PSG11 (pregnancy-specific beta-1-glycoprotein 11) is a member of the pregnancy-specific glycoprotein family, which represents the most abundant trophoblastic proteins in maternal blood during human pregnancy 1. PSG11 is located on chromosome 19.1-13.3 within a cluster of 11 PSG genes and belongs to subgroup 3 based on its C-terminal exon structure 2. The protein exhibits immunoregulatory functions, particularly in stimulating interleukin-10 (IL-10) secretion from monocytes 3. PSG11 expression in the uterine endometrium during the peri-implantation period is significantly reduced in women with recurrent first-trimester abortions compared to controls, suggesting a role in pregnancy maintenance 3. The gene shows cell-cell adhesion properties and is regulated by epigenetic mechanisms, with CTCF depletion leading to downregulation of PSG11 expression 4. Clinical studies have identified PSG11 as a potential biomarker, with copy-number deletions enriched in preeclampsia patients 5 and altered expression levels associated with ectopic pregnancy diagnosis 6. These findings indicate PSG11 plays important roles in maternal-fetal immune tolerance and pregnancy outcome prediction.