CHR3 encodes chordin, a secreted protein that functions as a dorsalizing factor during early vertebrate development by binding to and sequestering bone morphogenetic proteins (BMPs) in latent complexes 1. This developmental gene is expressed at high levels in 7-day mouse embryos and decreases at later developmental stages, indicating a major role during gastrulation 1. The human CHR3 gene maps to chromosome 3 and shows continued expression in fetal and adult tissues, particularly liver and cerebellum, suggesting additional roles in organogenesis and homeostasis 12. Mechanistically, chordin acts as a BMP antagonist by binding to these growth factors and preventing their signaling. Recent research has identified chordin's involvement in endometrial decidualization, where it binds to BMP1 and releases BMP4, thereby activating BMP/Smad signaling pathways essential for successful embryo implantation 3. Additionally, chordin may play roles in cancer progression and therapeutic targeting, as it has been found amplified in certain cancers and correlates with poor survival in some carcinomas 4. The protein also participates in novel therapeutic mechanisms involving lysosomal metabolism and regulatory T cell depletion in cancer treatment 5.