Pheochromocytomas and paragangliomas are highly vascular tumors of the autonomic nervous system. Germline mutations, including those in hypoxia-related genes, occur in one third of the cases, but ...somatic mutations are infrequent in these tumors. Using exome sequencing of six paired constitutive and tumor DNA from sporadic pheochromocytomas and paragangliomas, we identified a somatic mutation in the HIF2A (EPAS1) gene. Screening of an additional 239 pheochromocytomas/paragangliomas uncovered three other HIF2A variants in sporadic (4/167, 2.3%) but not in hereditary tumors or controls. Three of the mutations involved proline 531, one of the two residues that controls HIF2α stability by hydroxylation. The fourth mutation, on Ser71, was adjacent to the DNA binding domain. No mutations were detected in the homologous regions of the HIF1A gene in 132 tumors. Mutant HIF2A tumors had increased expression of HIF2α target genes, suggesting an activating effect of the mutations. Ectopically expressed HIF2α mutants in HEK293, renal cell carcinoma 786-0, or rat pheochromocytoma PC12 cell lines showed increased stability, resistance to VHL-mediated degradation, target induction, and reduced chromaffin cell differentiation. Furthermore, mice injected with cells expressing mutant HIF2A developed tumors, and those with Pro531Thr and Pro531Ser mutations had shorter latency than tumors from mice with wild-type HIF2A. Our results support a direct oncogenic role for HIF2A in human neoplasia and strengthen the link between hypoxic pathways and pheochromocytomas and paragangliomas.
Metastatic pheochromocytomas and paragangliomas (PPGLs) are frequently associated with skeletal complications.
Primary objective: to describe the frequency of adverse skeletal related events (SREs) ...in PPGL patients with bone metastases (BMs). Secondary objectives: to 1) identify predictive and prognostic factors for SREs and 2) obtain information on the effectiveness of bone resorption inhibitors in reducing SRE risk and improving outcomes in term of survival and SREs time onset.
In this retrospective multicenter, multinational study, 294 PPGL patients were enrolled.
SREs occurred in 90 patients (31 %). Fifty-five patients (19 %) had bone fractures, 47 (16 %) had spinal cord compression, and 11 (4 %) had hypercalcemia. Twenty-two patients (7 %) had more than one SRE. Sixty-four patients (22 %) underwent surgery, and 136 (46 %) underwent radiotherapy. SREs occurred a median of 4.4 months after diagnosis of BM (range, 0–246.6 months). Independent factors associated with reduced risk of SREs in multivariable analysis were I-131-MIBG radionuclide therapy (hazard ratio HR, 0.536 95 % CI, 0.309–0.932; P = .027) and absence of liver metastases (HR, 0.638 95 % CI, 0.410–0.992; P = .046). The median overall survival duration was 5.3 year. In multivariable analysis, age younger than 48 years at PPGL diagnosis (HR, 0.558 95 % CI, 0.3877–0.806; P = .002), absence of liver metastases (HR, 0.618 95 % CI, 0.396–0.965; P = .034), treatment with bisphosphonates or denosumab (HR, 0.598 95 % CI, 0.405–0.884; P = .010), and MIBG radionuclide therapy (HR, 0.444 95 % CI, 0.274–0.718; P = .001) were associated with a reduced risk of death.
SREs occur frequently and early in bone-metastatic PPGL patients but do not negatively impact survival. MIBG radionuclide therapy and treatment with bone resorption inhibitors are associated with favorable outcome.
•What is the SREs frequency in PPGL with BM?•Retrospective multicenter study: 31 % of PPGL patients with BM experienced SREs.•mOS was 5 years, with 67 % of SREs occurring within the first year of BM diagnosis.•Prognosis was not negatively affected by SREs.•SREs are observed frequently and early in patients with PPGL who have BM.
Abstract
Context
Limited information is available concerning the genetic spectrum of pheochromocytoma and paraganglioma (PPGL) patients in South America. Germline SDHB large deletions are very rare ...worldwide, but most of the individuals harboring the SDHB exon 1 deletion originated from the Iberian Peninsula.
Objective
Our aim was to investigate the spectrum of SDHB genetic defects in a large cohort of Brazilian patients with PPGLs.
Methods
Genetic investigation of 155 index PPGL patients was performed by Sanger DNA sequencing, multiplex ligation-dependent probe amplification, and/or target next-generation sequencing panel. Common ancestrality was investigated by microsatellite genotyping with haplotype reconstruction, and analysis of deletion breakpoint.
