Expression of the SART‐1 tumor rejection antigen in breast cancer

We investigated in breast cancers the expression of the SART‐1 gene encoding tumor rejection antigens. SART‐1 mRNA was expressed in all of the samples tested. The SART‐1₈₀₀ antigen was detectable in 20 of 50 (40%) breast cancer tissues and all breast cancer cell lines tested, but not in normal breast tissues. The SART‐1₈₀₀⁺ breast cancer cells transfected with HLA‐A2601 or HLA‐A2402 cDNA were recognized by the HLA‐A26‐restricted and SART‐1‐specific cytotoxic T lymphocytes (CTLs) or the HLA‐A24‐restricted and SART‐1‐specific CTLs, respectively. Among the 20 SART‐1₈₀₀⁺ tumors, 9 or 8 tumors expressed estrogen receptor or progesterone receptor, respectively. Therefore, the patients with HLA‐A26 or ‐A24 haplotype might be appropriate candidates for specific immunotherapy with the SART‐1 peptides independently or in combination with hormone therapy. Int. J. Cancer 80:64–67, 1999. © 1999 Wiley‐Liss, Inc.