DUSP19 (dual specificity phosphatase 19) is an atypical MAPK phosphatase located on chromosome 2 that dephosphorylates both serine/threonine and tyrosine residues 1. The protein functions as a negative regulator of MAPK signaling pathways, particularly JNK signaling 2. DUSP19 plays protective roles in multiple pathophysiological contexts: in spinal cord injury, DUSP19 overexpression suppresses NF-κB pathway activation and reduces apoptosis and inflammatory cytokine release (IL-6, IL-8) in microglia 3. In osteoarthritis, DUSP19 acts downstream of leptin to inhibit chondrocyte apoptosis by dephosphorylating JNK, with reduced DUSP19 expression observed in OA cartilage 4. DUSP19 also regulates tumor invasiveness through VEGFR3 dephosphorylation in pancreatic neuroendocrine tumors, with PTEN transcriptionally upregulating DUSP19 expression to suppress VEGFR3 phosphorylation and reduce invasion 5. In spinal cord injury, circ_HIPK3 alleviates injury through miR-222-3p-mediated DUSP19 upregulation 6. DUSP19 participates in mitotic regulation 7 and serves as a prognostic biomarker in prostate cancer as a target of hsa-mir-503 8. These findings establish DUSP19 as a multifunctional phosphatase with therapeutic potential in inflammatory, degenerative, and neoplastic diseases.