The carbohydrate structure of glycoproteins is considered to be tissue-specific or cell type-specific, but there have been no reports on the differences of the carbohydrate structure of alpha-fetoproteins (AFPs) produced by histologically identical tumors in different tissues. The lectin affinity electrophoresis of hepatoid adenocarcinomas and yolk sac tumors from different organs suggested that either the tumor heterogeneity or the tissue specificity is possibly involved, the lectin reactivity of the AFP sugar chain structure produced by the tumors in different tissues.