Context:Telomerase promoter mutations (TERT) were recently described in follicular cell-derived thyroid carcinomas (FCDTC) and seem to be more prevalent in aggressive cancers.Objectives:We aimed to evaluate the frequency of TERT promoter mutations in thyroid lesions and to investigate the prognostic significance of such mutations in a large cohort of patients with differentiated thyroid carcinomas (DTCs).Design:This was a retrospective observational study.Setting and Patients:We studied 647 tumors and tumor-like lesions. A total of 469 patients with FCDTC treated and followed in five university hospitals were included. Mean follow-up (±SD) was 7.8 ± 5.8 years.Main Outcome Measures:Predictive value of TERT promoter mutations for distant metastasization, disease persistence at the end of follow-up, and disease-specific mortality.Results:TERT promoter mutations were found in 7.5% of papillary carcinomas (PTCs), 17.1% of follicular carcinomas, 29.0% of poorly differentiated carcinomas, and 33.3% of anaplastic thyroid carcinomas. Patients with TERT-mutated tumors were older (P < .001) and had larger tumors (P = .002). In DTCs, TERT promoter mutations were significantly associated with distant metastases (P < .001) and higher stage (P < .001). Patients with DTC harboring TERT promoter mutations were submitted to more radioiodine treatments (P = .009) with higher cumulative dose (P = .004) and to more treatment modalities (P = .001). At the end of follow-up, patients with TERT-mutated DTCs were more prone to have persistent disease (P = .001). TERT promoter mutations were significantly associated with disease-specific mortality [in the whole FCDTC (P < .001)] in DTCs (P < .001), PTCs (P = .001), and follicular carcinomas (P < .001). After adjusting for age at diagnosis and gender, the hazard ratio was 10.35 (95% confidence interval 2.01–53.24; P = .005) in DTC and 23.81 (95% confidence interval 1.36–415.76; P = .03) in PTCs.Conclusions:TERT promoter mutations are an indicator of clinically aggressive tumors, being correlated with worse outcome and disease-specific mortality in DTC. TERT promoter mutations have an independent prognostic value in DTC and, notably, in PTC.

Cancer stem cells are a subpopulation of cells within a tumour believed to confer resistance to standard cancer therapies. Although many studies have addressed the specific mechanisms of tumour recurrence driven by cancer stem cells, cellular metabolism is an often-neglected attribute. The metabolic features of cancer stem cells are still poorly understood, and they thus constitute a promising field in cancer research. The findings published so far point to a distinct metabolic phenotype in cancer stem cells, which might depend on the cancer type, the model system used or even the experimental design, and several controversies still need to be tackled. This Review describes the metabolic phenotype of cancer stem cells by addressing the main metabolic traits in different tumours, including glycolysis and oxidative, glutamine, fatty acid and amino acid metabolism. In the context of these pathways, we also mention the specific alterations in metabolic enzymes and metabolite levels that have a role in the regulation of cancer stemness. Determining the role of metabolism in supporting resistance to therapy driven by cancer stem cells can raise the opportunity for novel therapeutic targets, which might not only eliminate this resistant population, but, more importantly, eradicate the whole tumour in a relapse-free scenario.

Human hotspot TERT promoter (TERTp) mutations have been reported in a wide range of tumours. Several studies have shown that TERTp mutations are associated with clinicopathological features; in some instances, TERTp mutations were considered as biomarkers of poor prognosis. The rs2853669 SNP, located in the TERT promoter region, was reported to modulate the increased TERT expression levels induced by the recurrent somatic mutations. In this study we aimed to determine the frequency and prognostic value of TERTp mutations and TERT rs2853669 SNP in 504 gliomas from Portuguese and Brazilian patients. TERTp mutations were detected in 47.8% of gliomas (216/452). Glioblastomas (GBM) exhibited the highest frequency of TERTp mutations (66.9%); in this glioma subtype, we found a significant association between TERTp mutations and poor prognosis, regardless of the population. Moreover, in a multivariate analysis, TERTp mutations were the only independent prognostic factor. Our data also showed that the poor prognosis conferred by TERTp mutations was restricted to GBM patients

Mitochondria are central organelles for cellular metabolism. In cancer cells, mitochondrial oxidative phosphorylation (OXPHOS) dysfunction has been shown to promote migration, invasion, metastization and apoptosis resistance. With the purpose of analysing the effects of OXPHOS dysfunction in cancer cells and the molecular players involved, we generated cybrid cell lines harbouring either wild-type (WT) or mutant mitochondrial DNA (mtDNA) [tRNAmut cybrids, which harbour the pathogenic A3243T mutation in the leucine transfer RNA gene (tRNAleu)]. tRNAmut cybrids exhibited lower oxygen consumption and higher glucose consumption and lactate production than WT cybrids. tRNAmut cybrids displayed increased motility and migration capacities, which were associated with altered integrin-β1 N-glycosylation, in particular with higher levels of β-1,6-N-acetylglucosamine (GlcNAc) branched N-glycans. This integrin-β1 N-glycosylation pattern was correlated with higher levels of membrane-bound integrin-β1 and also with increased binding to fibronectin. When cultured in vitro, tRNAmut cybrids presented lower growth rate than WT cybrids, however, when injected in nude mice, tRNAmut cybrids produced larger tumours and showed higher metastatic potential than WT cybrids. We conclude that mtDNA-driven OXPHOS dysfunction correlates with increased motility and migration capacities, through a mechanism that may involve the cross talk between cancer cell mitochondria and the extracellular matrix.

Pheochromocytomas (PCC) and sympathetic paragangliomas (PGL) are rare neuroendocrine tumors, which derive from chromaffin cells occurring in the adrenal medulla and extra-adrenal sympathetic paraganglia. PCC and PGL are often benign, catecholamine-producing tumors, responsible for a myriad of symptoms that may be potentially hazardous to the patient. In contrast, nonsecreting parasympathetic PGL, derived from chief cells, develop mainly in the head and neck region. Although PCC/PGL are more commonly sporadic tumors, germline mutations are present in up to 40% of the patients, ranking these tumors among those with the highest degree of heritability. PCC/PGL are associated with a variety of hereditary syndromes, comprising genetic alterations in RET, NF1, VHL, and SDHx genes, the last 2 being involved in regulating the hypoxia pathway. Additional hypoxia pathway-related genes have been recently associated with PCC/PGL development, namely EGLN1 and EPAS1. Thus, dysregulation of the hypoxia pathway seems to play a major role in PCC/PGL development, in particular through the stabilization of hypoxia-inducible factors and the appearance of a pseudohypoxia signature. This article is focused on reviewing the tumorigenic mechanisms resultant from VHL, SDHx, EGLN1, and EPAS1 mutations, as well as the associated tumors, namely PCC/PGL, and extra manifestations such as polycythemia. In the light of the recent discoveries, hypoxia pathway molecules appear as key players in PCC/PGL development.