Javier Aller

Whole-Exome Sequencing Identifies MDH2 as a New Familial Paraganglioma Gene

Disruption of the Krebs cycle is a hallmark of cancer. IDH1 and IDH2 mutations are found in many neoplasms, and germline alterations in SDH genes and FH predispose to pheochromocytoma/paraganglioma and other cancers. We describe a paraganglioma family carrying a germline mutation in MDH2, which encodes a Krebs cycle enzyme. Whole-exome sequencing was applied to tumor DNA obtained from a man age 55 years diagnosed with multiple malignant paragangliomas. Data were analyzed with the two-sided Students t and Mann-Whitney U tests with Bonferroni correction for multiple comparisons. Between six- and 14-fold lower levels of MDH2 expression were observed in MDH2-mutated tumors compared with control patients. Knockdown (KD) of MDH2 in HeLa cells by shRNA triggered the accumulation of both malate (mean ± SD: wild-type [WT] = 1±0.18; KD = 2.24±0.17, P = .043) and fumarate (WT = 1±0.06; KD = 2.6±0.25, P = .033), which was reversed by transient introduction of WT MDH2 cDNA. Segregation of the mutation with disease and absence of MDH2 in mutated tumors revealed MDH2 as a novel pheochromocytoma/paraganglioma susceptibility gene.

Recommendations for somatic and germline genetic testing of single pheochromocytoma and paraganglioma based on findings from a series of 329 patients

Background Nowadays, 65–80% of pheochromocytoma and paraganglioma (PPGL) cases are explained by germline or somatic mutations in one of 22 genes. Several genetic testing algorithms have been proposed, but they usually exclude sporadic-PPGLs (S-PPGLs) and none include somatic testing. We aimed to genetically characterise S-PPGL cases and propose an evidence-based algorithm for genetic testing, prioritising DNA source. Methods The study included 329 probands fitting three criteria: single PPGL, no syndromic and no PPGL family history. Germline DNA was tested for point mutations in RET and for both point mutation and gross deletions in VHL, the SDH genes, TMEM127, MAX and FH. 99 tumours from patients negative for germline screening were available and tested for RET, VHL, HRAS, EPAS1, MAX and SDHB. Results Germline mutations were found in 46 (14.0%) patients, being more prevalent in paragangliomas (PGLs) (28.7%) than in pheochromocytomas (PCCs) (4.5%) (p=6.62×10−10). Somatic mutations were found in 43% of those tested, being more prevalent in PCCs (48.5%) than in PGLs (32.3%) (p=0.13). A quarter of S-PPGLs had a somatic mutation, regardless of age at presentation. Head and neck PGLs (HN-PGLs) and thoracic-PGLs (T-PGLs) more commonly had germline mutations (p=2.0×10−4 and p=0.027, respectively). Five of the 29 metastatic cases harboured a somatic mutation, one in HRAS. Conclusions We recommend prioritising testing for germline mutations in patients with HN-PGLs and T-PGLs, and for somatic mutations in those with PCC. Biochemical secretion and SDHB-immunohistochemistry should guide genetic screening in abdominal-PGLs. Paediatric and metastatic cases should not be excluded from somatic screening.

No clinically significant valvular regurgitation in long-term cabergoline treatment for prolactinoma.

An association between treatment for Parkinsons disease with certain dopaminergic drugs and development of cardiac valve impairment has been reported. Recent studies in hyperprolactinaemic patients treated with cabergoline (CAB) have shown either no significant findings or mild tricuspid regurgitation.

Escape and lipodystrophy in acromegaly during pegvisomant therapy, a retrospective multicentre Spanish study

Pegvisomant is an effective treatment for acromegaly.

