Cowden syndrome (CS) is a rare genetic condition due to the various germline mutations in the phosphatase and tensin homologue on chromosome ten ( PTEN ) tumour suppressor gene. As a result, CS is characterised by an increased risk of developing various benign and malignant tumours, such as thyroid, breast, endometrial and urogenital neoplasms, as well as gastrointestinal tract tumours. However, the neuroendocrine tumour association with CS is not elucidated yet. We present a case of a 46-year-old male patient diagnosed with testicular seminoma and follicular thyroid cancer in his medical history. Our patient met the clinical diagnostic criteria of Cowden syndrome. Genetic analysis established the clinical diagnosis; a known heterozygous PTEN mutation was detected [ PTEN (LRG_311t1)c.388 C > T (p.Arg130Ter)]. Incidentally, he was also seen with multiple pulmonary lesions during his oncological follow-up. A video-assisted thoracoscopic left lingula wedge resection and later resections from the right lung were performed. Histological findings revealed typical pulmonary carcinoid tumours and smaller tumorlets. Somatostatin receptor SPECT-CT, 18 F-FDG-PET-CT and 18 F-FDOPA-PET-CT scans and endoscopy procedures could not identify any primary tumours in other locations. Our patient is the first published case of Cowden syndrome, associated with multifocal pulmonary carcinoids. Besides multiple endocrine neoplasia type 1, we propose Cowden syndrome as another hereditary condition predisposing to multiple pulmonary tumorlets and carcinoid tumours.

The human hormonal regulatory system is expanding by several recently identified members, however, there are still many traditional hormones with poorly known functions. Examples for conventional regulatory molecules without clarified relevance include the oxytocin of the pituitary, dehydroepiandrosterone (DHEA) of the adrenal cortex or calcitonin produced by the C-cells of the thyroid gland.

MicroRNAs, the endogenous mediators of RNA interference, interact with the renin-angiotensin-aldosterone system, regulate aldosterone secretion and aldosterone effects. Some novel data show that the expression of some microRNAs is altered in primary aldosteronism, and some of these appear to have pathogenic relevance, as well. Differences in the circulating microRNA expression profiles between the two major forms of primary aldosteronism, unilateral aldosterone-producing adenoma and bilateral adrenal hyperplasia have also been shown. Here, we present a brief synopsis of these findings focusing on the potential relevance of microRNA in primary aldosteronism.

MicroRNAs provide an additional layer in the regulation of gene expression acting as repressors with several targets at the posttranscriptional level. This study describes microRNA expression patterns during differentiation and activation of mast cells. The expression levels of 567 different mouse miRNAs were compared by microarray between c-Kit+ committed progenitors, mucosal mast cells, resting and IgE-crosslinked BMMCs in vitro. The strongest upregulation of miR-132 upon IgE-mediated activation was validated in human cord blood-derived mast cells as well. HB-EGF growth factor also upregulated upon activation and was ranked high by more prediction algorithms. Co-transfection of miR-132 mimicking precursor and the 3′UTR of human Hbegf-containing luciferase vector proves that the predicted binding site is functional. In line with this, neutralization of miR-132 by anti-miR inhibitor leads to sustained production of HB-EGF protein in activated mast cells. Our data provide a novel example for negative regulation of a growth factor by an upregulated miRNA.

