The EBAG9 (Estrogen Receptor-Binding Site Associated Antigen 9) gene, also known as RCAS1. encodes a protein initially identified for its estrogen receptor (ER)-binding properties. It is broadly expressed in hormone-responsive tissues and cancers, including breast, prostate, and ovarian malignancies. EBAG9 has dual roles in cancer progression and immune regulation. It promotes tumorigenesis by enhancing cell proliferation, inhibiting apoptosis, and facilitating metastasis. Simultaneously, EBAG9 modulates immune responses by suppressing the exocytosis of cytotoxic granules in cytotoxic T lymphocytes (CTLs), thereby impairing antitumor immunity—a mechanism linked to tumor immune evasion.
EBAG9 antibodies are critical tools for studying its expression patterns, molecular interactions, and pathophysiological roles. These antibodies enable detection of EBAG9 in clinical samples via techniques like immunohistochemistry (IHC) and Western blotting, revealing its overexpression in various cancers correlating with poor prognosis. Researchers also utilize EBAG9 antibodies to explore its regulatory networks, such as ER-dependent signaling and interactions with apoptosis-related proteins (e.g., caspases). Recent studies highlight EBAG9's potential as a therapeutic target, with antibody-based strategies aiming to neutralize its immunosuppressive effects or inhibit oncogenic functions. Despite progress, the precise mechanisms underlying EBAG9's pleiotropic roles remain under investigation, emphasizing the continued importance of specific antibodies in advancing both basic and translational research.