Clinical investigation and ret proto / 西安交通大学学报(医学版)

【Objective】 To investigate the clinical features and gene analysis of one pedigree with multiple endocrine neoplasia type 2A （MEN2A） so as to clarify the diagnosis and classification of the disease， guide treatment and prevention， and improve prognosis. 【Methods】 The clinical data of a 36-member MEN2A family， including 6 probands， with medullary thyroid carcinoma， were investigated， and the peripheral blood genomic DNA of 28 family members （blood sample of one proband was not collected） was extracted. PCR amplification was performed on exons 8， 10， 11， 13， 14， 15 and 16 of the RET gene， and the products were directly sequenced. 【Results】 Review of the medical history showed that two probands with medullary thyroid carcinoma were accompanied with hyperparathyroidism， and one family member had pheochromocytoma. The RET gene mutation test confirmed that 13 family members， consisting of 5 probands and 8 family members， had the RET proto-oncogene exon 10 missense mutation. The heterozygous missense had mutation c.1852T>A， leading to the conversion of cysteine （TGC） at position 618 to serine （AGC） （Cys618Ser）. All subjects carrying RET gene Cys618Ser mutation had abnormal thyroid ultrasound change， accompanied with elevated calcitonin levels. Subjects carrying wild type of RET gene had normal calcitonin levels. The family was finally diagnosed with MEN2A by RET gene detection. 【Conclusion】 RET gene detection plays key role in the diagnosis and treatment of patients with MEN2A family and has guiding value in the follow-up and prognosis of asymptomatic carriers. There is a positive correlation between calcitonin level and the RET protooncogene mutation Cys618Ser. Patients suspected of MEN2A should be screened in time.

Síndromes de neoplasia endocrina múltiple: revisión radiológica / Multiple Endocrine Neoplasia Syndromes: Radiological Review

Los síndromes de neoplasia endocrina múltiple (MEN), incluyen una serie de enfermedades con alteraciones genéticas que se caracterizan por la presencia de tumores que afectan a dos o más glándulas endocrinas. Son síndromes con una herencia autosómica dominante e incluyen tres patrones: MEN 1 (síndrome de Wermer), MEN 2 (que incluye MEN 2A o síndrome de Sipple y MEN 2B o síndrome de Wagenmann-Froboese) y MEN 4. Los adenomas paratiroideos y el carcinoma medular tiroideo, son los tumores más frecuentes del MEN tipo 1 y 2 respectivamente. Esos síndromes son más comunes en pacientes jóvenes, con patología de afectación bilateral, múltiple o multifocal y, sobre todo, en pacientes con antecedentes familiares. Es necesario el trabajo en equipo de endocrinólogos, cirujanos, oncólogos y radiólogos para optimizar el tratamiento de esos pacientes.

Multiple endocrine neoplasia (MEN) encompasses a serial of familial genetically disorders in wich tumors simultaneusly occur in two or more endocrine organs. MEN síndromes are autosomal-dominant disorders categorized into three main patterns: MEN 1 (Wermer syndrome), MEN 2 (includes MEN 2A o Sipple syndrome and MEN 2B o Wagenmann-Froboese syndrome) and MEN 4. Parathyroid adenomas and medullary thyroid carcinoma are the most frecuent tumors in MEN 1 and MEN 2 respectively. These entities will be suspected in younger patients, bilateral, multiple or multifocal disease and, specially, in patients with family background. Cooperation between endocrinologist, surgeons, oncologists and radiologists is pivotal for optimizing patient treatment.

The mutation site and the targeted therapy of RET proto-oncogene in medullary thyroid carcinoma / 中华内分泌外科杂志

Medullary thyroid carcinoma (MTC) is an endocrine tumor originating from the parafollicular cells of the thyroid gland.The mutation of RET gene has been considered as the molecular basis of MTC.Different types of MTC have different RET mutation sites,and the corresponding clinical manifestations and prognosis are also very different.RET gene detection is helpful for individual accurate gene diagnosis,molecular risk assessment,individual analysis and early prevention management.Nowadays,targeted therapy for RET gene mutations in MTC has developed rapidly.Some of those drugs,which have been approved for clinical application,bring new hope for advanced MTC.

