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Objective: Pheochromocytomas (PCCs) are neuroendocrine tumors that occur in the adrenal medulla, whereas paragangliomas (PGLs) arise from paraganglia in the head, neck, thorax, or abdomen. In a variety of tumors, cancer cells with stem cell-like properties seem to form the basis of tumor initiation because of their ability to self-renew and proliferate. Specifically targeting this small cell population may lay the foundation for more effective therapeutic approaches. In the present study, we intended to identify stem cells in PCCs/PGLs. Design:We examined the immunohistochemical expression of 11 stem cell markers (SOX2, LIN28, NGFR, THY1, PREF1, SOX17, NESTIN, CD117, OCT3/4, NANOG, and CD133) on tissue microarrays containing 208 PCCs/PGLs with different genetic backgrounds from five European centers. Results: SOX2, LIN28, NGFR, and THY1 were expressed in more than 10% of tumors, and PREF1, SOX17, NESTIN, and CD117 were expressed in !10% of the samples. OCT3/4, NANOG, and CD133 were not detectable at all. Double staining for chromogranin A/SOX2 and S100/SOX2 demonstrated SOX2 immunopositivity in both tumor and adjacent sustentacular cells. The expression of SOX2, SOX17, NGFR, LIN28, PREF1, and THY1 was significantly associated with mutations in one of the succinate dehydrogenase (SDH) genes. In addition, NGFR expression was significantly correlated with metastatic disease. Conclusion: Immunohistochemical expression of stem cell markers was found in a subset of PCCs/PGLs. Further studies are required to validate whether some stem cell-associated markers, such as SOX2, could serve as targets for therapeutic approaches and whether NGFR expression could be utilized as a predictor of malignancy. [ABSTRACT FROM AUTHOR]

Objective: Head-neck paragangliomas (HNPGLs) are rare tumors with approximately half arising due to germline pathogenic variants (PVs) in succinate dehydrogenase genes (SDHx). Patients with HNPGL have heterogeneous propensity to recur and metastasize. Thus, we aim to assess prevalence and predictors of recurrent (RD) and/or metastatic disease in patients with and without SDHx-related HNPGLs., Design and Methods: This cross-sectional study used retrospective data of 214 patients enrolled in six referral centers. Data included sex, age, primary tumor treatment, location, and size, biochemical phenotype, germline PVs, presence of RD (locoregional or new tumor), and/or metastasis., Results: Patients with and without SDHx-related HNPGLs showed 74% and 40% prevalence of RD, respectively. Patients without SDHx-related HNPGLs presented with recurrent tumors only in head-neck regions. The only independent predictor for RD in the entire cohort was presence of SDHx PVs. Metastatic prevalence reached 9%-13%. For patients with SDHx-related HNPGLs, large tumor size (>2.3 cm, OR:50.0, CI:2.6-977.6), young age at initial diagnosis (<42years, OR:27.3, CI:1.8-407.2), and presence of SDHB PV (OR:15.6; CI:1.5-164.8) were independent predictors of metastasis. For patients without SDHx-related HNPGLs, only carotid-body location was an independent predictor of metastasis (OR:18.9, CI:2.0-182.5)., Conclusions: Patients without SDHx-related HNPGLs require long-term follow-up due to high prevalence of RD with imaging largely restricted to head-neck regions. As carotid-body HNPGLs have the highest metastatic risk among sporadic tumors, radical treatment with frequent follow-up is suggested until population-based data are available. Importantly, patients with SDHx-related HNPGLs might benefit from early radical treatment when tumors are still small to reduce metastatic risk., Competing Interests: Conflict of interest: The authors have no conflicts of interest to declare., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Society of Endocrinology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Introduction: Growth hormone (GH)-secreting pituitary tumors (GHomas) are the most common acromegaly cause. At diagnosis, most of them are macroadenomas, and up to 56% display cavernous sinus invasion. Biomarker assessment associated with tumor growth and invasion is important to optimize their management., Objectives: The study aims to identify clinical/hormonal/molecular biomarkers associated with tumor size and invasiveness in GHomas and to analyze the influence of pre-treatment with somatostatin analogs (SSAs) or dopamine agonists (DAs) in key molecular biomarker expression., Methods: Clinical/analytical/radiological variables were evaluated in 192 patients from the REMAH study (ambispective multicenter post-surgery study of the Spanish Society of Endocrinology and Nutrition). The expression of somatostatin/ghrelin/dopamine system components and key pituitary/proliferation markers was evaluated in GHomas after the first surgery. Univariate/multivariate regression studies were performed to identify association between variables., Results: Eighty percent of patients harbor macroadenomas (63.8% with extrasellar growth). Associations between larger and more invasive GHomas with younger age, visual abnormalities, higher IGF1 levels, extrasellar/suprasellar growth, and/or cavernous sinus invasion were found. Higher GH1 and lower PRL/POMC/CGA/AVPR1B/DRD2T/DRD2L expression levels (P < .05) were associated with tumor invasiveness. Least Absolute Shrinkage and Selection Operator's penalized regression identified combinations of clinical and molecular features with areas under the curve between 0.67 and 0.82. Pre-operative therapy with DA or SSAs did not alter the expression of any of the markers analyzed except for DRD1/AVPR1B (up-regulated with DA) and FSHB/CRHR1 (down-regulated with SSAs)., Conclusions: A specific combination of clinical/analytical/molecular variables was found to be associated with tumor invasiveness and growth capacity in GHomas. Pre-treatment with first-line drugs for acromegaly did not significantly modify the expression of the most relevant biomarkers in our association model. These findings provide valuable insights for risk stratification and personalized management of GHomas., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Society of Endocrinology.)

