In the presence of secreted BAFF, the human monocytic leukemia-derived, p53-deficient cell line THP-1 activated NF-κB, which in turn transcriptionally induced the production of SASP factors, while p53-proficient human senescent fibroblasts activated a p53-dependent gene expression program. The gene discussed is TNFSF13B; the disease is monocytic leukemia.