A differential diagnosis of inherited endocrine tumors and their tumor counterparts

Inherited endocrine tumors have been increasingly recognized in clinical practice, although some difficulties still exist in differentiating these conditions from their sporadic endocrine tumor counterparts. Here, we list the 12 main topics that could add helpful information and clues for performing an early differential diagnosis to distinguish between these conditions. The early diagnosis of patients with inherited endocrine tumors may be performed either clinically or by mutation analysis in at-risk individuals. Early detection usually has a large impact in tumor management, allowing preventive clinical or surgical therapy in most cases. Advice for the clinical and surgical management of inherited endocrine tumors is also discussed. In addition, recent clinical and genetic advances for 17 different forms of inherited endocrine tumors are briefly reviewed.

Narrowing the gap of personalized medicine in emerging countries: the case of multiple endocrine neoplasias in Brazil

The finished version of the human genome sequence was completed in 2003, and this event initiated a revolution in medical practice, which is usually referred to as the age of genomic or personalized medicine. Genomic medicine aims to be predictive, personalized, preventive, and also participative (4Ps). It offers a new approach to several pathological conditions, although its impact so far has been more evident in mendelian diseases. This article briefly reviews the potential advantages of this approach, and also some issues that may arise in the attempt to apply the accumulated knowledge from genomic medicine to clinical practice in emerging countries. The advantages of applying genomic medicine into clinical practice are obvious, enabling prediction, prevention, and early diagnosis and treatment of several genetic disorders. However, there are also some issues, such as those related to: (a) the need for approval of a law equivalent to the Genetic Information Nondiscrimination Act, which was approved in 2008 in the USA; (b) the need for private and public funding for genetics and genomics; (c) the need for development of innovative healthcare systems that may substantially cut costs (e.g. costs of periodic medical followup); (d) the need for new graduate and postgraduate curricula in which genomic medicine is emphasized; and (e) the need to adequately inform the population and possible consumers of genetic testing, with reference to the basic aspects of genomic medicine.

MENX and MEN4

Multiple endocrine neoplasias are autosomal dominant disorders characterized by the occurrence of tumors in at least two endocrine glands. Two MEN syndromes have long been known and are well characterized: the MEN type 1 (MEN1) and type 2 (MEN2). These syndromes are caused by germline mutations in the MEN1 and RET genes, respectively, and have a different tumor spectrum. Recently, a variant of the MEN syndromes arose spontaneously in a rat colony and was named MENX. Affected animals consistently develop multiple endocrine tumors, with a spectrum that shares features with both MEN1 and MEN2 human syndromes. Genetic studies identified a germline mutation in the Cdkn1b gene, encoding the p27 cell cycle inhibitor, as the causative mutation for MENX. Capitalizing on these findings, heterozygous germline mutations in the human homologue, CDKN1B, were searched for and identified in patients with multiple endocrine tumors. As a consequence of this discovery, a novel human MEN syndrome, named MEN4, was recognized, which is caused by mutations in p27. Altogether, these studies identified Cdkn1b/CDKN1B as a novel tumor susceptibility gene for multiple endocrine tumors in both rats and humans. Here we review the characteristics of the MENX and MEN4 syndromes and we briefly address the main function of p27 and how they are affected by MENX/4-associated mutations.

Análise do gene AIP na acromegalia familial isolada / Analysis of the AIP gene in familial isolated acromegaly

