Gene ontology analysis of the genes bound by PML-RARα and containing NF-κB binding sites revealed an enrichment of genes involved in haematopoiesis, immune system development and myeloid cell differentiation, suggesting that PML-RARα blockade of NF-κB activity may also contribute to the block in myeloid cell differentiation seen in APL (Table 2). This evidence concerns the gene NFKB1 and acute promyelocytic leukemia.