Diagnóstico, tratamento e seguimento do carcinoma medular de tireoide: recomendações do Departamento de Tireoide da Sociedade Brasileira de Endocrinologia e Metabologia / Diagnosis, treatment, and follow-up of medullary thyroid carcinoma: recommendations by the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism

Introdução O carcinoma medular de tireoide (CMT) origina-se das células parafoliculares da tireoide e corresponde a 3-4% das neoplasias malignas da glândula. Aproximadamente 25% dos casos de CMT são hereditários e decorrentes de mutações ativadoras no proto-oncogene RET (REarranged during Transfection). O CMT é uma neoplasia de curso indolente, com taxas de sobrevida dependentes do estádio tumoral ao diagnóstico. Este artigo descreve diretrizes baseadas em evidências clínicas para o diagnóstico, tratamento e seguimento do CMT. Objetivo O presente consenso, elaborado por especialistas brasileiros e patrocinado pelo Departamento de Tireoide da Sociedade Brasileira de Endocrinologia e Metabologia, visa abordar o diagnóstico, tratamento e seguimento dos pacientes com CMT, de acordo com as evidências mais recentes da literatura. Materiais e métodos: Após estruturação das questões clínicas, foi realizada busca das evidências disponíveis na literatura, inicialmente na base de dados do MedLine-PubMed e posteriormente nas bases Embase e SciELO – Lilacs. A força das evidências, avaliada pelo sistema de classificação de Oxford, foi estabelecida a partir do desenho de estudo utilizado, considerando-se a melhor evidência disponível para cada questão. Resultados Foram definidas 11 questões sobre o diagnóstico, 8 sobre o tratamento cirúrgico e 13 questões abordando o seguimento do CMT, totalizando 32 recomendações. Como um todo, o artigo aborda o diagnóstico clínico e molecular, o tratamento cirúrgico inicial, o manejo pós-operatório e as opções terapêuticas para a doença metastática. Conclusões O diagnóstico de CMT deve ser suspeitado na presença de nódulo tireoidiano e história ...

Introduction Medullary thyroid carcinoma (MTC) originates in the thyroid parafollicular cells and represents 3-4% of the malignant neoplasms that affect this gland. Approximately 25% of these cases are hereditary due to activating mutations in the REarranged during Transfection (RET) proto-oncogene. The course of MTC is indolent, and survival rates depend on the tumor stage at diagnosis. The present article describes clinical evidence-based guidelines for the diagnosis, treatment, and follow-up of MTC. Objective The aim of the consensus described herein, which was elaborated by Brazilian experts and sponsored by the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism, was to discuss the diagnosis, treatment, and follow-up of individuals with MTC in accordance with the latest evidence reported in the literature. Materials and methods: After clinical questions were elaborated, the available literature was initially surveyed for evidence in the MedLine-PubMed database, followed by the Embase and Scientific Electronic Library Online/Latin American and Caribbean Health Science Literature (SciELO/Lilacs) databases. The strength of evidence was assessed according to the Oxford classification of evidence levels, which is based on study design, and the best evidence available for each question was selected. Results Eleven questions corresponded to MTC diagnosis, 8 corresponded to its surgical treatment, and 13 corresponded to follow-up, for a total of 32 recommendations. The present article discusses the clinical and molecular diagnosis, initial surgical treatment, and postoperative management of MTC, as well as the therapeutic options for metastatic disease. Conclusions 7 .

The rare intracellular RET mutation p.S891A in a Chinese Han family with familial medullary thyroid carcinoma.

We report intracellular RET mutation in a Han Chinese pedigree with familial medullary thyroid carcinoma (FMTC). Direct sequencing of RET proto-oncogene identified a missense c.2671T>G (p.S891A) mutation in 6 of 14 family members. The single nucleotide polymorphisms c. 135A>G (p.A45A), IVS4+48A>G, c. 1296A>G (p.A432A), c. 2071G>A (p.G691S), c. 2307T>G (p.L769L) and a variant c. 833C>A (p.T278N) were also found in 6 carriers. Among 5 of the 6 carriers presented medullary thyroid carcinoma (MTC) as an isolated clinical phenotype, with elevated basal serum calcitonin (Ct). Two underwent non-normative thyroidectomy either two or four times without physician awareness or diagnosis of this disease at initial treatment, but with elevated Ct. One with elevated pre-Ct accepted total thyroidectomy (TT) with modified bilateral neck dissection (MBiND), and whose seventh posterior rib MTC metastases was confirmed 5 months after surgery. Moreover, results of two affected individuals with elevated Ct were reduced to normal after TT with MBiND or prophylactic VI compartmental dissection. However, only another carrier with the variant p.T278N had slightly elevated Ct rejected surgery and was strictly monitored. Given these case results, we suggest that screening of RET and pre-surgical Ct levels in the management of MTC patients is essential for earlier diagnosis and more normative initial treatment, that FMTC patients with cervical lymph nodes metastases may be cured by TT with MBiND, and that prophylactic VI compartmental dissection should be avoided when Ct levels are low.

