Different Types Of Pituitary Adenomas Research Articles

Diagnosis and management of pituitary adenomas in children and adolescents.

Pituitary adenomas (PAs)-also now called pituitary neuroendocrine tumours or Pit-NETS-are rare in children and adolescents and exceptional below the age of 10. Most evidence-based high-quality data are derived from larger studies in adult patients. We will review recent knowledge on the epidemiology, clinical features, diagnosis, and treatment modalities of the different types of pituitary adenomas diagnosed in children and adolescents, emphasizing the many reasons why these cases should be discussed within pituitary-specific multidisciplinary teams with experts from both paediatric and adult practice. Paediatric PA presents multiple peculiarities that may challenge their adequate management. They are overall proportionally larger and more aggressive than in adults, with potential mass effects including hypopituitarism. Hormonal hypersecretion is frequent, resulting in clinical syndromes affecting normal growth and pubertal development. Prolactinomas represent the most frequent subtype of PA found during childhood, followed by adrenocorticotropin (ACTH) and growth hormone (GH)-secreting adenomas, while clinically non-functioning adenomas are exceptionally diagnosed before the age of 16. The occurrence of a pituitary tumour in a young individual should also prompt genetic testing in each case, searching for either germline mutations in one of the known genes that may drive inherited/familial PA (such as the multiple endocrine neoplasia type 1 or MEN1 gene, or the aryl hydrocarbon receptor interacting protein or AIP gene), or for a mosaic activating mutation of GNAS as found in the McCune-Albright syndrome.

Expression analysis of necroptosis related genes and lncRNAs in patients with pituitary neuroendocrine tumors

Necroptosis can either be the cause of tumorigenesis or it can impede its process. Recently, it has been proved that long non-coding RNAs (lncRNAs) have different crucial roles at cellular level, especially on cell death. Regarding the important role of necroptosis and lncRNAs in the pathogenesis of different cancers, especially pituitary adenomas (PAs), we assessed expression levels of two necroptosis related genes, namely TRADD and BIRC2, in addition to three related lncRNAs, namely FLVCR1-DT, MAGI2-AS3, and NEAT1 in PAs compared with adjacent normal tissues (ANTs). TRADD had no significant difference between two groups; however, BIRC2, FLVCR1-DT, MAGI2-AS3, and NEAT1 were upregulated in PAs compared to ANTs (Expression ratios [95% CI] = 2.3 [1.47–3.6], 2.13 [1.02–4.44], 3.01 [1.76–5.16] and 2.47 [1.37–4.45], respectively). When taking into account different types of PAs, significant upregulation of BIRC2, MAGI2-AS3 and NEAT1 was recorded in non-functioning PAs compared with corresponding ANTs (Expression ratios [95% CI] =1.9 [1.04–3.43], 2.69 [1.26–5.72] and 2.22 [0.98–5.01], respectively). Additionally, higher levels of BIRC2 were associated with higher flow of CSF (P value=0.048). Moreover, higher Knosp classified tumors had lower levels of BIRC2 (P value=0.001). Finally, lower levels of MAGI2-AS3 were associated with larger tumor size (P value=0.006). NEAT1 expression was correlated with FLVCR1-DT and TRADD. TRADD expression was correlated with FLVCR1-DT. Additional correlation was observed between expression of BIRC2 and MAGI2-AS3. In sum, this study provides evidence that dysregulated levels of studied genes could contribute to the pathogenesis of pituitary tumors.

