A systematic survey of LU domain-containing proteins reveals a novel human gene, LY6A, which encodes the candidate ortholog of mouse Ly-6A/Sca-1 and is aberrantly expressed in pituitary tumors / 医学前沿

The Ly-6 and uPAR (LU) domain-containing proteins represent a large family of cell-surface markers. In particular, mouse Ly-6A/Sca-1 is a widely used marker for various stem cells; however, its human ortholog is missing. In this study, based on a systematic survey and comparative genomic study of mouse and human LU domain-containing proteins, we identified a previously unannotated human gene encoding the candidate ortholog of mouse Ly-6A/Sca-1. This gene, hereby named LY6A, reversely overlaps with a lncRNA gene in the majority of exonic sequences. We found that LY6A is aberrantly expressed in pituitary tumors, but not in normal pituitary tissues, and may contribute to tumorigenesis. Similar to mouse Ly-6A/Sca-1, human LY6A is also upregulated by interferon, suggesting a conserved transcriptional regulatory mechanism between humans and mice. We cloned the full-length LY6A cDNA, whose encoded protein sequence, domain architecture, and exon-intron structures are all well conserved with mouse Ly-6A/Sca-1. Ectopic expression of the LY6A protein in cells demonstrates that it acts the same as mouse Ly-6A/Sca-1 in their processing and glycosylphosphatidylinositol anchoring to the cell membrane. Collectively, these studies unveil a novel human gene encoding a candidate biomarker and provide an interesting model gene for studying gene regulatory and evolutionary mechanisms.

Apoplexy in sporadic pituitary adenomas: a single referral center experience and AIP mutation analysis

ABSTRACT Objective: To analyze the clinical, laboratory, and radiological findings and management of patients with clinical pituitary apoplexy and to screen for aryl hydrocarbon receptor-interacting protein (AIP) mutations. Subjects and methods: The clinical findings were collected from the medical records of consecutive sporadic pituitary adenoma patients with clinical apoplexy. Possible precipitating factors, laboratory data, magnetic resonance imaging (MRI) findings and treatment were also analyzed. Peripheral blood samples were obtained for DNA extraction from leukocytes, and the entire AIP coding region was sequenced. Results: Thirty-five patients with pituitary adenoma were included, and 23 (67%) had non-functioning pituitary adenomas. Headache was observed in 31 (89%) patients. No clear precipitating factor was identified. Hypopituitarism was observed in 14 (40%) patients. MRI from 20 patients was analyzed, and 10 (50%) maintained a hyperintense signal in MRI performed more than three weeks after pituitary apoplexy (PA). Surgery was performed in ten (28%) patients, and 25 (72%) were treated conservatively with good outcomes. No AIP mutation was found in this cohort. Conclusion: Patients with stable neuroophthalmological impairments can be treated conservatively if no significant visual loss is present. Our radiological findings suggest that hematoma absorption lasts more than that observed in other parts of the brain. Additionally, our study suggests no benefits of AIP mutation screening in sporadic patients with apoplexy.

Proteína moduladora de la actividad del receptor de aril hidrocarburos (AIP): genética, bioquímica e impacto clínico / Aryl hydrocarbon receptor interacting protein (AIP): genetics, biochemistry and clinical impact

El gen AIP (proteína moduladora de la actividad del receptor de aril hidrocarburos) se localiza en la región 11q13.2 y codifica para una proteína de 330 aminoácidos que interactúa con el factor de transcripción AhR (receptor para aril hidrocarburos). Las mutaciones en este gen se han asociado con adenomas pituitarios aislados de tipo familiar (APAF). Se caracterizan por una presentación temprana (alrededor de 20 años), por lo regular producen hormona de crecimiento y/o prolactina, tienen un comportamiento clínico agresivo y poca respuesta a análogos de somatostatina.

The AIP gene (aryl hydrocarbon receptor interacting protein) is located on chromosome 11q13.2 and encodes a 330 amino acid protein which interacts with the aryl hydrocarbon receptor (AHR) transcription factor. Mutations in the AIP gene have been associated with familial isolated pituitary adenomas (FIPA). They characterize by an early-onset (around the age of 20 years old) and for being aggressive, growth hormone and/or prolactin-secreting tumors, with poor response to somatostatin analogues.

