Whole-Exome Screening and Analysis of Signaling Pathways in Multiple Endocrine Neoplasia Type 1 Patients with Different Outcomes: Insights into Cellular Mechanisms and Possible Functional Implications

Multiple endocrine neoplasia type 1 (MEN1) is a syndrome characterized by tumors in multiple organs. Although being a dominantly inherited monogenic disease, disease phenotypes are unpredictable and differ even among members of the same family. There is growing evidence for the role of modifier genes in the alteration of the course of this disease. However, genome-wide screening data are still lacking. In our study, we addressed the different outcomes of the disease, focusing on pituitary and adrenocortical tumors. By means of exome sequencing we identified the affected signaling pathways that segregated with those symptoms. Most significantly, we identified damaging alterations in numerous structural genes responsible for cell adhesion and migration. Additionally, in the case of pituitary tumors, genes related to neuronal function, survival, and morphogenesis were repeatedly identified, while in patients with adrenocortical tumors, TLR10, which is involved in the regulation of the innate immunity, was commonly modified. Our data show that using exome screening, it is possible to find signatures which correlate with the given clinical MEN1 outcomes, providing evidence that studies addressing modifier effects in MEN1 are reasonable.

Whole-exome sequencing as a tool for searching for genetic background modifiers in MEN1 patients with neuroendocrine pancreatic tumours, including insulinomas

INTRODUCTION

Multiple endocrine neoplasia type 1 (MEN1) is a monogenic disease caused by inactivating variants in the MEN1 gene. Although the reason for its development is well-known, disease phenotypes are unpredictable and differ even among carriers of the same pathogenic driver mutation. Genetic, epigenetic, and environmental factors may play a role in driving the individual phenotype. Those factors, however, still mostly remain unidentified. In our work, we focused on the inherited genetic background in pancreatic neuroendocrine neoplasms (pNENs) in MEN1 patients, and the pancreatic tumour subgroup with insulinoma.

MATERIAL AND METHODS

Whole exome sequencing was performed in MEN1 patients. The symptoms of interest were pancreatic neuroendocrine tumours in one analysis and insulinoma in the second. The study included families as well as unrelated cases. Genes with variants that are not neutral to the encoded gene product were defined in symptom-positive patients as compared to symptom-negative controls. The interpretation of the results was based on functional annotations and pathways shared between all patients with the given symptom in the course of MEN1.

RESULTS

Whole-exome screening of family members and unrelated patients with and without pNENs revealed a number of pathways that are common for all the analysed cases with pNENs. Those included pathways crucial for morphogenesis and development, proper insulin signalling, and structural cellular organization. An additional analysis of insulinoma pNEN patients revealed additional pathways engaged in glucose and lipid homeostasis, and several non-canonical insulin-regulating mechanisms.

CONCLUSIONS

Our results show the existence of pathways that are identified in a non-literature-predefined manner, which might have a modifying function in MEN1, differentiating the specific clinical outcomes. Those results, although preliminary, provide evidence of the reasonableness of performing large-scale studies addressing the genetic background of MEN1 patients in determining their individual outcomes.

How much of the predisposition to Hashimoto's thyroiditis can be explained based on previously reported associations?

PURPOSE

Our insight in the genetics of Hashimoto's thyroiditis (HT) has become clearer through information provided by genome-wide association studies and candidate gene studies, but remains still not fully understood. Our aim was to assess how many different genetic risk variants contribute to the development of HT.

METHODS

147 HT cases (10.2% men) and 147 controls (13.6% men) were qualified for the analysis. Intrinsic and environmental factors were controlled for. Polymorphisms (SNP) were chosen based on the literature and included markers of the genes PTPN22, CTLA4, TG, TPO among others, and of genomic regions pointed by GWAS studies. SNP were typed on a microarray. Variants in the HLA-DRB1 gene were identified by Sanger sequencing.

RESULTS

Multivariate predisposition to HT was modeled. Based on the investigated group, a model of seven variables was obtained. The variability explained by this model was assessed at only 5.4821% (p = 2 × 10^-6), which indicates that many dozens of factors are required simultaneously to explain HT predisposition.

CONCLUSIONS

We analyzed genetic regions commonly and most significantly associated with autoimmune thyroid disorders in the literature, on a carefully selected cohort. Our results indicated a lack of possibility to predict the risk of HT development, even with a multivariate model. We therefore conclude that strong associations of single genetic regions with HT should be interpreted with great caution. We believe that a change in the attitude towards genetic association analyses of HT predisposition is necessary. Studies including multiple factors simultaneously are needed to unravel the intricacies of genetic associations with HT.

