Endocrine Abstracts

Somatostatin and its analogues negatively regulate the growth of multiple epithelial cell types. This anti-proliferative effect occurs through multiple mechanisms, one of which is cell cycle arrest at the G0/G1 phase. p27, a cyclin-dependent kinase inhibitor, has a negative influence on cell cycle progression, and there are recent data suggesting that somatostatin increases p27 levels. We have previously shown that pituitary adenoma cells contain less p27 protein than normal p...

Background: Although the role of hypermethylation of certain tumor suppressor genes are known in pituitary adenomas little information is available regarding whole methylation-demethylation status and especially regarding its correlation with clinical parameters. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) is an easy and accurate method to detect the level of methylcytosine (5 mC) and the demethylation intermedier hydroxymethylcytosine (5 hmC) ...

Background: Although pituitary adenomas are common endocrine neoplasms, the background of their pathogenesis has not clearly revealed. G1/S checkpoint alterations of the cell cycle have already been described in these tumours. MicroRNAs (miRs) which are small, non-coding RNA molecules, and posttranscriptionally regulate protein expression have also identified as potential pathogenic factors in certain cases. Our aim was to determine miR expression profile in pituitary adenomas...

Introduction: MicroRNAs (miRs) are 16–29 nucleotide long, non-coding RNA molecules that post-transcriptionally regulate gene expression via RNA interference. It has been shown that they participate in control of cell proliferation, cell differentiation, signal transduction, cell death and carcinogenesis.Aim: To examine the role of the miRs in sporadic pituitary tumourigenesis.Methods: Twenty-five sporadic pituitary adenoma spe...

We report a family with a novel heterozygous mutation of the menin gene. This gene encodes a tumor suppressor protein which is responsible for multiple endocrine neoplasia type 1. The index female patient presented with symptoms of mild gastric hyperacidity and recurrent kidney stones. Family history revealed, that the daughter, as well as two sisters of the index patient had operations for primary hyperparathyroidism (PHPT). Clinical studies in the index patient showed elevat...

Aim: Clinical acromegaly is characterized by high GH secretion in the presence of high circulating IGF-I levels. We therefore hypothesized that the physiological IGF-I-GH negative feedback loop may be reset in somatotroph adenomas, and we investigated the role of type 1 IGF receptor (IGF-R) and GH receptor (GHR) by quantifying mRNA expression in somatotroph tumours, and investigated the possible presence of mutations of the GHR gene.Methods: Pituitary t...

Introduction: There are three principal high-throughput methods that have been widely used to determine whole genome miRNAs expression profiles: i) microarrays, ii) qPCR based arrays, and iii) next generation sequencing (NGS). Our aim was to compare the results obtained from these platforms in normal and adenomatous pituitary samples and to validate the results by an independent sample set using qPCR.Material and methods: Using four normal pituitary (NP)...

Carney complex (CNC) is an autosomal dominant multiple neoplasia syndrome featuring cardiac, endocrine, cutaneous and neural tumours, as well as a variety of pigmented lesions of the skin and mucosa. Pituitary GH-secreting tumours are found in approximately 10% of patients with CNC. One of the genes responsible for CNC, the PRKAR1A gene, located on human chromosome 17q22-24, has recently been cloned. This represents a putative tumour suppressor gene, coding for the type 1alpha...

Introduction: Disrupted mitochondrial functions and genetic variations of mitochondrial DNA (mtDNA) have been observed in different tumors. Regarding pituitary adenomas mtDNA was evaluated only in oncocytic type using PCR based methods and it showed high prevalence of Complex I variants. Next generation sequencing (NGS) allows high throughput sequencing and it is useful for accurate identification of heteroplasmy of mitochondrial genome as well.Aim: We a...

Background: In our previous works the interdependence of DNA demethylation with proliferation and differentiation of pituitary neuroendocrine tumours (PitNET) and the inhibitory effect of Aspirin on pituitary cell proliferation were demonstrated. Although the role of Aspirin in epigenetic regulation was described in other malignancies, its correlation with pituitary tumorigenesis is currently unknown.Our objective: was to investigate the genomic and epig...