RESUMO
This study aimed to evaluate the effect of miR-23b-3p on growth hormone (GH) in pituitary cells of Yanbian yellow cattle. The mRNA and protein levels of GH and miR-23b-3p target genes were measured by real time fluorescence quantitative PCR (qPCR) and Western blot, respectively. The target relationship of miR-23b-3p was validated by double luciferase reporter gene system. The results showed that GH mRNA and protein levels in pituitary cells of Yanbian yellow cattle were significantly lower in the miR-23b-3p-mi group than in the NC group (P<0.01), while GH mRNA and protein levels were higher in the miR-23b-3p-in group than in the iNC group (P<0.05). The result of bioinformatics analysis and double luciferase reporter gene system validation proved that miR-23b-3p targeted 3'UTR of pituitary specific transcription factor 1 (POU1F1). POU1F1 mRNA and protein levels were lower miR-23b-3p-mi group than in the NC group (P<0.01), while POU1F1 mRNA and protein levels were higher in the miR-23b-3p-in group than in the iNC group (P<0.01). These results demonstrated that miR-23b-3p could regulate GH expression in pituitary cells by regulating POU1F1 gene.
Assuntos
Hormônio do Crescimento , MicroRNAs , Fator de Transcrição Pit-1 , Animais , Bovinos/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Hormônio do Crescimento/genética , Hormônio do Crescimento/metabolismo , Fator de Transcrição Pit-1/genética , Fator de Transcrição Pit-1/metabolismo , Hipófise/metabolismo , Regulação da Expressão Gênica , Regiões 3' não Traduzidas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
The pathogenesis of anti-pituitary-specific transcription factor-1 (PIT-1) hypophysitis was gradually revealed as cases emerged. Our comprehensive analysis, including all reported cases, identified a new instance of anti-PIT-1 hypophysitis postimmune checkpoint inhibitor therapy. All 9 patients exhibited extremely low growth hormone (GH), prolactin (PRL), and thyroid-stimulating hormone (TSH) levels; 2 had a slightly atrophic pituitary gland; 4 had thymoma, and 5 had malignant neoplasms of diffuse large B-cell lymphoma (DLBCL) and other origins. Patients with thymoma showed multiple autoimmune diseases. HLA-A*24:02 and/or A*02:06 were present in six and DR53 in 5 cases analyzed. High anti-PIT-1 antibody titers and ectopic PIT-1 expression in the cytosol and nucleus of the tumor tissues were observed in patients with thymoma or DLBCL, whereas it was exclusively observed in the nuclei of a bladder cancer patient. These findings provide new insights into the pathophysiology of paraneoplastic autoimmune hypophysitis.
Assuntos
Doenças Autoimunes , Hipofisite Autoimune , Hipofisite , Timoma , Neoplasias do Timo , Humanos , Autoanticorpos , Fator de Transcrição Pit-1 , Fatores de TranscriçãoRESUMO
Anti-pituitary-specific transcription factor-1 (PIT-1) hypophysitis, a paraneoplastic syndrome resulting from an autoimmune response against PIT-1, typically manifests with undetectable levels of growth hormone (GH) and prolactin (PRL), and significantly low levels of serum thyroid-stimulating hormone (TSH) at diagnosis. These hormonal levels are highly specific to this disease and serve as key diagnostic indicators. Herein, we present a detailed clinical course of a 69-year-old male with a history of gastric cancer and lymph node metastases who developed anti-PIT-1 hypophysitis after the initiation of immune checkpoint inhibitor (ICI) therapy, specifically nivolumab, oxaliplatin, and capecitabine. The patient was referred to our department owing to decreased TSH, free triiodothyronine (T3), and free thyroxine (T4) levels after two doses of nivolumab. Initially suspected as central hypothyroidism due to ICI-related hypophysitis, further assessment confirmed the diagnosis of anti-PIT-1 hypophysitis. Notably, GH, PRL, and TSH levels markedly declined, leading to complete deficiencies 2 months after the first nivolumab dose-a pattern consistent with that of previous cases of anti-PIT-1 hypophysitis. Therefore, this report not only presents an atypical subset of ICI-related hypophysitis but also delineates the process of hormone impairment leading to complete deficiencies in anti-PIT-1 hypophysitis. This case highlights the importance of vigilant monitoring for endocrine issues in patients undergoing ICI therapy, given the escalating incidence of immune-related adverse events associated with the extensive use of ICI therapy for various cancers.