Estudios clínicos y genéticos en tres miembros de una familia afectados con adenomas hipofisarios aislados con prolactinomas homogéneos / Clinical and genetic studies of a three-member familial isolated pituitary adenoma with homogeneous prolactinomas

La mayoría de los adenomas hipofisarios son esporádicos, pero un 3-5% puede ocurrir en un contexto familiar y hereditario. Este es el caso de la neoplasia endocrina múltiple de tipo 1 (NEM1), complejo de Carney (CNC) y adenomas hipofisarios aislados familiares (FIPA). El FIPA es una condición infrecuente, que ocurre en un contexto familiar, no asociada a NEM t ipo1 ni CNC. Los FIPA pueden ser homogéneos (todos los adenomas tienen el mismo fenotipo) o heterogéneos (diferente fenotipo tumoral). Describimos una familia congolesa en la que dos hermanas y una prima fueron diagnosticadas a los 29, 32 y 40 años, respectivamente, con un prolactinoma (FIPA homogéneo). Las pacientes presentaron macroadenomas no invasivos al momento del diagnóstico, con buena respuesta biológica y tumoral al tratamiento con cabergolina hasta una dosis máxima de 1.5 mg/semanal. De las dos hermanas, una cursó un embarazo sin complicaciones. Durante el seguimiento de 12 años, ninguna de ellas presentó elementos clínicos o biológicos compatibles con NEM1 o CNC, por lo que dichos genes no se estudiaron. El análisis genético en dos de las pacientes permitió descartar la posibilidad de una mutación germinal del gen aryl hydrocarbon receptor interacting protein (AIP). Se considera que el 80% de los pacientes con FIPA no presentan mutación del gen AIP, por lo que se requieren futuros estudios en este tipo de familias, para poder determinar otros genes afectados involucrados en su fisiopatología.

Most pituitary adenomas are sporadic, but 3-5% can occur in a family and hereditary context. This is the case of multiple endocrine neoplasia type 1 (MEN1), Carney complex (CNC) and familial isolated pituitary adenomas (FIPA). FIPA is an infrequent condition that occurs in a family context, not associated with MEN type1 or CNC. FIPA kindred can be homogeneous (all adenomas affected in the family having the same tumor phenotype) or heterogeneous (different tumor phenotypes in the affected members). We describe a Congolese family in which two sisters and a cousin were diagnosed with a prolactinoma (homogenous FIPA) at the ages of 29, 32 and 40 years, respectively. The patients presented with macroadenomas at the time of diagnosis, non-invasive tumors and good biological response to cabergoline treatment (maximum dose of 1.5 mg/weekly). Of these two sisters, one went through a pregnancy without complications. Because no MEN1 and CNC clinical and biochemical features were detected during the 12-year follow-up, these genes were not investigated. The genetic analysis of the aryl hydrocarbon receptor interacting protein (AIP) was normal. As nearly 80% of patients with FIPA do not have a mutation in the AIP gene, future studies in these families are required to identify other affected genes involved in their physiopathology.

Hereditary pituitary tumor syndromes: genetic and clinical aspects

ABSTRACT The pituitary gland is responsible for the synthesis and secretion of various hormones that play a key role in regulating endocrine function and homeostasis. Pituitary adenomas (PA) are benign epithelial tumors arising from the endocrine cells of the anterior pituitary gland. Clinically relevant PA are relatively common and they occur in 0.1% of the general population. They are mostly benign monoclonal neoplasms that arise from any of the five hormone-secreting cell types of the anterior pituitary gland. PA are categorized as either functioning or non-functioning, depending on whether or not they produce a hormonal hypersecretion syndrome. Both functioning and non-functioning adenomas can produce symptoms or signs resulting from compression of the optic chiasm or invasion of cavernous sinuses. Only 5% of PA occur within the context of hereditary syndromes with reasonably well-defined oncogenic mechanisms. The vast majority of PA are sporadic, and their etiopathogenesis remains largely unknown. Pituitary tumor oncogenesis involves several mechanisms that eventually lead to abnormal cell proliferation and dysregulated hormone production. Among these factors, we found inactivating mutations of tumor suppressor genes, activating mutation of oncogenes and the participation of hormonal signals coming from the hypothalamus, all resulting in cell-cycle regulation abnormalities. In this review, we summarize the clinical and pathophysiological aspects of the different hereditary pituitary tumor syndromes.

