CTAGE4 is a tumor-associated antigen belonging to the CTAGE gene family with expression patterns suggesting roles in cancer and development. The protein localizes to the endoplasmic reticulum (ER) and participates in ER-to-Golgi vesicle-mediated transport and protein secretion pathways, indicating involvement in secretory protein trafficking [GO annotations]. CTAGE4 demonstrates tumor-specific expression and generates serologic responses in cancer patients, including those with cutaneous T cell lymphoma and melanoma, suggesting immunogenic properties 1. Notably, CTAGE4 expression is upregulated in triple-negative breast cancer cells treated with combinatorial JQ1 and GSK2801 therapy, indicating involvement in drug-responsive transcriptional networks 2. Beyond cancer, CTAGE4 genetic variants have been associated with severe retinopathy of prematurity in preterm infants 3 and implicated in rare multisystemic disorders involving growth retardation, intellectual disability, and hepatopathy 4, suggesting broader developmental significance. The gene represents a candidate for cancer immunotherapy development given its tumor-specific expression pattern and ability to elicit immune responses, though its precise mechanistic role in disease pathogenesis remains incompletely characterized.