Correlation analysis of anterior pituitary hormone and tumor size in patients with pituitary adenomas

Objective: To summarize the correlation between anterior pituitary function and tumor size in patients with different hormone-secreting pituitary adenomas. Methods: This was a retrospective case series study. The clinical data of 1 946 patients with pituitary adenoma hospitalized in the First Medical Center of Chinese PLA General Hospital from January 1, 2005, to December 31, 2020, were collected. The correlation between tumor size and anterior pituitary hormone levels was analyzed using Spearman rank correlation analysis in different types of pituitary adenomas. Results: The median age of the 1 946 patients was 45.1 years, of which 857 (44.0%) were men. The maximum tumor diameter of the patients [M (Q1, Q3)] was 22 (14, 30) mm. Tumor size in nonfunctioning adenomas (n=1 191) was negatively correlated with adrenocorticotropic hormone (ACTH) (r=-0.11, P<0.001), growth hormone (r=-0.13, P<0.001), and luteinizing hormone (men: r=-0.26, P<0.001, women: r=-0.31, all P<0.001). The tumor size of somatotropic adenomas (n=297) was positively correlated with growth hormone (r=0.46, P<0.001), but negatively correlated with male testosterone (r=-0.41, P<0.001). The tumor size of ACTH-secreting pituitary adenomas (n=155) was positively correlated with the ACTH level at 8∶00 AM (r=0.25, P<0.001); however, no correlation was found with cortisol at 8∶00 AM (P>0.05). The tumor size of prolactinomas (n=303) was positively correlated with the prolactin level (men: r=0.34, P=0.001; women: r=0.13, P=0.070). Conclusions: The correlation between the function of the anterior pituitary and size of the tumor depends on the cellular origin of the pituitary adenoma and specific type of hormone secretion. In somatotroph adenomas, ACTH-secreting pituitary adenomas, and prolactinomas, there is a positive correlation between tumor size and level of hormones secreted by the corresponding tumors. In patients with nonfunctioning adenomas, the tumor size was negatively correlated with the hormone levels of the pituitary-adrenal and pituitary-growth hormone axes.

Germline loss-of-function PAM variants are enriched in subjects with pituitary hypersecretion.

Pituitary adenomas (PAs) are common, usually benign tumors of the anterior pituitary gland which, for the most part, have no known genetic cause. PAs are associated with major clinical effects due to hormonal dysregulation and tumoral impingement on vital brain structures. PAM encodes a multifunctional protein responsible for the essential C-terminal amidation of secreted peptides. Following the identification of a loss-of-function variant (p.Arg703Gln) in the peptidylglycine a-amidating monooxygenase (PAM) gene in a family with pituitary gigantism, we investigated 299 individuals with sporadic PAs and 17 familial isolated PA kindreds for PAM variants. Genetic screening was performed by germline and tumor sequencing and germline copy number variation (CNV) analysis. In germline DNA, we detected seven heterozygous, likely pathogenic missense, truncating, and regulatory SNVs. These SNVs were found in sporadic subjects with growth hormone excess (p.Gly552Arg and p.Phe759Ser), pediatric Cushing disease (c.-133T>C and p.His778fs), or different types of PAs (c.-361G>A, p.Ser539Trp, and p.Asp563Gly). The SNVs were functionally tested in vitro for protein expression and trafficking by Western blotting, splicing by minigene assays, and amidation activity in cell lysates and serum samples. These analyses confirmed a deleterious effect on protein expression and/or function. By interrogating 200,000 exomes from the UK Biobank, we confirmed a significant association of the PAM gene and rare PAM SNVs with diagnoses linked to pituitary gland hyperfunction. The identification of PAM as a candidate gene associated with pituitary hypersecretion opens the possibility of developing novel therapeutics based on altering PAM function.

Identification of the Extradural and Intradural Extension of Pituitary Adenomas to the Suprasellar Region: Classification, Surgical Strategies, and Outcomes.