Two Cases of Multiple Endocrine Neoplasia Type II with RET Mutaion / 임상소아혈액종양

Multiple endocrine neoplasia type 2(MEN2) is a rare autosomal dominant inherited disorder characterized by the presence of medullary thyroid carcinoma, pheochromocytoma and other hyperplasia and/or neoplasia of different endocrine tissues in a single patient. MEN 2 is caused by germline mutations in the RET proto-oncogene is located on the pericentromeric region of chromosome 10 (10q11.2). We present our experience with two rare cases of MEN 2, an 11-years-old girl and a 10-years-old boy. Their parents had medullary thyroid carcinoma and genetic analysis showed the missense mutation of RET. They were screened for mutations in the RET proto-oncogene and RET mutations were found at codons 634 and 641. They were asymptomatic state but the girl had prophylactic total thyroidectomy. Children of families with RET mutations may develop early cancers and require prophylactic thyroidectomy before eight years.

Two Cases of Multiple Endocrine Neoplasia Type II with RET Mutaion / 임상소아혈액종양

Multiple endocrine neoplasia type 2(MEN2) is a rare autosomal dominant inherited disorder characterized by the presence of medullary thyroid carcinoma, pheochromocytoma and other hyperplasia and/or neoplasia of different endocrine tissues in a single patient. MEN 2 is caused by germline mutations in the RET proto-oncogene is located on the pericentromeric region of chromosome 10 (10q11.2). We present our experience with two rare cases of MEN 2, an 11-years-old girl and a 10-years-old boy. Their parents had medullary thyroid carcinoma and genetic analysis showed the missense mutation of RET. They were screened for mutations in the RET proto-oncogene and RET mutations were found at codons 634 and 641. They were asymptomatic state but the girl had prophylactic total thyroidectomy. Children of families with RET mutations may develop early cancers and require prophylactic thyroidectomy before eight years.

Carcinoma medular de tiroides: estudio multicéntrico. Presentación y evolución en 219 pacientes / Medullary Thyroid Carcinoma: Clinical Presentation and Outcome in 219 Patients

Ante la baja frecuencia del carcinoma medular de tiroides (CMT), en el Departamento de Tiroides de SAEM nos propusimos realizar un estudio de cohorte, observacional, retrospectivo y multicéntrico. Se incluyeron 219 pacientes con diagnóstico histológico de CMT. El 65 % fueron mujeres, la edad promedio fue de 39 ± 20 años (1 a 84 años); 44-% de los casos fueron familiares. Las formas de presentación más frecuentes fueron nódulo tiroideo (58 %) y pesquisa genética por antecedente familiar (22 %). Si bien la citología tiroidea fue diagnóstica de CMT en el 39 % de los casos, fue determinante de indicación quirúrgica en el 79 %. En el 47 % de los pacientes el diagnóstico de CMT se obtuvo previamente al tratamiento quirúrgico inicial por punción aspiración con aguja fina (PAAF), estudio genético o nivel de calcitonina (CT)). El 65 % se presentó en estadios avanzados (TNM III y IV). El estudio del protoncogen RET se realizó en 162 pacientes (74 %). En el 49 % se observó mutación siendo la más frecuente (76 %) en el codón 634. La forma hereditaria más frecuentemente observada fue el síndrome de neoplasia endocrina múltiple (NEM) 2A (57 % de los casos familiares), seguida por carcinoma medular familiar (25 %) y NEM 2B (13 %). Los casos familiares tuvieron menor edad al diagnóstico y mayor frecuencia de diagnóstico prequirúrgico. Los casos índice tuvieron mayor edad al momento del diagnóstico, mayores niveles de antígeno carcinoembrionario (CEA) y CT prequirúrgicos, mayor proporción de estadios III y IV y mayor porcentaje de evidencia de enfermedad al momento de la última consulta que aquellos detectados por pesquisa. En 143 pacientes (65 %) se obtuvieron registros completos de seguimiento en los que se analizaron los factores relacionados con la evolución. La mediana de seguimiento fue de 44 meses: fallecieron 21 pacientes (14,6 %) y 122 (86 %) viven; 76 de estos (54 %) se encuentran libres de enfermedad. El grupo con evidencia de enfermedad se presentó en estadios más avanzados. Resultaron factores de mayor riesgo para evidencia de enfermedad: sexo masculino, CMT esporádico, niveles elevados de CT prequirúrgicos, estadio IV y presencia de metástasis. Los niveles de CT posquirúrgicos fueron menores en aquellos pacientes que en la evolución final no presentaron evidencia de enfermedad. El principal factor pronóstico de la evolución de los pacientes con CMT fue el estadio de presentación, determinando la importancia del diagnóstico precoz con el fin de poder implementar un tratamiento quirúrgico curativo en estadios menos avanzados.

