[Clinical genetics of neuroendocrine tumors]

Neuroendocrine tumors (NETs) are a heterogeneous group of benign and malignant neoplasias, detectable in the context of hereditary tumor syndromes in up to 30% of cases. The pathogenic understanding of NETs has increased considerably during the last decade, mainly due to the identification of underlying genetic defects and the availability of genetically modified animal models. These developments are reflected in a revised WHO classification of gastrointestinal NETs. In contrast to a variety of rare neuroendocrine tumor syndromes, multiple endocrine neoplasia syndrome type 1 (MEN1) and type 2 (MEN2) play clinically significant roles due to their common incidence. MEN1 and MEN2 are classic autosomal-dominant familial tumor diseases with a high penetrance and variable clinical expression, caused by germ line mutations of the MEN1 tumor suppressor gene and the RET protooncogene, respectively. The clinical management of patients with NETs has changed significantly after the introduction of clinical genetic screening. The detection of MEN1 mutations allows for risk-adapted treatment and follow-up. RET gene analysis can identify individuals with a very high risk to develop familial medullary cancer (MEN2), who may be successfully treated by prophylactic thyroidectomy. NETs thus represent a paradigmatic example of the successful link between basic genetic science and clinical care in molecular medicine.