Results
Among 155 index patients, heterozygous germline SDHB pathogenic or likely pathogenic variants were identified in 22 cases (14.2%). The heterozygous SDHB exon 1 complete deletion was the most frequent genetic defect in SDHB, identified in 8 out of 22 (36%) of patients. Haplotype analysis of 5 SDHB flanking microsatellite markers demonstrated a significant difference in haplotype frequencies in a case-control permutation test (P = 0.03). More precisely, 3 closer/informative microsatellites were shared by 6 out of 8 apparently unrelated cases (75%) (SDHB-GATA29A05-D1S2826-D1S2644 | SDHB-186-130-213), which was observed in only 1 chromosome (1/42) without SDHB exon 1 deletion (X2 = 29.43; P < 0.001). Moreover, all cases with SDHB exon 1 deletion had the same gene breakpoint pattern of a 15 678 bp deletion previously described in the Iberian Peninsula, indicating a common origin.
Conclusion
The germline heterozygous SDHB exon 1 deletion was the most frequent genetic defect in the Brazilian PPGL cohort. Our findings demonstrated a founder effect for the SDHB exon 1 deletion in Brazilian patients with paragangliomas.
The role for hormone parameters at adrenal venous sampling (AVS) in predicting clinical and biochemical outcome remains controversial.
To investigate the impact of hormone parameters at AVS under ...cosyntropin stimulation on lateralization and on complete biochemical and clinical outcome.
We retrospectively evaluated 150 sequential AVS under cosyntropin infusion. Bilateral successful cannulation rate was 83.3% (n = 140), 47.9% bilateral and 52.1% unilateral. The lateralization index (LI), aldosterone/cortisol ratio (A/C) in the dominant adrenal vein (AV), relative aldosterone secretion index (RASI = A/C in AV divided by A/C in inferior vena cava) were assessed. The contralateral suppression (CS) percentage was defined by (1 - nondominant RASI) *100.
A nondominant RASI <0.5 (CS >50%) had 86.84% sensitivity and 92.96% specificity to predict contralateral lateralization. An A/C ratio in dominant AV >5.9 (74.67% sensitivity and 80% specificity) and dominant RASI >4.7 (35.21% sensitivity and 88.06% specificity) had a worst performance to predict ipsilateral lateralization. Complete biochemical and clinical cure were significantly more frequent in the patients with CS >50% 98.41% vs. 42.86% (p < 0.001) and 41.94% vs. 0% (p < 0.001). CS correlated with high aldosterone at diagnosis (p < 0.001) and low postoperative aldosterone levels at 1 month (p = 0.019). Postoperative biochemical hypoaldosteronism was more frequent in patients with CS >50% (70% vs. 16.67%, p = 0.014). In multivariable analysis, a CS >50% was associated with complete biochemical cure (OR 125, 95%CI 11.904-5,000; p = 0.001) and hypertension remission (OR 12.19, 95%CI 2.074-250; p = 0.023).
A CS >50% was an independent predictor of complete clinical and biochemical cure. Moreover, it can predict unilateral PA and postoperative biochemical hypoaldosteronism. Our findings underscore the usefulness of CS for clinical decision-making.
Objective
Few and conflicting reports have characterized the genetics of paediatric pheochromocytomas and paragangliomas (PPGLs). This study aimed to investigate the clinical and genetic features of ...Brazilian children with PPGL.
Patients and Methods
This study included 25 children (52% girls) with PPGL. The median age at diagnosis was 15 years (4‐19). The median time of follow‐up was 145 months. The genetic investigation was performed by Sanger DNA sequencing, multiplex ligation‐dependent probe amplification and/or target next‐generation sequencing panel.
Results
Of the 25 children with PPGL, 11 (44%), 4 (16%), 2 (8%), 1 (4%) and 7 (28%) had germline VHL pathogenic variants, SDHB, SDHD, RET and negative genetic investigation, respectively. Children with germline VHL missense pathogenic variants were younger than those with SDHB or SDHD genetic defects median (range), 12 (4‐16) vs. 15.5 (14‐19) years; P = .027. Moreover, 10 of 11 cases with VHL pathogenic variants had bilateral pheochromocytoma (six asynchronous and four synchronous). All children with germline SDHB pathogenic variants presented with abdominal paraganglioma (one of them malignant). The two cases with SDHD pathogenic variants presented with head and neck paraganglioma. Among the cases without a genetic diagnosis, 6 and 2 had pheochromocytoma and paraganglioma, respectively. Furthermore, metastatic PPGL was diagnosed in four (16%) of 25 PPGL.
