The Urokinase-Type Plasminogen Activator Receptor (uPAR) as a Mediator of Physiological and Pathological Processes:...

The urokinase-type plasminogen activator receptor (uPAR) plays a pivotal role in regulating extracellular proteolysis, cell migration, immune responses, and tissue remodeling across diverse physiological and pathological contexts. This review provides detailed insights into the structure of uPAR, ligand interactions, and signaling mechanisms, emphasizing its central function in cancer progression, including tumor invasion, metastasis, angiogenesis, and modulation of the tumor microenvironment. We also summarize the involvement of uPAR as a key player in cardiovascular, infectious, and neurological diseases, where it contributes to inflammation, tissue damage, and disease progression. However, translational gaps remain, most notably inconsistent assay harmonization (especially for suPAR), uncertain context-specific cut-offs and patient-selection criteria and limited multicenter validation for uPAR-targeted imaging and therapeutics. This review addresses these gaps by synthesizing cross-disease evidence to clarify clinical use cases and outline practical selection frameworks. Furthermore, we discuss the clinical potential of uPAR as a diagnostic and prognostic biomarker in diverse disease contexts, along with recent advances in therapeutic strategies targeting uPAR.