OY-TES-1 is a member of CT antigens, which was originally identified as the human homologue of proacrosin binding protein sperm protein 32 precursor. OY-TES-1 mRNA was expressed not only in testis but also in different malignant tissues, including bladder, breast, lung, liver, colon and epithelial ovarian cancers. About 3.5% to 10.5% of cancer patients have developed humoral immune response to OY-TES-1. A HLA-A24-binding peptide was identified and recognized by CD8+ T-cell, and thus caused cytotoxicity to tumor cells expressing OY-TES-1. More recently, researches indicated that OY-TES-1 normalized mitotic spindle function to promote cancer cell proliferation, and expressed in mesenchymal stem cells. In the mouse, two functional forms of OY-TES-1 were produced by pre-mRNA alternative splicing, and may play different role in spermiogenesis and fertilization.
