HPGD and cholangiocarcinoma: It plays important roles in the progress of cholangiocarcinoma through targeting PTEN/AKT pathway [27,28], TIMP3 (tissue inhibitor of metalloproteinases 3) [29], 15-PGDH (15-hydroxyprostaglandin dehydrogenase) [24], or EMT (epithelial–mesenchymal transition) [30].