Amiodarone and the thyroid

Amiodarone, a benzofuranic iodine-rich antiarrhythmic drug, causes thyroid dysfunction in 15-20% of cases. Amiodarone can cause both hypothyroidism (AIH, amiodarone-induced hypothyroidism) and thyrotoxicosis (AIT, amiodarone-induced thyrotoxicosis). AIH is treated by L-thyroxin replacement and does not need amiodarone discontinuation. There are two main forms of AIT: type 1, a form of true iodine-induced hyperthyroidism; and type 2, a drug-induced destructive thyroiditis. However, mixed/indefinite forms exist, contributed to by both pathogenic mechanisms. Type 1 AIT usually occurs in diseased thyroid glands, whereas type 2 AIT develops in substantially normal thyroid glands. Thioamides represent the first-line treatment for type 1 AIT, but iodine-replete glands are poorly responsive; sodium/potassium perchlorate, by inhibiting thyroidal iodine uptake, may increase the response to thioamides. Type 2 AIT is best treated by oral glucocorticoids. Response depends on thyroid volume and severity of thyrotoxicosis. Mixed/indefinite forms may require a combination of thioamides, potassium perchlorate, and steroids. Radioiodine treatment is usually not feasible because amiodarone-related iodine load decreases thyroidal radioiodine uptake. Thyroidectomy represents an important and helpful option in cases resistant to medical therapy. Surgery performed by a skilled surgeon may represent an emergent treatment in patients who have severe cardiac dysfunction.

A novel in-frame deletion in MEN1 (p.Ala416del) causes familial multiple endocrine neoplasia type 1 with an aggressive phenotype and unexpected inheritance pattern

The present study describes a family with multiple endocrine neoplasia type 1 (MEN1) caused by a previously undescribed in-frame deletion c.1246_1248delGCC (Ala416del) in the MEN1 gene. Evidence for the pathogenic character of this mutation, which triggers an aggressive clinical outcome, is demonstrated. Aggregation analysis in the tested family was strongly suggestive of causality of the detected mutation. This was supported by the analysis of LOH (loss of heterozygosity) in tumor-derived DNA and by computational analysis of the functional and structural implications of the mutation. Different phenotypic characteristics were identified among family members, which is typical for MEN1. Additionally, an unexpected disease inheritance pattern was observed in this kindred, in which either all or none of the siblings of one branch inherited the disease.

Glucagon-Like Peptide-1 Receptor Imaging with [Lys (40) (Ahx-HYNIC- (99 m) Tc/EDDA)NH 2 ]-Exendin-4 for the Diagnosis of Recurrence or Dissemination of Medullary Thyroid Cancer: A Preliminary Report

Introduction. Epidemiological studies on medullary thyroid cancer (MTC) have shown that neither a change in stage at diagnosis nor improvement in survival has occurred during the past 30 years. In patients with detectable serum calcitonin and no clinically apparent disease, a careful search for local recurrence, and nodal or distant metastases, should be performed. Conventional imaging modalities will not show any disease until basal serum calcitonin is at least 150 pg/mL. The objective of the study was to present the first experience with labelled glucagon-like peptide-1 (GLP-1) analogue [Lys(40)(Ahx-HYNIC-(99m)Tc/EDDA)NH2]-exendin-4 in the visualisation of MTC in humans. Material and Method. Four patients aged 22-74 years (two with sporadic and two with MEN2 syndrome-related disseminated MTC) were enrolled in the study. In all patients, GLP-1 receptor imaging was performed. Results. High-quality images were obtained in all patients. All previously known MTC lesions have been confirmed in GLP-1 scintigraphy. Moreover, one additional liver lesion was detected in sporadic MTC male patient. Conclusions. GLP-1 receptor imaging with [Lys(40)(Ahx-HYNIC-(99m)Tc/EDDA)NH2]-exendin-4 is able to detect MTC lesions. GLP-1 scintigraphy can serve as a confirmatory test in MTC patients, in whom other imaging procedures are inconsistent.

Glucagon-like peptide-1 receptor imaging with [Lys40(Ahx-HYNIC- 99mTc/EDDA)NH2]-exendin-4 for the detection of insulinoma

PURPOSE

The objective of this article is to present a new method for the diagnosis of insulinoma with the use of [Lys(40)(Ahx-HYNIC-(99m)Tc/EDDA)NH2]-exendin-4.

METHODS

Studies were performed in 11 patients with negative results of all available non-isotopic diagnostic methods (8 with symptoms of insulinoma, 2 with malignant insulinoma and 1 with nesidioblastosis). In all patients glucagon-like peptide-1 (GLP-1) receptor imaging (whole-body and single photon emission computed tomography/CT examinations) after the injection of 740 MBq of the tracer was performed.

