L'adénome hypophysaire isolé dans le syndrome 3P (Pheochromocytoma, Paraganglioma, and Pituitary adenoma)

Thèse présentée sous la forme d'une "Thèse Article"Objective: Pituitary adenomas (PAs) can occur sporadically or less frequently be inherited. A syndromic association with PAs and pheochromocytoma/paraganglioma (PPGL), called “3PAs”, was recently described, and is sometimes associated with mutations in PPGL-predisposing genes such as SDHx or MAX. In “3PAs” patients, PAs can occur before PPGL. Our objective was to determine the prevalence of SDHx/MAX mutations in patients with isolated PAs and the characteristics of such patients.Design: Genes involved in PAs (AIP/MEN1/CDKN1B) or PPGLs (SDHx/MAX) were sequenced using next-generation sequencing in patients with isolated PAs. Next, we conducted a review of the published cases of PAs in the setting of “3PAs”.Results: A total of 263 patients were recruited. Seven pathogenic or likely pathogenic variants were found in AIP, 2 in MEN1, 2 in SDHA, and 1 in SDHC. The prevalence of SDHx mutations reached 1.1% (3/263). Among the thirty patients with PAs harbouring SDHx/MAX (27 from the literature and 3 from this study), 6/30 (20%) developed PAs before PPGL, and 8/30 (26.7%) had isolated PAs. Sixteen presented a familial history of PPGL/PA. The PA was a macroprolactinoma in the majority of cases and occurred at an older age than AIP/MEN1-mutated patients.Conclusion: we found for the first time SDHx mutations in patients bearing PAs without any familial or personal PPGL history suggesting a new gateway into SDHx related diseases.Nevertheless, a genetic screening of SDHx remains not justified in case of isolated PAs, except if a familial history of PPGL is present. Further studies are justified to clarify whether SDHx could be new candidate genes, particularly in familial isolated (macro)prolactinomas.Contexte : les adénomes hypophysaires peuvent survenir de façon sporadique ou moins fréquemment être héréditaires. Une association syndromique entre adénome hypophysaire et phéochromocytome/paragangliome (PPGL), nommée « 3PAs » a récemment été décrite et est parfois associée à des mutations des gènes de prédisposition aux PPGL tels que SDHx ou MAX. Chez les patients « 3PAs », l’adénome hypophysaire peut survenir avant le PPGL. Notre objectif est de déterminer la prévalence des mutations de SDHx/MAX chez les patients porteurs d’un PA isolé et les caractéristiques de ces patients.Objectif : nous avons séquencé par séquençage haut-débit les gènes impliqués dans les adénomes hypophysaires (AIP/MEN1/CDKN1B) ou les PPGLs (SDHx/MAX) chez des patients avec un adénome hypophysaire isolé. Par la suite, nous avons réalisé une revue des cas publiés de d’adénomes hypophysaires rentrant dans le cadre du syndrome « 3PAs ».Résultats : nous avons recruté 263 patients. Sept variants pathogéniques ou probablement pathogéniques ont été retrouvés dans AIP, 2 dans MEN1, 2 dans SDHA et 1 dans SDHC. La prévalence des mutations de SDHx atteignait 1.1% (3/263). Parmi les 30 patients avec un adénome hypophysaire portant une mutation de SDHx/MAX (27 dans la littérature et 3 dans notre étude), 6/30 (20%) ont développé leur adénome hypophysaire avant le PPGL et 8/30 (26.7%) présentaient un adénome hypophysaire isolé. Seize avaient un antécédent familial d’adénome hypophysaire ou de PPGL. L’âge de survenue de l’adénome hypophysaire était plus élevé chez ces patients que chez les patients mutés AIP/MEN1. Ils avaient plus de macroadénomes que les patients contrôlés, en particulier de macroprolactinomes.Conclusion : nous avons trouvé pour la première fois, des mutations de SDHx chez des patients présentant un adénome hypophysaire sans antécédent familial ou personnel de PPGL, suggérant une nouvelle porte d’entrée dans les pathologies liées aux gènes SDHx/MAX. Néanmoins, un dépistage génétique de SDHx reste non justifié dans le cas d’adénomes hypophysaires isolés, à l’exception de la présence d’un antécédent familial de PPGL. D’autres études sont nécessaires pour clarifier si les gènes SDHx peuvent être de nouveaux gènes candidats, en particulier dans les (macro)prolactinomes familiaux