Assuntos
Hipofisite , Inibidores de Checkpoint Imunológico , Humanos , Masculino , Idoso , Inibidores de Checkpoint Imunológico/efeitos adversos , Inibidores de Checkpoint Imunológico/uso terapêutico , Hipofisite/induzido quimicamente , Hipofisite/tratamento farmacológico , Fator de Transcrição Pit-1 , Hipofisite Autoimune/tratamento farmacológico , Hipofisite Autoimune/diagnóstico , Nivolumabe/efeitos adversos , Nivolumabe/uso terapêutico , Neoplasias Gástricas/tratamento farmacológico , Autoanticorpos/sangueRESUMO
This paper reports the clinical and genetic characteristics of a case of combined pituitary hormone deficiency type I (CPHD1) caused by POU domain, class 1, transcription factor 1 (POU1F1) gene variation. A 2 years and 3 months old girl mainly presented with short stature, special facial features of prominent forehead, enophthalmos, and short mandible, loose skin, central hypothyroidism, complete growth hormone deficiency, and anterior pituitary hypoplasia. Gene analysis identified a novel heterozygous mutation, c.889C>T (p.R297W), in POU1F1 gene, and this locus of her parents was wild-type. This mutation was analyzed as a possible pathogenic variant according to the guidelines of the American College of Medical Genetics and Genomics, which has not been previously reported in the literature and conforms to the autosomal dominant inheritance. This child was diagnosed with CPHD1. Her height increased by 19.8 cm and showed a catch-up growth trend after one year of combined treatment with growth hormone and euthyrox. This study enriches the mutation spectrum of POU1F1 gene and has important significance for the diagnosis and classification of combined pituitary hormone deficiency.
Assuntos
Pré-Escolar , Feminino , Humanos , Hipopituitarismo , Mutação , Fator de Transcrição Pit-1 , Fatores de TranscriçãoRESUMO
A acromegalia consiste num aumento persistente do hormônio de crescimento (GH) e em 98% dos casos é causada por um Adenoma de hipófise produtor de GH (ou Tumores neuroendócrinos da pituitária, principalmente os de linhagem PIT 1). Tumores neuroendócrinos da pituitária da linhagem fator de transcrição - PIT1 podem ser somatotróficos, mamossomatotróficos, Misto lactotrófico-somatotrófico, tumor de células tronco acidófilo e pluri-hormonais imaturos e maduros, alvos deste estudo. Mecanismos genéticos e epigenéticos, principalmente dos genes Neoplasia Endócrina Múltipla tipo 1 (MEN1), Caderia 23 (CDH23) e o gene Guanine Nucleotide-Binding Protein Alpha Stimulating Activity Polypeptide (GNAS) estão relacionados a tumorigênese dos Adenomas somatotróficos. Através da morfologia e estudos moleculares é possível determinar o subtipo histológico mais fidedigno e assim a melhor conduta terapêutica e de acompanhamento
Acromegaly consists of a persistent increase in GH and in 98% of cases is caused by a GH-producing pituitary adenoma (or pituitary neuroendocrine tumors, mainly those of the PIT 1 lineage). Pituitary neuroendocrine tumors of the PIT1 lineage can be somatotrophic, mammosomatotrophic, mixed lactotrophic-somatotrophic, stem cell acidophilic and immature and mature plurihormonal, the targets of this study. Genetic and epigenetic mechanisms, especially in the MEN1 (multiple endocrine neoplasia type 1), CDH23 (Cadherin 23) and GNAS (Guanine Nucleotide-Binding Protein Alpha Stimulating Activity Polypeptide) genes, are related to the tumorigenesis of somatotrophic adenomas. Through morphology and molecular studies we are able to determine the most reliable histological subtype and thus the best therapeutic and follow-up approach
Assuntos
Humanos , Masculino , Feminino , Neoplasias Hipofisárias , Acromegalia , Fator de Transcrição Pit-1 , Epigenômica , Genética , Biologia MolecularRESUMO
<p><b>OBJECTIVE</b>This study aimed to investigate the susceptibility of mice with streptozotocin(STZ)-induced diabetes mellitus (TIDM) to the uptake of pentavalent inorganic arsenic (iAsV) and the possible molecular mechanism.</p><p><b>METHODS</b>TIDM was induced in mice by STZ. TIDM and normal mice were treated with 15.0 mg/kg Na2HAsO4·12H2O by intragastric administration. Then, the concentrations of arsenic in various tissues were measured by atomic fluorescence spectrometry. The gene expression levels of Pit1 and Pit2 were quantified by real-time RT-PCR, and their protein levels were detected by Western blotting in mouse heart, kidney, and liver tissues.</p><p><b>RESULTS</b>The concentrations of arsenic in STZ-induced TIDM mouse tissues were higher at 2 h after intragastric administration of Na2HAsO4·12H2O. Compared with the levels in normal mice, PIT1 and PIT2, which play a role in the uptake of iAsV, were upregulated in the livers and hearts of TIDM mice. PIT1 but not PIT2 was higher in TIDM mouse kidneys. The upregulation of Pit1 and Pit2 expression could be reversed by insulin treatment.</p><p><b>CONCLUSION</b>The increased uptake of iAsV in TIDM mouse tissues may be associated with increased PIT1 and/or PIT2 expression.</p>
