ISG15 and colorectal carcinoma: The results summarized in Figure 4C demonstrate that the suppression of ISG15 levels in human CRC cells, or the inhibition of NF-κB signaling, both reduced not only the free pool of ISG15, but also the extent of ISG15 conjugates formation, suggesting that increased ISGylation in L1-overexpressing cells might be required for the promotion of CRC progression.