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Rationale : Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors that present variable outcomes. To date, no effective therapies or reliable prognostic markers are available for patients who develop metastatic PPGL (mPPGL). Our aim was to discover robust prognostic markers validated through in vitro models, and define specific therapeutic options according to tumor genomic features. Methods : We analyzed three PPGL miRNome datasets (n=443), validated candidate markers and assessed them in serum samples (n=36) to find a metastatic miRNA signature. An integrative study of miRNome, transcriptome and proteome was performed to find miRNA targets, which were further characterized in vitro . Results : A signature of six miRNAs (miR-21-3p, miR-183-5p, miR-182-5p, miR-96-5p, miR-551b-3p, and miR-202-5p) was associated with metastatic risk and time to progression. A higher expression of five of these miRNAs was also detected in PPGL patients' liquid biopsies compared with controls. The combined expression of miR-21-3p/miR-183-5p showed the best power to predict metastasis (AUC=0.804, P =4.67·10 -18 ), and was found associated in vitro with pro-metastatic features, such as neuroendocrine-mesenchymal transition phenotype, and increased cell migration rate. A pan-cancer multi-omic integrative study correlated miR-21-3p levels with TSC2 expression, mTOR pathway activation, and a predictive signature for mTOR inhibitor-sensitivity in PPGLs and other cancers. Likewise, we demonstrated in vitro a TSC2 repression and an enhanced rapamycin sensitivity upon miR-21-3p expression. Conclusions : Our findings support the assessment of miR-21-3p/miR-183-5p, in tumors and liquid biopsies, as biomarkers for risk stratification to improve the PPGL patients' management. We propose miR-21-3p to select mPPGL patients who may benefit from mTOR inhibitors.

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.

Introduction: The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that began in Wuhan (China), that spread rapidly worldwide, seriously affecting the population leading to a public health emergency declared by the World Health Organization. It is unknown how SARS-CoV-2 infection can affect thyroid function. In this study, we describe the characteristics of an unusual analytical interference that may explain the false detection of hypothyroidism in patients with SARS-CoV-2 infection. This is the first time that a phenomenon of this nature has been described in patients with COVID-19 and underlying thyroid dysfunction. Material and Methods: Observational study of patients admitted for severe COVID-19 infection and underlying thyroid disease. Results: TSH levels presented an atypical pattern different from that of Euthyroid Sick Syndrome (ESS), confirmed by the lack of response to substitution treatment. We develop different studies to confirm or eliminate potential interferences, being diagnosed of a possible macro-TSH. Conclusion: It is important to consider that in patients with COVID-19 and high concentrations of TSH and thyroid hormones within reference ranges with lack of response to treatment, one of the possible causes to consider is the presence of macro-TSH. The presence of macro-TSH interference in COVID-19 patients requires extreme precautions to avoid errors in diagnosis or treatment (replacement dose adjustment) in patients with hypothyroidism secondary to an underlying disease.