Study of major genetic factors involved in pituitary tumorigenesis and their impact on clinical and biological characteristics of sporadic somatotropinomas and non-functioning pituitary adenomas

Genetic and functional aberrations of guanine nucleotide-binding protein, alpha stimulating (GNAS), aryl hydrocarbon receptor interacting protein (AIP), and pituitary tumor transforming gene (PTTG) are among the most prominent events in pituitary tumorigenesis. A cohort of Brazilian patients with somatotropinomas (n=41) and non-functioning pituitary adenomas (NFPA, n=21) from a single tertiary-referral center were evaluated for GNAS and AIP mutations and gene expression of AIP and PTTG. Results were compared to the clinical and biological (Ki67 and p53 expression) characteristics of tumors and their response to therapy, if applicable. Genetic analysis revealed that 27% of somatotropinomas and 4.8% of NFPA harbored GNAS mutations (P=0.05). However, no differences were observed in clinical characteristics, tumor extension, response to somatostatin analog therapy, hormonal/surgical remission rates, Ki67 index, and p53 expression between mutated and non-mutated somatotropinomas patients. PTTG overexpression (RQ mean=10.6, min=4.39, max=11.9) and AIP underexpression (RQ mean=0.56, min=0.46-max=0.92) were found in virtually all cases without a statistically significant relationship with clinical and biological tumor features. No patients exhibited somatic or germline pathogenic AIP mutations. In conclusion, mutations in GNAS and abnormal PTTG and AIP expression had no impact on tumor features and treatment outcomes in this cohort. Our data support some previous studies and point to the need for further investigations, probably involving epigenetic and transcriptome analysis, to improve our understanding of pituitary tumor behavior.

Mutation and genomic amplification of the PIK3CA proto-oncogene in pituitary adenomas

The tumorigenesis of pituitary adenomas is poorly understood. Mutations of the PIK3CA proto-oncogene, which encodes the p110-α catalytic subunit of PI3K, have been reported in various types of human cancers regarding the role of the gene in cell proliferation and survival through activation of the PI3K/Akt signaling pathway. Only one Chinese study described somatic mutations and amplification of the PIK3CA gene in a large series of pituitary adenomas. The aim of the present study was to determine genetic alterations of PIK3CA in a second series that consisted of 33 pituitary adenomas of different subtypes diagnosed by immunohistochemistry: 6 adrenocorticotropic hormone-secreting microadenomas, 5 growth hormone-secreting macroadenomas, 7 prolactin-secreting macroadenomas, and 15 nonfunctioning macroadenomas. Direct sequencing of exons 9 and 20 assessed by qPCR was employed to investigate the presence of mutations and genomic amplification defined as a copy number ≥4. Previously identified PIK3CA mutations (exon 20) were detected in four cases (12.1%). Interestingly, the Chinese study reported mutations only in invasive tumors, while we found a PIK3CA mutation in one noninvasive corticotroph microadenoma. PIK3CA amplification was observed in 21.2% (7/33) of the cases. This study demonstrates the presence of somatic mutations and amplifications of the PIK3CA gene in a second series of pituitary adenomas, corroborating the previously described involvement of the PI3K/Akt signaling pathway in the tumorigenic process of this gland.

Familial gigantism

Familial GH-secreting tumors are seen in association with three separate hereditary clinical syndromes: multiple endocrine neoplasia type 1, Carney complex, and familial isolated pituitary adenomas.

