Glucose-dependent insulinotropic peptide receptor overexpression in adrenocortical hyperplasia in MEN1 syndrome without loss of heterozygosity at the 11q13 locus

BACKGROUND: The molecular mechanisms involved in the genesis of the adrenocortical lesions seen in MEN1 syndrome (ACL-MEN1) remain poorly understood; loss of heterozygosity at 11q13 and somatic mutations of MEN1 are not usually found in these lesions. Thus, additional genes must be involved in MEN1 adrenocortical disorders. Overexpression of the glucose-dependent insulinotropic peptide receptor has been shown to promote adrenocortical tumorigenesis in a mice model and has also been associated with ACTH-independent Cushing syndrome in humans. However, to our knowledge, the status of glucose-dependent insulinotropic peptide receptor expression in adrenocortical lesions in MEN1 has not been previously investigated. OBJECTIVE: To evaluate glucose-dependent insulinotropic peptide receptor expression in adrenocortical hyperplasia associated with MEN1 syndrome. MATERIALS/METHODS: Three adrenocortical tissue samples were obtained from patients with previously known MEN1 germline mutations and in whom the presence of a second molecular event (a new MEN1 somatic mutation or an 11q13 loss of heterozygosity) had been excluded. The expression of the glucose-dependent insulinotropic peptide receptor was quantified by qPCR using the DDCT method, and b-actin was used as an endogenous control. RESULTS: The median of glucose-dependent insulinotropic peptide receptor expression in the adrenocortical lesions associated with MEN1 syndrome was 2.6-fold (range 1.2 to 4.8) higher than the normal adrenal controls (p = 0.02). CONCLUSION: The current study represents the first investigation of glucose-dependent insulinotropic peptide receptor expression in adrenocortical lesions without 11q13 loss of heterozygosity in MEN1 syndrome patients. Although we studied a limited number of cases of MEN1 adrenocortical lesions retrospectively, our preliminary data suggest an involvement of glucose-dependent insulinotropic peptide receptor overexpression in the etiology of adrenocortical hyperplasia. New prospective studies will be able to clarify the exact role of the glucose-dependent insulinotropic peptide receptor in the molecular pathogenesis of MEN1 adrenocortical lesions.

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.

Classical osteoblastoma, atypical osteoblastoma, and osteosarcoma: a comparative study based on clinical, histological, and biological parameters

OBJECTIVE: To investigate the biological behavior of classical and atypical osteoblastomas in comparison to osteosarcomas. METHODS: Based on histological parameters, 30 osteoblastomas were subclassified as classical osteoblastomas (23/30) or atypical osteoblastoma (high cellularity, prominent blue osteoid, and epithelioid osteoblasts-7/30). Comparative immunohistochemical and clinical analysis was performed in 17 cases of patients with high-grade osteosarcoma. Formalin-fixed, paraffin-embedded archival tissue was immunostained for p53 and proliferation cell nuclear antigen. Tumors with positive p53 stain underwent molecular analyses for fragments of exon 10. RESULTS: The mean proliferating cell nuclear antigen indexes for classical osteoblastoma, atypical osteoblastoma, and osteosarcoma were 33 percent, 61 percent, and 79 percent, respectively. The atypical subgroup showed similar results to those of the osteosarcoma group (P < 0.001). p53 protein was detected in 4 (13 percent) osteoblastomas (3 of these were atypical osteoblastoma), and 4 osteosarcomas (23 percent) also showed p53 positivity. DNA mutation performed in p53-positive cases was confirmed in exon 10 in 2 atypical osteoblastomas (2/3), 1 classical osteoblastoma (1/1), and 1 osteosarcoma (1/4). Disease recurrence was correlated with p53 expression (P = 0.009), atypical subtype (P = 0.031), spiculated blue bone on histology (P = 0.018), and proliferatingcell nuclear antigen labeling index > 40 (P = 0.015). CONCLUSION: These results validate atypical osteoblastoma as an entity, with p53 and proliferation cell nuclear antigen immunoexpression closer to that of osteosarcoma than of classical osteoblastoma. Proliferating cell nuclear antigen labeling index and p53 may be useful predictors of recurrence.

