Accumulation of -Catenin Protein and Mutations in Exon 3 of -Catenin Gene in Gastrointestinal Carcinoid Tumor

The molecular basis of carcinogenesis in gastrointestinal carcinoid tumors is not well understood. To clarify the contribution of the Wnt/ catenin signaling to this type of carcinogenesis, we investigated 72 cases of gastrointestinal carcinoid tumor both immunohistochemically and by direct sequencing of -catenin. Accumulation of -catenin in the cytoplasm and/or nucleus was observed in 57 cases (79.2%). We also detected mutations in exon 3 of -catenin in 27 cases (37.5%) and one mutation in APC (1.4%). Our results suggest that alterations in the Wnt/ -catenin signaling pathway may be involved in the development of gastrointestinal carcinoid tumors.