Clinical and genetic aspects of familial isolated pituitary adenomas

Pituitary adenomas represent a group of functionally diverse neoplasms with relatively high prevalence in the general population. Most occur sporadically, but inherited genetic predisposing factors are increasingly recognized. Familial isolated pituitary adenoma is a recently defined clinical entity, and is characterized by hereditary presentation of pituitary adenomas in the absence of clinical and genetic features of syndromic disease such as multiple endocrine neoplasia type 1 and Carney complex. Familial isolated pituitary adenoma is inherited in an autosomal dominant manner and accounted for approximately 2-3% of pituitary tumors in some series. Germline mutations in the aryl-hydrocarbon interacting protein gene are identified in around 25% of familial isolated pituitary adenoma kindreds. Pituitary adenomas with mutations of the aryl-hydrocarbon interacting protein gene are predominantly somatotropinomas and prolactinomas, but non-functioning adenomas, Cushing disease, and thyrotropinoma may also occur. These tumors may present as macroadenomas in young patients and are often relatively difficult to control. Furthermore, recent evidence indicates that aryl-hydrocarbon interacting protein gene mutations occur in >10% of patients with sporadic macroadenomas that occur before 30 years of age, and in >20% of children with macroadenomas. Genetic screening for aryl-hydrocarbon interacting protein gene mutations is warranted in selected high-risk patients who may benefit from early recognition and follow-up.

Pituitary tumors in patients with MEN1 syndrome

We briefly review the characteristics of pituitary tumors associated with multiple endocrine neoplasia type 1. Multiple endocrine neoplasia type 1 is an autosomal-dominant disorder most commonly characterized by tumors of the pituitary, parathyroid, endocrine-gastrointestinal tract, and pancreas. A MEDLINE search for all available publications regarding multiple endocrine neoplasia type 1 and pituitary adenomas was undertaken. The prevalence of pituitary tumors in multiple endocrine neoplasia type 1 may vary from 10% to 60% depending on the studied series, and such tumors may occur as the first clinical manifestation of multiple endocrine neoplasia type 1 in 25% of sporadic and 10% of familial cases. Patients were younger and the time between initial and subsequent multiple endocrine neoplasia type 1 endocrine lesions was significantly longer when pituitary disease was the initial manifestation of multiple endocrine neoplasia type 1. Tumors were larger and more invasive and clinical manifestations related to the size of the pituitary adenoma were significantly more frequent in patients with multiple endocrine neoplasia type 1 than in subjects with non-multiple endocrine neoplasia type 1. Normalization of pituitary hypersecretion was much less frequent in patients with multiple endocrine neoplasia type 1 than in subjects with non-multiple endocrine neoplasia type 1. Pituitary tumors in patients with multiple endocrine neoplasia type 1 syndrome tend to be larger, invasive and more symptomatic, and they tend to occur in younger patients when they are the initial presentation of multiple endocrine neoplasia type 1.

Variable clinical expression in patients with a germline MEN1 disease gene mutation: clues to a genotype-phenotype correlation

Multiple endocrine neoplasia type 1 is an inherited endocrine tumor syndrome, predominantly characterized by tumors of the parathyroid glands, gastroenteropancreatic tumors, pituitary adenomas, adrenal adenomas, and neuroendocrine tumors of the thymus, lungs or stomach. Multiple endocrine neoplasia type 1 is caused by germline mutations of the multiple endocrine neoplasia type 1 tumor suppressor gene. The initial germline mutation, loss of the wild-type allele, and modifying genetic and possibly epigenetic and environmental events eventually result in multiple endocrine neoplasia type 1 tumors. Our understanding of the function of the multiple endocrine neoplasia type 1 gene product, menin, has increased significantly over the years. However, to date, no clear genotype-phenotype correlation has been established. In this review we discuss reports on exceptional clinical presentations of multiple endocrine neoplasia type 1, which may provide more insight into the pathogenesis of this disorder and offer clues for a possible genotype-phenotype correlation.