In their elegant study published in the December 15, 2009 issue of Clinical Cancer Research , Soon and colleagues described differences in the microRNA expression profiles of adrenocortical tumors (ACT) and established predictors for poor prognosis. Twenty-three microRNAs were found to be significantly differentially expressed between adrenocortical adenomas (ACA) and carcinomas (ACC) but only two between normal adrenal cortices (NA) and ACTs by microarray analysis. Four microRNAs were validated by quantitative real-time PCR (1). In our previous study published in the September 2009 issue of Endocrine-Related Cancer (epub 22 June; ref. 2), we have performed an integrative bioinformatic analysis on ACTs including parallel microRNA (Taqman TLDA Panel) and mRNA profiling and pathway analysis. We have found 22 microRNAs with significant differences in expression among NA, hormonally inactive ACA, cortisol-producing ACA, and ACC. Six microRNAs were validated by quantitative real-time PCR. dCT miR-511 − dCT miR-503 (dCT, delta cycle threshhold) was identified as the best predictor of malignancy. Whereas the number of significantly differentially expressed microRNAs was highly similar in the two studies, only two were common in both: miR-503 and miR-181b (both overexpressed in ACCs). There are several differences between the structures of the two studies that might have accounted for these discrepancies. Although the number of tumors included in the study by Soon et al. was higher (27 ACA and 22 ACC) than in ours (19 ACA and 7 ACC), the groups have not been subdivided based on hormone secretion in the former. We have studied only cortisol-secreting ACCs, and ACAs have been subdivided into inactive ACA ( n = 10) and cortisol-producing ACA ( n = 9) groups. Both ACAs and ACCs express glucocorticoid receptors that are even overexpressed in ACCs (3). Adrenocortical microRNA expression patterns might be influenced by glucocorticoids. 1 1 A. Patocs, Z. Tombol, P.M. Szabo, P. Igaz, K. Racz, unpublished results. This might argue against the establishment of tumor groups irrespective of their hormonal activity. Furthermore, we have studied intact NA ( n = 10) removed from patients operated for malignant kidney tumors, whereas Soon et al. used NA samples ( n = 6) from adrenalectomy specimens away from the site of the adenoma. He et al. reported that the overexpression of miR-221 characteristic for papillary thyroid cancer can be detected in the unaffected, histologically normal tissue surrounding the tumor (4). It is possible that a similar phenomenon might also exist in ACTs, and this could be related to the finding that only two microRNAs were significantly differentially expressed between NA and tumors. Further studies will be necessary to clarify the relevance and potential diagnostic applicability of microRNAs for adrenocortical tumors. Disclosure of Potential Conflicts of Interest No potential conflicts of interest were disclosed.

Sporadic adrenocortical tumours are common, but their pathogenesis is poorly elucidated. In this study, we present a meta-analysis and review of gene expression microarray and comparative genome hybridization (CGH) studies performed to date on these tumours, including our own data. Data of whole genome microarray studies from altogether 164 tumours (97 benign, 67 malignant) and 18 normal tissues were reclassified and reanalysed. Significant gene sets and cytogenetic changes from publications without available genomic data were also examined including 269 benign, 215 malignant tumour and 30 normal tissues. In our experimental study, 11 tumour and four normal samples were analysed by parallel mRNA and CGH profiling. Data were examined by an integrative bioinformatics approach (GeneSpring, Gene Set Enrichment Analysis and Ingenuity Pathway Analysis softwares) searching for common gene expression changes and paralleling chromosome aberrations. Both meta-analysis of available mRNA and CGH profiling data and our experimental study revealed three major pathogenetic pathways: (1) cell cycle, (2) retinoic acid signalling (including lipopolysaccharide/Toll like receptor 4 pathway), (3) complement system and antigen presentation. These pathways include novel, previously undescribed pathomechanisms of adrenocortical tumours, and associated gene products may serve as diagnostic markers of malignancy and therapeutic targets.

Adrenocortical cancer is a rare tumor with poor prognosis. Whereas most cases occur in a sporadic setting, there are very rare hereditary forms that are important for the understanding of tumor pathogenesis. The hereditary syndromes associated with adrenocortical cancer are: Li-Fraumeni's syndrome, Beckwith-Wiedemann's syndrome and familial adenomatous polyposis, whereas multiple endocrine neoplasia type 1, Carney's complex and McCune-Albright's syndrome mostly predispose to benign adrenocortical tumors. Overexpression of insulin like growth factor 2, activation of Wnt/beta-catenin and cAMP-protein kinase A signaling, as well as mutations of p53 and MEN1 genes are regarded as major pathogenetic mechanisms. Options for medical treatment of adrenocortical cancer are rather limited. Recently published molecular-bioinformatical studies have revealed several previously unknown pathogenetic pathways that may even represent potential drug targets. In this study, the pathogenesis of hereditary tumor syndromes, the alterations in sporadic tumors and the most recent molecular-bioinformatical observations are discussed.

