CTAGE1 (cutaneous T cell lymphoma-associated antigen 1) functions as a cancer-testis antigen that is normally restricted to testicular germ cells but becomes aberrantly expressed in various malignancies 1. The gene belongs to a rapidly expanding primate-specific gene family that underwent significant duplication events during human evolution, with positive selection acting on single-exon copies 2. CTAGE1 localizes to the endoplasmic reticulum membrane and participates in protein secretion and vesicle-mediated transport from the ER to Golgi apparatus. In pathological contexts, CTAGE1 is robustly expressed in cutaneous T-cell lymphoma (CTCL) patients and cell lines, distinguishing malignant tissue from normal skin and benign inflammatory conditions 1. The gene is also expressed across all tested high-grade glioma cell lines, suggesting broader oncological relevance 3. Additionally, genetic variants in CTAGE1, particularly rs4331426, have been associated with tuberculosis susceptibility, with meta-analyses showing increased TB risk especially in African populations 45. The ectopic expression of CTAGE1 in cancers makes it a potential biomarker for malignancy and a candidate target for cancer immunotherapy, though its precise molecular mechanisms in disease pathogenesis require further investigation.