Cristina Lamas

RET Cys634Arg mutation confers a more aggressive multiple endocrine neoplasia type 2A phenotype than Cys634Tyr mutation

OBJECTIVE Specific germline mutations in the RET proto-oncogene are correlated with clinical features in multiple endocrine neoplasia type 2A (MEN2A); however, data are scarce regarding differences in clinical profiles dependent on the type of nucleotide and amino acid substitution at the same codon. We aimed to analyse differences in clinical risk profiles and outcomes among different amino acids encoded by codon 634. DESIGN The study was retrospective and multicentric. METHODS We collected data included in the Spanish Online National Database from patients with MEN2A carrying a RET proto-oncogene mutation on codon 634. The mean follow-up time was 7.6±6.9 years (1-32). RESULTS Patients (n=173) from 49 unrelated families were C634Y carriers, and 26 patients from eight different families had C634R mutation. We found higher penetrance of medullary thyroid carcinoma, phaeochromocytoma and hyperparathyroidism (P<0.001, P=0.007 and P<0.001 respectively) in C634R carriers than in C634Y carriers. The Kaplan-Meier estimate of cumulative lymph node and distant metastases rates showed that these events occurred earlier in patients harbouring the C634R mutation (P<0.001). A multivariate adjusted Cox regression analysis indicated that the C634R mutation was an independent factor for persistent/recurrent disease (hazard ratio, 3.17; 95% CI: 1.66-6.03; P<0.001). CONCLUSIONS Our results suggest that there could be clinical differences caused by different amino acid substitutions at codon 634; specifically, the C634R mutation was associated with a more aggressive MEN2A phenotype than the C634Y mutation.

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.

Guía clínica de manejo de la diabetes insípida y del síndrome de secreción inapropiada de hormona antidiurética en el postoperatorio de la cirugía hipofisaria

Changes in water metabolism and regulation of vasopressin (AVP) or antidiuretic hormone (ADH) are common complications of pituitary surgery. The scarcity of studies comparing different treatment and monitoring strategies for these disorders and the lack of prior clinical guidelines makes it difficult to provide recommendations following a methodology based on grades of evidence. This study reviews the pathophysiology of diabetes insipidus and inappropriate ADH secretion after pituitary surgery, and is intended to serve as a guide for their diagnosis, differential diagnosis, treatment, and monitoring.

Contribution of molecular analysis to the typification of the non-functioning pituitary adenomas

Aim The WHO Classification of Tumours of Endocrine Organs considers the inmunohistochemical characterization of pituitary adenomas (PA) as mandatory for patient diagnosis. Recent advances in the knowledge of the molecular patterns of these tumours could complement this classification with gene expression profiling. Methods Within the context of the Spanish Molecular Registry of Pituitary Adenomas (REMAH), a multicentre clinical-basic research project, we analysed the molecular phenotype of 142 PAs with complete IHC and clinical information. Gene expression levels of all pituitary hormones, type 1 corticotrophin-releasing hormone receptor, dopamine receptors and arginine vasopressin receptor 1b were measured by quantitative real-time polymerase chain reaction. In addition, we used three housekeeping genes for normalization and a pool of nine healthy pituitary glands from autopsies as calibration reference standard. Results Based on the clinically functioning PA (FPA: somatotroph, corticotroph, thyrotroph and lactotroph adenomas), we established the interquartile range of relative expression for all genes studied in each PA subtype. That allowed molecularly the different PA subtypes, including the clinically non-functioning PA (NFPA). Afterwards, we estimated the concordance of the molecular and immunohistochemical classification with clinical diagnosis in FPA and between them in NFPA. The kappa values were higher in molecular than in immunohistochemical classification in FPA and showed a bad concordance in all NFPA subtypes. Conclusions According to these results, the molecular characterization of the PA complements the IHC analysis, allowing a better typification of the NFPA.

Is it time to consider the expression of specific-pituitary hormone genes when typifying pituitary tumours?