ObjectiveSuprasellar pituitary adenomas (PAs) can be located in either extradural or intradural spaces, which impacts surgical strategies and outcomes. This study determined how to distinguish these two different types of PAs and analyzed their corresponding surgical strategies and outcomes.MethodsWe retrospectively analyzed 389 patients who underwent surgery for PAs with suprasellar extension between 2016 to 2020 at our center. PAs were classified into two main grades according to tumor topography and their relationships to the diaphragm sellae (DS) and DS-attached residual pituitary gland (PG). Grade 1 tumors were located extradurally and further divided into grades 1a and 1b, while grade 2 tumors were located intradurally.ResultsOf 389 PAs, 292 (75.1%) were surrounded by a bilayer structure formed by the DS and the residual PG and classified as grade 1a, 63 (16.2%) had lobulated or daughter tumors resulting from the thinning or absence of the residual PG and subsequently rendering the bilayer weaker were classified as Grade 1b, and the remaining 34 (8.7%) PAs that broke through the DS or traversed the diaphragmic opening and encased suprasellar neurovascular structures were classified as Grade 2. We found that the gross total removal of the suprasellar part of grade 1a, 1b, and 2 PAs decreased with grading (88.4%, 71.4%, and 61.8%, respectively). The rate of major operative complications, including cerebrospinal fluid leakage, hemorrhage, and death, increased with grading.ConclusionsIt is essential to identify whether PAs with suprasellar extension are located extradurally or intradurally, which depends on whether the bilayer structure is intact. PAs with an intact bilayer structure were classified as grade 1. These were extradural and usually had good surgical outcomes and lower complications. PAs with no bilayer structure surrounding them were classified as grade 2. These were intradural, connected to the cranial cavity, and had increased surgical complications and a lower rate of gross total removal. Different surgical strategies should be adopted for extradural and intradural PAs.

Genetic and Epigenetic Causes of Pituitary Adenomas.

Pituitary adenomas (PAs) can be classified as non-secreting adenomas, somatotroph adenomas, corticotroph adenomas, lactotroph adenomas, and thyrotroph adenomas. Substantial advances have been made in our knowledge of the pathobiology of PAs. To obtain a comprehensive understanding of the molecular biological characteristics of different types of PAs, we reviewed the important advances that have been made involving genetic and epigenetic variation, comprising genetic mutations, chromosome number variations, DNA methylation, microRNA regulation, and transcription factor regulation. Classical tumor predisposition syndromes include multiple endocrine neoplasia type 1 (MEN1) and type 4 (MEN4) syndromes, Carney complex, and X-LAG syndromes. PAs have also been described in association with succinate dehydrogenase-related familial PA, neurofibromatosis type 1, and von Hippel–Lindau, DICER1, and Lynch syndromes. Patients with aryl hydrocarbon receptor-interacting protein (AIP) mutations often present with pituitary gigantism, either in familial or sporadic adenomas. In contrast, guanine nucleotide-binding protein G(s) subunit alpha (GNAS) and G protein-coupled receptor 101 (GPR101) mutations can lead to excess growth hormone. Moreover, the deubiquitinase gene USP8, USP48, and BRAF mutations are associated with adrenocorticotropic hormone production. In this review, we describe the genetic and epigenetic landscape of PAs and summarize novel insights into the regulation of pituitary tumorigenesis.

Clinical efficacy of optical coherence tomography in sellar mass lesions: a meta-analysis.

Although optical coherence tomography (OCT) of the eyes has been studied to detect and monitor sellar masses, there is no recommendation for selecting the most effective measurement of OCT in clinical practice. Thus, we conducted a meta-analysis to examine the efficacy of OCT in sellar mass lesions. We conducted a literature search in PubMed and EMBASE through April 26, 2020. The primary outcomes were the thickness of the peripapillary retinal nerve fiber layer (pRNFL) and the macular ganglion cell complex (mGCC). The secondary outcomes included the thickness of the macular ganglion cell and inner plexiform layer (mGCIPL) and macular thickness. Random-effects models were used in all meta-analyses. Additionally, we conducted meta-regressions and subgroup analyses. We included 22 studies, involving 1347 eyes of patients and 1198 eyes of controls. When compared with the control group, the reductions in pRNFL, mGCC and macular thickness in the patient group were significantly different, whereas significant thinning of the mGCIPL was restricted to the nasal hemiretina. Furthermore, we found that before visual field (VF) defects occurred, significant thinning of the pRNFL and mGCC thickness could be detected by OCT. The change in OCT parameters also showed different patterns in different types of pituitary adenomas. Sellar mass lesions were associated with the changes in OCT measurements. The characteristic patterns of the OCT parameters may refine the diagnostic accuracy. Moreover, the alterations of OCT metrics before VF defects indicate the efficacy of OCT in early detection. Different types of pituitary adenomas may vary in OCT measurements, and their specific features warrant further research efforts.

