Chemoprevention with Somatuline© Delays the Progression of Pancreatic Neuroendocrine Neoplasms in a Mouse Model of Multiple Endocrine Neoplasia Type 1 (MEN1).

OBJECTIVE: Long-acting synthetic somatostatin analogues (SSA) are an essential part of the treatment of neuroendocrine neoplasms. We evaluated the chemopreventive effects of a long-acting somatostatin analogue on the development of pancreatic neuroendocrine neoplasms (pNENs) in a genetically engineered MEN1 knockout mouse model. MATERIALS AND METHODS: Heterozygote MEN1 knockout mice were injected every 28 days subcutaneously with the somatostatin analogue lanreotide (Somatuline Autogel©; Ipsen Pharma) or a placebo starting at day 35 after birth. Mice were euthanized after 6, 9, 12, 15 and 18 months, and the size and number of pNENs were measured due histological analysis and compared to the placebo group. RESULTS: The median tumor size of pNENs was statistically significantly smaller after 9 (control group vs. SSA group; 706.476 µm2 vs. 195.271 µm2; p = 0.0012), 12 (placebo group vs. SSA group 822.022 vs. 255.482; p ≤ 0.001), 15 (placebo group vs. SSA group 1192.568 vs. 273.533; p ≤ 0.001) and after 18 months (placebo group vs. SSA group 1328.299 vs. 864.587; p ≤ 0.001) in the SSA group. Comparing the amount of tumors in both groups, a significant reduction was achieved in treated Men1(+/-) mice (41%, p = 0.002). Immunostaining showed, however, no significant difference in the expression of the apoptosis marker caspase-3, but a significant difference in Ki67 index as a marker for tumor cell proliferation (p ≤ 0.005). CONCLUSION: Long-acting somatostatin analogues may be an effective chemopreventive approach to delay the progression of MEN1-associated pNENs. After our preclinical results, we would recommend to evaluate the effects of long-acting SSA in a prospective clinical trial.

[Multiple endocrine neoplasia syndroms. Type 1]. / Dauginiu endokrininiu naviku sindromai. Pirmas tipas.

Multiple endocrine neoplasia (MEN) type 1 syndrome or Wermer syndrome is a classical malignant neoplasia syndrome, inherited in the autosomal dominant pattern, when hyperplastic and/or neoplastic injury develops synchronously or metachronously in the cells of the parathyroid gland, pancreas islets, hypophysis, and rarer in other neuroendocrine organs. The syndrome develops when germinative MEN 1--neoplasia suppression gene inactivation mutations occurs. More than 95 percent of patients have this MEN 1 gene mutation, when the penetration of mutation is almost 100 percent. An early stage of this syndrome is hyperfunction in organs, with the syndromes of hormone excess, later benign and/or malign neoplasia develops, this mostly determines the prognosis for the patient. The risk of this syndrome developing should be estimated for all the patients diagnosed with endocrine organ hyperplasia, which determines hyperfunction, or endocrine organs neoplasia. For patients with multiple endocrine neoplasia type 1 syndrome, endocrine neoplasia develops earlier than in sporadic cases; multifocality is typical for them. Multifocality of neoplasia, typical combinations of injuries and anamnesis of the family helps to diagnose the syndrome. Diagnosis is confirmed through genetical analysis, which is also important in determining the inheritors of mutations, potential patients. After genetically diagnosing multiple endocrine neoplasia type 1 syndrome, it is not enough to analyze and look after patients with malignant neoplasia, or to make early diagnosis on pre-neoplasic disease and neoplasia, or to apply means of prevention and start well-timed treatment, but also to diagnose this syndrome for the patient's relatives, and to determine their risk of getting cancer. This opens new possibilities in early diagnostics and prevention of malignant neoplasia. The main purpose of this literature review is to introduce medical-practitioners to the newest theories of type 1 multiple endocrine neoplasia syndrome pathogenesis, clinical peculiarities, methods of diagnostics and treatment.

[Prophylactic thyroidectomy in carriers of RET oncogene mutation carriers]. / Profylaktisk tyreoidektomi hos baerere av mutasjoner i RET-onkogenet.

