In particular, Dai et al. showed in mice models of CCA that conjugated BAs stimulated tumor growth, upregulated the phosphorylated kinase inhibitor B (IkB), and increased interleukin-6 (IL-6) and cyclooxygenase-2 (COX-2), while free BAs decreased tumor growth, downregulated the phosphorylated IkB, and decreased IL-6 and COX-2 [44]. Here, PTGS2 is linked to cholangiocarcinoma.