Neuroendocrine tumors of the gastrointestinal tract: recent advances in molecular genetics, diagnosis, and treatment.

PURPOSE OF REVIEW: Neuroendocrine tumors of the gastrointestinal tract represent a small area within oncology, but many new data have been reported during the past year. This paper updates the recent findings. RECENT
FINDINGS: An N-terminally truncated variant of heat shock protein 70 (Hsp70) has been identified in neuroendocrine tumors but not in normal pancreatic islets. CDX-2 is a homeobox gene product essential for intestinal development and differentiation that is expressed at high levels in intestinal neuroendocrine tumors, but not in other types. A new marker has been identified, neuroendocrine secretory protein-55, a member of the chromogranin family, specific for endocrine pancreatic tumors but not for intestinal neuroendocrine tumors. Positron emission tomography has significantly improved imaging of neuroendocrine tumors of the gastroenteropancreatic tract. Tracers such as C-5-hydroxy-L-tryptophan show very high sensitivity for detection of tumors, higher than for somatostatin receptor scintigraphy. A new somatostatin analogue SOM230 binding to four of five somatostatin receptors has recently come into clinical trials.
SUMMARY: Increased knowledge of the molecular background for the development of neuroendocrine tumors may improve the management of these tumors in the future. New tumor markers have been developed and the localization techniques have been significantly improved. That will of course lead to earlier diagnosis and improved possibilities for surgical cure of these patients.