Due to the low frequency of medullary thyroid cancer (MTC), an observational, cohort, retrospective multicenter study was conducted at the Thyroid Department of the Endocrine and Metabolism Argentine Society (SAEM). We included 219 patients with histologically proven MTC, with a mean age of 39 ± 20 yr (range 1-84 years). Sixty five percent were women and 44% were familial cases. The most common presentations were thyroid nodule (58 %) and genetic screening due to family history (22 %). In 39 % of patients, diagnosis of MTC was made by fine needle aspiration, but cytology led to surgery in 79 %. In 47 % of patients, MTC was diagnosed by cytology, calcitonin (CT) levels or genetic studies prior to initial surgery. Sixty five percent of patients had advanced stages of the disease (TNM III or IV) at diagnosis. Proto-oncogene RET was studied in 162 patients (74 %). In 49% a mutation was reported, most frequently in codon 634 (76 %). Regarding hereditary forms of MTC, MEN 2A was the most frequent (57%), followed by familial MTC in 25 % and MEN 2B in 13 % of cases. Familial cases were younger subjects and had more frequently a pre-surgery diagnosis. Index cases were older, with higher CEA and CT levels, presented in more advanced stages and had more frequently evidence of disease at final assessment than patients who were diagnosed by genetic screening. Follow-up records of 143 patients were analyzed (65%); median time was 44 months; 21 patients died (14.6 %) and 122 survived (86 %), 76 showed no evidence of disease (NED) (54 %). High risk factors for evidence of disease at the final evaluation were: male gender, sporadic MTC, higher CT pre-surgery levels, stage IV and metastasis. Post surgery CT levels were lower in patients with NED. Stage at initial diagnosis was the main prognostic factor in patients with MTC, determining the importance of early detection for performing curative surgery in less advanced stages.

Genetic analysis of a Chinese Han family with multiple endocrine neoplasia type 2A.

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant disorder that can be distinguished as three different syndromes: multiple endocrine neoplasia type 2A (MEN2A), MEN2B and familial medullary thyroid carcinoma (FMTC). This disorder is usually caused by the mutations of the rearranged during transfection protooncogene gene (RET) or the neurotrophic tyrosine kinase receptor type 1 gene (NTRK1). To investigate the genetic cause in a Chinese Han family with MEN2A and the genotype-phenotype correlations, nine members belonging to 3 generations of MEN2A family with 5 affected subjects underwent genetic analysis. Standard GTG-banded karyotype analysis and sequencing of the RET and NTRK1 genes were performed to identify the genetic cause of this family. A heterozygous mutation p.Cys634Arg in the RET gene was identified in 5 patients with MEN2A and one asymptomatic family member. The phenotype of patients was that of classic MEN2A, characterized by medullary thyroid carcinoma and phaeochromocytoma. The clinical features of all cases with RET mutations varied greatly, including onset age of clinical manifestations, severity and comorbidities. Thus, this study not only identified the hereditary nature of the MEN2A in the cases, but also discovered a family member harboring the same p.Cys634Arg mutation, who was unaware of his condition. These finding may provide new insights into the cause and diagnosis of MEN2A and have implications for genetic counseling.