Conclusions
Most of the paediatric PPGL were hereditary and multifocal. The majority of the affected genes belong to pseudohypoxic cluster 1, with VHL being the most frequently mutated. Therefore, our findings impact surgical management and surveillance of children with PPGL.
Few studies demonstrated a percentage decrease in the estimated glomerular filtration rate (eGFR) at a single time and the rate of hypoaldosteronism after adrenalectomy for primary aldosteronism ...(PA). Our aim was to investigate the evolution of renal function and the hypoaldosteronism risk after adrenalectomy for PA. Aldosterone, renin, eGFR, and electrolyte levels were determined before and at 1 week, 1, 3 and 6 months after unilateral adrenalectomy in 94 PA patients (40 men and 54 women). The main outcome was the postoperative eGFR decline using analysis of covariance with the preoperative eGFR as a covariate. eGFR decreased during first postoperative week compared to 3 months before surgery. During the first 6 months, eGFR remained stable at similar levels to the first week after surgery. Age (p=0.001), aldosterone levels (p=0.021) and eGFR 3 months before surgery (p+<+0.0001) had a significant correlation with eGFR during first postoperative week. High aldosterone levels at diagnosis were correlated with decline in renal function in the univariate model (p=0.033). In the multivariate analysis, aldosterone levels at diagnosis had a tendency to be an independent predictor of renal function after surgery (p=0.059). Postoperative biochemical hypoaldosteronism was diagnosed in 48% of the cases after adrenalectomy, but prolonged hyperkalemia occurred in only 4 cases (4.5%). Our findings showed a decrease of eGFR after unilateral adrenalectomy for PA. Additionally, aldosterone levels at diagnosis correlated with postoperative renal function. Postoperative biochemical hypoaldosteronism occurred in almost half of the patients, but prolonged hyperkalemia with fludrocortisone replacement was less frequent.
Familial primary aldosteronism (PA) is rare and mostly diagnosed in early-onset hypertension (HT). However, 'sporadic' bilateral adrenal hyperplasia (BAH) is the most frequent cause of PA and remains ...without genetic etiology in most cases. Our aim was to investigate new genetic defects associated with BAH and PA. We performed whole-exome sequencing (paired blood and adrenal tissue) in six patients with PA caused by BAH that underwent unilateral adrenalectomy. Additionally, we conducted functional studies in adrenal hyperplastic tissue and transfected cells to confirm the pathogenicity of the identified genetic variants. Rare germline variants in phosphodiesterase 2A (PDE2A) and 3B (PDE3B) genes were identified in three patients. The PDE2A heterozygous variant (p.Ile629Val) was identified in a patient with BAH and early-onset HT at 13 years of age. Two PDE3B heterozygous variants (p.Arg217Gln and p.Gly392Val) were identified in patients with BAH and HT diagnosed at 18 and 33 years of age, respectively. A strong PDE2A staining was found in all cases of BAH in zona glomerulosa and/or micronodules (that were also positive for CYP11B2). PKA activity in frozen tissue was significantly higher in BAH from patients harboring PDE2A and PDE3B variants. PDE2A and PDE3B variants significantly reduced protein expression in mutant transfected cells compared to WT. Interestingly, PDE2A and PDE3B variants increased SGK1 and SCNN1G/ENaCg at mRNA or protein levels. In conclusion, PDE2A and PDE3B variants were associated with PA caused by BAH. These novel genetic findings expand the spectrum of genetic etiologies of PA.
Confirmatory tests represent a fundamental step in primary aldosteronism (PA) diagnosis, but they are laborious and often require a hospital environment due to the risks involved.
To evaluate the ...efficacy of oral furosemide as a new confirmatory test for PA diagnosis.
We prospectively evaluated the diagnostic performance of 80 mg of oral furosemide in 64 patients with PA and 22 with primary hypertension (controls). Direct renin concentration (DRC) was measured before, and 2 hours and 3 hours after the oral furosemide. In addition, the oral furosemide test was compared with 2 other confirmatory tests: the furosemide upright test (FUT) and saline infusion test (SIT) or captopril challenge test (CCT) in all patients with PA.
