Serine-phosphorylation of β-catenin targets it for ubiquitination-degradation [27], and it is notable that we saw a dramatic decrease in phosphorylated β-catenin in all three LKB1-attenuated ICC cell lines, while total β-catenin was not altered (Figure 5C). This evidence concerns the gene STK11 and intrahepatic cholangiocarcinoma.