Results of repeated transsphenoidal surgery in Cushing's disease. Long-term follow-up

OBJECTIVE Transsphenoidal surgery (TSS) is the treatment of choice for Cushings disease (CD). However, the best treatment option when hypercortisolism persists or recurs remains unknown. The aim of this study was to analyze the short and long-term outcome of repeat TSS in this situation and to search for response predictors. PATIENTS AND METHODS Data from 26 patients with persistent (n=11) or recurrent (n=15) hypercortisolism who underwent repeat surgery by a single neurosurgeon between 1982 and 2009 were retrospectively analyzed. Remission was defined as normalization of urinary free cortisol (UFC) levels, and recurrence as presence of elevated UFC levels after having achieved remission. The following potential outcome predictors were analyzed: adrenal status (persistence or recurrence) after initial TSS, tumor identification in imaging tests, degree of hypercortisolism before repeat TSS, same/different surgeon in both TSS, and time to repeat surgery. RESULTS Immediate postoperative remission was achieved in 12 patients (46.2%). Five of the 10 patients with available follow-up data relapsed after surgery (median time to recurrence, 13 months). New hormone deficiencies were seen in seven patients (37%), and two patients had cerebrospinal fluid leakage. No other major complications occurred. None of the preoperative factors analyzed was predictive of surgical outcome. CONCLUSIONS When compared to initial surgery, repeat TSS for CD is associated to a lower remission rate and a higher risk of recurrence and complications. Further studies are needed to define outcome predictors.

Influence of RET mutations on the expression of tyrosine kinases in medullary thyroid carcinoma

The therapeutic options for patients with metastatic medullary thyroid carcinoma (MTC) have recently increased due to the development of tyrosine kinase inhibitors (TKIs), some of which have achieved remarkable clinical responses in MTC patients. However, the molecular basis for the large variability in TKI responses is unknown. In this exploratory study, we investigated the expression of eight key TKI target proteins (EGFR, KIT, MET, PDGFRB, VEGF (VEGFA), VEGFR1 (FLT1), VEGFR2 (KDR), and VEGFR3 (FLT4)) by immunohistochemistry in 103 molecularly characterized MTC samples and identified the associated clinical and molecular features. A number of MTC samples exhibited a high expression of VEGFR2 and VEGFR3, which were overexpressed in 57 and 43% of the MTC samples respectively. VEGFR1, PDGFRB, VEGF, KIT, and MET were present in 34-20% of the cases, while EGFR was highly expressed in only 10% of the MTC samples. Some proteins exhibited large differences in expression between sporadic and familial cases, suggesting that different RET mutations may be associated with the immunohistochemical profiles. MTC samples with the C634 RET mutation exhibited a higher expression of VEGFR3 and KIT than the M918T RET-mutated and non-mutated RET tumor samples (P=0.005 and P=0.007 respectively) and a lower expression of VEGFR1 (P=0.04). Non-mutated RET MTC cases exhibited a lower expression of PDGFRB (P=0.04). Overall, this is the first study, to our knowledge, to show that multiple TKI targets are highly expressed in a subset of MTCs, suggesting that molecular stratification of patients may have the potential to improve TKI therapies for MTC.

PheoSeq: A Targeted Next-Generation Sequencing Assay for Pheochromocytoma and Paraganglioma Diagnostics

Genetic diagnosis is recommended for all pheochromocytoma and paraganglioma (PPGL) cases, as driver mutations are identified in approximately 80% of the cases. As the list of related genes expands, genetic diagnosis becomes more time-consuming, and targeted next-generation sequencing (NGS) has emerged as a cost-effective tool. This study aimed to optimize targeted NGS in PPGL genetic diagnostics. A workflow based on two customized targeted NGS assays was validated to study the 18 main PPGL genes in germline and frozen tumor DNA, with one of them specifically directed toward formalin-fixed paraffin-embedded tissue. The series involved 453 unrelated PPGL patients, of whom 30 had known mutations and were used as controls. Partial screening using Sanger had been performed in 275 patients. NGS results were complemented with the study of gross deletions. NGS assay showed a sensitivity ≥99.4%, regardless of DNA source. We identified 45 variants of unknown significance and 89 pathogenic mutations, the latter being germline in 29 (7.2%) and somatic in 58 (31.7%) of the 183 tumors studied. In 37 patients previously studied by Sanger sequencing, the causal mutation could be identified. We demonstrated that both assays are an efficient and accurate alternative to conventional sequencing. Their application facilitates the study of minor PPGL genes, and enables genetic diagnoses in patients with incongruent or missing clinical data, who would otherwise be missed.

