BCORL1 (BCL6 corepressor like 1) is an X-linked transcriptional corepressor that functions as a negative regulator of gene expression 1. The protein operates by being recruited to promoter regions by sequence-specific DNA-binding proteins such as BCL6, where it mediates transcriptional repression through histone deacetylase activities and chrX remodeling mechanisms 1. BCORL1 plays important roles in hematopoiesis and lymphoid development 1. Somatic mutations in BCORL1 occur in hematologic malignancies and aplastic anemia, predominantly as frameshifts, nonsense, and missense mutations distributed across the gene length 1. These disruptive mutations result in loss of full-length protein expression, consistent with a tumor suppressor function 1. Clinically, BCORL1 mutations show paradoxical favorable outcomes in certain contexts. In aplastic anemia patients, BCORL1 mutations correlated with better response to immunosuppressive therapy and improved overall survival 2, with mutations associated with lower risk of secondary myeloid neoplasm progression 3. In acute myeloid leukemia treated with venetoclax/azacitidine, BCORL1 mutation predicted longer overall survival 4. Germline BCORL1 mutations cause Shukla-Vernon syndrome, a rare X-linked genetic disorder 1. BCORL1 mutations have also been identified in Wilms tumors and endometrial stromal sarcomas, though their specific functional roles in these contexts remain incompletely understood 5, 6.