MicroRNAs are involved in the pathogenesis of several tumors, however, there have been no data on microRNA expression in pheochromocytomas to date. The objective of our study was to perform microRNA expression profiling in sporadic and hereditary benign, and recurring adrenomedullary tumors. Furthermore, the applicability of formalin-fixed paraffin-embedded tissue samples for the analysis of microRNA expression in pheochromocytomas was examined. MicroRNA expression data of three matched frozen and formalin-fixed paraffin-embedded samples were correlated. A total of 21 formalin-fixed paraffin-embedded samples (sporadic benign, multiple endocrine neoplasia 2, von Hippel-Lindau disease, sporadic recurring) were subjected to microRNA expression profiling using microarrays. MicroRNAs with significant differences in expression were validated and sample sizes were extended including tumors from neurofibromatosis type 1 patients by real-time quantitative reverse-transcription PCR (n=33). MicroRNA target prediction was carried out by TargetScan and MicroCosm Targets. Pathway analysis of targets was performed by Ingenuity Pathway Analysis and DIANA mirPath. Furthermore, microRNA expression profiles of a malignant pheochromocytoma and a pair of primary and recurrent tumors were studied by TaqMan Human MicroRNA Cards. MicroRNA expression correlated well between frozen and formalin-fixed paraffin-embedded samples (70–92%). Microarray analysis revealed 16 significantly differentially expressed microRNAs. Five of these were validated by real-time RT-PCR. miR-139-3p, miR-541 and miR-765 were significantly differentially expressed between sporadic benign and von Hippel-Lindau-related pheochromocytomas. Significantly higher expression of miR-885-5p and miR-1225-3p was found in multiple endocrine neoplasia type 2 and sporadic recurring pheochromocytomas, respectively. Pathway analysis revealed the possible involvement of Notch- and G-protein-coupled receptor signaling in tumor recurrence. MicroRNA expression profiles in the primary recurrent and recurring malignant comparisons have been similar. In conclusion, we have proved that formalin-fixed paraffin-embedded samples can be used for the analysis of microRNA expression in pheochromocytomas. MicroRNA expression patterns differ between various sporadic, hereditary and recurring tumors and miR-1225-3p may be useful for identifying recurring pheochromocytomas.

MicroRNAs (miRNA) are small non-coding RNA molecules involved in the posttranscriptional regulation of gene expression. miRNAs bind specifically to the 3' untranslated region of messenger RNA (mRNA) molecules and induce translational repression or mRNA degradation. Potential miRNA targets can be predicted by various computational algorithms that take several parameters into consideration and calculate probability scores for each miRNA-mRNA interaction. In this review, three of the most frequently used algorithms (TargetScan, PicTar and miRBase) are compared, and their strengths and weaknesses are highlighted. These algorithms use different input databases and mathematical models that may lead to discrepancies of the outputs. As currently there is no unambiguous evidence for the preference of any of these algorithms, simultaneous analysis by all can be an effective approach. For this purpose a novel software was developed which is capable of collecting all available data about each miRNA-mRNA interaction retrieved by these databases and identifying common putative targets. Another major problem is related to difficulties of experimental validation, therefore only a minority of in silico predicted targets could be validated to date. Following a brief description of the available experimental target validation methods, the authors attempt to provide suggestions for designing in vitro validation approaches.

