[The phenotypic expressions of AFP producing gastric carcinoma]

The phenotypic expressions of AFP producing gastric carcinomas were investigated by histological, immunohistochemical, mucinhistochemical and biochemical studies. Intramucosal histology was well differentiated adenocarcinoma in fifteen out of seventeen cases. In the invasive area, papillary or papillary and solid structure of the cancer cells with clear cytoplasms were in fourteen cases, but there were only three cases that showed hepatoid structure. In the mucinhistochemistry, thirteen cases (76%) showed intestinal type mucin. And in the lectin binding property of serum AFP, five of seven cases showed yolk sac tumor like pattern and the other two cases showed hepatic pattern. These results suggests that most of the AFP producing gastric carcinomas derive from intramucosal intestinal type well differentiated adenocarcinoma, that retrodifferentiated to fetal intestine in the invasive area and produce fetal intestinal type AFP.