UBASH3B, also known as T-cell ubiquitin ligand 2 or suppressor of T-cell receptor signaling 1 (STS-1), is an atypical protein tyrosine phosphatase with a ubiquitin-binding domain. It plays a role in various cellular processes, including cell signaling, immune responses, and cellular development. In the context of cancer, UBASH3B has been implicated in tumorigenesis and cancer progression. Its abnormal expression is associated with the worsening of various cancers, and it may serve as a potential therapeutic target for inhibiting cancer growth. UBASH3B is also being investigated as a prognostic biomarker in prostate cancer, where its expression levels correlate with immune cell infiltration and overall prognosis. Furthermore, UBASH3B is involved in the regulation of immune responses, and its dysfunction has been linked to autoimmune diseases. It is expressed primarily in T-cells and has been associated with the regulation of T-cell receptor signaling.