Expression of β-catenin in MCL tumors. (A) Immunohistochemistry using paraffin-embedded MCL tumors showed nuclear staining of β-catenin in a positive case (left panel). Only weak cytoplasmic staining was found in the tumor cells in a negative case, although endothelial cells showed intense cytoplasmic staining (right panel). (B) Immunohistochemistry using paraffin-embedded MCL tumors showed intense cytoplasmic staining of p-GSK3β in a positive case (left panel), but no appreciable staining in a negative case (right panel).