Importantly, blocking the activity of NF-κB by the transfection of a dominant negative mutant of IκBα not only significantly reduced MMP-9 expression but also obviously abrogated the invasive abilities of URGCP-overexpressing NSCLC cells (Fig. 6F and 6G), suggesting the importance of NF-κB signaling in the URGCP-induced MMP-9 expression and invasive phenotype of NSCLC cells. This evidence concerns the gene NFKB1 and non-small cell lung carcinoma.