It has been shown that DET and IDET inhibited constitutive activation of NF-κB in human multiple myeloma (MM.1S and U266) and head and neck squamous cell carcinoma (SCC4 and LICR-LON-HN5) cells, which are known to constitutively express active NF-κB. This evidence concerns the gene NFKB1 and head and neck squamous cell carcinoma.