Different causes and mechanisms have been postulated for chemoresistance in CRC, e.g. via signaling pathways like NFKB, Wnt/ β-catenin, and PI3K/AKT which lead to ABC transporters overexpression or the overexpression of Thymidylate synthase and FOXO1 proteins in CRC [3, 6]. This evidence concerns the gene ABCG2 and colorectal carcinoma.