The cut-off of 7.6 µU/mL for DRC at 2 hours after oral furosemide had a sensitivity of 92%, specificity of 82%, and accuracy of 90% for PA diagnosis. In 5 out of 6 controls with low-renin hypertension, which might represent a PA spectrum, renin remained suppressed. Excluding these 6 controls with low-renin hypertension, the DRC cut-off of 10 µU/mL at 2 hours after oral furosemide had a sensitivity of 95.3%, specificity of 93.7% and accuracy of 95% for PA diagnosis. DRC after 3 hours of oral furosemide did not improve diagnostic performance. Using the cut-off of 10 µU/mL, the oral furosemide test and the FUT were concordant in 62 out of 64 (97%) patients with PA. Only 4 out of 64 cases with PA (6.4%) ended the oral furosemide test with potassium <3.5 mEq/L. Hypotension was not evidenced in any patient with PA during the test.
The oral furosemide test was safe, well-tolerated and represents an effective strategy for PA investigation.
Von Hippel-Lindau (VHL) disease is an autosomal dominant syndrome caused by germline mutations in the
gene. Guidelines recommend pheochromocytoma (PHEO) biochemical screening should start at age 5 ...years.
Genotype-phenotype correlations in VHL, focusing on PHEO penetrance in children, were studied.
We retrospectively evaluated 31 individuals (median age at diagnosis was 26 years) with diagnosed VHL disease.
PHEO was diagnosed in six children with VHL. A large PHEO (5 cm) was detected in a 4-year-old boy with p.Gly114Ser mutation. PHEO penetrance was 55% starting at age 4 years.
missense mutations were identified in 11 of 22 families (50%), frameshift mutations in four (18.2%), stop codon in three (13.6%), splicing site in two (9.1%), and large gene deletion in two (9.1%). The codon 167 (n = 10) was a hotspot for
mutations and was significantly associated with PHEO (90%
38%;
= 0.007). PHEOs and pancreatic neuroendocrine tumors (PNETs) were strongly associated with
missense mutations compared with other mutations (89.5%
0% and 73.7%
16.7%;
= 0.0001 and 0.002, respectively). In contrast, pancreatic cysts (91.7%
26.3%;
= 0.0001), renal cysts (66.7%
26.3%;
= 0.027), and central nervous system hemangioblastomas (91.7%
47.3%;
= 0.012) were more frequent in VHL with nonmissense mutations.
missense mutations were highly associated with PHEO and PNETs. Our data support that in children with VHL harboring missense mutations, biochemical screening for PHEO should be initiated at diagnosis.
Context: Previous studies have shown that double RET mutations may be associated with unusual multiple endocrine neoplasia type 2 (MEN 2) phenotypes.
Objective: Our objective was to report the ...clinical features of patients harboring a previously unreported double mutation of the RET gene and to characterize this mutation in vitro.
Patients: Sixteen patients from four unrelated families and harboring the C634Y/Y791F double RET germline mutation were included in the study.
Results: Large pheochromocytomas measuring 6.0–14 cm and weighing up to 640 g were identified in the four index cases. Three of the four tumors were bilateral. High penetrance of pheochromocytoma was also seen in the C634Y/Y791F-mutation-positive relatives (seven of nine, 77.7%). Of these, two cases had bilateral tumors, one presented with multifocal tumors, two cases had large tumors (>5 cm), and one case, which was diagnosed with a large (5.5 × 4.5 × 4.0 cm) pheochromocytoma, reported early onset of symptoms of the disease (14 yr old). The overall penetrance of pheochromocytoma was 84.6% (11 of 13). Development of medullary thyroid carcinoma in our patients seemed similar to that observed in patients with codon 634 mutations. Haplotype analysis demonstrated that the mutation did not arise from a common ancestor. In vitro studies showed the double C634Y/Y791F RET receptor was significantly more phosphorylated than either activated wild-type receptor or single C634Y and Y791F RET mutants.
Conclusions: Our data suggest that the natural history of the novel C634Y/Y791F double mutation carries a codon 634-like pattern of medullary thyroid carcinoma development, is associated with increased susceptibility to unusually large bilateral pheochromocytomas, and is likely more biologically active than each individual mutation.
A novel double RET germline mutation identified in four unrelated MEN 2A families with very high penetrance of pheochromocytoma is characterized in vitro.