Objective: The therapeutic options for metastatic pheochromocytomas/paragangliomas (mPPGLs) include chemotherapy with cyclophosphamide/vincristine/dacarbazine (CVD), temozolomide monotherapy, radionuclide therapies, and tyrosine kinase inhibitors such as sunitinib. The objective of this multicenter retrospective study was to evaluate and compare the responses of mPPGLs including those with pathogenic variants in succinate dehydrogenase subunit B (SDHB), to different systemic treatments., Design: This is a retrospective analysis of treatment responses of mPPGL patients (n = 74) to systemic therapies., Methods: Patients with mPPGLs treated at 6 specialized national centers were selected based on participation in the ENSAT registry. Survival until detected progression (SDP) and disease-control rates (DCRs) at 3 months were evaluated based on imaging reports., Results: For the group of patients with progressive disease at baseline (83.8% of 74 patients), the DCR with first-line CVD chemotherapy was 75.0% (n = 4, SDP 11 months; SDHB [n = 1]: DCR 100%, SDP 30 months), with somatostatin peptide receptor-based radionuclide therapy (PPRT) 85.7% (n = 21, SDP 17 months; SDHB [n = 10]: DCR 100%, SDP 14 months), with 131I-meta-iodobenzylguanidine (131I-MIBG) 82.6% (n = 23, SDP 43 months; SDHB [n = 4]: DCR 100%, SDP 24 months), with sunitinib 100% (n = 7, SDP 18 months; SDHB [n = 3]: DCR 100%, SDP 18 months), and with somatostatin analogs 100% (n = 4, SDP not reached). The DCR with temozolomide as second-line therapy was 60.0% (n = 5, SDP 10 months; SDHB [n = 4]: DCR 75%, SDP 10 months)., Conclusions: We demonstrate in a real-life clinical setting that all current therapies show reasonable efficacy in preventing disease progression, and this is equally true for patients with germline SDHB mutations., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of European Society of Endocrinology.)

