Neuroendocrine carcinoma arising in a hepatitis C virus-infected liver: mechanism of the tumor development may be similar to that of development of pancreatic neuroendocrine cells.

We experienced a case of neuroendocrine carcinoma (NC). The tumor developed in the cirrhotic liver of a 62-year-old Japanese man who had been infected with hepatitis C virus. The tumor cells showed high N/C ratio, formed many rosettes, and expressed CD56, synaptophysin, HepPar1 and pancreatic and duodenal homeobox 1. MIB1 expression was 65%. Because both liver and pancreas are derived from a common endodermal layer during fetal development, we speculated that the tumor may have formed via the interaction of neurogenin 3, insulinoma-associated 1 gene and NeuroD/beta2, which are involved in the stage at which some pancreatic cells commit to becoming endocrine cells. Molecular analysis revealed that the NC had higher relative expression levels of mRNA of the three molecules than did the nontumorous liver. The results indicate that the NC in this patient may have formed via the same mechanism that acts in the development of pancreatic neuroendocrine cells.