PROP1 and CTNNB1 expression in adamantinomatous craniopharyngiomas with or without β-catenin mutations

INTRODUCTION: Activating mutations in exon 3 of the β-catenin gene are involved in the pathogenesis of adamantinomatous craniopharyngiomas. Recently, the interaction between β-catenin and PROP1 has been shown to be responsible for pituitary cell lineage determination. We hypothesized that dysregulated PROP1 expression could also be involved in the pathogenesis of craniopharyngiomas OBJECTIVES: To determine whether dysregulated gene expression was responsible for tumor pathogenesis in adamantinomatous craniopharyngiomas, the β-catenin gene was screened for mutations, and the expression of the β-catenin gene and PROP1 was evaluated. β-catenin gene was amplified and sequenced from 14 samples of adamantinomatous craniopharyngiomas. PROP1 and β-catenin gene expression was assessed by real-time RT-PCR from 12 samples, and β-catenin immunohistochemistry was performed on 11 samples. RESULTS: Mutations in the β-catenin gene were identified in 64 percent of the adamantinomatous craniopharyngiomas samples. Evidence of β-catenin gene overexpression was found in 71 percent of the tumors with β-catenin mutations and in 40 percent of the tumors without mutations, and β-catenin immunohistochemistry revealed a nuclear staining pattern for each of the analyzed samples. PROP1 expression was undetectable in all of the tumor samples. CONCLUSION: We found evidence of β-catenin gene overexpression in the majority of adamantinomatous craniopharyngiomas, and we also detected a nuclear β-catenin staining pattern regardless of the presence of a bcatenin gene mutation. These results suggest that WNT signaling activation plays an important role in the pathogenesis of adamantinomatous craniopharyngiomas. Additionally, this study was the first to evaluate PROP1 expression in adamantinomatous craniopharyngiomas, and the absence of PROP1 expression indicates that this gene is not involved in the pathogenesis of this tumor, at least in this cohort.

Familial isolated pituitary adenomas experience at a single center: clinical importance of AIP mutation screening / Experiência de um único centro em adenoma hipofisário familiar isolado: importância clínica do rastreio de mutação do AIP

We present four FIPA kindred discussing clinical and molecular data and emphasizing the differences regarding AIP status, as well as the importance of genetic screening. Family 1 consists of five patients harboring somatotropinomas with germline E24X mutation in AIP. In one of the patients, acromegaly was diagnosed through active screening, being cured by surgery. Families 2 and 3 are composed of two patients with non-functioning pituitary adenomas. Family 4 comprises patients harboring a prolactinoma and a somatotropinoma. No mutations in AIP were found in these families. No patient in Family 1 was controlled with octreotide treatment, while the acromegalic patient in Family 4 was controlled with octreotide LAR. In conclusion, FIPA is a heterogeneous condition, which may be associated with AIP mutation. Genomic and clinical screening is recommended in families with two or more members harboring pituitary adenomas, allowing early diagnosis and better outcome.

Apresentamos dados clínicos e moleculares de quatro famílias com adenoma hipofisário familiar isolado (FIPA) enfatizando as diferenças na presença ou não de mutação do AIP e a importância da triagem genética. A Família 1 é composta por cinco pacientes portadores de somatotropinomas com mutação germinativa E24X no AIP. Um dos pacientes foi diagnosticado por meio de rastreio ativo, com cura cirúrgica. As Famílias 2 e 3 apresentam em sua composição dois pacientes com adenomas hipofisários não funcionantes. A Família 4 compreende dois pacientes, um com prolactinoma e outro com somatotropinoma. Não foi encontrada mutação no AIP nessas famílias. Na Família 1, não houve resposta ao octreotide, enquanto o paciente acromegálico da Família 4 foi controlado com a medicação. Em conclusão, a FIPA é uma condição heterogênea que pode estar associada à mutação do AIP e o rastreio genético/clínico é recomendado nas famílias com dois ou mais membros portadores de adenoma hipofisário. Isso permite um diagnóstico precoce, com melhor prognóstico.

