The NF-κB element (−600) is required for gelatinase B/MMP-9 transcription induced during spontaneous epithelial to neuroblast transition and by all-trans-retinoic acid in human neuroblastoma cells [123,124], by TNF-α in HT-1080 fibrosarcoma cells and rabbit fibroblasts [119,125,126], IL1β [127], Bcl2 [128], HIV-1-Tat [129], KiSS1 [130], synergistic combinations of cytokines and growth factors [126,131] and thioredoxin [132], acting in concert with other elements including the AP-1 site at position −79. This evidence concerns the gene MMP9 and neuroblastoma.