Biological and molecular aspects of gastroenteropancreatic neuroendocrine tumors

Neuroendocrine tumors of the digestive tract are rare entities characterize d by significant phenotype differences and traditionally considered to orig inate from cells of the diffuse endocrine system of the pancreas and gut, T wo major categories with significant phenotype and clinical behavior differ ences are identified as well-differentiated and poorly differentiated tumor s, Investigation on the molecular basis of tumor development points to an i mportant role for the multiple endocrine neoplasia syndrome type-1 (MEN1) g ene because of its frequent abnormality observed both in well-differentiate d and poorly differentiated tumors, Other genes are possibly involved, thou gh the available data need support from studies on larger series of tumors. Copyright (C) 2000 S. Karger AG, Basel.