Clinicopathological analysis of 250 cases of pituitary adenoma under the new WHO classification.

Pituitary adenomas (PAs) are a common subtype of intracranial tumors. The aim of the present study was to analyse the clinical and pathological features of different types of pituitary adenomas (PAs) according to the 2017 World Health Organisation Endocrine Organ Tumor Classification guidelines. The clinical data of 250 patients with PAs were collected and analysed. Differences in the incidence of invasion, recurrence and apoplexy in patients between high- and low-risk PAs were compared, as were differences in the Ki-67 index between invasive and non-invasive PAs and between recurrent PAs and non-recurrent PAs. Of the 250 cases, 45 cases were diagnosed as somatotroph adenomas, 26 cases as lactotroph adenomas, 1 case as thyrotroph adenoma, 61 cases as corticotroph adenomas, 93 cases as gonadotropin adenomas, 15 cases as null cell adenomas and 9 cases as plurihormonal adenomas. There were 5 types of high-risk pituitary adenoma identified: 17 cases of sparsely granulated somatotroph adenoma, 11 cases of lactotroph adenoma in men, 3 cases of plurihormonal PIT-1 positive adenoma and 42 cases of silent corticotroph adenoma. Crooke's cell adenoma was not identified. High-risk PAs had significantly higher rates of invasion, recurrence and apoplexy compared with that in low-risk types (P<0.001). Invasive PAs had a significantly higher Ki-67 index compared with that in non-invasive PAs (3.5±1.8 vs. 2.8±1.3; P<0.01). Recurrent PAs had a significantly higher Ki-67 index compared with that in non-recurrent PAs (3.9±1.9 vs. 2.8±1.3; P<0.001). According to the 2017 classification criteria, patients most frequently had gonadotrophin cell adenomas, followed by corticotroph adenomas and the proportion of null cell adenomas was reduced. Differences were noted in the proliferation, recurrence and apoplexy characteristics of high-risk PAs and low-risk PAs. The invasion and recurrence of PAs were found to be related to the Ki-67 index.

Analysis of pituitary adenoma expression patterns suggests a potential role for the NeuroD1 transcription factor in neuroendocrine tumor-targeting therapies

NeuroD1’s roles in the pathogenesis of pituitary adenomas and in the biology of the normal adult pituitary gland have been insufficiently researched. Much of the work investigating its expression patterns has yielded contradictory results. Objective: morphological study of NeuroD1 transcription factor expression in different types of pituitary adenomas and in normal adult human pituitary glands. Materials and methods: This study analyzed 48 pituitary adenomas and nine normal pituitary glands. In all cases, immunohistochemical study was performed with antibodies to NeuroD1, 6 hormones of adenohypophysis, Ki-67, and CK7. We used confocal laser scanning microscopy, electron microscopy and electron immunocytochemistry. Results: NeuroD1 expression was detected in all cases of plurihormonal adenomas, mammosomatotropinomas, corticotropinomas, prolactinomas, gonadotropinomas, null-cell pituitary adenomas, and in normal pituitary glands. The average numbers of NeuroD1 expressing cells in normal adenohypophysis specimens were significantly lower than in the adenomas overall (p=0.006). NeuroD1 expression was confirmed by several methods (in prolactinomas, by double stain immunohistochemistry; in mammosomatotropinomas, by double stain immunohistochemistry, confocal laser scanning microscopy, and electron immunocytochemistry; and in somatotropinomas, by electron immunocytochemistry). Conclusion: Immunohistochemistry, confocal microscopy, and double label electron immunocytochemistry confirmed NeuroD1’s key role in the pathogenesis of pituitary tumors, regardless of their hormonal state. Its expression level in pituitary adenomas is significantly higher than in the normal pituitary gland and has no reliable correlation with any studied hormones or Ki-67. These findings suggest that NeuroD1 should be investigated further as a potential molecular target in tumor-targeting therapies.