Objective: Within the past decade, important genetic drivers of pheochromocytoma and paraganglioma (PPGLs) development have been identified. The pathophysiological mechanism that translates these alterations into functional autonomy and potentially malignant behavior has not been elucidated in detail. Here we used MALDI-mass spectrometry imaging (MALDI-MSI) of formalin-fixed paraffin-embedded tissue specimens to comprehensively characterize the metabolic profiles of PPGLs., Design and Methods: MALDI-MSI was conducted in 344 PPGLs and results correlated with genetic and phenotypic information. We experimentally silenced genetic drivers by siRNA in PC12 cells to confirm their metabolic impact in vitro., Results: Tissue abundance of kynurenine pathway metabolites such as xanthurenic acid was significantly lower (P = 2.35E-09) in the pseudohypoxia pathway cluster 1 compared to PPGLs of the kinase-driven PPGLs cluster 2. Lower abundance of xanthurenic acid was associated with shorter metastasis-free survival (log-rank tests P = 7.96E-06) and identified as a risk factor for metastasis independent of the genetic status (hazard ratio, 32.6, P = 0.002). Knockdown of Sdhb and Vhl in an in vitro model demonstrated that inositol metabolism and sialic acids were similarly modulated as in tumors of the respective cluster., Conclusions: The present study has identified distinct tissue metabolomic profiles of PPGLs in relation to tumor genotypes. In addition, we revealed significantly altered metabolites in the kynurenine pathway in metastatic PPGLs, which can aid in the prediction of its malignant potential. However, further validation studies will be required to confirm our findings.

Objective: Excess catecholamine release by pheochromocytomas and paragangliomas (PPGL) leads to characteristic clinical features and increased morbidity and mortality. The influence of PPGLs on metabolism is ill described but may impact diagnosis and management. The objective of this study was to systematically and quantitatively study PPGL-induced metabolic changes at a systems level., Design: Targeted metabolomics by liquid chromatography-tandem mass spectrometry of plasma specimens in a clinically well-characterized prospective cohort study., Methods: Analyses of metabolic profiles of plasma specimens from 56 prospectively enrolled and clinically well-characterized patients (23 males, 33 females) with catecholamine-producing PPGL before and after surgery, as well as measurement of 24-h urinary catecholamine using LC-MS/MS., Results: From 127 analyzed metabolites, 15 were identified with significant changes before and after surgery: five amino acids/biogenic amines (creatinine, histidine, ornithine, sarcosine, tyrosine) and one glycerophospholipid (PCaeC34:2) with increased concentrations and six glycerophospholipids (PCaaC38:1, PCaaC42:0, PCaeC40:2, PCaeC42:5, PCaeC44:5, PCaeC44:6), two sphingomyelins (SMC24:1, SMC26:1) and hexose with decreased levels after surgery. Patients with a noradrenergic tumor phenotype had more pronounced alterations compared to those with an adrenergic tumor phenotype. Weak, but significant correlations for 8 of these 15 metabolites with total urine catecholamine levels were identified., Conclusions: This first large prospective metabolomics analysis of PPGL patients demonstrates broad metabolic consequences of catecholamine excess. Robust impact on lipid and amino acid metabolism may contribute to increased morbidity of PPGL patients.

Objective: Our objective was to improve molecular diagnostics in patients with hereditary pheochromocytoma and paraganglioma (PPGL) by using next-generation sequencing (NGS) multi-gene panel analysis. Derived from this study, we here present three cases that were diagnosed with NF1 germline mutations but did not have a prior clinical diagnosis of neurofibromatosis type 1 (NF1)., Design: We performed genetic analysis of known tumor predisposition genes, including NF1 , using a multi-gene NGS enrichment-based panel applied to a total of 1029 PPGL patients. We did not exclude genes known to cause clinically defined syndromes such as NF1 based on missing phenotypic expression as is commonly practiced., Methods: Genetic analysis was performed using NGS (TruSight Cancer Panel/customized panel by Illumina) for analyzing patients' blood and tumor samples. Validation was carried out by Sanger sequencing., Results: Within our cohort, three patients, who were identified to carry pathogenic NF1 germline mutations, attracted attention, since none of the patients had a clinical suspicion of NF1 and one of them was initially suspected to have MEN2A syndrome due to co-occurrence of a medullary thyroid carcinoma. In these cases, one splice site, one stop and one frameshift mutation in NF1 were identified., Conclusions: Since phenotypical presentation of NF1 is highly variable, we suggest analysis of the NF1 gene also in PPGL patients who do not meet diagnostic NF1 criteria. Co-occurrence of medullary thyroid carcinoma and PPGL was found to be a clinical decoy in NF1 diagnostics. These observations underline the value of multi-gene panel NGS for PPGL patients., (© 2018 European Society of Endocrinology.)

