S100A10 (p11) is a calcium-binding protein that forms a heterotetramer with annexin A2 (ANXA2), creating the AIIt complex that regulates plasminogen activation and cellular survival mechanisms 1. S100A10 serves as the primary plasminogen receptor within this complex, mediating the conversion of plasminogen to plasmin, which promotes extracellular matrix degradation 2. The protein exhibits critical dependence on ANXA2 for stability, as S100A10 undergoes rapid proteasomal degradation in the absence of its binding partner 1. In cancer contexts, elevated S100A10 expression correlates with poor prognosis and chemoresistance across multiple cancer types, with the S100A10-ANXA2 complex preventing apoptosis in transformed epithelial cells through ROS-mediated p38MAPK pathway suppression 34. Neurologically, S100A10 functions in stress-induced depression, where its loss in specific prefrontal cortex neurons contributes to depressive behaviors that can be reversed by antidepressants 5. Additionally, S100A10 serves as an astrogliosis marker, with upregulation observed during neuroinflammatory conditions including SARS-CoV2 infection and intracerebral hemorrhage, where it facilitates protective astrocyte phenotype conversion 67. The protein's diverse functions span cancer progression, neuroplasticity, and inflammatory responses.