OBJETIVOS: Investigar o comportamento biológico de osteoblastomas clássicos e atípicos comparados com osteossarcomas. MÉTODOS: Com base em parâmetros histológicos classificamos um grupo de 30 osteoblastomas nos subgrupos de osteoblastomas clássicos (23/30) e de osteoblastomas atípicos (que apresentam como característica grande celularidade, osteóide azul proeminente e osteoblastos epitelióide-7/30). Como efeito de comparação dos resultados imunohistoquímicos e análise clínica, avaliamos 17 pacientes com osteosarcoma de grau avançado. Os cortes histológicos com bloco de parafina fixado em formalina foram imunocorados para p53 e antígeno nuclear de célula em proliferação. Tumores com coloração positiva para p53 tiveram análise molecular para fragmentos do exon 10. RESULTADOS: O índice médio de antígeno nuclear de célula em proliferação para osteoblastoma clássico, osteoblastoma atípico e osteosarcoma foram de 33 por cento, 61 por cento e 79 por cento, respectivamente. O subgrupo atípico demonstrou resultados similares aos dos osteosarcomas (p<0,001). Foram detectadas proteína p53 em 4 (13 por cento) osteoblastomas; 3 desses foram osteoblastomas atípicos, sendo que 4 osteosarcomas (23 por cento) também demonstraram p53 positivo. A mutação do DNA nos casos positivos de p53 foi confirmada no exon 10 em dois osteoblastomas atípicos (2/3), um osteoblastoma clássico (1/1) e um osteosarcoma (1/4). A recorrência da doença foi correlacionada com a expressão do p53 (p=0,009), subtipo atípico (p=0,031), osso azul espiculado no resultado da histologia (p=0,018), e índice de marcação pelo antígeno nuclear de célula em proliferação > 40 (p=0,015). CONCLUSÃO: Esses resultados validam os osteoblastomas atípicos como entidade real, com imunoexpressão das proteínas p53 e antígeno nuclear de célula em proliferação mais perto do osteosarcoma do que do osteoblastoma clássico. O índice de marcação pelo antígeno nuclear de célula em proliferação e o p53 podem...

Presença da mutação Arg337His do supressor tumoral P53 e mapa de deleção do cromossomo 17 em crianças e adultos com tumores adrenocorticais / Presence of the mutation Arg337His of the tumor suppressor P53 and deletion mapping of chromosome 17 in children and adults with adrenocorticol tumors

A mutação germinativa, Arg337His, do gene supressor tumoral p53 foi pesquisada em 71 pacientes brasileiros portadores de tumores adrenocorticais isolados. Análise de segregação evidenciou um mesmo haplótipo, associado à mutação Arg337His, configurando efeito fundador para esta mutação. Mapa de deleção para o cromossomo 17 demonstrou uma elevada freqüência 17/29 (59por cento), de perda completa deste cromossomo tanto em tumores benignos quanto malignos mostrando que não há correlação entre perda do cromossomo 17 e agressividade tumoral nestes pacientes. Instabilidade cromossômica envolvendo os cromossomos 2, 9 e 11 foi verificada nos pacientes que perderam o cromossomo 17. Perda de 3 ou mais cromossomos pode contribuir para o diagnóstico de malignidade nos tumores adrenocorticais / The Arg337His mutation of the P53 tumor suppressor was investigated in 71 Brazilian patients with isolated adrenocortical tumors. Segregation analysis evidenced the same haplotype, associated with Arg337His mutation, indicating a founder effect. Deletion mapping for chromosome 17 demonstrated a high frequency 17/29 (59 per cent) of chromosomal loss in both, benign and malignant tumors, without correlation between loss of chromosome 17 and tumor behavior. Chromosomal instability, involving chromosomes 2, 9 and 11 was verified in patients that had loss of chromosome 17. The concomitant loss involving of 3 or more chromosomes can contribute for diagnosis of malignancy in adrenocortical tumors...