A acromegalia é doença insidiosa e desfigurante caracterizada por um crescimento desproporcional dos ossos das mãos, pés e do crânio devido à exposição crônica a altos níveis de hormônio de crescimento (GH) e de seu efetor insuline growth factor 1 (IGF-1). Trata-se de uma doença rara, com incidência estimada de 3-4 casos por milhão, com prevalência de aproximadamente 50 casos por milhão de pessoas. A principal causa da acromegalia é a presença de um tumor hipofisário secretor de GH (somatotropinoma). Caso o somatotropinoma ocorra durante a infância ou adolescência, antes do fechamento das epífises dos ossos longos, a criança crescerá longitudinalmente de forma descontrolada, caracterizando a forma clínica gigantismo. Na grande maioria dos casos a acromegalia se apresenta na forma esporádica, entretanto casos familiais da doença podem ocorrer associados à Neoplasia Endócrina Múltipla tipo 1 (NEM-1), ao complexo de Carney (CNC) e à acromegalia familial isolada (IFS). Os genes responsáveis pela NEM-1 (MEN1) e CNC (PRKAR1A) foram clonados há mais 10 anos, entretanto etiologia molecular da IFS permaneceu desconhecida até recentemente. Vierimaa et al. (2006) combinaram estudos de ligação por análise de polimorfismos e estudos de expressão gênica e identificaram mutações no gene AIP em famílias com acromegalia não-NEM-1 e não-CNC; além de perda de heterozigose (LOH) nos somatotropinomas dos pacientes com mutação AIP. No presente estudo, investigamos o gene AIP em três famílias brasileiras com IFS e em seus tumores (hipofisários e não-hipofisários). Descrevemos uma nova mutação AIP (Y268X) em uma família brasileira com IFS, confirmando o papel desse novo gene na predisposição a tumores hipofisários. A partir de dados gerados em uma extensa revisão da literatura, sugerimos que os tumores hipofisários familiais isolados são doenças multigênicas que possuiriam um gene principal, mas que sofreriam influência de outros genes/loci ainda pouco caracterizados...

Acromegaly is a rare disfigurating and insidious disease characterized by enlargement of hands, feet and skull bones due to excess of growth hormone (GH) secreted by a pituitary tumor (somatotropinoma). The majority of the cases with acromegaly is sporadic, however it may occur in association with inherited disorders as Multiple Endocrine Neoplasia type 1 (MEN1), Carney complex (CNC) and Isolated Familial Somatotropinoma (IFS). The genes associated with MEN1 syndrome (MEN1) and CNC (PRKAR1A) have been described more than a decade ago, however until very recently the molecular etiology of IFS remained unknown. Using a combined strategy of single nucleotide polymorphism (SNP) analysis and gene expression analysis, Vierimaa et al. (2006) described mutations in the AIP gene occurring in families with acromegaly not associated with MEN1 and CNC. In the current study, we investigated three Brazilian families with IFS and were able to describe two germline mutations in the AIP gene, confirming the role of this new gene in the predisposition to familial somatotropinoma. We revised the literature of genetic studies of isolated pituitary adenoma syndromes, which indicated a genetic heterogeneity as well as possible multigenic inheritance for these diseases. Thus, we investigated the role of several genes/loci (SSTR2, SSTR5, CDKN1B, AHR, PRKAR1A, PTTG, PROP1, MEG3, RB1 and 2p16) selected as potentially acting as phenotypic modulators in IFS. Our data indicate that AIP-mutated patients are prone to pituitary disease, however it is necessary the co-segregation of markers located at oncogenic regions to the development of the pituitary tumors and manifestation of the disease. Herein, we also present the first somatic analysis of non-pituitary tumors of AIP-mutated patients. A potential role of AIP, which is implicated in the cAMP pathway, could not be excluded in the development of an adrenocortical carcinoma.

G691S/S904S polymorphism in the RET protooncogene of a 25-year-old medical student with bilateral pheochromocytoma.

The case of a 25-year-old medical student with bilateral pheochromocytoma is described. Following diagnostic testing, tumors were surgically removed. Genetic analysis revealed that the patient is a heterozygote with the following mutations on opposite homologs: G691S (exon 11) and S904S (TCC-TCG, exon 15), suggesting the diagnosis of multiple endocrine neoplasia 2A (MEN2A). A diagnosis of MEN2 would be an indication of thyroidectomy in this patient. Although this mutation is described in the literature, it has no known connection to pheochromocytomas. Therefore, it is unknown whether there is a causal connection between the G691S genotype and the pheochromocytomas in this patient. If so, G691S is to be added to the list of genotypes causing MEN2A. Here, the procedure of sequencing the RET protooncogene is described and a possible association between the G691S genotype and MEN2A is discussed.