Assuntos
Animais , Masculino , Camundongos , Arsênio , Farmacocinética , Diabetes Mellitus Experimental , Metabolismo , Poluentes Ambientais , Farmacocinética , Regulação da Expressão Gênica , Fisiologia , Camundongos Endogâmicos ICR , Proteínas Cotransportadoras de Sódio-Fosfato Tipo III , Genética , Metabolismo , Fator de Transcrição Pit-1 , Genética , MetabolismoRESUMO
OBJECTIVE: The expression of transcription factors involved in early pituitary development, such as PROP1 and POU1F1, has been detected in pituitary adenoma tissues. In this study, we sought to characterize the transcriptional profiles of PROP1, POU1F1, and TBX19 in functioning and nonfunctioning pituitary adenomas in an attempt to identify their roles in tumorigenesis and hormone hypersecretion. METHODS: RT-qPCR analyses were performed to assess the transcriptional pattern of PROP1, POU1F1, TBX19, and hormone-producing genes in tissue samples of corticotrophinomas (n = 10), somatotrophinomas (n = 8), and nonfunctioning adenomas (n = 6). RESULTS: Compared with normal pituitary tissue, POU1F1 was overexpressed in somatotrophinomas by 3-fold. PROP1 expression was 18-fold higher in corticotrophinomas, 10-fold higher in somatotrophinomas, and 3-fold higher in nonfunctioning adenomas. TBX19 expression was 27-fold higher in corticotrophinomas. Additionally, the level of TBX19 mRNA positively correlated with that of pro-opiomelanocortin (r = 0.49, p = 0.014). CONCLUSIONS: Our data demonstrate that PROP1 is overexpressed in pituitary adenomas, mainly in corticotrophinomas. Together with previously published data showing that patients who harbor PROP1 loss-of-function mutations present a progressive decline in corticotrope function, our results support a role for PROP1 in pituitary tumor development and in the maintenance of cell lineages committed to corticotrophic differentiation. .
Assuntos
Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Adenoma Hipofisário Secretor de ACT/metabolismo , Adenoma/metabolismo , Proteínas de Homeodomínio/metabolismo , Proteínas de Neoplasias/metabolismo , Proteínas com Domínio T/metabolismo , Fator de Transcrição Pit-1/metabolismo , Adenoma Hipofisário Secretor de ACT/genética , Adenoma Hipofisário Secretor de ACT/patologia , Adenoma/genética , Adenoma/patologia , Diferenciação Celular , Proteínas de Homeodomínio/genética , Imuno-Histoquímica , Proteínas de Neoplasias/genética , Hipófise , Reação em Cadeia da Polimerase em Tempo Real , RNA Mensageiro/metabolismo , Proteínas com Domínio T/genética , Fator de Transcrição Pit-1/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Background: Congenital hypopituitarism is an uncommon cause of hypophyseal insufficiency It is less common than growth hormone deficiency which has an incidence of 1:4.000 to 1:8.000 Uve newborns. Early diagnosis ofthis condition is important to prevent impairment of cognitive function, poor growth and alterations in metabolic profile in these patients. Aim: To report 23 patients diagnosed with congenital hypopituitarism. Material and methods: Retrospective review of clinical records of 23 patients (12 males) with congenital hypopituitarism, diagnosed during a 21 years period. In a group of 16 patients a molecular study was performed searching for mutations in HESX1, PROP-1 or POUF-1. Results: Short stature was the most frequent sign at the first evaluation, followed by neonatal hypoglycemia and presence of nistagmus, strabismus, atrophic optic nerve or malformations in the middle Une showed in CNS imaging, suggesting septo-optic-dysplasia. All male patients diagnosed during neonatal period, exhibited micropenis. CNS images showed isolated hypophyseal hypoplasia or associated to an ectopic neurohypophysis in most patients. No patient in the subgroup subjected to molecular analysis had any of the mutations in the searched genes. Conclusions: The diagnosis of hypopituitarism must be based on clinical grounds, speciaUy when hypoglycemia, prolonged jaundice, micropenis or midline alterations are found in the neonatal period.
