PFDN5 (prefoldin subunit 5) functions as a molecular chaperone that binds nascent polypeptides and facilitates their transfer to the cytosolic chaperonin complex, promoting proper protein folding in competitive cellular environments. Beyond its canonical chaperoning role, PFDN5 associates with microtubules and suppresses Tau aggregation, with neuronal overexpression ameliorating Tau-induced neurodegeneration and memory deficits 1. PFDN5 also represses MYC transcriptional activity and regulates multiple cellular pathways including cell cycle progression and TGF-β signaling 2. Clinically, PFDN5 serves as a prognostic biomarker across multiple diseases. In B-cell acute lymphoblastic leukemia, reduced cerebrospinal fluid PFDN5 reactivity predicts central nervous system leukemia development 3. Anti-PFDN5 antibodies constitute a novel biomarker for uveitis in ankylosing spondylitis, with elevated antibodies correlating with disease presence 4. PFDN5 shows differential expression in focal segmental glomerulosclerosis and gastric cancer, with potential diagnostic and therapeutic applications 52. In breast cancer, lower PFDN5 expression associates with poorer prognosis, though PFDN5 paradoxically promotes both G2/M arrest and enhanced migration, while favorably influencing tumor immune microenvironment through macrophage polarization 6. PFDN5 also represents a therapeutic target in hepatic fibrosis via PI3K/AKT pathway regulation 7.