Telomerase Reverse Transcriptase Mutations Research Articles

TERT mutation in glioma: Frequency, prognosis and risk

Telomerase reverse transcriptase (TERT) has received a great deal of attention in recent years for its role as a prognostic and predictive molecular marker of glioma. However, the results of studies examining its mutation frequency and predictive value are inconsistent, and several studies have investigated the association between TERT gene polymorphisms and gliomagenesis. We used a meta-analysis approach to examine these unsolved problems. A bibliography search using EMBASE and MEDLINE was performed to identify potentially relevant articles and conference abstracts that investigated TERT mutations in glioma. The references contained in the identified trials were also examined to identify any other relevant published or unpublished articles. Sixteen studies were included. Pooled estimates of the relative risks (RR), 95% confidence intervals (95% CI), hazard ratios (HR) and frequency were calculated. TERT mutations occurred frequently in glioblastoma (69%) and oligodendrogliomas (72%) but were less frequent in astrocytomas (24%) and oligoastrocytomas (38%). The HR for glioma patients with TERT mutations versus wild type TERT was 1.63 (95% CI 1.35–1.98). TERT polymorphisms were associated with an increased risk of glioma compared to controls (RR=1.28, 95% CI 1.23–1.33). Our study shows that the TERT gene is a valuable prognostic and predictive biomarker of glioma, and TERT gene polymorphisms are significantly associated with an increased risk of glioma.

Low Prevalence of Somatic TERT Promoter Mutations in Classic Papillary Thyroid Carcinoma.

BackgroundTranscriptional activating mutations of telomerase reverse transcriptase (TERT) are associated with more aggressive thyroid cancer. We evaluated the significance of TERT promoter mutations in Korean patients with classic papillary thyroid cancer (PTC).MethodsGenomic DNA was isolated from four thyroid cancer cell lines and 35 fresh-frozen PTC tissues. TERT promoter mutations (C228T and C250T) and the BRAF V600E mutation were evaluated by polymerase chain reaction amplification and direct sequencing.ResultsThe CC228229TT mutation in the TERT promoter was detected in BCPAP cells and the C250T mutation was found in 8505C cells. No TERT promoter mutation was observed in Cal-62 or ML-1 cells. The C228T mutation was found in only 1 of 35 (2.8%) PTCs and no C250T mutations were detected in any of the study subjects. The BRAF V600E mutation was found in 20 of 35 (57.1%) PTCs. One patient with the C228T TERT mutation also harbored the BRAF V600E mutation and developed a recurrence.ConclusionThe prevalence of somatic TERT promoter mutations was low in Korean patients with classic PTC. Therefore, the prognostic role of TERT promoter mutations might be limited in this patient cohort.

Gene mutations, chromosome aberrations and prognosis of uveal melanoma

Incidence of Uveal melanoma (UM), is only secondary to cutaneous melanoma and is common primary intraocular malignant tumor of in adults.Recent studies suggest that its occurrence is related with gene mutation, chromosome aberrations and molecular pathway abnormalities.The mutations include GNAQ gene, GNA11 gene, microRNA (miRNA) (miR-34a, miR-182, miR-137). Mutations of GNAQ gene and GNA11 gene activate relevant pathways, such as MEK/ATK pathway, to promote UM metastasis, which makes the poor prognosis.Different miRNAs target the correspending genes and affect the prognosis.And the mutations of telomerase reverse transcriptase, all of them adjust the specific molecular pathways to affect tumor occurrence, development, metastasis and prognosis.Molecular genetic studies confirm that most patients with UM have chromosome 1, 3, 6, 8, 9 alterations, making the chromosome gain or less, leading to more susceptible invasion and metastasis and influencing prognosis.This paper reviewed the gene mutation and chromosome aberrations in order to provide new targets for the treatment of UM. Key words: Uveal melanoma; Gene mutation; Chromosome aberrations; GNAQ gene; GNA11 gene

Hotspot TERT promoter mutations are rare events in testicular germ cell tumors.