Assuntos
Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Hipopituitarismo/congênito , Hipopituitarismo/genética , Seguimentos , Proteínas de Homeodomínio/genética , Hipopituitarismo/diagnóstico , Mutação , Estudos Retrospectivos , Fator de Transcrição Pit-1/genética , Fatores de Transcrição/genéticaRESUMO
<p><b>OBJECTIVE</b>To elucidate the effect of interleukin-1 beta (IL-1 beta) on human growth hormone (hGH) gene expression in a rat somatotropic pituitary cell line MtT/S.</p><p><b>METHODS</b>Stably transfected MtT/S cells were firstly established by transfecting 484-Luc1 plasmid which contained hGH gene promoter -484 to +30 bp and luciferase reporter gene. The effect of IL-1 beta on hGH gene expression was determined by assaying the luciferase activities. RT-PCR method was also used to determine whether IL-1 recepor mRNA was expressed in MtT/S cells.</p><p><b>RESULTS</b>The 10(3) U/mL IL-1 beta stimulated secretion and synthesis of GH, and promoted the 5'-promoter activity of GH gene in stably transfected MtT/SGL cells with the action of 1.38 times above the control. Among inhibitors of signaling transduction pathways, mitogen-activated protein kinase kinase (MAPKK/MEK) inhibitor PD98059 (40 micromol/L) and p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 (5 micromol/L) completely blocked the stimulatory effect of IL-1 beta, and phosphatidylinositol-3-kinase (PI3-K) inhibitor LY294002 partly abolished the effect of IL-1 beta. Western blot analysis further confirmed the activation of phosphorylated MEK and p38 MAPK in MtT/SGL cells. Neither over-expression of Pit-1 nor inhibition of Pit-1 expression affected induction of hGH promoter activity by IL-1 beta. A series of deletion constructs of hGH promoter were created to identify the DNA sequence that mediated the effect of IL-1 beta, and results showed that the stimulatory effect of IL-1 beta was abolished following deletion of the -196 to -132 bp fragment.</p><p><b>CONCLUSIONS</b>IL-1 beta promotes GH secretion and synthesis in rat MtT/S somatotroph cells. The stimulatory effect of IL-1 beta on hGH gene promoter appears to require the activation of MEK, p38 MAPK, PI3-K, and a fragment of promoter sequence that spans the -196 to -132 bp of the gene, but it may be unlinked with Pit-1 protein.</p>
Assuntos
Animais , Humanos , Ratos , Linhagem Celular , Inibidores Enzimáticos , Metabolismo , Hormônio do Crescimento Humano , Genética , Metabolismo , Interleucina-1beta , Genética , Metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno , Metabolismo , Regiões Promotoras Genéticas , Receptores de Interleucina-1 , Genética , Metabolismo , Somatotrofos , Biologia Celular , Fisiologia , Fator de Transcrição Pit-1 , Metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno , MetabolismoRESUMO
Combined Pituitary Hormone Deficiency (CPHD) is a prevalent disease in Neuroendocrinology services. The genetic form of CPHD may originate from mutations in pituitary transcription factor (PTF) genes and the pituitary image in these cases may give a clue of what PTF is most probably mutated: defects in LHX4 are usually associated with ectopic posterior pituitary (EPP); defects in LHX3, PIT1, and PROP1, with normally placed posterior pituitary (NPPP); HESX1 mutations are associated with both. OBJECTIVE: To identify mutations in PTF genes in patients with idiopathic hypopituitarism followed in our service, based on the presence or absence of EPP on sellar MRI. METHODS: Forty patients with idiopathic hypopituitarism (36 families, 9 consanguineous), followed in the Neuroendocrinology Outpatient Clinic of UNIFESP, Brazil, were submitted to sequencing analyses of PTF genes as follows: LHX3, HESX1, PIT1, and PROP1 were sequenced in patients with NPPP (26/40) and HESX1 and LHX4 in patients with EPP (14/40). RESULTS: We identified only PROP1 mutations in 9 out of 26 patients with CPHD and NPPP (35 percent). Since eight of them came from 4 consanguineous families, the prevalence of PROP1 mutations was higher when only consanguineous families were considered (44 percent, 4/9). At the end of the study, we decided to sequence PROP1 in patients with EPP, just to confirm that they were not candidates for PROP1 mutations. No patients with EPP had PROP1 or other PTF mutations. CONCLUSIONS: Patients with idiopathic CPHD and NPPP, born from consanguineous parents, are the strong candidates for PROP1 mutations. Other developmental gene(s) may be involved in the genesis of idiopathic hypopituitarism associated with EPP.
