MEN1 gene mutations are a rare event in patients with sporadic neuroendocrine tumors

BACKGROUND: Neuroendocrine tumors of the gastroenteropancreatic (GEP) tract are encountered either as a sporadic type or as part of multiple endocrine neoplasia type 1 (MEN-1) syndrome. Inactivating MEN1 gene mutations have been found to be responsible for this syndrome and have also been described in sporadic cases. The aim of the present study was to evaluate the presence of mutations in the MEN1 gene in a series of 10 well-differentiated neuroendocrine tumors: five of the foregut and five of the midgut tract. METHODS: Retrospective screening for MEN1 gene mutations was carried out in 10 archived, paraffin-embedded neuroendocrine tumors. Polymerase chain reaction amplification and automated sequence analysis of the DNA extracted from the tumors were performed. RESULTS: One mutation (359 del 4) in exon 2 of the MEN1 gene was identified in a neuroendocrine tumor of the foregut (VIPoma of the pancreas). No mutation was identified in midgut neuroendocrine tumors. CONCLUSIONS: Our data confirm that retrospective genetic analysis can be used to identify mutations in the MEN1 gene and indicate that somatic MEN1 gene mutations are a rare event in sporadic neuroendocrine GEP tumors. The frequency of these mutations was 10% in our series, which may differ from that in other studies, due to the small number of cases analyzed.