BCL11B is a transcription factor essential for T-lymphocyte development and function. It serves as a key regulator of thymocyte differentiation and survival, controlling the responsiveness of hematopoietic stem cells to chemotactic signals by modulating CCR7 and CCR9 receptor expression 1. BCL11B enhances IL2 expression in activated CD4+ T-lymphocytes through IL2 promoter regulation 2. The protein functions as a transcriptional regulator in regulatory T cells (Tregs), with its promoter occupied by Treg-associated transcription factors including RUNX1, ETS1, and CREB 3. BCL11B plays a critical role in maintaining T cell identity by safeguarding against natural killer cell reprogramming through physical interaction with DNA methyltransferase DNMT1, which stabilizes BCL11B and maintains DNA methylation of NK cell-related genes 4. Clinically, BCL11B alterations are significant in hematologic malignancies, with BCL11B-activating rearrangements incorporated into early T-precursor acute lymphoblastic leukemia classification 5. BCL11B transcriptional deregulation defines a specific genetic subgroup of immature T-ALL 6, and BCL11B alterations represent a major entity in pediatric acute myeloid leukemia classification 7. The gene is associated with severe combined immunodeficiency and intellectual developmental disorders.