Cation–Cation Complexes of Pentavalent Uranyl: From Disproportionation Intermediates to Stable Clusters

International audienceAbstract Three new cation–cation complexes of pentavalent uranyl, stable with respect to the disproportionation reaction, have been prepared from the reaction of the precursor [(UO 2 py 5 )(KI 2 py 2 )] n ( 1 ) with the Schiff base ligands salen 2− , acacen 2− , and salophen 2− (H 2 salen= N , N ′‐ethylene‐bis(salicylideneimine), H 2 acacen= N , N ′‐ethylenebis(acetylacetoneimine), H 2 salophen= N , N ′‐phenylene‐bis(salicylideneimine)). The preparation of stable complexes requires a careful choice of counter ions and reaction conditions. Notably the reaction of 1 with salophen 2− in pyridine leads to immediate disproportionation, but in the presence of [18]crown‐6 ([18]C‐6) a stable complex forms. The solid‐state structure of the four tetranuclear complexes, {[UO 2 (acacen)] 4 [μ 8 ‐] 2 [K([18]C‐6)(py)] 2 } ( 3 ) and {[UO 2 (acacen)] 4 [μ 8 ‐]} ⋅ 2 [K([222])(py)] ( 4 ), {[UO 2 (salophen)] 4 [μ 8 ‐K] 2 [μ 5 ‐KI] 2 [(K([18]C‐6)]} ⋅ 2 [K([18]C‐6)(thf) 2 ] ⋅ 2 I ( 5 ), and {[UO 2 (salen) 4 ][μ 8 ‐Rb] 2 [Rb([18]C‐6)] 2 } ( 9 ) ([222]=[222]cryptand, py=pyridine), presenting a T‐shaped cation–cation interaction has been determined by X‐ray crystallographic studies. NMR spectroscopic and UV/Vis studies show that the tetranuclear structure is maintained in pyridine solution for the salen and acacen complexes. Stable mononuclear complexes of pentavalent uranyl are also obtained by reduction of the hexavalent uranyl Schiff base complexes with cobaltocene in pyridine in the absence of coordinating cations. The reactivity of the complex [U V O 2 (salen)(py)][Cp* 2 Co] with different alkali ions demonstrates the crucial effect of coordinating cations on the stability of cation–cation complexes. The nature of the cation plays a key role in the preparation of stable cation–cation complexes. Stable tetranuclear complexes form in the presence of K + and Rb + , whereas Li + leads to disproportionation. A new uranyl–oxo cluster was isolated from this reaction. The reaction of [U V O 2 (salen)(py)][Cp* 2 Co] (Cp*=pentamethylcyclopentadienyl) with its U VI analogue yields the oxo‐functionalized dimer [UO 2 (salen)(py)] 2 [Cp* 2 Co] ( 8 ). The reaction of the {[UO 2 (salen) 4 ][μ 8 ‐K] 2 [K([18]C‐6)] 2 } tetramer with protons leads to disproportionation to U IV and U VI species and H 2 O confirming the crucial role of the proton in the U V disproportionation

Early Detection of Relapse by ctDNA Sequencing in a Patient with Metastatic Thymic Tumor and MEN1 Mosaicism

International audienceAbstract Context Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disease caused by inactivating mutations in the MEN1 gene. In the literature, few cases of MEN1 have been reported because of mosaic MEN1 mutations. Objective We performed an extensive molecular characterization in several lesions and blood samples, including plasmatic circulating cell-free DNA (ccfDNA) in an exceptional case of a patient with MEN1 mosaicism causing primary hyperparathyroidism, multiple pancreatic neuroendocrine tumors (NETs), and a metastatic thymic NET. Methods Blood, ccfDNA and multiple tissue analysis were performed by next-generation sequencing. Results MEN1 mosaicism was confirmed by multiple tissue analysis. Somatic analysis of the largest pancreatic NET revealed the same MEN1 second-hit mutation as found in the thymic lesion, demonstrating its metastatic origin from the thymic lesion. Moreover, in ccfDNA we found the mosaic MEN1 mutation but also the somatic second-hit mutation found in the thymic primary tumor, revealing the presence of circulating tumor DNA (ctDNA). After surgical removal of the pancreatic metastasis, the mutated fraction of both mutations decreased, before increasing again several weeks before a new clinical relapse, suggesting that thymic ctDNA may be used as an early tumor biomarker. Conclusion This exceptional MEN1 case highlighted (1) the importance of looking for MEN1 mosaicism, (2) that MEN1 mosaicism can cause very aggressive disease, and (3) the interest in analyzing ccfDNA for confirming MEN1 mosaicism but also as a potential tumor biomarker for NET