Multiple endocrine neoplasia: the Chilean experience

Multiple endocrine neoplasia (MEN) types 1 and 2 are genetic diseases that are inherited as autosomal traits. The major clinical manifestations of multiple endocrine neoplasia type 1 include the so-called "3 P's": parathyroid, pituitary, and pancreatic tumors, including gastroenteroneuroendocrine tumors. Genetic testing can be performed on patients and the potential carriers of the menin gene mutation, but the genotype-phenotype correlation in multiple endocrine neoplasia type 1 is less straightforward than multiple endocrine neoplasia type 2. Most likely, the main advantage of genetic testing in MEN1 is to exclude from further studies those who are negative for the genetic mutation if they belong to a family with a known history of MEN1. In Chile, we started with rearranged during transfection proto-oncogene genetic testing (MEN2) 15 years ago. We carried out a prophylactic total thyroidectomy to prevent medullary thyroid carcinoma in a three-year-old girl who presented with microscopic medullary thyroid carcinoma. More than 90% of the individuals who tested positive using a genetic test achieved a biochemical cure compared with only 27% of patients who receive a clinical diagnosis. Mutations are mainly located in exon 11; the most common is C634W, rather than C634R. Hypertensive crisis was the cause of death in three patients, and extensive distant metastases occurred in nine (including two patients with multiple endocrine neoplasia type 2B) of 14 patients. Earlier recognition of medullary thyroid carcinoma and the other features of the disease, especially pheochromocytoma, will improve the survival rate of patients with multiple endocrine neoplasia.

RET codon 609 mutations: a contribution for better clinical managing

Medullary thyroid carcinoma currently accounts for 5-8% of all thyroid cancers. The clinical course of this disease varies from extremely indolent tumors that can go unchanged for years to an extremely aggressive variant that is associated with a high mortality rate. As many as 75% of all medullary thyroid carcinomas are sporadic, with an average age at presentation reported as 60 years, and the remaining 25% are hereditary with an earlier age of presentation, ranging from 20 to 40 years. Germline RET proto-oncogene mutations are the genetic causes of multiple endocrine neoplasia type 2 and a strong genotype-phenotype correlation exists, particularly between a specific RET codon mutation and the (a) age-related onset and (b) thyroid tumor progression, from C-cell hyperplasia to medullary thyroid carcinoma and, ultimately, to nodal metastases. RET mutations predispose an individual to the development of medullary thyroid carcinomas and can also influence the individual response to RET protein receptor-targeted therapies. RET codon 609point mutations are rare genetic events belonging to the intermediate risk category for the onset of medullary thyroid carcinoma. A large genealogy resulting in a less aggressive form of medullary thyroid carcinoma is associated with the high penetrance of pheochromocytoma and has been reported in the literature. In this short review article, we comment on our previous report of a large multiple endocrine neoplasia type 2A kindred with the same Cys609Ser germline RET mutation in which, conversely, the syndrome was characterized by a slightly aggressive, highly penetrant form of medullary thyroid carcinoma that was associated with low penetrance of pheochromocytoma and primary hyperparathyroidism.

RET haplotype, not linked to the C620R activating mutation, associated with Hirschsprung disease in a novel MEN2 family

Hirschsprung disease is a congenital form of aganglionic megacolon that results from cristopathy. Hirschsprung disease usually occurs as a sporadic disease, although it may be associated with several inherited conditions, such as multiple endocrine neoplasia type 2. The rearranged during transfection (RET) proto-oncogene is the major susceptibility gene for Hirschsprung disease, and germline mutations in RET have been reported in up to 50% of the inherited forms of Hirschsprung disease and in 15-20% of sporadic cases of Hirschsprung disease. The prevalence of Hirschsprung disease in multiple endocrine neoplasia type 2 cases was recently determined to be 7.5% and the cooccurrence of Hirschsprung disease and multiple endocrine neoplasia type 2 has been reported in at least 22 families so far. It was initially thought that Hirschsprung disease could be due to disturbances in apoptosis or due to a tendency of the mutated RET receptor to be retained in the Golgi apparatus. Presently, there is strong evidence favoring the hypothesis that specific inactivating haplotypes play a key role in the fetal development of congenital megacolon/Hirschsprung disease. In the present study, we report the genetic findings in a novel family with multiple endocrine neoplasia type 2: a specific RET haplotype was documented in patients with Hirschsprung disease associated with medullary thyroid carcinoma, but it was absent in patients with only medullary thyroid carcinoma. Despite the limited number of cases, the present data favor the hypothesis that specific haplotypes not linked to RET germline mutations are the genetic causes of Hirschsprung disease.

