NFKB1 and colon carcinoma: For example, while TLR9 is expressed at the apical and basolateral surface of human colon carcinoma cells and can bind agonist on both membranes, signaling from basolateral stimulation leads to a strong activation of NF-kB through canonical pathways, whereas apical stimulation leads to accumulation of ubiquitinated IkappaB, thereby leading to shunted NF-kB signaling (Fig. 2D) (17).