Next-generation sequencing of microRNAs reveals a unique expression pattern in different types of pituitary adenomas.

Pituitary adenomas (PAs) are considered the most common intracranial tumor to cause serious morbidity because of dysregulated pituitary hormone secretions. Aberrant expression of microRNAs (miRNAs) is correlated with the development and function of the pituitary gland as well as the tumorigenesis of hypothalamic-pituitary axis-related pituitary tumors. In this study, we showed the differential expression patterns of miRNAs in NFPAs (nonfunctioning pituitary adenomas), GHPAs (growth hormone-secreting pituitary adenomas) and PRLPAs (prolactin-secreting pituitary adenomas) compared to those in three normal pituitary glands using the HiSeq 2000 sequencing system (Illumina). We validated miRNA expression using real-time quantitative polymerase chain reaction (RT-qPCR) analyses of samples from 73 patients (13 GHPAs, 42 NFPAs, and 18 PRLPAs) and 6 normal pituitary gland. We observed that miR-34c-3p was significantly downregulated in our PRLPA samples (p < 0.01), along with miR-34b-5p, miR-378 and miR-338-5p (all p < 0.05). In NFPAs, miR-493-5p was downregulated, and miR-181b-5p was significantly upregulated (p < 0.01). In GHPAs, miR-184 was significantly upregulated (p < 0.05). We observed that the tumor suppressive miR-124-3p was downregulated in both NFPAs and GHPAs. Taken together, we showed distinctive miRNA expression patterns in these three PAs, and these miRNA signatures in PA may have therapeutic potential as novel biomarkers for each type of PA.

Oncogene-Induced Senescence in Pituitary Adenomas--an Immunohistochemical Study.

Oncogene-induced senescence (OIS) serves as an initial barrier to cancer development, being proposed as a possible explanation for the usually benign behavior of the pituitary adenomas. We aimed to explore the immunohistochemical expression of the OIS markers, senescence-associated lysosomal β-galactosidase (SA-β-GAL), p16, and p21 in different types of 345 pituitary adenomas and compared it with the expression in the normal pituitary and in the specimens from the repeated surgeries. SA-β-GAL was overexpressed in the pituitary adenomas, compared to the normal pituitaries. Growth hormone (GH) producing adenomas showed the strongest SA-β-GAL, with densely granulated (DG)-GH adenomas more reactive than the sparsely granulated (SG). Nuclear p21 was decreased in the adenomas, except for the SG-GH adenomas that had higher p21 than the normal pituitaries and the other adenomas. p16 was significantly lower in the adenomas, without type-related differences. SA-β-GAL was slightly lower and p16 slightly higher in the recurrences. Our findings indicate alterations of the senescence program in the different types of pituitary adenomas. Activation of senescence in the pituitary adenomas presents one possible explanation for their usually benign behavior, at least in the GH adenomas that show a synchronous increase of two OIS markers. However, subdivision into GH adenoma subtypes reveals differences that reflect complex regulatory mechanisms influenced by the interplay between the granularity pattern and the hormonal factors, with possible impact on the different clinical behavior of the SG- and DG-GH adenoma subtypes. p16 seems to have a more prominent role in the pituitary tumorigenesis than in the senescence. Recurrent growth in a subset of the pituitary adenomas is not associated with consistent changes in the senescence pattern.

The dopastatin BIM-23A760 distinctly influences key functional endpoints in different types of pituitary adenomas and normal pituitaries: role of somatostatin and dopamine receptor profile

The dopastatin BIM-23A760 distinctly influences key functional endpoints in different types of pituitary adenomas and normal pituitaries: role of somatostatin and dopamine receptor profile

Demographic study of pituitary adenomas undergone trans-sphenoidal surgery in Loghman Hakim Hospital, Tehran, Iran 2001-2013.

