Many investigations have demonstrated an inhibitory effect of curcumin on the proteolytic activities and expression levels of the gelatinases MMP-2 and -9 in a series of cancer cell lines [51,52,53,54]; such suppressions of various MMPs by curcumin were mainly caused by interference with the transcriptional activities of AP-1 and NF-κB [55]. Here, NFKB1 is linked to cancer.