Retroperitoneoscopic adrenalectomy in pheochromocytoma

Since the first laparoscopic adrenalectomy, the technique has evolved and it has become the standard of care for many adrenal diseases, including pheochromocytoma. Two laparoscopic accesses to the adrenal have been developed: transperitoneal and retroperitoneal. Retroperitoneoscopic adrenalectomy may be recommended for the treatment of pheochromocytoma with the same peri-operative outcomes of the transperitoneal approach because it allows direct access to the adrenal glands without increasing the operative risks. Although technically more demanding than the transperitoneal approach, retroperitoneoscopy can shorten the mean operative time, which is critical for cases with pheochromocytoma where minimizing the potential for intra-operative hemodynamic changes is essential. Blood loss and the convalescence time can be also shortened by this approach. There is no absolute indication for either the transperitoneal or retroperitoneal approach; however, the latter procedure may be the best option for patients who have undergone previous abdominal surgery and obese patients. Also, retroperitoneoscopic adrenalectomy is a good alternative for treating cases with inherited pheochromocytomas, such as multiple endocrine neoplasia type 2A, in which the pheochromocytoma is highly prevalent and frequently occurs bilaterally.

RET gene mutations and polymorphisms in medullary thyroid carcinomas in Indian patients.

Germline mutations of RET gene are pathognomonic of multiple endocrine neoplasia (MEN; MEN 2A/MEN 2B) and familial medullary thyroid carcinoma (FMTC), constituting 25% of medullary thyroid carcinomas (MTCs). We investigated RET gene mutations and polymorphisms at exons 10, 11, 13, 14, 15 and 16 in 140 samples, comprising 51 clinically diagnosed MTC patients, 39 family members of patients and 50 normal individuals. The method of choice was PCR and direct nucleotide sequencing of the PCR products. RET gene mutations were detected in 15 (29.4%) patients, with MEN 2A/FMTC in 13 patients and MEN 2B in 2 patients. Further, 39 family members of seven index cases were analysed, wherein four of the seven index cases showed identical mutations, in 13 of 25 family members. We also examined single nucleotide polymorphisms (SNPs) in RET gene exons in 101 unrelated samples. Significant differences in the allelic frequencies of SNPs at codons 691, 769, 836 and 904 between patient and control groups were not observed. However, SNP frequencies were significantly different in the Indian group as compared with other European groups. We identified two novel, rare and unique SNPs separately in single patients. Our study demonstrated presence of MEN 2A/MEN 2B/FMTC-associated mutations in accordance with the reported literature. Thus, RET gene mutations in exons 10, 11, 13, 14, 15 and 16 constitute a rapid test to confirm diagnosis and assess risk of the disease in familial MEN 2A/MEN 2B/FMTC.

Multiple Endocrine Neoplasia Type 2B: Early Diagnosis by Multiple Mucosal Neuroma and Its DNA Analysis

Multiple endocrine neoplasia type 2B (MEN 2B) is a rare disease caused by germline mutations in the RET proto-oncogene and is transmitted in an autosomal dominant fashion. It is characterized by medullary thyroid carcinoma, pheochromocytoma and mucosal neuroma developing in the tongue, lip, intestinal tract, palate etc. Among these neoplasias, mucosal neuroma generally develops from early childhood. Therefore, early detection and proper treatment can minimize the disease course. Here we describe a 9-year-old male who presented with multiple verrucous papules and nodules on his lips, tongue and gingiva that were there since birth. Histologic findings of his lips and tongue showed well-defined nerve bundles and DNA analysis revealed a M918T mutation at codon 918 of the RET oncogene. He was diagnosed early as having MEN 2B according to his genetic and phenotypic features.

Unpredicted tachycardia and hypotension in a patient with medullary thyroid cancer and undiagnosed pheochromocytoma: A case report / 대한마취과학회지

A 35 year old woman with hypercalcitoninemia was scheduled for an operation to treat her medullary thyroid cancer (MTC). TIVA with propofol and remifentanil was planned, and about 3 minutes after the infusion of anesthetics, her heart rate was suddenly elevated to 180/min and the systolic blood pressure was lowered to nearly 50 mmHg. The blood pressure returned to normal after the injection of phenylephrine 100 microgram and a rapid infusion of 700 ml crystalloid solution. After the operation, bilateral pheochromocytoma and a RET proto-oncogene mutation related with multiple endocrine neoplasia 2A (MEN-2A) were found. Patients with MTC can present with peripheral vasodilation and relative hypovolemia that are related with hypercalcitoninemia. Patients with MEN-2A can be anesthetized for a MTC operation without the appropriate preparation for their pheochromocytoma. Therefore, we suggest that patients with MTC and hypercalcitoninemia should be cautiously anesthetized with TIVA. They also should be screened for pheochromocytoma and the RET proto-oncogene mutation to prevent deleterious hemodynamic events during anesthesia.

