We analyzed gene expression levels of NF-κB1, NF-κB2, and Rel in 49 B-cell chronic lymphocytic leukemia, 8 B-cell non-Hodgkin’s lymphoma, 3 acute myeloid leukemia, 3 chronic myeloid leukemia, 2 hairy cell leukemia, 2 myelodysplastic syndrome, and 2 T-cell large granular lymphocytic leukemia patients using real-time polymerase chain reaction. The gene discussed is REL; the disease is hairy cell leukemia.