The Characteristics of Immunoreactivity of Alpha-fetoprotein Producing Gastric Cancer

Alphafetoprotein (AFP) producing gastric cancer (AFP-GC) is very malignant and highly metastatic compared with common gastric cancer. We encountered six patients with AFP-GC. The purpose of this study was to characterize the immunoreactivity of alpha-fetoprotein producing gastric cancer, using a panel of hepatocytic markers, including alpha-fetoprotein, hepatocyte antigen, carcinoembryonic antigen, and CD10. Five of 6 cases showed cytoplasmic reactivity for alpha-fetoprotein. Immunoreactivity with a cytoplasmic, membranous, or canalicular pattern, or a mixed pattern was found for polyclonal CEA. Positive immunostaining for hepatocyte antigen was noted in only 2 of 6 cases. Negative immunostaining was found in all 6 patients for CD10. This study demonstrated that most AFP producing gastric cancer, hepatoid or non-hepatoid, were immunoreactive for AFP and p-CEA, but non-reactive for CD10. Therefore, CD-10 might be helpful to distinguish primary hepatocellular carcinoma from AFP-GC when it metastasizes to the liver. In this small series of patients with gastric cancer, AFP production indicated the poor prognosis, regardless hepatoid or non-hepatoid.