Absence of PRKAR1A loss of heterozygosity in laser-captured microdissected pigmented nodular adrenocortical tissue from a patient with Carney complex caused by the novel nonsense mutation p. Y21X / Ausência da perda de heterozigose do PRKAR1A em células capturadas por microdissecção a laser de tecido de nódulo pigmentoso adrenocortical de um paciente com complexo de Carney causado por uma nova mutação nonsense

OBJECTIVE: Primary pigmented nodular adrenocortical disease (PPNAD) is the main endocrine manifestation of Carney complex, a multiple neoplasia syndrome caused by PRKAR1A gene mutations. The presence of PRKAR1A loss of heterozygosity (LOH) in adrenocortical tumorigenesis remains controversial. The aim of the present study is to investigate the presence of PRKAR1A LOH in adrenocortical cells in a patient with Carney complex. METHODS: The LOH was investigated using a PRKAR1A informative intragenic marker by GeneScan software analysis in DNA obtained from laser-captured microdissected cells of several adrenal nodules. Patients: A young adult male patient with Carney complex and his family were studied. RESULTS: A novel heterozygous mutation (p. Y21X) was identified at PRKAR1A in blood DNA of the male proband and his relatives. No PRKAR1A LOH was evidenced in the laser-captured microdissected cells from PPNAD tissue by different methodologies. CONCLUSION: We identified a new PRKAR1A nonsense mutation and in addition we did not evidence PRKAR1A LOH in laser-captured nodules cells, suggesting that adrenocortical tumorigenesis in PPNAD may occurs apart from the second hit.

OBJETIVO: A doença adrenocortical nodular pigmentosa primária (PPNAD) é uma das manifestações do complexo de Carney, uma neoplasia endócrina múltipla causada por mutações no PRKAR1A. A perda de heterozigose (LOH) do PRKAR1A na tumorigenese adrenal permanece controversa dada à possibilidade de contaminação com o tecido normal. Nosso objetivo foi investigar a presença de LOH no PRKAR1A a partir de células do nódulo adrenal de um paciente com complexo de Carney. MÉTODOS: A pesquisa da LOH do PRKAR1A foi realizada através do estudo de um marcador intragênico em DNA de células do nódulo adrenal microdissecadas a laser, evitando contaminação com o tecido normal. Pacientes: Um paciente com PPNAD e cinco familiares foram estudados. RESULTADOS: A nova mutação (p. Y21X) foi identificada no PRKAR1A sem evidência de LOH no tecido adrenal. CONCLUSÃO: Identificamos uma nova mutação no PRKAR1A e não evidenciamos LOH nas células dos nódulos adrenocorticais, sugerindo que a PPNAD possa ocorrer na ausência de um segundo evento molecular.

Primary pigmented nodular adrenocortical disease associated with Carney complex: case report and literature review

CONTEXT: Carney complex (CNC), a familial multiple neoplasm syndrome with dominant autosomal transmission, is characterized by tumors of the heart, skin, endocrine and peripheral nervous system, and also cutaneous lentiginosis. This is a rare syndrome and its main endocrine manifestation, primary pigmented nodular adrenal disease (PPNAD), is an uncommon cause of adrenocorticotropic hormone-independent Cushing's syndrome. CASE REPORT: We report the case of a 20-year-old patient with a history of weight gain, hirsutism, acne, secondary amenorrhea and facial lentiginosis. Following the diagnosing of CNC and PPNAD, the patient underwent laparoscopic bilateral adrenalectomy, and she evolved with decreasing hypercortisolism. Screening was also performed for other tumors related to this syndrome. The diagnostic criteria, screening and follow-up for patients and affected family members are discussed.

CONTEXTO: O complexo de Carney (CNC), uma síndrome de neoplasia múltipla familiar com transmissão autossômica dominante, caracteriza-se por tumores cardíacos, cutâneos, endócrinos e do sistema nervoso periférico, além de lentiginose cutânea. RELATO DE CASO: Devido à raridade da síndrome, bem como de sua principal manifestação endócrina, a doença adrenal nodular pigmentada primária (PPNAD), causa incomum de síndrome de Cushing ACTH-independente, relatamos o caso de uma paciente de 20 anos com história de ganho de peso, hirsutismo, acne, amenorréia secundária e lentiginose em face. Após estabelecido o diagnóstico de CNC e PPNAD, a paciente foi submetida a adrenalectomia bilateral via laparoscópica, evoluindo com melhora do hipercortisolismo. Também foi realizado rastreamento para os demais tumores relacionados à síndrome. Serão discutidos os critérios diagnósticos, o rastreamento e o acompanhamento dos pacientes e familiares afetados.