Objective: Testing for succinate dehydrogenase subunit B (SDHB) mutations is recommended in all patients with metastatic phaeochromocytomas and paragangliomas (PPGLs), but may not be required when metastatic disease is accompanied by adrenaline production. This retrospective cohort study aimed to establish the prevalence of SDHB mutations among patients with metastatic PPGLs, characterised by production of adrenaline compared with those without production of adrenaline, and to establish genotype–phenotype features of metastatic PPGLs according to underlying gene mutations., Design and Methods: Presence of SDHB mutations or deletions was tested in 205 patients (114 males) aged 42+/-16 years (range 9–86 years) at diagnosis of metastatic PPGLs with and without adrenaline production., Results: Twenty-three of the 205 patients (11%) with metastatic PPGLs had disease characterised by production of adrenaline, as defined by increased plasma concentrations of metanephrine larger than 5% of the combined increase in both normetanephrine and metanephrine. None of these 23 patients had SDHB mutations. Of the other 182 patients with no tumoural adrenaline production, 51% had SDHB mutations. Metastases in bone were 36–41% more prevalent among patients with SDHB mutations or extra-adrenal primary tumours than those without mutations or with adrenal primary tumours. Liver metastases were 81% more prevalent among patients with adrenal than extra-adrenal primary tumours., Conclusion: SDHB mutation testing has no utility among patients with adrenaline-producing metastatic PPGLs, but is indicated in other patients with metastatic disease. Our study also reveals novel associations of metastatic spread with primary tumour location and presence of SDHB mutations.

Objective: The aim of this study was to investigate the presence of germline mutations in the CDKN1B gene that encodes the cyclin-dependent kinase (Cdk) inhibitor p27 in multiple endocrine neoplasia 1 (MEN1)-like Spanish index patients. The CDKN1B gene has recently been identified as a tumor susceptibility gene for MEN4, with six germline mutations reported so far in patients with a MEN-like phenotype but negative for MEN1 mutations., Design and Methods: Fifteen Spanish index cases with MEN-like symptoms were screened for mutations in the CDKN1B gene and the mutant variant was studied functionally by transcription/translation assays in vitro and in transiently transfected HeLa cells., Results: We report the identification of a heterozygous GAGA deletion in the 5'-UTR of CDKN1B, NM&#95;004064.3:c.-32&#95;-29del, in a patient affected by gastric carcinoid tumor and hyperparathyroidism. This deletion falls inside the region that is responsible for CDKN1B transcription and is predicted to destroy a secondary stem and loop structure that includes the GAGAGA element responsible for ribosome recruitment. Accordingly, in vitro studies of coupled transcription/translation assays and transient transfection in HeLa cells showed that the GAGA deletion in the CDKN1B 5'-UTR significantly impairs the transcription of downstream reporter luciferase (of ∼40-60%) and, possibly, the translation of the corresponding mRNA. This mutation was associated with a significant reduction in the amount of CDKN1B mRNA in peripheral blood leukocytes from the patient, as demonstrated by quantitative real-time PCR., Conclusions: Our results confirm that germline CDKN1B mutations may predispose to a human MEN4 condition and add novel evidence that alteration in the transcription/translation rate of CDKN1B mRNA might be the mechanism implicated in tumor susceptibility.