Endocrine tumors of the gastrointestinal system

Abstract

Endocrine tumors of the gastrointestinal tract constitute a heterogeneous anatomical and functional group of cells with respect to clinical syndromes, clinico-pathological associations, and prognosis. The WHO classification is now used for the diagnosis and classification of these tumors with respect to anatomical location, tumor cell type, and differentiation. These include well-differentiated endocrine tumors with benign behavior, low-grade well-differentiated endocrine carcinomas, and high-grade poorly differentiated endocrine carcinomas. Cellular and molecular studies, such as Ki67 index, p53 overexpression or mutations, and loss of heterozygosity have contributed to the understanding of these tumors and the ability to predict the behavior of these tumors. © 2010 Springer-Verlag New York.