In accordance with the consideration that the cells of the tumor stroma are a key determinant in tumor promotion [58], we found that tumor microenvironment co-cultures produced strikingly higher amounts of invasion related proteinase (MMP-13), had markedly higher activation levels of NF-κB compared to CRC high density mono-cultures and significant up-regulation of CSC markers expression. Here, NFKB1 is linked to colorectal carcinoma.