Heterogeneous genetic background of Hungarian patients with pheochromocytoma/paraganglioma requires gene panel testing

Introduction Pheochromocytomas and paragangliomas (Pheo/PGL) are rare neuroendocrine tumours arising from the adrenal medulla or the symphathetic paraganglia, respectively. Germline mutations are present in w40% of the patients. To date, at least 16 genes have been demonstrated to be involved in the genetic background of Pheo/PGL. Prioritization in order of genes tested can be applied, but if the probability of a disease-associated germline mutation exceeds 10% the testing of all susceptibility genes is recommended. Using next generation sequencing (NGS) based methods for genetic testing of Pheo/PGL associated genes progressively becomes part of the routine diagnostics. Objective To assess the genetic background of Hungarian patients with Pheo/PGL and to develop a NGS based gene panel assay for analysis of Pheo/PGL susceptibility genes. Methods We examined 131 patients with the diagnosis of Pheo/PGL diagnosed and nursed at the 2nd Department of Medicine, Semmelweis University. The prevalence of the germline mutations of Pheo/PGL genes was determined using conventional methods. Genotype-phenotype correlations were evaluated. A gene panel covering 15 genes (RET, VHL, NF1, EPAS, EGLN1, KIF1B, SDHA, SDHB, SDHAF2, SDHC, SDHD, FH, MAX, TMEM127, MEN1) was developed and analytical sensitivity was evaluated on 36 patients with known genetic background. Library preparation was performed using SeqCapEZ capture platform with our probe design. Illumina MiSeq instrument was used for sequencing. Sequencing data were analysed with GATK workflow. Variant annotation was performed with SNPeffect. Results Germline mutations of Pheo/PGL genes were present in at 34% of the patients: 10 (7.6%) SDHB, 9 (6.9%) RET, 5 (3.8%) VHL, TMEM127, MDH2, 4 (3%) NF1, 3 (2.3%) SDHD, 2 (1.5%) SDHC and KIF1B. 5 of 10 SDHB mutation carriers developed malignant disease. Homozygous form of a MDH2 variant was associated with malignancy. Among the 10 patients with bilateral adrenal Pheo 4 RET, 2 TMEM127 and 1 VHL mutations were identified. The coverage of genes in our panel was higher than 150 reads in all regions and all known mutations were correctly identified. Discussion Our findings regarding the prevalence of germline mutations in the development of Pheo/PGL are in accordance with the literature. No founder mutation occurred in our population as we could detect mutations in 9 genes, underlining the need of novel methods for mutation analysis in everyday clinical practice. Our NGSbased gene panel performed accurately, however two recently identified genes (MDH2, GOT2) were not covered

Preventive medicine of von Hippel-Lindau disease-associated pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PanNETs) are rare in von Hippel-Lindau disease (VHL) but cause serious morbidity and mortality. Management guidelines for VHL-PanNETs continue to be based on limited evidence, and survival data to guide surgical management are lacking. We established the European-American-Asian-VHL-PanNET-Registry to assess data for risks for metastases, survival and long-term outcomes to provide best management recommendations. Of 2330 VHL patients, 273 had a total of 484 PanNETs. Median age at diagnosis of PanNET was 35 years (range 10-75). Fifty-five (20%) patients had metastatic PanNETs. Metastatic PanNETs were significantly larger (median size 5 vs 2\u2009cm; P\u20091.5\u2009cm in diameter were operated. Ten-year survival was significantly longer in operated vs non-operated patients, in particular for PanNETs <2.8\u2009cm vs 652.8\u2009cm (94% vs 85% by 10 years; P\u2009=\u20090.020; 80% vs 50% at 10 years; P\u2009=\u20090.030). This study demonstrates that patients with PanNET approaching the cut-off diameter of 2.8\u2009cm should be operated. Mutations in exon 3, especially of codons 161/167 are at enhanced risk for metastatic PanNETs. Survival is significantly longer in operated non-metastatic VHL-PanNETs

Genetics of Pheochromocytomas and Paragangliomas Determine the Therapeutical Approach

Pheochromocytomas and paragangliomas are the most heritable endocrine tumors. In addition to the inherited mutation other driver mutations have also been identified in tumor tissues. All these genetic alterations are clustered in distinct groups which determine the pathomechanisms. Most of these tumors are benign and their surgical removal will resolve patient management. However, 5–15% of them are malignant and therapeutical possibilities for them are limited. This review provides a brief insight about the tumorigenesis associated with pheochromocytomas/paragangliomas in order to present them as potential therapeutical targets

Membrane-bound estrogen receptor alpha initiated signaling is dynamin dependent in breast cancer cells

Abstract Background Although membrane-associated estrogen receptors (mERs) have been known to play important role in steroid-induced signal transmission, we still know little about their function in the estrogen-induced proliferation of breast cancer cells. Methods In our current work we tried to separate membrane-initiated estrogen receptor signaling from the overall estrogenic effect in MCF-7 breast carcinoma cells. Re-analyzing expression data from multiple microarray experiments, we selected a set of key regulatory genes involved in proliferation regulation and estrogen signaling to monitor estrogen-induced transcription changes. We then compared these expression changes after 17β-estradiol and a membrane receptor selective estrogen–BSA treatment using quantitative real-time PCR. In order to follow receptor trafficking we used light and electron microscopy. Results Our quantitative real-time PCR results confirmed that the selective membrane receptor agonist, estrogen–BSA induces similarly pronounced expression changes regarding these genes as 17β-estradiol. Morphological study revealed that the membrane-bound form of classical estrogen receptor alpha is internalized after ligand binding via dynamin-dependent, caveola-mediated endocytosis. Inhibition of this internalization with dynamin inhibitor, dynasore practically abolished the regulatory effect of E2-BSA, suggesting that interaction and internalization with the scaffold protein is necessary for effective signaling. Conclusions The physiological role of plasma membrane estrogen receptor alpha is intensively studied, yet there are still several aspects of it to be resolved. The dynamin-dependent, ligand-mediated internalization of mERs seems to play an important role in estrogen signaling. Our results may serve as another example of how membrane initiated estrogen signaling and nuclear receptor initiated signaling overlap and form an intertwined system.