The abnormal activation of telomerase, codified by the telomerase reverse transcriptase (TERT) gene, is related to one of cancer hallmarks. Hotspot somatic mutations in the promoter region of TERT, specifically the c.-124:C>T and c.-146:C>T, were recently identified in a range of human cancers and have been associated with a more aggressive behavior. Testicular germ cell tumors frequently exhibit a good prognosis; however, the development of refractory disease is still a clinical challenge. In this study, we aim to evaluate for the first time the presence of the hotspot telomerase reverse transcriptase gene promoter mutations in testicular germ cell tumors. A series of 150 testicular germ cell tumor cases and four germ cell tumor cell lines were evaluated by PCR followed by direct Sanger sequencing and correlated with patient's clinical pathological features. Additionally, we genotyped the telomerase reverse transcriptase gene promoter single nucleotide polymorphism rs2853669 (T>C) located at -245 position. We observed the presence of the TERT promoter mutation in four patients, one exhibited the c.-124:C>T and three the c.-146:C>T. No association between TERT mutation status and clinicopathological features could be identified. The analysis of the rs2853669 showed that variant C was present in 22.8% of the cases. In conclusion, we showed for the first time that TERT promoter mutations occur in a small subset (~3%) of testicular germ cell tumors.

Frequent TERT Promoter Mutations in Ocular Surface Squamous Neoplasia.

Ocular surface squamous neoplasia, including intraepithelial neoplasia (CIN) and invasive squamous cell carcinoma (SCC), are one of the most common malignant tumors of the conjunctiva. Little is known of the genetic alterations involved in their pathogenesis. Promoter mutations in telomerase reverse transcriptase (TERT) have been identified in various cancers, including many associated with ultraviolet (UV) exposure. Our study analyzes the mutation rate and clinicopathological associations of TERT promoter mutations in ocular surface squamous neoplasia. DNA was isolated and the region of the TERT promoter where hotspot mutations can occur analyzed by Sanger-sequencing in 48 ocular surface squamous neoplasia tumor samples (6 CIN and 42 SCC). An analysis of associations between TERT promoter mutation status and various clinicopathological parameters was performed. We identified TERT promoter mutations in 21 of 48 ocular surface squamous neoplasia samples (43.8%), including 4 in CIN and 17 in SCC. The mutations consisted of 8 Chr.5:1295228C>T, 1 Chr.5:1295228_1295229CC>TT, 5 Chr.5:1295242_1295243CC>TT, and 12 Chr.5:1295250C>T mutations. All mutations were C>T or CC>TT alterations, demonstrating a UV-signature. TERT promoter mutations showed no statistically significant associations with clinicopathological parameters. Telomerase reverse transcriptase promoter mutations are found in almost half of ocular surface squamous neoplasias and have a mutation profile supporting UV induction as the major source of mutagenesis. We conclude that UV induced TERT promoter mutations leading to aberrant overexpression of telomerase is a major pathogenetic factor in ocular surface squamous neoplasia.

Preoperative Assessment of TERT Promoter Mutation on Thyroid Core Needle Biopsies Supports Diagnosis of Malignancy and Addresses Surgical Strategy.

In the last decade, several molecular markers have been proposed to improve the diagnosis of thyroid nodules. Among these, mutations in the telomerase reverse transcriptase (TERT) promoter have been correlated to malignant tumors, characterized by highest recurrence and decreased patients' survival. This suggests an important role of TERT mutational analysis in the clinical diagnosis and management of thyroid cancer patients. The aim of the study was to demonstrate the adequacy of core needle biopsy (CNB) for the preoperative assessment of TERT mutational status, to reach a more accurate definition of malignancy and a more appropriate surgical planning. Indeed, CNB is gaining momentum for improving diagnosis of thyroid nodules deemed inconclusive by fine needle aspirate (FNA). The study included 50 patients submitted to CNB due to inconclusive FNA report. TERT mutational status was correlated with BRAF mutation, definitive histology, and post-operative TNM staging of the neoplasia. C228T mutation of the TERT promoter was reported in 10% of the papillary carcinomas (PTC) series. When compared with final histology, all cases harboring TERT mutation resulted as locally invasive PTCs. The prevalence of TERT mutated cases was 17.6% among locally advanced PTCs. TERT analysis on CNB allows the assessment of the pathological population on paraffin sections before DNA isolation, minimizing the risk of false negatives due to poor sampling that affects FNA, and gathering aggregate information about morphology and TERT mutational status. Data indicating a worse outcome of the tumor might be used to individualize treatment decision, surgical option, and follow-up design.

