For example, NSC697923, an inhibitor of the E2 enzyme Ubc13, has been shown to inhibit the formation of Lys63-linked ubiquitin chains, NF-κB activity and the proliferation of diffuse large B-cell lymphoma cells; it is currently in preclinical trials in the context of melanoma, B-cell lymphoma, neuroblastoma and colorectal cancer [156]. This evidence concerns the gene NFKB1 and colorectal cancer.