Germinal defects of SDHx genes in patients with isolated pituitary adenoma

International audienceThe ‘3PAs’ syndrome, associating pituitary adenoma (PA) and pheochromocytoma/paraganglioma (PPGL), is sometimes associated with mutations in PPGL-predisposing genes, such as SDHx or MAX . In ’3PAs’ syndrome, PAs can occur before PPGL, suggesting a new gateway into SDHx/MAX- related diseases. Objective: To determine the SDHx/MAX mutation prevalence in patients with isolated PAs and characterize PAs of patients with SDHx/MAX mutations. Design: Genes involved in PAs ( AIP/MEN1/CDKN1B ) or PPGLs ( SDHx/MAX ) were sequenced in patients with isolated PAs. We then conducted a review of cases of PA in the setting of ’3PAs’ syndrome. Results: A total of 263 patients were recruited. Seven (likely) pathogenic variants were found in AIP , two in MEN1 , two in SDHA , and one in SDHC . The prevalence of SDHx mutations reached 1.1% (3/263). Of 31 reported patients with PAs harboring SDHx/MAX mutations (28 published cases and 3 cases reported here), 6/31 (19%) developed PA before PPGL and 8/31 (26%) had isolated PA. The age of onset was later than in patients with AIP/MEN1 mutations. PAs were mainly macroprolactinomas and showed intracytoplasmic vacuoles seen on histopathology. Conclusions: We discovered SDHx mutations in patients bearing PA who had no familial or personal history of PPGL. However, the question of incidental association remains unresolved and data to determine the benefit of SDHx/MAX screening in these patients are lacking. We recommend that patients with isolated PA should be carefully examined for a family history of PPGLs. A family history of PPGL, as well as the presence of intracytoplasmic vacuoles in PA, requires SDHx/MAX genetic testing of patients

Characterization of the ability of a, second-generation SST-DA chimeric molecule, TBR-065, to suppress GH secretion from human GH-secreting adenoma cells

International audienceSomatostatin (SST) and dopamine (DA) inhibit growth hormone (GH) secretion and proliferation of GH-secreting pituitary adenomas (GHomas) through binding to SSTR2 and D2R receptors. Chimeric SST-DA compounds (Dopastatins) display increased potency in inhibiting GH secretion, as compared with individual SST or DA analogs (alone or combined)

Systematic detection of mosaicism by using digital NGS reveals three new MEN1 mosaicisms

International audiencePurpose Mosaicism is a feature of several inherited tumor syndromes. Only a few cases of mosaicism have been described in multiple endocrine neoplasia type 1 (MEN1). Next-generation sequencing (NGS) offers new possibilities for detecting mosaicism. Here, we report the first study to systematically look for MEN1 mosaicism, using blood DNA, in MEN1-suspected patients but without MEN1 pathogenic variants (PV) in a heterozygous state. Methods Digital targeted NGS, including unique molecular identifiers (UMIs), was performed in routine practice, and the analytic performance of this method was verified. Results Among a cohort of 119 patients harboring from 2 to 5 MEN1 lesions, we identified 3 patients with MEN1 mosaic PVs. The allele frequencies ranged from 2.3 to 9.5%. The detection rate of MEN1 mosaicism in patients bearing at least 3 MEN1 lesions was 17% (3/18). No cases were detected in patients with two lesions. Conclusion We report here three new cases with MEN1 mosaicism. This study examined the performance of UMI in the diagnosis of MEN1 mosaicism in routine practice, and our results underline that the frequency of mosaicism is probably underestimated in patients with suspected MEN1