Deficiência Combinada de Hormônios Hipofisários (DCHH) é uma doença prevalente em todos os serviços de Neuroendocrinologia. A DCHH de origem genética pode resultar de mutações nos genes de fatores de transcrição hipofisários (FTH), e a ressonância magnética (RM) de sela desses pacientes pode indicar qual FTH tem maior probabilidade de estar mutado: mutações no LHX4 estão geralmente associadas a neuro-hipófise ectópica (NHE); mutações no LHX3, PIT1 e PROP1, a neuro-hipófise tópica (NHT); mutações no HESX1 podem estar associadas a NHE e NHT. OBJETIVO: Identificar mutações nos FTH em pacientes acompanhados em nosso serviço, portadores de hipopituitarismo idiopático, selecionando os genes a serem estudados de acordo com a presença ou ausência de NHE à RM sela. MÉTODOS: Os genes dos FTH foram seqüenciados em 40 pacientes com hipopituitarismo idiopático (36 famílias, 9 consangüíneas), acompanhados na unidade de Neuroendocrinologia da UNIFESP, SP, Brasil: LHX3, HESX1, PIT1 e PROP1 foram seqüenciados nos pacientes com NHT (26/40) e HESX1 e LHX4, nos pacientes com NHE (14/40). RESULTADOS: Somente mutações PROP1 foram identificadas em 9 de 26 pacientes (35 por cento) com NHT, 8 deles provenientes de 4 famílias consangüíneas (4/9, 44 por cento). Uma vez que mutações no PROP1 foram tão freqüentes, decidimos, ao final do estudo, seqüenciá-lo também nos pacientes com NHE. Nenhum paciente com NHE apresentou mutações no PROP1 ou em outro FTH. CONCLUSÃO: Mutações no gene PROP1 foram encontradas em 22,5 por cento (9/40) de todos os pacientes, em 35 por cento (9/26) dos pacientes com NHT e em 44 por cento (4/9) se considerarmos somente as famílias consangüíneas. Portanto, pacientes com DCHH idiopática e NHT, provenientes de famílias de pais consangüíneos, são os melhores candidatos a mutações PROP1.
Assuntos
Adolescente , Adulto , Criança , Feminino , Humanos , Masculino , Proteínas de Homeodomínio/genética , Hipopituitarismo/genética , Fator de Transcrição Pit-1/genética , Fatores de Transcrição/genética , Análise Mutacional de DNA , Predisposição Genética para Doença/genética , Hipopituitarismo/diagnóstico , Imageamento por Ressonância Magnética , Mutação de Sentido Incorreto , Hormônios Neuro-Hipofisários/deficiência , Hormônios Neuro-Hipofisários/genética , Análise de Sequência de DNARESUMO
Sequence polymorphisms in the growth hormone (GH) gene and its transcriptional regulators, Pit-1 and Prop-1, were evaluated for associations with growth and carcass traits in two populations of Brangus bulls Chihuahuan Desert Rangeland Research Center (CDRRC, N = 248 from 14 sires) and a cooperating breeding program (COOP, N = 186 from 34 sires). Polymorphisms were SNP mutations in intron 4 (C/T) and exon V (C/G) in GH, A/G in exon VI in Pit-1, and A/G in exon III in Prop-1. In the COOP population, bulls of Pit-1 GG genotype had a significantly greater percentage of intramuscular fat than bulls of the AA or AG genotype, and bulls of the Prop-1 AA genotype had significantly greater scrotal circumference than bulls of AG or GG genotypes at ~365 days of age. Also, heterozygous genotypes for the two GH polymorphisms appeared advantageous for traits of muscularity and adiposity in the COOP population. The heterozygous genotype of GH intron 4 SNP was associated with advantages in weight gain, scrotal circumference, and fat thickness in the CDRRC population. The two GH polymorphisms accounted for ³27.7% of the variation in these traits in the CDRRC population; however, R2 was <5% in the COOP population. Based on haplotype analyses the two GH SNPs appeared to be in phase; the haplotype analyses also paralleled with the genotype analyses. Polymorphisms in GH and its transcriptional regulators appear to be predictors of growth and carcass traits in Brangus bulls, particularly those with heterozygous GH genotypes
Assuntos
Animais , Bovinos , DNA , Bovinos/genética , Hormônio do Crescimento/genética , Proteínas de Homeodomínio/genética , Característica Quantitativa Herdável , Fator de Transcrição Pit-1/genética , Composição Corporal/genética , Bovinos/crescimento & desenvolvimento , Genótipo , Haplótipos , Fenótipo , Polimorfismo Genético/genéticaRESUMO