Early diagnosis of multiple endocrine neoplasia type 2B: a challenge for physicians / Diagnóstico precoce de neoplasia endócrina múltipla tipo 2B: um desafio para os médicos

BACKGROUND: The hereditary form of medullary thyroid carcinoma may occur isolated as a familial medullary thyroid carcinoma (FMTC) or as part of Multiple Endocrine Neoplasia 2A (MEN2A) and 2B (MEN2B). MEN2B is a rare syndrome, its phenotype may usually, but not always, be noted by the physician. In the infant none of the MEN2B characteristics are present, except by early gastrointestinal dysfunction caused by intestinal neuromas. When available, genetic analysis confirms the diagnosis and guides pre-operative evaluation and extent of surgery. Here we report four cases of MEN2B in which the late diagnosis had a significant impact in clinical evolution and, potentially, in overall survival...

A forma hereditária do carcinoma medular da tiróide pode ocorrer de modo isolado, o carcinoma medular da tiróide familiar (FMTC), ou como parte das neoplasias endócrinas múltiplas tipo 2A (MEN2A) e 2B (MEN2B). MEN2B é uma síndrome rara e seu fenótipo é usualmente, mas nem sempre, notado pelo médico. Na infância, nenhuma das características de MEN2B estão presentes, exceto pela disfunção gastrintestinal precoce, causada pelos neuromas intestinais. Quando disponível, a análise genética confirma o diagnóstico e orienta a avaliação pré-operatória e extensão da cirurgia. Neste artigo, apresentamos quatro casos de MEN2B, nos quais o diagnóstico tardio teve impacto significativo na evolução clínica e, potencialmente, na mortalidade em geral...

Importância da identificação das mutações do protooncogene RET e sua atuação no desenvolvimento dos diversos fenótipos das neoplasias endócrinas múltiplas tipo 2 / Importance of RET proto-oncogene mutations identification and its performance in thedevelopment of the multiples endocrines neoplasias type 2 several phenotypes

A hereditariedade autossômica dominante da neoplasia endócrina múltipla tipo 2 (NEM 2) relaciona-se à ativação do proto-oncogene RET, através de mutações missense. As mutações do RET são encontradas em 95% dos casos índices de NEM 2 e apresentam relação direta entre sua localização codon específica e os diversos fenótipos desenvolvidos, dentre eles, carcinoma medular datireóide, feocromocitoma e/ou hiperparatireoidismo. Baseando-se em análises bioquímicas e genéticas, é possível efetuar um diagnósticoprematuro, viabilizando a intervenção cirúrgica em tempo hábil. A periodicidade da monitorização bioquímica é ditada pelo fenótipopresente, pelas manifestações clínicas familiares e pelo genótipo RET. A recomendação da análise genética deve ser feita a todos indivíduos afetados e também a seus ascendentes e descendentes diretos, caso alguma mutação esteja presente; permitindo identificar os portadores de mutações RET, previamente ao início da sintomatologia. Neste trabalho, serão discutidos os aspectos molecularesdos diversos fenótipos da NEM 2, bem como a importância da identificação genotípica do proto-oncogene RET e sua interação com os testes bioquímicos visando o diagnóstico precoce, prevenção, monitorização, screening familiar e, portanto, maior sobrevidado paciente.

The dominant autossomic hereditarity of the multiple endocrine neoplasia type 2 (MEN 2) is related to RET proto-oncogene activation, through mutations missense. RET mutations are found in 95% of MEN 2 index cases and present direct relation between its specific localization codon and the diverse developed phenotypes, among them, medullary thyroid carcinoma, pheochromocytoma and/or hyperparathyroidism. Being based on biochemists and genetics analyses, it is possible to perform a premature diagnosis, making possible a surgical intervention in the right time. The biochemist monitoring regularity is determined by present phenotype, the familiar clinical manifestations and RET genotype. The recommendation of the genetic analysis must be made to all affected individuals and also their ascendants and descendants, in case some mutation is present, allowing to identify the RET mutations carriers previously to the beginning of the symptomatology. In this work, the molecular aspects of MEN 2 diverse phenotypes will be discussed, as well as the importance of the RET proto-oncogene genotypic identification and its interaction with the biochemists tests aiming the precocious diagnosis, prevention, monitoring, familiar screening e, therefore, the patient’s longer survival.

