PTP4A1 is a protein tyrosine phosphatase that plays diverse roles in cellular signaling and disease pathogenesis. In vascular endothelial cells, PTP4A1 functions as an anti-inflammatory regulator by dephosphorylating upstream stimulatory factor 1 (USF1) at residue S309, promoting transcription of TNFAIP3/A20 and subsequent NF-κB pathway inhibition, thereby reducing cell adhesion molecule expression and vascular inflammation 1. In metabolic regulation, hepatic PTP4A1 prevents hepatosteatosis and maintains glucose homeostasis by activating the CREBH/FGF21 axis 2. The protein also regulates peripheral nerve myelination by dephosphorylating cytohesin-2 at Tyr381, with PTP4A1 acting as a negative regulator of myelin thickness in Schwann cells 3. However, PTP4A1 demonstrates oncogenic properties in multiple cancers, promoting cell proliferation, migration, and invasion through interactions with PTEN and activation of PI3K/AKT signaling in intrahepatic cholangiocarcinoma 4, and enhancing TGFβ signaling through SRC-ERK-SMAD3 pathway regulation in systemic sclerosis fibrosis 5. PTP4A1 is frequently targeted by tumor suppressor microRNAs, including miR-1271 in hepatocellular carcinoma 6 and miR-339-5p in glioma 7, highlighting its pathological significance in cancer progression.