Background:Pituitary adenomas (PAs) are abnormal benign tumors that develop in the pituitary gland. This study aimed to assess the prevalence of different types of PAs with an indication for trans-sphenoidal surgery in a well-defined population referred to Loghman Hakim Hospital during 2001–2013.Subjects and Methods:In this retrospective study, the prevalence rate and symptoms associated with pituitary mass and hormone excess in operated patients were investigated. The diagnosis was verified after retrieval of clinical, hormonal, radiological, and pathological data. Demographic data were collected in all cases. Descriptive analysis, t-test, one-way analysis of variance and Fischer exacts test were used.Results:A total of 278 patients with PAs who underwent surgical interventions were evaluated. Most of the patients were aged 40–50 years with an average of 41 ± 14. The most prominent complaint was pressure effect, which was detected in 153 cases (55.2%). At the second place, hormonal disorders were observed in 125 cases (44.8%). Type of pituitary tumors were: Prolactinomas (29.1%), growth hormone (GH)-producing tumors (25%), nonfunctioning PAs (28.4%), adrenocorticotropic hormone (ACTH)-producing tumors (2.1%), thyroid stimulating hormone (TSH)-producing tumors (0.7%), GH/prolactin (13.6%), GH/ACTH (0.3%), and TSH/ACTH (0.3%). Fifty-seven patients presented with recurrent adenomas. Pituitary apoplexy was found in 11 patients. One case of Sheehan syndrome was recorded among these. The correlations between clinical symptoms and patients, age and sex were not significant.Conclusion:The overview of demographic characteristics in Iranian patients with PAs with surgical indication has been discussed in the present investigation. The prevalence of different types of PAs and the most common clinical symptoms have been demonstrated.

Topoisomerase IIα as a prognostic factor in pituitary tumors.

There is an ongoing search for markers of pituitary tumor proliferation and progression that could facilitate further treatment and patient monitoring. We studied topoisomerase IIα (topo IIα) expression in different types of pituitary adenomas to evaluate its prognostic value. In a retrospective study of 60 patients (mean age, 46.7 ±17.6 y) who underwent pituitary tumor surgery, expression of topo IIα was assessed by immunohistochemistry and compared with histopathological tumor features, clinical symptoms, magnetic resonance imaging, and postoperative tumor recurrence or progression. Expression of topo IIα was observed in 44 of 60 pituitary adenomas (73%). The highest topo IIα index was observed in adrenocorticotropic hormone (ACTH)-secreting tumors (median, 1.13% [0.37-1.21]), followed by silent-ACTH tumors (0.94% [0.89-1.0]), and hormone immunonegative adenomas (0.8% [0.65-1.55]). There were no differences in topo IIα expression with respect to age or sex. Significant correlations were observed between the topo IIα index and tumor size, its invasiveness, abnormal ocular test results, and postoperative tumor recurrence. In patients with a topo IIα index exceeding 1%, we observed a 3.5-fold higher relative risk of tumor recurrence as compared with patients with a topo IIα index lower than 1% (95% confidence interval: 1.8-6.9; P <0.001). Patients with acromegaly who received somatostatin analogues before the surgery had a lower median topo IIα index compared with untreated patients (0%[0-0.22] vs. 0.71% [0.17-1.0]; P <0.05). In our study group, a topo IIα index exceeding 1% was a prognostic factor for tumor recurrence or progression, especially in patients with hormonally inactive adenomas, which facilitates patient selection for intensive postoperative treatment. Use of somatostatin analogues in acromegaly inhibits topo IIα expression, providing molecular evidence for the effectiveness of these analogues.

