Re-Recognizing the Cellular Origin of the Primary Epithelial Tumors of the Liver

Jiliang Feng,1 Ruidong Zhu,2 Yu Yin,3 Shanshan Wang,1 Lei Zhou,4 Fudong Lv,1 Dawei Zhao5 1Clinical-Pathology Center, Beijing You-An Hospital, Capital Medical University, Beijing, 100069, People’s Republic of China; 2General Surgical Center, Beijing You-An Hospital, Capital Medical University, Beijing, 100069, People’s Republic of China; 3Department of Pathology, Anhui Medical University, Hefei, 230032, People’s Republic of China; 4Department of Pathology, First Affiliated Hospital of Bengbu Medical College/Bengbu Medical College, Bengbu, 233004, People’s Republic of China; 5Department of Medical Imaging, Capital Medical University, Beijing, 100069, People’s Republic of ChinaCorrespondence: Jiliang FengClinical-Pathology Center, Beijing You-An Hospital, Capital Medical University, No. 8, Xitoutiao, Youanmenwai Street, FengTai District, Beijing, 100069, People’s Republic of ChinaTel +86-10-83997342Fax +86-10-83997343Email jiliangfeng@ccmu.edu.cnAbstract: The primary epithelial tumors of the liver (PETL) are composed of a series of heterogeneous tumors. Although the classification of PETLs has been updated several times by the World Health Organization, the cellular origins of some tumors in this family remain to be precisely depicted. In addition, certain tumors in different categories have similar histology, molecular phenotypes and biological characteristics, suggesting that they may have the same cellular origin. In this work, a narrative review method was adopted to review the relevant papers. By comparing the expression profiles of biomarkers of liver epithelium at different lineages and stages of differentiation, the cells-of-origin of some major members of the PETL family were reassessed. We propose that 1) hepatic adenomas, hepatocellular carcinomas (HCCs) and pure fetal hepatoblastomas (HBs) share the same spectrum in their cellular origin including the hepatocytic-committed progenitors (HCP) and their differentiated descendants. 2) Bile duct adenomas, peribiliary cysts and intrahepatic cholangiocellular carcinomas (ICCs) can share the same spectrum in their cellular origin including the cholangiocytic-committed progenitors (CCP) and their differentiated descendants. 3) The cells-of-origin of embryonal HBs include liver stem cells (LSCs), hepatoblasts, and transitional cells between them. Embryonal HB with small cell element, small cell undifferentiated HB and small cell neuroendocrine carcinoma of the liver can have the same or similar cells-of-origin from LSC. Embryonal HB lacking the small cell component of the LSC phenotype and presenting both hepatocytic and bile duct/ductule components may originate from actual hepatoblasts/hepatic progenitor cells (HPCs) as the combined HCC-ICC does. 4) Teratoid hepatoblastoma and mixed epithelial/mesenchymal HBs can be derived from the LSCs or even less committed extrahepatic pluripotent stem cell. 5) Many members of the PETLs family, including those derived from LSCs, hepatoblasts/HPCs, early HCPs and CCPs, have neuroendocrine potentiality. Except for those primary hepatic neuroendocrine tumor (PHNET) exhibit hepatocytic and/or cholangiocytic phenotypes, other PHNETs subtype may be derived from the descendants of LSC that differentiate towards the upper digestive tract, pancreas or other lineages.Keywords: HCC, tumor-initiating cell, hepatic progenitor, neuroendocrine tumors, hepatoblastoma