Screening of RET gene mutations in multiple endocrine neoplasia type-2 using Conformation Sensitive Gel Electrophoresis (CSGE)

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant inherited tumor syndrome caused by RET proto-oncogene germline mutations (RET). Here we tested the Conformation Sensitive Gel Electrophoresis (CSGE) as a screening method for RET hot-spot mutations. Seven MEN2 families were studied by direct sequencing analysis, CSGE and Single Strand Conformational Polymorphism (SSCP). Using CSGE/SSCP, we were able to detect four out of five types of RET mutations verified by sequencing analysis: Cys620Arg, Cys634Arg, Cys634Tyr, and Met918Thr, furthermore a missense substitution at codon 648 (Val648Ile). RET polymorphisms 691 and 769 were also verified. Data obtained using CSGE/SSCP were fully concordant. We conclude that CSGE showed to be a sensitive, fast, low-cost, and simple procedure to detect RET mutations in codons which are reported as the most prevalent RET variants (~ 95 percent) in large MEN2 series. As to the Val804Met mutation, this method still needs to be optimized.

A neoplasia endócrina múltipla tipo 2 (NEM2) é uma síndrome tumoral herdada por mutações germinativas no proto-oncogene RET (RET). Analisamos a aplicação do método Eletroforese em Gel Sensível à Conformação (CSGE) no rastreamento de mutações hot spots do RET. Sete famílias com NEM2 foram rastreadas pelo seqüenciamento gênico, CSGE e análise do Polimorfismo Conformacional de Cadeia Simples (SSCP). Usando ambas as metodologias de rastreamento, identificamos quatro dos cinco tipos de mutações verificadas pelo seqüenciamento: Cys620Arg, Cys634Arg, Cys634Tyr e Met918Thr, além da variação gênica Val648Ile. Das análises englobando mutações hot spots do RET, 90,6 por cento concordaram com o seqüenciamento genético (incluindo a variação gênica Val648Ile). Polimorfismos nos códons 691 e 769 foram documentados. Os dados obtidos por CSGE/SSCP foram totalmente concordantes. Concluímos que o CSGE revelou ser metodologia sensível, rápida, de fácil execução e baixo custo no rastreamento de mutações nos códons associados à grande maioria (~ 95 por cento) dos pacientes com NEM2.

Analysis of RET Gene Point Mutation in a Family with Multiple Endocrine Neoplasia Type 2A / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Multiple Endocrine Neoplasia type 2A (MEN 2A) is a syndrome that encompasses medullary thyroid carcinoma, pheochromocytoma, and hyperparathyroidism. Since MEN 2A is inherited as autosomal dominant, early detection and treatment is crucial. A genetic analysis of RET proto-oncogene of the family members of an index patient diagnosed as MEN 2A is reported. SUBJECTS AND METHOD: A patient diagnosed as MEN 2A and his 13 family members across two generations were studied. Initially, DNA was extracted from the peripheral blood leukocyte of family members and PCR amplification of exons 10, 11, 13, 14, 15, and 16 was performed, followed by investigation of point mutation on the RET proto-oncogene using a DNA sequence analyzer. Cervical ultrasonography was carried out in the 3 nephews who were revealed to have RET proto-oncogene point mutation. RESULTS: Point mutations of TGC (cys) to TGG (Trp) at codon 634 of exon 11 at RET proto-oncogene was detected by using automatic DNA sequence analyzing method in the index patient. The same point mutation was identified in 7 of the 13 family members. Cervical ultrasonography revealed bilateral thyroid nodules in all 3 nephews who had point mutations of RET proto-oncogene. CONCLUSION: With the genetic analysis of RET proto-oncogene, limitations of the conventional calcitonin stimulation test may be overcome, and a more complete approach can be achieved through early diagnosis by carrying out this screening test for point mutations in family members of the patient with MEN 2A.