RESULTS

Both sensitivity and specificity of GLP-1 receptor imaging were assessed to be 100 % in patients with benign insulinoma. In all eight cases with suspicion of insulinoma a focal uptake in the pancreas was found. In six patients surgical excision of the tumour was performed (type G1 tumours were confirmed histopathologically). In one patient surgical treatment is planned. One patient was disqualified from surgery. In one case with malignant insulinoma pathological accumulation of the tracer was found only in the region of local recurrence. The GLP-1 study was negative in the other malignant insulinoma patient. In one case with suspicion of nesidioblastosis, a focal accumulation of the tracer was observed and histopathology revealed coexistence of insulinoma and nesidioblastosis.

CONCLUSION

[Lys(40)(Ahx-HYNIC-(99m)Tc/EDDA)NH2]-exendin-4 seems to be a promising diagnostic tool in the localization of small insulinoma tumours, but requires verification in a larger series of patients.

Current and future medical therapy, and the molecular features of adrenocortical cancer

Adrenocortical carcinoma (ACC) is a rare neoplasm with very poor prognosis despite the recent development of aggressive antitumor therapies. The cause of adrenal cancer remains elusive, but some molecular mechanisms could be responsible for its development. Target-specific therapies have been developed for a number of human malignancies and have resulted in therapeutic benefits in some cancer patients. However, these therapies are only effective in cases in which the corresponding targets are expressed in tumor tissues. Molecular analysis has had a significant impact on the understanding of the pathogenetic mechanism of ACC development and the evaluation of prognostic and predictive markers, among which alterations of the IGF system, the Wnt pathway, p53 and molecules involved in cancer cell invasion properties and angiogenesis seem to be very promising. These molecular markers may not just play a role in the biology of these tumors and have prognostic implications, but can also be used as potential targets for treatment. The aim of this review is to summarize the genetic and molecular events implied in the pathogenesis of ACC and to highlight challenges to the development of anticancer agents in recent patents.

Repeated cycles of peptide receptor radionuclide therapy (PRRT)--results and side-effects of the radioisotope 90Y-DOTA TATE, 177Lu-DOTA TATE or 90Y/177Lu-DOTA TATE therapy in patients with disseminated NET

PURPOSE

PRRT is a known tool in the management of patients with disseminated and inoperable NETs. The aim of study was to assess the effectiveness of the repeated cycles of PRRT in patients with disseminated and inoperable NETs.

MATERIAL AND METHODS

Eighty nine patients were included in the PRRT. Among them 16 patients (18%) were qualified for a repeated PRRT cycle due to progression of the disease. In one of the patients qualified for the repeated cycle, PRRT was used as neoadjuvant therapy. The results and side-effects of the repeated cycles of PRRT were analyzed.

RESULTS

Disease stabilization was observed in 10 patients 6 months after the repeated PRRT cycle and in 5 patients after 12 and 18 months. Ten of the patients who had received repeated PRRT cycles died. In the case of neoadjuvant therapy, further reduction of the tumor size was observed, enabling qualification for surgery. Clinically significant reduction in the mean values of morphological parameters was not observed. Only after 12 and 18 months the mean values of creatinine levels were higher than the normal range (only in 2 patients).

CONCLUSIONS

The repeated cycles of PRRT did not cause a clinically significant increase of the toxicity of PRRT. The changes in kidney and blood morphology parameters were transient. The repeated cycles of PRRT enabled stabilization of the disease.

Efficacy and safety of 90Y-DOTATATE therapy in neuroendocrine tumours

BACKGROUND

The aim of this study was to assess the efficacy and toxicity of peptide receptor radionuclide therapy (PRRT) with the use of the high affinity somatostatin receptor subtype 2 analogue, (90)Y labelled Tyr3-octreotate, ((90)Y-DOTATATE) in neuroendocrine tumours (NETs).

MATERIAL AND METHODS

46 patients with disseminated or non-operable NET were enrolled in this study. The (90)Y-DOTATATE therapeutic activity was calculated per total body surface area up to a total of 7.4 GBq/m(2) administered in three to five cycles, repeated every four to nine weeks. Before and after the therapy, blood tests for haematology, kidney and liver function, and chromogranin A were performed.

RESULTS

Out of 46 (90)Y-DOTATATE treated patients, one died before completing the therapy and 16 died after completing the therapy, among them one due to myocardial infarction. After 12 month follow-up, stabilisation of disease was observed in 47%, partial remission in 31%, and progression in 9% of the 45 patients who completed the therapy. Five patients died before completion of 12 months of follow-up. One of the patients died due to myocardial infarction. In one case, the information after 12 months is incomplete. The progression free survival was 37.4 months. During 12 months follow-up, transient decrease of PLT, WBC and haemoglobin values was observed. A transient increase of creatinine level (within normal ranges) and decrease of GFR values were found.

CONCLUSIONS

NETs (90)Y-DOTATATE therapy results in symptomatic relief and tumour mass reduction. The mild critical organ toxicity does not limit the PRRT of NETs.