Role of 3D volume growth rate for drug activity evaluation in meningioma clinical trials: the example of the CEVOREM study

International audienceAbstract Background We aimed to improve the assessment of the drug activity in meningioma clinical trials based on the study of the 3D volume growth rate (3DVGR) in a series of aggressive meningiomas. We secondarily aimed to correlate 3DVGR study with patient outcome. Methods We performed a post hoc analysis based on volume data and 3DVGR extracted from CEVOREM study including 18 patients with 32 recurrent high-grade meningiomas and treated with everolimus and octreotide. The joint latent class model was used to classify tumor 3DVGR undertreatment. Results Class 1 includes lesions responding to treatment with decrease in volume in the first 3 months, and then a stabilization thereafter (9.5% of tumors) (mean pretreatment 3DVGR = 6.13%/month; mean undertreatment 3DVGR = −18.7%/month within 3 first months and −0.14%/month after the 3 first months). Class 2 includes lesions considered as stable or with a slight increase in volume undertreatment (65.5%) (mean pretreatment 3DVGR = 6.09%/month; undertreatment 3DVGR = −0.09% within the first 3 months). Class 3 includes lesions without 3DVGR decrease (25%) (mean pretreatment 3DVGR = 46.9%/month; mean undertreatment 3DVGR = 19.2%/month within the first 3 months). Patients with class 3 lesions had a significantly worse progression-free survival (PFS) rate than class 1 and 2 ones. Conclusions Tumor 3DVGR could be helpful to detect early signal of drugs antitumoral activity or nonactivity. This volume response classification could help in the assessment of drug activity in tumors with mostly volume stabilization and rare response as aggressive meningiomas even with a low number of patients in complement to 6 months PFS

Somatotroph Tumors and the Epigenetic Status of the GNAS Locus

International audienceBackground: Forty percent of somatotroph tumors harbor recurrent activating GNAS mutations, historically called the gsp oncogene. In gsp-negative somatotroph tumors, GNAS expression itself is highly variable; those with GNAS overexpression most resemble phenotypically those carrying the gsp oncogene. GNAS is monoallelically expressed in the normal pituitary due to methylation-based imprinting. We hypothesize that changes in GNAS imprinting of gsp-negative tumors affect GNAS expression levels and tumorigenesis. Methods: We characterized the GNAS locus in two independent somatotroph tumor cohorts: one of 23 tumors previously published (PMID: 31883967) and classified by pan-genomic analysis, and a second with 82 tumors. Results: Multi-omics analysis of the first cohort identified a significant difference between gsp-negative and gsp-positive tumors in the methylation index at the known differentially methylated region (DMR) of the GNAS A/B transcript promoter, which was confirmed in the larger series of 82 tumors. GNAS allelic expression was analyzed using a polymorphic Fok1 cleavage site in 32 heterozygous gsp-negative tumors. GNAS expression was significantly reduced in the 14 tumors with relaxed GNAS imprinting and biallelic expression, compared to 18 tumors with monoallelic expression. Tumors with relaxed GNAS imprinting showed significantly lower SSTR2 and AIP expression levels. Conclusion: Altered A/B DMR methylation was found exclusively in gsp-negative somatotroph tumors. 43% of gsp-negative tumors showed GNAS imprinting relaxation, which correlated with lower GNAS, SSTR2 and AIP expression, indicating lower sensitivity to somatostatin analogues and potentially aggressive behavior

Multiple endocrine neoplasia type 1 caused by mosaic mutation: clinical follow-up and genetic counseling?

International audienceMEN1 is an autosomal dominant hereditary syndrome characterized by several endocrine tumors, in most cases affecting the parathyroid glands, pancreas, and anterior pituitary. It is the result of inactivating mutations in the tumor suppressor gene MEN1. More than 1300 different mutations have been identified in this gene. Mosaic MEN1 mutations have been previously described in only a few patients in the literature. In this paper, we provide a review of six cases of MEN1 mosaicism reported in the literature supplemented with six additional cases described by the French TENgen network of laboratories. This review highlights that (i) MEN1 mosaicism is not associated with a mild phenotype and results in the same natural history as heterozygous MEN1 mutation and (ii) that more systematic detection of MEN1 mosaic mutation enables improvements in both patient monitoring and genetic counseling