Expression of cyclooxygenase-2 (COX-2) in pituitary tumours

SummaryBackgroundMicrovessel density in angiogenesis is regarded as a prognostic factor of tumour invasiveness, independent of cell proliferation. In recent studies of pituitary tumours, correlation between the expression of cyclooxygenase-2 (COX-2) and micro-vascularization density and microvessel surface density has been established. We studied the expression of COX-2 in different types of pituitary adenomas to determine the usefulness of COX-2 expression as a prognostic factor of tumour progression or recurrence in patients with hypophyseal tumours.Material/MethodsWe retrospectively studied a group of 60 patients of mean age 46.7±17.6 (range, 18 to 85) years who underwent pituitary tumour surgery. Expression of COX-2, as determined by immunohistochemistry, was analyzed in relation to histopathology features of tumour, clinical symptoms, MR imaging and post-operative recurrence/progression of disease.ResultsCOX-2 was expressed in adenomas of 87% of patients, with a median index value of 57.5% [IQR=60.5]. Highest COX-2 expression was observed in hormonally inactive adenomas and gonadotropinomas and lowest in prolactinomas. We found no differences in COX-2 expression with respect to patient age, gender, tumour size, degree of tumour invasiveness, or whether tumours were immunopositive or immunonegative for pituitary hormones, nor have we found any relation between COX-2 expression and recurrence or progression of tumour size.ConclusionsCOX-2 does not appear to be a predictive factor for recurrence or progression of tumour size. Nevertheless, due to the observed relatively high expression of COX-2 in pituitary adenomas, further studies with COX-2 inhibitors are justified in these tumours.

Study on chang of histopathology and molecular biology of NPY in human pituitary adenomas

Objective To investigate the localization of neuropeptide Y(NPY) in the subcellular structure and expression of NPY in human pituitary adenomas, and their specificity and relationship. Method The tissues of pituitary adenomas were obtained from 57 patients with pituitary adenomas who underwent surgery in the department of neurosurgery in General hospital of Tianjin Medical University. The localization of NPY in pituitary adenoma cells was studied by immuno-electron microscopy. The expression of NPY in all patients with pituitary adenomas were studied by immunohischemical analysis and RT-PCR. Results (1)Immuno-electron microscopy demonstrated that the positive NPY was located mainly in the secretory granulas in cell matrix of pituitary adenomas. Gold particles were sparsely detected in the rough endoplasmic reticulum and cell matrix. (2) Immunohistochemical analysis showed that NPY was immunodetected in 59.6% (34/57) patients with pituitary adenomas. NPY expression was significantly different among different types of pituitary adenomass (P<0.05). NPY was immunodetected in 91.7% of gonadotrophic adenomas, 66.7% of GH and ACTH adenomas, 50% of null cell adenoma and plurihormonal adenoma, 25% of prolaetinomas. There was significant difference among them(χ~2=11.64, P=0.04). (3) RT-PCR showed that there was signification differentiation (F=4.21, P<0.01) among the expression of NPY in different types of pituitary adenoma. The NPY expression in gonadotrophic adenomas was the highest (7.00±8.32),with 9.3-fold(q=5.2616, P<0.01)compared with prolactinomas(0.75±0.11),5.8-fold (q=5.0143, P<0.01) with non-thnctional adenomas (1.79±2.13),2.7-fold (q=4.07, P<0.05) with GH adenomas (2.59±3.06). There was no significant differentiation among the rest groups. Conclusions (1)NPY really exists in human pituitary adenomas. (2)NPY expression is significantly different among different types of pituitary adenomas. The NPY expression level in gonadotrophic adenomas is the highest, the lowest in prolactinomas. (3)These results will provide sound bases for further research of the action of NPY in human pituitary. Key words: Pituitary neoplasms; Neuropeptide Y; Subcellular structure; Gene

Quality of life in patients with pituitary tumors

Quality of life (QoL) is impaired in patients with pituitary tumors, even after biochemical cure. However, it is not usually assessed in daily practice. The aim of this study is to highlight recent findings on QoL in the different types of pituitary adenomas and hypopituitarism. Patients with acromegaly or Cushing's syndrome have the greatest impairment of QoL, and concomitant hypopituitarism worsens it further. The use of disease-generated QoL questionnaires allows dimensions specifically affected in that disease to be addressed and these dimensions are more sensitive to change after successful therapy; in some cases, improvement in patients' sense of well-being has been shown despite no hormonal change, indicating that evaluation of QoL is not such a soft end-point as thought by some. Systematic evaluation of QoL in patients with pituitary diseases provides information not always contemplated by hormonal and routine clinical evaluation; this allows detection of not often contemplated health problems, which may then be approached and treated, improving the care provided to these patients.