Descobrindo genes no século XXI: enfoque na área de onco-endocrinologia / Discovering genes in the XXI century: focus in the onco-endocrinology

A área de endocrinologia genética e oncológica tem sido alvo de enorme avanço nos anos recentes. A descoberta de genes responsáveis por neoplasias hereditárias nas últimas décadas representou uma fonte importante de informações concernentes à avaliaçäo de risco, prevençäo e aconselhamento genético. Neste particular, a caracteri-zaçäo do gene responsável pela neoplasia endócrina múltipla tipo 2 (MEN 2) representou a "pedra angular" para o desenvolvimento do campo de oncogenética clínica. Portanto, estima-se que o estudo genético e funcional das neoplasias hereditárias será igualmente capaz de liderar o avanço para um melhor manuseio clínico e terapêutico destas doenças. Um dos grandes desafios do futuro reside em se entender o intrincado mecanismo de interaçäo entre genes e proteínas no controle do desenvolvimento e regulaçäo dos diferentes sistemas biológicos. Uma das conseqüências mais antecipadas deste avanço é a sua aplicaçäo para o tratamento específico e "individualizado" de todas as doenças humanas. Esta breve revisäo tratará de aspectos gerais que envolvem o processo de identificaçäo de novos genes e sua associaçäo com condições clínicas específicas. As técnicas clássicas de clonagem seräo apresentadas ao lado de estratégias modernas de identificaçäo e análise de genes. O papel da bioinformática no Projeto Genoma Humano e o imenso potencial que esta informaçäo traz para acelerar o processo de caracterizaçäo de novos grupos de genes seräo brevemente discutidos.

Tumorigênese molecular tiroideana: implicações para a prática médica / Molecular thyroid tumorigenesis: implications for the medical practice

Esta revisäo apresenta aspectos de utilidade prática da tumorigênese tiroideana. O mais importante é a possibilidade de se fazer o diagnóstico genético precoce dos indivíduos portadores de mutações do gene RET em famílias com carcinoma medular de tiróide e neoplasia endócrina múltipla tipo 2. Além disso, discutem-se dados relativos à patogénese molecular dos carcinomas diferenciados da tiróide, relacionados aos rearranjos entre RET e outros genes no caso do carcinoma papilífero (RET/PTC) e entre PAX-8 e PPARgI no carcinoma folicular da tiróide. A seguir, analisam-se as mutações que causam ganho de funçäo no receptor de TSH, causadoras dos nódulos autônomos. Finalmente, apresenta-se o emprego do RNA mensageiro da tiroglobulina no seguimen-to de pacientes com câncer de tiróide.

Mutaciones de línea germinal del proto oncogen ret en pacientes chilenos con cáncer medular tiroideo hereditario y esporádico / Germline mutations of the ret proto oncogen in chilean patients with hereditary and sporadic medullary thyroid carcinoma

Background: Medullary thyroid carcinoma (MTC) may occur either as a sporadic or familial disease. Multiple endocrine neoplasia (MEN) type 2, inherited as an autosomal dominant disease, is characterized by MTC only (FMTC) or coexistence of MTC with other endocrine neoplasia (NEM 2A, 2B). Germline mutations of the RET proto-oncogene (cRet) are found in the inherited forms and in some apparently sporadic MTC cases. Aim: To study RET mutations in 8 families with MEN 2. Material and methods: RET mutations were screened in peripheral blood DNA from 18 patients and 87 high risk carriers belonging to 8 MEN 2 families and 52 sporadic MTC. Exons 10, 11, 13, 14, 15 and 16 of the c-Ret were amplified by polymerase chain reaction (PCR) and examined by direct sequencing of PCR products and/or restriction enzyme analysis. Results: Five MEN 2A and one FMTC families with a germline mutation at codon 634, one MEN 2A and one FMTC family carrying a mutation at codon 620 were identified. Mutations were found in 23 out of 87 high risk carriers. In addition, we detected a S891A (exon 15) germline mutation in a sporadic MTC patient and in one out of her three sons and V804M (exon 14) in another sporadic MTC case and in one out of his six relatives, indicating in both cases the presence of a sporadic misclassified familial disease. Conclusions: These results underscore the importance of routine application of c-Ret testing in all cases of MTC either familial or sporadic