Tall cell papillary thyroid carcinoma: new diagnostic criteria and mutations in BRAF and TERT.

The tall cell (TC) variant of papillary thyroid carcinoma (PTC) has an unfavorable prognosis. The diagnostic criteria remain inconsistent, and the role of a minor TC component is unclear. Molecular diagnostic markers are not available; however, there are two potential candidates: BRAF V600E and telomerase reverse transcriptase (TERT) promoter mutations. Using a novel approach, we enriched a collective with PTCs that harbored an adverse outcome, which overcame the limited statistical power of most studies. This enabled us to review 125 PTC patients, 57 of which had an adverse outcome. The proportion of TCs that constituted a poor prognosis was assessed. All of the tumors underwent sequencing for TERT promoter and BRAF V600E mutational status and were stained with an antibody to detect the BRAF V600E mutation. A 10% cutoff for TCs was significantly associated with advanced tumor stage and lymph node metastasis. Multivariate analysis showed that TCs above 10% were the only significant factor for overall, tumor-specific, and relapse-free survival. Seven percent of the cases had a TERT promoter mutation, whereas 61% demonstrated a BRAF mutation. The presence of TC was significantly associated with TERT promoter and BRAF mutations. TERT predicted highly significant tumor relapse (P<0.001). PTCs comprised of at least 10% TCs are associated with an adverse clinical outcome and should be reported accordingly. BRAF did not influence patient outcome. Nevertheless, a positive status should encourage the search for TCs. TERT promoter mutations are a strong predictor of tumor relapse, but their role as a surrogate marker for TCs is limited.

O071 : Telomerase reverse transcriptase mutations are associated with hepatocellular carcinoma in nash

O071 TELOMERASE REVERSE TRANSCRIPTASE MUTATIONS ARE ASSOCIATED WITH HEPATOCELLULAR CARCINOMA IN NASH B. Donati, E. Vanni, P. Dongiovanni, M. Iavarone, R. Rametta, C. Rosso, A. Carnelutti, S. Petta, A.L. Fracanzani, H.L. Reeves, J.F. Dofour, L. Miele, Q. Anstee, E. Bugianesi, G. Soardo, S. Fargion, L. Valenti. Pathophysiology and Transplantation, Universita degli Studi di Milano, Milano, Medical Sciences, University of Turin, Turin, Internal Medicine, Gastroenterology, Fondazione IRCCS Ca’ Granda, Milano, Internal Medicine, University of Udine, Udine, Gastroenterology, University of Palermo, Palermo, Italy; Medicine, Freeman Hospital, Newcastle Upon Tyne, United Kingdom; Clinical Research, University of Bern, Bern, Switzerland; Internal Medicine, Catholic University, Rome, Italy; Cellular Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom; Gastroenterology, University of Turin, Turin, Italy E-mail: donatibenedetta@gmail.com

Molecular alterations in endometrial and ovarian clear cell carcinomas: clinical impacts of telomerase reverse transcriptase promoter mutation