BACKGROUND: Medullary thyroid cancer may be inherited dominantly. Germline mutations in the RET oncogene which code for a receptor tyrosine kinase cause MEN2. Thyroidectomy is recommended in family members who carry a mutation. MATERIAL AND METHODS: We have thyroidectomized four children from three families, 12, 10, 7 and 6 years old, because of germline mutations. RESULTS: The 12-year-old had developed a minimal medullary cancer with microscopic lymph node metastases; the others showed variable degrees of C-cell hyperplasia. The mutations were located on exon 10 (C620F) in the two patients from one family, on exon 11 (C634R) in the second family and on exon 14 (V804M) in the third family. In the families with the codon 620 and codon 634 mutations, only medullary thyroid cancer has been diagnosed. In the family with the codon 804 mutation, the index patient has been operated for a pheochromocytoma. The longterm clinical course seems more favorable in the family with the codon 620 mutation than in the two other families. With knowledge of the family mutations, we found that two out of nine family members we previously have thyroidectomized following calcitonin testing did not carry the family mutation. INTERPRETATION: Genetic diagnostic is a safe and reliable predictive test for familial medullary thyroid cancer and should be carried out in any individual with this cancer. Thyroidectomy is recommended in gene carriers at the age of six.

Menin mutations in the diagnosis and prediction of multiple endocrine neoplasia type 1.

INTRODUCTION: Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by the development of multiple endocrine adenomas, typically in the pancreas, anterior pituitary, and parathyroid glands. The disease is associated with germ-line mutations of the menin gene, a putative tumor-suppressor gene located on human chromosome 11q13. METHODS: To facilitate the diagnosis and prediction of MEN1 in patients and their relatives, we developed a molecular two-step strategy to screen for menin gene mutations. DNA fragments covering the entire menin coding sequence are generated from patient cDNA by polymerase reaction (PCR) and subsequently analyzed by single-strand conformational polymorphism electrophoresis (SSCP). Fragments with aberrant SSCP migration are DNA-sequenced to directly characterize menin mutations. In a second diagnostic step, genomic DNA of healthy relatives of the corresponding MEN1 index patient is analyzed by PCR, with only the specific exon amplified harboring the family-specific mutation. Mutation-specific restriction enzyme digestion of this PCR product finally allows the identification of mutation carriers through pathological restriction fragment patterns. RESULTS: Using this approach, we identified an in-frame deletion mutation (delta Tyr Met) located in menin exon 4 (codon 227-228) that co-segregates with the disease phenotype in a large MEN1 family from Southern Germany. CONCLUSION: It is likely that the direct molecular analysis of menin gene mutations will replace the genetic and biochemical screening tests currently used in the clinical management of MEN1 families. In addition, these studies may provide clues to the tumor biology of both sporadic and MEN1-associated endocrine adenomas.

The prevalence of MEN-1 in Tasmania.

BACKGROUND: An extensive programme was undertaken to trace and screen four known families in Tasmania with multiple endocrine neoplasia type 1 (MEN-1). METHODS: Written and personal contact was made with family members over the age of 20 years recommending a review by family practitioners for the purpose of recording their medical history and collecting a blood sample. Those suspected of MEN-1 were referred to our Department for further investigation. RESULTS: In January 1993, the total number of individuals alive and known to be affected by MEN-1 was 107, giving a prevalence of MEN-1 disease in Tasmania of 23/100 000. The estimated prevalence of MEN-1 trait in Tasmania (including affected cases and those considered at 50% risk of possessing the trait) is 45/100 000. CONCLUSION: The prevalence of MEN-1 has never previously been determined accurately. The prevalence of MEN-1 in Tasmania is at the upper end of the possible range and would justify the allocation of resources for screening programmes equal to those available for the detection of several less prevalent genetic diseases.

[Screening of multiple endocrine neoplasias type 1. Reflexions of the Study Group on Multiple Endocrine Neoplasias type 1]. / Dépistage des néoplasies endocriniennes multiples de type 1 (NEM 1). Réflexion du Groupe d'Etude des Néoplasies Endocriniennes Multiples de type 1 (GENEM 1).

The "Groupe d'Etude des Néoplasies Endocriniennes Multiples de type 1 (GENEM 1)" is a French group involved in a comprehensive multicentre study of Multiple Endocrine Neoplasia type 1 syndrome (NEM 1). The objectives of this group are to define diagnostic and therapeutic protocols and to carry out genetic research on NEM1. The first aim of physicians is to recognize the syndrome and to determine the appropriate screening especially into two circumstances: 1 degree In case of isolated and sporadic glandular disease -i-e-parathyroid glands, endocrine pancreas, antehypophysis, adrenal glands and neuroendocrine tumors? 2 degrees In case of very high probability of NEM 1 syndrome? This paper answers these two questions, based on the analysis of the first 150 cases collected by the GENEM 1.