Somatostatin–dopamine ligands in the treatment of pituitary adenomas

Somatostatin receptors (sst1-5) and dopamine receptor 2 (D2DR) are well expressed and co-localized in several human pituitary adenomas, suggesting possible functional interactions in the control of hormonal hypersecretion and tumor cell growth. The present review describes the expression and functionality of these receptors in the different classes of human pituitary adenomas. The sst2 agonists, octreotide and lanreotide, control GH hypersecretion and tumor growth in about 65% of somatotropinomas. The D2DR agonists, bromocriptine and cabergoline, control about 90% of prolactinomas. Such drugs are much less effective in the control of the others pituitary adenomas also expressing ssts and D2DR receptors. The second part summarizes the current knowledge on new chimeric compounds with sst2, sst5, and D2DR affinity. Such ligands bearing distinct ssts and DRD2 pharmacophores may synergistically produce an increased control of secretion and/or of proliferation in the different types of pituitary adenomas. The mechanisms of action of such chimeric molecules through increased binding affinities, prolonged bioavailability, ligand-induced modulation of receptors heterodimerization, are discussed.

Relevance of coexpression of somatostatin and dopamine D2 receptors in pituitary adenomas

Dopamine and somatostatin are both involved in the negative control of normal pituitary cells. Dopamine subtype 2 receptor (D2DR) and somatostatin receptor (sst) agonists, mainly directed to sst2, are used in the treatment of pituitary adenomas. Nevertheless, a majority of corticotroph and gonadotroph adenomas and a third of somatotroph adenomas are still not sufficiently controlled by these treatments. D2DR and sst1, 2, 3 and 5 are present in most pituitary adenomas. These receptors may interact by heterodimerization as shown for sst1-sst5, sst5-D2DR, sst2-sst3 and sst2-D2DR suggesting possible additive effects. D2DR and sst2 agonist cotreatment showed limited additivity on GH secretion in acromegaly. Moreover, new chimeric compounds with sst2, D2DR and sst5 affinity have shown an increased control of secretion and/or proliferation of different types of pituitary adenomas in cell culture. Together with the multi-sst ligand drugs recently developed, these dopamine-somatostatin ligands represent a new opportunity in the combinatory treatment of pituitary adenomas.

Expression of epidermal growth factor receptor in neoplastic pituitary cells: evidence for a role in corticotropinoma cells

The oncogenic effects of epidermal growth factor (EGF) have long been established. EGF receptor (EGFr) is overexpressed in many types of tumors and constitutes a target for cancer treatment. The pituitary gland is a target of EGF action and it is very likely that EGFr plays a role in pituitary tumor formation and progression. However, there is a controversy in the literature concerning EGFr expression in the different types of pituitary adenomas. In the present study we investigated the expression pattern of the wild type EGFr (EGFrWT) and the constitutively active variant III (EGFrvIII) at the mRNA and protein levels in a large series of pituitary tumors. EGFrWT was found in a high percentage of hormone-secreting tumors, but only in a small fraction of non-functioning pituitary adenomas, while no expression of the EGFrvIII could be detected by nested RT-PCR in any tumor. Among the hormone-secreting adenomas, the highest incidence of EGFr expression was found in Cushing's pituitary adenomas. Furthermore, immunohistochemistry for the phosphorylated EGFr revealed the presence of activated EGFr in most Cushing's adenomas, compared with most pituitary adenomas. Taking into account that downregulation of p27/Kip1 plays a significant role in corticotrope tumorigenesis and that EGFr mitogenic signaling results in decreased p27/Kip1, we searched for a correlation between EGFr expression and p27/Kip1 levels in corticotropinomas. Low p27/Kip1 immunoreactivity was observed in corticotropinomas expressing EGFr. On the other hand, somatotropinomas expressing EGFr had high p27/Kip1 immunoreactivity. These data suggest a corticotrope-specific phenomenon and indicate that EGFr may have a role in the unbalanced growth of corticotrope tumoral cells.