Aggressive prolactinoma in a child related to germline mutation in the ARYL hydrocarbon receptor interacting protein (AIP) gene / Prolactinoma agressivo na infância relacionado à mutação no gene da proteína Aryl hidrocarbono (AIP)

The objective of this study was to describe a familial screening for AIP mutations in the context of aggressive prolactinoma in childhood. A 12-year-old boy, presented headaches and bilateral hemianopsia. He had adequate height and weight for his age (50th percentile), Tanner stage G1 P1. His bone age was 10 years. Prolactin was 10.560 ng/mL (3-25), FSH and LH were undetectable, IGF-1, TSH, Free T4, ACTH, and cortisol were within normal ranges. MRI showed a pituitary macroadenoma, 5.3 X 4.0 X 3.5 cm with compression of the optic chiasm, bilateral cavernous sinus invasion, encasement of carotids, and extension to clivus. Surgical debulking was performed. Resistance to cabergoline was characterized and he was submitted to two surgeries and radiotherapy. Immunohistochemical evaluation included prolactin, ACTH, GH, FSH, LH,AIP, c-erb B2, Ki-67, and p53. Genomic DNA was isolated from the index case and 48 relatives, PCR and sequencing were performed.A germline A195V mutation in AIP was identified in the index case and in five asymptomatic relatives. Germline mutations in the AIP gene may be involved in the predisposition to pituitary adenoma formation, as cause or co-factor in pathogenesis of aggressive tumors in young patients.

O objetivo deste estudo foi descrever o rastreamento familiar para mutações AIP em paciente portador de prolactinoma agressivo e resistente na infância. Um menino de 12 anos foi avaliado com queixa de cefaleia e hemianopsia bitemporal. Apresentava peso e altura adequados para a idade (percentil 50), estádio puberal Tanner G1 P1 e idade óssea de 10 anos. Prolactina 10.560 ng/mL (3-25), FSH e LH indetectáveis, IGF-1, TSH, T4 livre, ACTH, e cortisol normais. A ressonância magnética de sela evidenciou macroadenoma hipofisário, 53 X 40 X 35 mm com compressão de quiasma ótico, invasão de seios cavernosos, envolvimento de carótidas internas e extensão para o clivus. Foi realizada descompressão cirúrgica por via transesfenoidal e caracterizada resistência a doses máximas de cabergolina, sendo o paciente operado por mais duas vezes e submetido à radioterapia. Realizou-se imuno-histoquímica para prolactina, ACTH, GH, FSH, LH, AIP, c-erb B2, Ki-67 e p53. O DNA genômico foi extraído do caso índice e de 48 familiares, e PCR e sequenciamento. Uma mutação A195V na AIP foi detectada no paciente e em cinco parentes assintomáticos. As mutações no gene da AIP podem estar envolvidas na predisposição à formação de adenomas, como causa ou cofator na patogênese de tumores agressivos em jovens.

Isolated familial somatotropinoma: 11Q13-LOH and gene/protein expression analysis suggests a possible involvement of aip also in non-pituitary tumorigenesis

OBJECTIVE: Non-pituitary tumors have been reported in a subset of patients harboring germline mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene. However, no detailed investigations of non-pituitary tumors of AIP-mutated patients have been reported so far. PATIENTS: We examined a MEN1- and p53-negative mother-daughter pair with acromegaly due to somatotropinoma. Subsequently, the mother developed a large virilizing adrenocortical carcinoma and a grade II B-cell non-Hodgkin's lymphoma. DESIGN: Mutational analysis was performed by automated sequencing. Loss-of-heterozygosity (LOH) analysis was carried out by sequencing and microsatellite analysis. AIP expression was assessed through quantitative PCR (qPCR) and immunohistochemistry. RESULTS: The functional inactivating mutation c.241C>T (R81X), which blocks the AIP protein from interacting with phosphodiesterase 4A (PDE4A), was identified in the heterozygous state in the leukocyte DNA of both patients. Analyzing the tumoral DNA revealed that the AIP wild-type allele was lost in the daughter's somatotropinoma and the mother's adrenocortical carcinoma. Both tumors displayed low AIP protein expression levels. Low AIP gene expression was confirmed by qPCR in the adrenocortical carcinoma. No evidence of LOH was observed in the DNA sample from the mother's B-cell lymphoma, and this tumor displayed normal AIP immunostaining. CONCLUSIONS: Our study presents the first molecular analysis of non-pituitary tumors in AIP-mutated patients. The finding of AIP inactivation in the adrenocortical tumor suggests that further investigation of the potential role of this recently identified tumor suppressor gene in non-pituitary tumors, mainly in those tumors in which the cAMP and the 11q13 locus are implicated, is likely to be worthwhile.