Neoplasias endócrinas múltiplas: papel da genética na gênese das proliferações celulares / Multiple endocrine neoplasia: role of genetics in the genesis of cellular proliferations

As síndromes de Neoplasias Endócrinas Múltiplas (NEM) são desordens de padrão autossômico dominante, caracterizadas pela ocorrência concomitante de múltiplas neoplasias comprometendo o sistema endócrino. A NEM tipo 1 se caracteriza por um fenótipo clínico que inclui comprometimento das paratireóides, pâncreas e hipófise. A alteração genética relacionada a esta síndrome foi mapeada no cromossomo 11q13 e o gene identificado como MEN1. A proteína codificada pelo gene MEN1 é denominada menin e, ligando-se ao fator de transcrição JunD, apresenta função de supressão tumoral. Mutações do gene MEN1 resultam na perda da função da proteína menin, levando à perda de controle da proliferação de células neuro-endócrinas. A NEM tipo 2 é subdividida em NEM2A e NEM2B. A NEM2A é caracterizada pela presença de carcinoma medular de tireóide (CMT), hiperparatireoidismo e feocromocitoma. Indivíduos com NEM2B apresentam carcinoma medular de tireóide e feocromocitoma, acompanhados por neuromas ou ganglioneuromas evidentes. O mecanismo de desenvolvimento das neoplasias na NEM2 difere da maioria dos outros mecanismos de carcinogênese, já que está relacionado a diferentes mutações no proto-oncogene RET. O proto-oncogene RET é um importante controlador da mitose e apoptose, e quando ativado, desencadeia uma cascata de sinalizações que culmina na tumorigênese.

Neoplasias endocrinas múltiples: un modelo clínico para aplicar técnicas de genética molecular / Multiple endocrine neoplasia: a clinical model for testing molecular genetic techniques

Multiple endocrine neoplasias (MEN) are syndromes inherited as autosomal dominant. The application of the techniques of molecular biology has made possible the identification of the genes causing MEN 1 and 2. The gene responsable for MEN 1 belongs to the family of tumor suppressor genes and encodes for a protein named MENIN whose function remains to be elucidated. The identification of mutant MEN 1 gene carriers who are at risk of developing this syndrome requires frequent biochemical screening for the development of endocrine tumors. MEN 2 is a consequence of mutations in the Ret proto- oncogene (c-Ret). This gene encodes for a tyrosine kinase receptor thought to play a role in the development of neural crest- derived tissue. Members of kindred with either MEN 2A or MEN 2B should be screened by direct DNA testing early in life for mutations in c-Ret. Those with the mutation should be advised to have thyroidectomy at five years of age in children with MEN 2A and earlier in children with MEN 2B . Some cases of sporadic MTC are actually MEN 2A or Familial MTC after c-Ret testing is done, therefore routine application of this test is recommended in all cases of apparent sporadic MTC

Familial cancers

Although cancer is common in the general population, only a small proportion is thought to be due to highly penetrant cancer genes. Families with a highly penetrant cancer predisposing gene may be recognised by the presence of a high number of individuals within the family with a particular cancer type, or individuals with features associated with rare inherited cancers, such as retinal changes or multiple colonic polyps. It is likely that there are many other less penetrant genes, which, in combination with environmental influences, will confer a greater lifetime predisposition to cancers. These genes are currently being identified through epidemiological studies

Diagnostico precoz de neoplasia endocrina multiple tipo 2 (MEN 2) por la deteccion de portadores de mutaciones en el proto-oncogen RET / Early diagnosis of multiple endocrine neoplasia type 2 by detection of matated RET proto-oncogene carriers

