Administration of exogeneous TGF-α and amphiregulin did not induce migration of the colorectal cancer cell lines (Supplementary Figure 4A), while blocking TGF-α and amphiregulin action did not diminish the effects of CCL20 in inducing CCL20 secretion (Supplementary Figure 4B) or proliferation (Supplementary Figure 4C). This evidence concerns the gene AREG and colorectal cancer.