Cytogenetic Characterizations of Central Nervous System Tumors: The First Comprehensive Report from a Single Institution in Korea

The World Health Organization (WHO) classification of central nervous system (CNS) tumors incorporates morphology, cytogenetics, molecular genetics, and immunologic markers. Despite the relatively large number of CNS tumors with clonal chromosome abnormalities, only few studies have investigated cytogenetic abnormalities for CNS tumors in Korea. Thus, we investigated 119 CNS tumors by conventional G-banded karyotypes to characterize patterns of chromosomal abnormalities involving various CNS tumors, and 92.4% of them were cultured and karyotyped successfully. Totally, 51.8% of karyotypable CNS tumors showed abnormal cytogenetic results, including neuroepithelial tumors (75.0%), meningeal tumors (71.1%), pituitary adenomas (4.2%), schwannomas (44.4%), and metastatic tumors (100.0%). Glioblastomas had hyperdiploid, complex karyotypes, mainly involving chromosomes Y, 1, 2, 6, 7, 10, 12, 13, and 14. Monosomy 22 was observed in 56.4% of meningiomas. There was a significant increase in the frequencies of karyotypic complexity according to the increase of WHO grade between grades I and II (P=0.0422) or IV (P=0.0101). Abnormal karyotypes were more complex at high-grade tumors, suggesting that the karyotype reflects the biologic nature of the tumor. More detailed cytogenetic and molecular characterizations of CNS tumors contribute to better diagnostic criteria and deeper insights of tumorigenesis, eventually resulting in development of novel therapeutic strategies.

Cytogenetic Characterizations of Central Nervous System Tumors: The First Comprehensive Report from a Single Institution in Korea

The World Health Organization (WHO) classification of central nervous system (CNS) tumors incorporates morphology, cytogenetics, molecular genetics, and immunologic markers. Despite the relatively large number of CNS tumors with clonal chromosome abnormalities, only few studies have investigated cytogenetic abnormalities for CNS tumors in Korea. Thus, we investigated 119 CNS tumors by conventional G-banded karyotypes to characterize patterns of chromosomal abnormalities involving various CNS tumors, and 92.4% of them were cultured and karyotyped successfully. Totally, 51.8% of karyotypable CNS tumors showed abnormal cytogenetic results, including neuroepithelial tumors (75.0%), meningeal tumors (71.1%), pituitary adenomas (4.2%), schwannomas (44.4%), and metastatic tumors (100.0%). Glioblastomas had hyperdiploid, complex karyotypes, mainly involving chromosomes Y, 1, 2, 6, 7, 10, 12, 13, and 14. Monosomy 22 was observed in 56.4% of meningiomas. There was a significant increase in the frequencies of karyotypic complexity according to the increase of WHO grade between grades I and II (P=0.0422) or IV (P=0.0101). Abnormal karyotypes were more complex at high-grade tumors, suggesting that the karyotype reflects the biologic nature of the tumor. More detailed cytogenetic and molecular characterizations of CNS tumors contribute to better diagnostic criteria and deeper insights of tumorigenesis, eventually resulting in development of novel therapeutic strategies.