El MEN 2 es un síndrome hereditario autosómico dominante, en el cual mutaciones del RET dan origen a tres fenotipos diferentes: carcinoma medular de tiroides familiar (CMTF), MEN 2A y MEN 2B. La identificación de mutaciones en el proto-oncogen RET predice el desarrollo de la enfermedad antes de las evidencias clínicas y bioquímicas. En este trabajo se identificaron portadores del RET por caracterización de mutaciones en pacientes y sus familiares. Se estudiaron 21 familias con CMTF (5 y 6 miembros), 4 con MEN 2A (dos de 5, una de 4 y otra de 3 miembros) y 2 con MEN 2B (5 y 1 miembros). Se obtuvieron muestras de ADN de sangre, en todos los casos y de tejido de feocromocitoma y/o tejido tiroideo en los operados. Se utilizó PCR para amplificar los exones 10, 11 y 16 con oligonucleótidos específicos, realizándose secuenciación directa de los fragmentos. En las familias con CMTF y con MEN 2A se encontraron mutaciones en el codón 634 del exón 11 en 16 sujetos, dectándose 9 casos con la mutación TGC r CGC (cisteína a arginina), 3 con TGC r TAC (cisteína a tirosina) y 4 con TGC r TTC (cisteína a fenilalanina). En los pacientes con MEN 2 B se encontró una mutación en el codón 918 del exón 16 ATG r ACG (meitonina a treonina). En tejido tumoral se detectó la misma mutación que en sangre periférica. El diagnóstico de MEN 2 fue confirmado en los 8 pacientes y detectado en 10 familiares. En los 5 portadores tiroidectomizados se encontró hiperplasia de células C o microcarcinoma in situ en 2 niños (9 y 12 años) y CMT en 3 adultos. La detección temprana de mutaciones del RET, especialmente en familiares seguida por tiroidectomía total, podría prevenir el desarrollo de CMT, modificado el desenlace fatal que ocurre cuando es diagnosticado tardíamente.

Feocromocitotoma bilateral maligno como componentes de adenomatosis endocrina multiple tipo II-A: presentacion de un caso y revision de la literatura / Bilateral malignant pheochromocytoma as component of multiple endocrine adenmatosis type II-A: presentation of a case and review of the literature

Se presenta el caso de un joven de 25 anos hospitalizado por un cuadro de hipertension arterial sistemica severa acompanado de bocio multinodular, a quien se le diagnostico adenomatosis endocrina multiple tipo II-A (AEM II-A). Se comprobo la presencia de feocromocitoma bilateral metastasico al encontrarse niveles elevados de acido venilmandelico en orina, dos masas suprarrenales bilaterales y una masa tumoral hepatica en el estudio tomografico de abdomen. En forma similar se evidenciaron nodulos hipocaptantes en tiroides, demostrandose que correspondian a un carcinoma medular de tiroides al realizar el estudio histopatologico. se logro el control de las cifras tensionales con la administracion de prazosin (12 mg/da) y labetalol (600 mg/dia) en el periodo preoperatorio, practicandose posteriormente la adrenalectomia subtotal bilateral y tiroidectomia total. En su evolucion postoperatoria el paciente presento episodios de hemorragia digestiva superior masiva debidos a multiples ulceras del tracto gastrointestinal, que ameritaron realizar una gastrectomia total para el control de la hemorragia. Se hace revision de la literatura con referencia particular al diagnostico y manejo del feocromocitoma maligno

Adenomatosis endócrinas múltiple tipos I y II

La adenomatosis endócrina múltiple es un síndrome adquirido por la herencia, y que da lugar a dos variedades importantes: la neoplasia endocrina múltiple tipo I y la Tipo II. Ambos padecimientos tiene una genética y embriológica. Se transmiten como un desorden autosómico dominante con alto grado de penetración, asimismo, derivan de la cresta neural, lo que apoya la teoría de que provienen de una célula progenitora única. La neoplasia endocrina múltiple tipo I, se caracteriza por la presencia conjunta de tumores de las paratiroides, hipófisi s y páncreas. La de tipo II tiene dos variedades: la lla que está formada por carcinoma medular del tiroides, fenocromocitoma e hiperparatiroidismo, y la IIb, que comprende al carcinoma medular del tiroides, feocromocitoma y neuromas mucosos. El cuadro clínico está en relación a la alteración endocrina predominante