CBFB

CBFB stands for core-binding factor subunit beta, a protein that forms part of the core-binding factor (CBF) transcriptional complex. It does not bind DNA on its own but partners with RUNX family transcription factors (RUNX1/2/3) to create a functional DNA-binding unit. This complex regulates the expression of genes important for hematopoiesis, skeletal development, and immune function by binding to specific DNA sequences.

The CBFB gene is located on chromosome 16q22 in humans and encodes multiple transcript variants that give rise to distinct protein isoforms. In normal cells, CBFβ stabilizes RUNX proteins and enhances their ability to regulate target genes, facilitating proper differentiation and development.

Clinical significance is most prominent in acute myeloid leukemia (AML). Inversion of chromosome 16 or the translocation t(16;16)(p13;q22) produces the CBFB–MYH11 fusion gene, generating a chimeric protein that disrupts RUNX1-dependent transcription and blocks myeloid differentiation. This rearrangement defines a subset of AML known as AML with inv(16) or t(16;16) and is often associated with abnormal eosinophils (the M4Eo subtype). Generally considered a favorable-risk cytogenetic entity in many treatment contexts, outcomes still vary, and monitoring for minimal residual disease is common practice.

Beyond oncology, CBFβ’s role in regulating RUNX activity underlines its importance in normal blood cell development and bone formation. Disruption of CBFβ–RUNX signaling can have widespread effects on hematopoietic and skeletal systems.