PLOD2 and biliary tract cancer: PLOD2 has been shown to promote metastasis in cancer such as breast cancer, biliary tract cancer and lung cancer (Du et al., 2017; He et al., 2018; Okumura et al., 2018), etc. Besides, PLOD2 was reported to play an important role in peritoneal dissemination of GC, and it was regulated by hypoxia-inducible factor-1 (HIF-1) and involved in extracellular matrix remodeling, alignment and mechanical properties (Kiyozumi et al., 2018).