Long-term treatment with pegvisomant for acromegaly: a 10-year experience.

Efficacy of the GH‐receptor antagonist pegvisomant (PEG) has differed between preclinical and observational studies mainly due to dose adjustment and IGF‐I normalization criteria. An escape phenomenon has also been described, but its definition and underlying causes have not been fully established.

A randomised, open-label, parallel group phase 2 study of antisense oligonucleotide therapy in acromegaly

Objective ATL1103 is a second-generation antisense oligomer targeting the human growth hormone (GH) receptor. This phase 2 randomised, open-label, parallel-group study assessed the potential of ATL1103 as a treatment for acromegaly. Design Twenty-six patients with active acromegaly (IGF-I >130% upper limit of normal) were randomised to subcutaneous ATL1103 200 mg either once or twice weekly for 13 weeks and monitored for a further 8-week washout period. Methods The primary efficacy measures were change in IGF-I at week 14, compared to baseline and between cohorts. For secondary endpoints (IGFBP3, acid labile subunit (ALS), GH, growth hormone-binding protein (GHBP)), comparison was between baseline and week 14. Safety was assessed by reported adverse events. Results and conclusions Baseline median IGF-I was 447 and 649 ng/mL in the once- and twice-weekly groups respectively. Compared to baseline, at week 14, twice-weekly ATL1103 resulted in a median fall in IGF-I of 27.8% (P = 0.0002). Between cohort comparison at week 14 demonstrated the median fall in IGF-I to be 25.8% (P = 0.0012) greater with twice-weekly dosing. In the twice-weekly cohort, IGF-I was still declining at week 14, and remained lower at week 21 than at baseline by a median of 18.7% (P = 0.0005). Compared to baseline, by week 14, IGFBP3 and ALS had declined by a median of 8.9% (P = 0.027) and 16.7% (P = 0.017) with twice-weekly ATL1103; GH had increased by a median of 46% at week 14 (P = 0.001). IGFBP3, ALS and GH did not change with weekly ATL1103. GHBP fell by a median of 23.6% and 48.8% in the once- and twice-weekly cohorts (P = 0.027 and P = 0.005) respectively. ATL1103 was well tolerated, although 84.6% of patients experienced mild-to-moderate injection-site reactions. This study provides proof of concept that ATL1103 is able to significantly lower IGF-I in patients with acromegaly.

Criterios para el diagnóstico y el control poscirugía de la acromegalia, y el cribado y el manejo de sus comorbilidades: recomendaciones de expertos

Acromegaly is a rare disease with many comorbidities that impair quality of life and limit survival. There are discrepancies in various clinical guidelines regarding diagnosis and postoperative control criteria, as well as screening and optimal management of comorbidities. This expert consensus was aimed at establishing specific recommendations for the Spanish healthcare system. The existing recommendations, the scientific evidence on which they are based, and the main controversies are reviewed. Unfortunately, the low prevalence and high clinical variability of acromegaly do not provide strong scientific evidences. To mitigate this disadvantage, a modified Delphi questionnaire, combining the best available scientific evidence with the collective judgment of experts, was used. The questionnaire, generated after a face-to-face debate, was completed by 17 Spanish endocrinologists expert in acromegaly. A high degree of consensus was reached (79.3%), as 65 of the total 82 statements raised were accepted. Some criteria for diagnosis and postoperative control were identified by this procedure. Regarding comorbidities, recommendations have been established or suggested for screening and management of oncological, cardiovascular, respiratory (sleep apnea), metabolic (dyslipidemia and diabetes), musculoskeletal, and hypopituitarism-related disorders. Consensus recommendations may facilitate and homogenize clinical care to patients with acromegaly in the Spanish health system.