Human T-cell leukemia virus basic leucine-zipper factor abrogated DNA-binding activity and reduced the steady-state levels of MafB, leading to the disruption of transcriptional control of cellular genes and induction of adult T-cell leukemia (Ohshima et al., 2010; Reinke et al., 2010). The gene discussed is MAFB; the disease is T-cell leukemia.