Aspectos moleculares da tumorigênese hipofisária: [revisão] / Molecular aspects of pituitary tumorigenesis: [review]

Os tumores hipofisários, adenomas em sua quase totalidade, são de ocorrência freqüente, representando 10 por cento a 15 por cento de todas as neoplasias intracranianas. Estas lesões são classificadas em microadenomas (< 10 mm) ou macroadenomas (> 10 mm) e como secretoras ou quiescentes (não-funcionantes). Estes tumores são capazes de secretar, de maneira autônoma, os hormônios adenohipofisários, como o hormônio de crescimento (GH), a prolactina (PRL), o hormônio adrenocorticotrófico (ACTH), o hormônio tireotrófico (TSH), o hormônio folículo estimulante (FSH) e o hormônio luteinizante (LH). A ocorrência de metástase, caracterizando um carcinoma hipofisário, é bastante rara, mas são relativamente comuns tumores de comportamento agressivo que exibem sinais de invasão local. Embora a sua patogênese ainda não seja plenamente caracterizada, muitos mecanismos moleculares envolvidos na tumorigênese hipofisária já foram desvendados. Nesta revisão, serão descritos avanços consideráveis realizados na última década relativos à compreensão dos fatores envolvidos na progressão tumoral, incluindo a participação de oncogenes, supressores tumorais e fatores de crescimento.

Pituitary tumors, almost invariably adenomas, are of frequent occurrence, accounting for 10 percent to 15 percent of all the intracranial neoplasm. They are classified as microadenomas (< 10 mm) or macroadenomas (> 10 mm) and as secreting or clinically non-secreting (or not functioning) adenomas. These tumors are autonomously capable to release pituitary hormones such as the growth hormone (GH), prolactin (PRL), adrenocorticotropic hormone (ACTH), thyroid stimulating hormone (TSH), follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The occurrence of metastases, characterizing a pituitary carcinoma, is exceedingly rare. However tumors with aggressive behavior, leading to local invasion, are relatively common. Although the pathogenesis of pituitary tumors is fully characterized, many molecular mechanisms of pituitary tumorigenesis had already been revealed. This review intents to describe advances in the understanding of the involved advances that have been made in the last decade concerning pituitary tumors progression, including the participation of oncogenes, tumor suppressor genes and growth factors.

Neoplasia endócrina múltipla tipo 1: diagnóstico clínico, laboratorial e molecular e tratamento das doenças associadas / Multiple endocrine neoplasia type 1 (MEN 1): clinical, biochemical and molecular diagnosis and treatment of the associated disturbances

As síndromes de neoplasias endócrinas múltiplas (NEM) incluem as do tipo 1 (MEN 1) e 2 (MEN 2), a síndrome de von Hippel-Lindau, neurofibromatose tipo 1 e o complexo de Carney. Estas são síndromes genéticas complexas decorrentes de ativação ou inativação de diferentes tipos de genes envolvidos na regulação da proliferação celular. Nesta revisão, discutiremos as manifestações clínicas e o acompanhamento da MEN 1, assim como o rastreamento genético de potenciais portadores de alterações no gene MEN 1. A MEN 1 inclui o desenvolvimento de hiperparatiroidismo primário multifocal, tumores de ilhotas pancreáticas e adenomas de hipófise. Além disso, alguns pacientes podem apresentar manifestações cutâneas como angiofibromas e colagenomas e ainda podem desenvolver outras neoplasias como tumores carcinóides, tumores de tiróide, adenomas de adrenal, lipomas, feocromocitomas e meningiomas. A MEN 1 é uma síndrome hereditária, transmitida de forma autossômica dominante e causada por mutação inativadora do gene MEN 1. O gene MEN 1 codifica uma proteína denominada "menin", que é um gene supressor tumoral. Vários estudos demonstraram sua importância na regulação da proliferação celular e confirmaram seu papel na patogênese da MEN 1. A identificação do gene MEN 1 e sua análise genética resultaram na possibilidade de monitoração de pacientes que ainda não apresentam manifestações clínicas associadas a esta síndrome e diagnóstico precoce e tratamento dos pacientes afetados. Tais medidas poderão implicar em sobrevida maior para estes pacientes. Estudos adicionais visando uma melhor compreensão da função e dos mecanismos de sinalização da proteína "menin" poderão propiciar alternativas terapêuticas para os pacientes que evoluem com malignização de tumores relacionados à MEN 1, podendo resultar em maior sobrevida.