CD164 is a sialomucin expressed on primitive hematopoietic progenitor cells that plays multifaceted roles in stem cell biology and disease. Its primary function involves regulating hematopoietic stem cell (HSC) adhesion and proliferation: CD164 mediates adhesion of CD34+ cells to bone marrow stroma while negatively regulating CD34+CD38lo/- cell proliferation 1. CD164 serves as a reliable marker for identifying the earliest branches of HSPCs specification and enriching both hematopoietic and skeletal stem cells for transplantation 23. The molecule modulates HSC migration through the CXCL12/CXCR4 axis and influences HSC homing 4. Beyond hematopoiesis, CD164 demonstrates oncogenic properties in glioblastoma, where overexpression promotes proliferation and progression via the AKT/PTEN pathway and autophagy signaling 56. In spermatogenesis, CD164 downregulation in idiopathic nonobstructive azoospermia promotes spermatogonial apoptosis, linking it to male infertility 7. CD164 is also essential for skeletal stem cell diversity and regeneration across skeletal sites 8. Germline variants in CD164 show opposite associations with different clonal hematopoiesis subtypes, suggesting key roles in hematopoietic disease susceptibility 4.