MAPK1 and hepatocellular carcinoma: According to Xu et al study, low ZAG levels in hepatocellular carcinoma cell lines enhance epithelial to mesenchymal transition (EMT) via the TGF1-ERK2 signaling pathway.20 This could occur by down-regulating epithelial markers (E-cadherin) and up-regulating mesenchymal markers (N-Cadherin).20 This may be linked to the fact that less differentiated tumors in the study did not express positive ZAG staining.