UBASH3B is a ubiquitin-associated SH3 domain-containing protein that functions as a tyrosine phosphatase regulating receptor signaling and cellular metabolism. Structurally, UBASH3B contains a histidine phosphatase domain and operates as a member of the TULA family of signaling regulators 1. Primary enzymatic functions include dephosphorylation of tyrosine-phosphorylated proteins such as EGFR, FAK, SYK, and ZAP70, thereby suppressing Syk/Zap-70-mediated signaling 1. At the molecular level, UBASH3B interferes with CBL-mediated degradation of activated receptor tyrosine kinases, promoting their accumulation on the cell surface and stabilizing EGFR levels 2. In cancer pathogenesis, elevated UBASH3B expression promotes tumor progression across multiple contexts. In lung adenocarcinoma, UBASH3B dephosphorylates MRPL12 at tyrosine 60, inhibiting its mitochondrial metabolism-promoting functions and suppressing tumorigenesis 3. Conversely, in head and neck squamous cell carcinoma, UBASH3B stabilizes EGFR and enhances downstream proliferative signaling, correlating with poor clinical outcomes 2. In pancreatic cancer, UBASH3B acts as a novel immune suppressive marker, negatively correlating with NK cell activation and mediating drug resistance 4. In hepatocellular carcinoma, UBASH3B participates in immunosuppressive signaling axes involving TAMs and T cells that reduce nivolumab response 5. Beyond oncology, genetic variants in UBASH3B associate with inflammatory disease risk, with the rs4936742 T allele increasing Behçet's disease susceptibility, particularly non-ocular presentations 6. UBASH3B also influences metabolic traits through methylation regulation affecting body mass index 7.