Graves' disease with an autonomously functioning thyroid nodule: case report

We present the case of a 68-year-old woman with Graves' disease, orbitopathy and an autonomously functioning thyroid nodule. Initially, the patient was diagnosed with orbitopathy as a sign of euthyroid Graves-Basedow's disease, confirmed by the presence of thyrotropin receptor antibodies. Five years later symptoms of hyperthyroidism occurred. Thyroid scan with iodine-131 (131I) showed a hot nodule in the right lobe. Recurrences of hyperthyroidism and short remissions were observed in the course of the disease - the symptoms typical of hyperthyroidism due to an autonomously functioning thyroid nodule. Fine needle aspiration biopsy of the nodule revealed no atypical follicular cells and the patient was scheduled for 131I treatment. She has been euthyroid for over one year.

Gene polymorphisms predisposing to cardiac hypertrophy in patients with cardiac syndrome X

Polymorphisms of the angiotensin-converting enzyme gene and endothelial nitric oxide synthase gene have been suggested to be associated with left ventricular hypertrophy. The aim of our study was to asses the association between above polymorphisms and left ventricular hypertrophy in patients with cardiac syndrome X. The presence of allele 4 of eNOS VNTR polymorphism could predispose to cardiac hypertrophy. The pathological course of postprandial lipemia in patients with CSX may add to the understanding of the CSX pathology.

[Diagnostic problems with recognition of primary hyperparathyroidism]

The aim of our study was to compare the results of biochemical and imaging investigations with histopathological diagnosis in operated patients with primary hyperparathyroidism. 46 subjects were included into the study, pathologically demonstrated as parathyroid adenoma--23 subjects, parathyroid hypertrophy--16, parathyroid carcinoma--2 and in 5 patients parathyroid gland was not found in resected tissue. The most frequent complications of primary hyperparathyroidism in our group were osteoporosis (87%) and nephrolithiasis (64.1%). 99mTc-MIBI imaging described as a parathyroid adenoma or parathyroid hypertrophy were confirmed pathologically in 52 and 57.1%, respectively. Three typical symptoms of primary hyperparathyroidism assessed in our study (hypercalcemia, hypercalciuria and increased concentration of parathormone) were observed only in about 50% patients with histopathological diagnosis of adenoma and hypertrophy. The lowest average calcium serum level (2.87 mmol/l), urinary calcium level (7.8 mmol/24h) and parathyroid hormone concentration (209.4 pg/ml) were observed in patients with parathyroid adenoma, the highest levels of these parameters were noticed in patients with parathyroid carcinoma (3.41 mmol/l; 14.6 mmol/24h; 687.8 pg/ml, respectively), patients with parathyroid adenoma were characterized by intermediate values (2.98 mmol/l; 9.7 mmol/24h; 285.5 pg/ml, respectively). After parathyroidectomy lowering in average calcium serum level (2.94 vs. 2.16 mmol/l), parathyroid hormone concentration (244.45 vs. 54.15 pg/ml) and increasing in average phosphate serum level (0.81 vs. 1.04 mmol/24h) were observed in our group. Finally, using different biochemical and imaging investigations is necessary for proper recognition of primary hyperparathyroidism due to occurring of oligosymptomatic cases.

[Changes in thyroid volume after radioactive iodine therapy in patients with single toxic thyroid nodule]

Radioactive iodine (131I) is a well-established therapeutic modality in the treatment of toxic solitary autonomous thyroid nodules. This method is preferred in patients with small, benign nodules. The aim of our study was to investigate the effects of radioiodine therapy on thyroid size in patients with a solitary toxic thyroid nodule. 22 patients with single nodule in USG and confirmed "hot" nodule in scintigraphy were enrolled in the study. Thyroid and nodule volume were determined by ultrasound before, 3 and 6 months after the administration of 131I. Thyroid function was assessed by TSH level prior to the treatment and 6 weeks after the therapy. Thyroid volume and nodule size decreased significantly within 3 and 6 months after 131I treatment. The mean reduction of thyroid volume within 6 month after treatment was 32%. Reduction in thyroid volume and nodule, size was significantly greater within first 3 months than within next 3 months. Patients with smaller nodules (less than 70% of thyroid volume) were characterized by greater reduction of goiter size than patients with nodules bigger or equal to 70% of thyroid volume.

[Preoperative diagnostics in patients with adrenal tumors]

The aim of the study was analysis of preoperative diagnostics of patients who underwent laparoscopic adrenalectomy. In the preoperative diagnostics in 10 patients (22.2%) pheochromocytoma was found, in 8 (17.8%) Conn's syndrome, in 4 (8.9%) Cushing's syndrome and in 1 (2.2%) adrenal virilization. Full accordance between histopathological findings and preoperative diagnosis was achieved in 91% of cases. Four cases of discrepancy were: 1 false positive preoperative diagnosis of aldosteronoma, 1 false positive and 2 false negative diagnosis of pheochromocytoma.