PSG6 (pregnancy-specific beta-1-glycoprotein 6) is a secreted placental protein belonging to the pregnancy-specific glycoprotein family, located in the extracellular region and involved in female pregnancy 1. PSG6 is expressed by trophoblastic cells and detectable in maternal serum from early pregnancy 1. The gene is regulated epigenetically through CTCF-mediated transcriptional control, with expression influenced by histone modifications at its promoter 2. PSG6 expression is transcriptionally regulated and can be stimulated by sodium butyrate, with the promoter region (-809/-44 bp) containing cis-acting regulatory sequences 3. Clinically, PSG6 serves as a potential diagnostic biomarker for placenta accreta spectrum (PAS), with expression progressively decreasing from placenta increta to percreta 1. PSG6 is significantly elevated in gestational diabetes mellitus (GDM) compared to obese controls, linking it to altered glucose metabolism 4. In early pregnancy complications, PSG6 is one of several pregnancy-specific glycoproteins that distinguish ectopic pregnancy from intrauterine pregnancy when used in multivariable biomarker panels 5. Additionally, elevated PSG6 expression is associated with increased mortality in gastric adenocarcinoma patients 6. These findings establish PSG6 as a multi-functional biomarker relevant to both pregnancy complications and cancer prognosis.