MAGEA11 is an X-linked cancer-germline antigen and androgen receptor (AR) coregulator that functions as a proto-oncogenic transcriptional coactivator 1. Structurally, MAGEA11 contains a conserved FXXIF coactivator-binding motif and nuclear localization signal acquired during primate evolution, enabling interaction with p160 coactivators, p300 acetyltransferase, and cyclin A 1. Mechanistically, MAGEA11 enhances AR transcriptional activity by modulating interdomain interactions and can form protein complexes with other MAGE proteins (e.g., MAGEA6) to stabilize and potentiate AR coactivation, preventing ubiquitin-dependent degradation 2. MAGEA11 expression is epigenetically regulated; DNA methylation at the promoter and a single Ets site regulates nucleosome occupancy at the transcriptional start site, controlling gene activation in response to DNMT/HDAC inhibition 3. In disease contexts, MAGEA11 overexpression associates with multiple malignancies. In gastric cancer, MAGEA11 promotes proliferation, migration, and invasion via E2F1 transcriptional activation and predicts poor prognosis 4. MAGEA11 is frequently expressed across human cancers with increased expression during tumor progression and correlates with poor survival 3. In polycystic ovary syndrome, elevated MAGEA11-AR complex formation in the endometrium causes delayed decidualization and impaired endometrial receptivity, contributing to infertility 5. MAGEA11 inhibits tumor suppressor pathways controlling growth inhibition and apoptosis 6. As a cancer-germline gene with restricted expression, MAGEA11 represents a potential immunotherapy target.