The aim of the present study is to check whether we can replicate, in an independent series, previous results showing that the molecular study of pituitary-specific gene expression complements the inmunohistochemical identification of pituitary neuroendocrine tumours. We selected 112 patients (51 (46.4%) women; mean age 51.4±16 years; 102 macroadenomas (91.9%), 9 microadenomas (8.1%)) with complete clinical, radiological, immunohistochemical and molecular data from our data set of pituitary neuroendocrine tumours. Patients were different from those previously studied. We measured the expression of the pituitary-specific hormone genes and type 1 corticotrophin-releasing hormone and arginine vasopressin 1b receptors, by quantitative real-time polymerase chain reaction using TaqMan probes. Afterwards, we identified the different pituitary neuroendocrine tumour subtypes following the 2017 World Health Organization classification of pituitary tumours, calculating the concordance between their molecular and immuhistochemical identification. The concordance between molecular and immunohistochemical identification of functioning pituitary neuroendocrine tumours with the clinical diagnosis was globally similar to the previous series, where the SYBR Green technique was used instead of TaqMan probes. Our results also corroborated the poor correlation between molecular and immunohistochemical detection of the silent pituitary neuroendocrine tumour variants. This discrepancy was more remarkable in lactotroph, null-cell and plurihormonal pituitary neuroendocrine tumours. In conclusion, this study validates the results previously published by our group, highlighting a complementary role for the molecular study of the pituitary-specific hormone genes in the typification of pituitary neuroendocrine tumours subtypes.

Análisis de los resultados del tratamiento de la enfermedad de Cushing en los hospitales de Castilla-La Mancha

OBJECTIVE Treatment of Cushings disease poses interesting dilemmas in clinical practice. The aim of our study was to analyze the outcomes of the different treatments, the control and recurrence rates, and the complications derived from them. MATERIAL AND METHODS Data were collected from the clinical records of 22 patients over 18 years of age (86.4% women). They had been diagnosed with Cushings disease between 2000 and 2012, and were monitored at Complejo Hospitalario Universitario-Albacete, Hospital Virgen de la Salud-Toledo Hospital General Universitario de Ciudad Real, Hospital Virgen de la Luz-Cuenca, Hospital Nuestra Señora del Prado-Talavera de la Reina, and Complejo Hospitalario la Mancha Centro-Alcázar de San Juan. RESULTS Surgery was the treatment of choice in all patients. Biochemical cure was achieved in 72.2% of patients. Nine patients developed in the early postoperative period diabetes insipidus, which became in 2 patients only. Surprisingly, 3 patients with normal postoperative neurohypophyseal function later developed permanent diabetes insipidus. New hormone deficiencies occurred in 7 patients. Seventeen patients received ketoconazole before surgery (5 of them after surgery also), and 70% of them achieved normal urinary free cortisol levels. Three patients also received radiotherapy, and all of them were cured after a median follow-up of 85.5 months; they developed no tumors or other complications. CONCLUSIONS Our study reports the outcomes of management of Cushings disease in non-reference centers for this disease, possibly giving a realistic picture of standard clinical practice for the condition in Spain.

Incidentalomas suprarrenales: experiencia clínica en los hospitales de Castilla-La Mancha

Objetivo El manejo de las masas suprarrenales descubiertas de manera incidental (incidentalomas) sigue siendo controvertido. El objetivo de este trabajo es describir las caracteristicas demograficas y clinicas, asi como el manejo diagnostico-terapeutico, de una serie de pacientes con incidentalomas suprarrenales atendidos en los principales hospitales de Castilla-La Mancha. Material y metodos Los datos se recogieron mediante revision de historias clinicas. Resultados Se revisaron las historias clinicas de 270 pacientes (el 28,1% de Toledo, el 25,9% de Albacete, el 24,1% de Ciudad Real, el 15,9% de Cuenca y el 5,9% de Guadalajara), con media de edad de 60,3 ± 12 anos y de los que el 53,3% eran mujeres. El 80,6% presentaba sobrepeso u obesidad; el 55,8%, hipertension arterial; el 25,6%, diabetes mellitus; el 15,6%, alteracion de la glucemia en ayunas o intolerancia hidrocarbonada; el 31,5%, osteopenia, y el 20,4%, osteoporosis; estos porcentajes son similares en los pacientes con sindrome de Cushing subclinico. El 66% de los tumores median menos de 3 cm y el 14,3% mas de 4 cm. El 85% fueron detectados por tomografia computarizada. Tras una mediana de seguimiento de 28,8 meses el 6% de los adenomas no funcionantes evolucionaron a un sindrome de Cushing subclinico, en un 9,4% de los casos el diametro de la masa aumento mas de 1 cm y en un 8,9% aparecio una masa contralateral. El 14,4% de los pacientes se sometieron a suprarrenalectomia quirurgica. Conclusiones Nuestro estudio confirma la evolucion favorable de la mayoria de los pacientes con incidentalomas suprarrenales y contribuye a un mejor conocimiento de esta entidad clinica.