NFKB1 and mature T-cell and NK-cell non-Hodgkin lymphoma: Interferon regulatory factor-4 (IRF-4) can also bind to the CD30 promoter region to induce its transcriptional activity, and NF-κB subunit NF-κB2 (p100/p52)and RELB are transcriptional activators of IRF-4 in PTCL cell lines, suggesting a positive feedback loop between CD30, NF-κB, and IRF-4 (76).