Os craniofaringiomas são os tumores mais frequentes da região hipotálamohipofisária na faixa etária pediátrica. Apesar de serem histologicamente benignos, sua tendência infiltrativa e seu comportamento agressivo resultam em significante morbimortalidade. Histologicamente podem ser divididos em dois subtipos: adamantinomatosos e papilíferos. A patogênese dos craniofaringiomas é pouco compreendida. Mutações no gene CTNNB1, que codifica a proteína beta-catenina, são a única alteração molecular conhecida até o momento implicada na tumorigênese dos craniofaringiomas adamantinomatosos. Tais mutações afetam o sítio de degradação da beta-catenina, que passa a se acumular no citoplasma e no núcleo, ativando excessivamente a via de sinalização WNT, através da ligação aos fatores de transcrição da família LEF/TCF, levando a tumorigênese. Recentemente foi descoberto um novo mecanismo de determinação da linhagem celular hipofisária regulado pela beta-catenina, através do qual ela interage diretamente com o PROP1 para determinar a diferenciação celular hipofisária. De acordo com esse modelo, o complexo protéico PROP1/beta- catenina atua simultaneamente como repressor do HESX1 e ativador do PIT1, dependendo dos co-fatores associados. Pacientes com mutações germinativas inativadoras no PROP1 desenvolvem hipopituitarismo e podem apresentar aumento hipofisário com imagens de ressonância nuclear magnética (RNM) da região selar muitas vezes semelhantes àquelas dos craniofaringiomas, com hiperssinal em T1. Por outro lado, camundongos com expressão persistente do Prop1 exibem defeitos na regulação da proliferação celular hipofisária, incluindo cistos da bolsa de Rathke, hiperplasia adenomatosa e tumores, sugerindo que mutações com ganho de função no PROP1 também poderiam contribuir para a patogênese de tumores hipofisários em seres humanos. A semelhança entre as imagens de RNM dos pacientes com craniofaringiomas e daqueles com aumento hipofisário devido a mutações...
Craniopharyngiomas are the the commonest tumors to involve the hypothalamo-pituitary regions in childhood population. Histologically they are benign, and can be divided in two primary subtypes: the adamantinomatous and the papillary. Although histologically benign, their infiltrative tendency and aggressive behavior can result in great morbidity. The pathogenesis of craniopharyngiomas is poorly understood. To date, beta-catenin gene (CTNNB1) mutations have been identified only in the adamantinomatous subtype. These mutations affect the degradation target box of beta-catenin that accumulates in the cytoplasm and the nucleus increasing the transcriptional activity of WNT pathway through interaction with the transcription factors of LEF/TCF family, leading to tumorigenesis. Recently, an interaction between beta-catenin and PROP1 was described as a new mecanism for beta-catenindependent regulation of pituitary cell-lineage determination. According to this novel model, the PROP1/beta-catenin proteic complex would act as a binary switch to simultaneously repress the transcription factor HESX1 and to activate expression of transcription factor PIT1, depending on the associated cofactors. Patients with loss-of-function mutations in PROP1 present combined pituitary hormonal deficiency generally associated with pituitary enlargement and the magnetic resonance imaging (MRI) of the sellar region in these patients sometimes resembles that of the craniopharyngiomas, with T1 hyperintense signal. On the other hand, transgenic mice with persistent Prop1 expression exhibit defects consistent with misregulation of pituitary cell proliferation, including adenomatous hyperplasia with formation of Rathke's cleft cysts and tumors suggesting that misregulation of PROP1 expression in human could contribute to pathogenesis of pituitary tumors. The similarity between the MRI images of craniopharyngiomas patients and that of patients with loss-of-function mutations in...