Gastric Cancers

We previously reported SART3 as a tumor‐rejection antigen recognized by histocompatibility leukocyte antigen (HLA)‐A24‐restricted cytotoxic T lymphocytes (CTLs). In this study, we investigated the expression of the SART3 antigen in gastric cancers, as a candidate for use in specific immunotherapy. The SART3 antigen was detected in 9 of 10 (90%) gastric cancer cell lines, 35 of 52 (67.3%) gastric cancer tissues, and 0 of 20 non‐tumorous gastric tissues. SART3‐derived peptides corresponding to positions 109–118 and 315–323 induced HLA‐A24‐restricted and tumorspecific CTLs from peripheral blood mononuclear cells (PBMCs) of gastric cancer patients. These peptide‐induced CTLs recognized HLA‐A24(+) SART3(+) gastric cancer cells, but not HLA‐A24(+) SART3(−) or HLA‐A24(−) SART3(+) gastric cancer cells. Therefore, the SART3 peptides could be useful in specific immunotherapy of gastric cancer patients.