Histamine is involved in the pathogenesis of several tumors; however, there are no data on its possible involvement in human adrenocortical tumorigenesis. The expression of genes and proteins involved in the biosynthesis (histidine decarboxylase, HDC), action (histamine receptors: HRH1–HRH4), and metabolism of histamine is largely unknown both in the normal human adrenal cortex and in adrenocortical tumors. In this study, we examined the expression of histamine-related genes and proteins and histamine content in normal adrenal cortex, benign adrenocortical adenomas, and malignant adrenocortical cancer (ACC). Fifteen normal adrenals and 43 tumors were studied. mRNA expression was examined by real time RT-PCR. Western-blotting and immunohistochemistry were used for the study of proteins. Tissue histamine content was determined by enzyme-linked immunosorbent assay. We found that all proteins involved in histamine biosynthesis and action are present both in the normal adrenal cortex and in the tumors studied. HDC expression and histamine content was highest in the normal tissues and lower in benign tumors, whereas it was significantly less in ACCs. HRH3 expression was significantly higher in ACC samples than in the other groups. Adrenocortical tumorigenesis might, thus, be characterized by reduced histamine biosynthesis; furthermore, different adrenocortical tumor subtypes may show unique histamine receptor expression profiles.

MicroRNAs (miRs) are involved in the pathogenesis of several neoplasms; however, there are no data on their expression patterns and possible roles in adrenocortical tumors. Our objective was to study adrenocortical tumors by an integrative bioinformatics analysis involving miR and transcriptomics profiling, pathway analysis, and a novel, tissue-specific miR target prediction approach. Thirty-six tissue samples including normal adrenocortical tissues, benign adenomas, and adrenocortical carcinomas (ACC) were studied by simultaneous miR and mRNA profiling. A novel data-processing software was used to identify all predicted miR-mRNA interactions retrieved from PicTar, TargetScan, and miRBase. Tissue-specific target prediction was achieved by filtering out mRNAs with undetectable expression and searching for mRNA targets with inverse expression alterations as their regulatory miRs. Target sets and significant microarray data were subjected to Ingenuity Pathway Analysis. Six miRs with significantly different expression were found. miR-184 and miR-503 showed significantly higher, whereas miR-511 and miR-214 showed significantly lower expression in ACCs than in other groups. Expression of miR-210 was significantly lower in cortisol-secreting adenomas than in ACCs. By calculating the difference between dCT(miR-511) and dCT(miR-503) (delta cycle threshold), ACCs could be distinguished from benign adenomas with high sensitivity and specificity. Pathway analysis revealed the possible involvement of G2/M checkpoint damage in ACC pathogenesis. To our knowledge, this is the first report describing miR expression patterns and pathway analysis in sporadic adrenocortical tumors. miR biomarkers may be helpful for the diagnosis of adrenocortical malignancy. This tissue-specific target prediction approach may be used in other tumors too.

Cushing's syndrome is a rare disease with significant morbidity and mortality. Surgical intervention represents the most effective treatment option in both adrenocorticotropin-dependent and -independent forms of hypercortisolism. It is not uncommon, however, that surgery fails to cure or control the disease. Pharmacotherapy with drugs inhibiting steroid biosynthesis can be effectively used in these cases in order to alleviate symptoms or even to induce chemical adrenalectomy. A few drugs inhibiting single or multiple steps in adrenal steroid biosynthesis can be used in clinical practice. Drugs predominantly inhibiting single enzymatic steps include the 11beta-hydroxylase inhibitor metyrapone and the 3beta-hydroxysteroid dehydrogenase inhibitor trilostane, whereas mitotane, aminoglutethimide, ketoconazole and etomidate block multiple enzymatic reactions. Etomidate is the only agent available for parenteral administration that renders it as a treatment of choice in critically ill patients requiring a rapid control of hypercortisolemia. Ketoconazole, metyrapone and aminoglutethimide can be used alone or in combination for the treatment of hypercortisolism caused by benign adrenocorticotropin- or cortisol-secreting tumors. The clinical utility of trilostane is variable. Besides blocking multiple steps in adrenal steroid biosynthesis, the DDT (insecticide) analogue mitotane also has adrenolytic properties by inducing mitochondrial degeneration that renders it superior to other drugs in the treatment of adrenocortical cancer. Severe side effects may develop during therapy with each aforementioned drug that include hepatic, endocrine and neurological toxicity. After summarizing the chemical and biological properties of steroid biosynthetic inhibitors, the authors describe their possible clinical applications and limitations.