Human pathology
-
α-Fetoprotein is expressed in hepatocellular carcinoma, yolk sac tumor, and some gastric carcinomas. The α-fetoprotein-producing gastric carcinoma composed of hepatoid and common adenocarcinoma shows morphological similarities to combined hepatocellular and cholangiocarcinoma. In this study, the expression of putative hepatic stem/progenitor markers (EpCAM, OV-6, DLK-1, and NCAM/CD56), hepatocyte markers (HepParI, α-fetoprotein, glypican 3), and the germ cell marker SALL4 was examined in α-fetoprotein-producing gastric carcinoma (20 cases) and combined hepatocellular and cholangiocarcinoma (20 cases) for evaluation of pathologic differentiation and also the histogenesis of both tumors. ⋯ The histogenesis of hepatoid gastric carcinoma expressing SALL4 seems to reflect fetal gut differentiation or involve the germ cell lineage and may be different from that of combined hepatocellular and cholangiocarcinoma involving the hepatic stem cell or progenitor cell lineages. In conclusion, hepatoid gastric carcinoma and combined hepatocellular and cholangiocarcinoma shared morphologies, whereas the distinction of hepatoid gastric carcinoma from combined hepatocellular and cholangiocarcinoma is possible by immunostaining for SALL4. These 2 tumors seem to differ in their histogenesis with respect to SALL4 expression.1.