Recently, mutations of telomerase reverse transcriptase (TERT) promoter were found in several types of cancer. A few reports demonstrate TERT promoter mutations in ovarian clear cell carcinomas but endometrial clear cell carcinoma has not been studied. The aims of this study were to compare differences of molecular alterations and clinical factors, and identify their prognostic impact in endometrial and ovarian clear cell carcinomas. We evaluated mutations of the TERT promoter and PIK3CA, expression of ARID1A, and other clinicopathological factors in 56 ovarian and 14 endometrial clear cell carcinomas. We found that TERT promoter mutations were present in 21% (3/14) of endometrial clear cell carcinomas and 16% (9/56) of ovarian clear cell carcinomas. Compared with ovarian clear cell carcinomas, endometrial clear cell carcinomas showed older mean patient age (P<0.001), preserved ARID1A immunoreactivity (P=0.017) and infrequent PIK3CA mutation (P=0.025). In ovarian clear cell carcinomas, TERT promoter mutations were correlated with patient age >45 (P=0.045) and preserved ARID1A expression (P=0.003). In cases of endometrial clear cell carcinoma, TERT promoter mutations were not statistically associated with any other clinicopathological factors. In ovarian clear cell carcinoma patients with early FIGO stage (stages I and II), TERT promoter mutation was an independent prognostic factor and correlated with a shorter disease-free survival and overall survival (P=0.015 and 0.009, respectively). In recurrent ovarian clear cell carcinoma patients with early FIGO stage, TERT promoter mutations were associated with early relapse within 6 months (P=0.018). We concluded that TERT promoter mutations were present in endometrial and ovarian clear cell carcinomas. Distinct molecular alteration patterns in endometrial and ovarian clear cell carcinomas implied different processes of tumorigenesis in these morphologically similar tumors. In ovarian clear cell carcinoma of early FIGO stage, patients with TERT promoter mutation require close follow-up during the initial 6 months following chemotherapy.

TERT Promoter Mutations and Tert Expression in Early-Stage (T1N0M0) Non-Small Cell Lung Cancer (NSCLC)

Background: The mutations detected in the promoter of the telomerase reverse transcriptase (TERT) gene,namely C228T and C250T, were first identified in melanoma and subsequently in several cancer models, notably glioma, thyroid cancer and bladder cancer. Recent findings demonstrate that mutation of the TERT promoter may be one of the most common genetic mechanisms contributing to telomerase activation in malignant cells. Mutation of the TERT promoter appears to be an indicator of worse outcome and is correlated with tumor aggressiveness and patient survival; however, to date the only two published studies reported a very low TERT mutation frequency in non-small cell lung cancer (NSCLC). Additionally, the relationship among the presence of these mutations, Tert expression and clinical outcome is unknown. Materials and methods: In this study, the polymerase chain reaction and direct sequencing analysis of a TERT promoter region using formalin-fixed and paraffin-embedded tissues were performed to investigate the presence of TERT promoter mutations in a series of 95 early-stage (T1N0M0) NSCLC samples, including 48 adenocarcinomas (ADCs) and 47 squamous cell carcinomas (SCCs).Then, immunohistochemical (IHC) staining was performed to detect the expression of Tert. Results and conclusions: We report that TERT promoter mutations are present in NSCLC with a frequency of 10.52%. TERT promoter mutations were identified in 7 (14.58%) ADCs and 3 (6.38%) SCCs. Tert was expressed in the cytoplasm of 55 samples out of 93 (59.1%) in 33 ADCs and 22 SCCs. The ADCs expressed Tert in a higher percentage of cases (71.7% vs. 46.8%). Although no correlations between the TERT mutations, Tert immunohistochemical expression, clinico-pathological parameters and survival were found in our series, this study represents a starting point for further research to better understand the molecular mechanisms involved in the transcriptional regulation of TERT and its role in lung cancer progression.

Two Novel, Co-Inherited, Telomerase Reverse Transcriptase (TERT) Mutations Resulting in Inherited Aplastic Anemia and Telomere Shortening

Inherited aplastic anemia syndromes generally present early in the first decade of life with tri-lineage bone marrow failure. Patients with a more gradual presentation of marrow failure may be missed in later childhood or misdiagnosed as a primary thrombocytopenia or neutropenia syndromes. This family cohort demonstrates a very slow evolution of inherited aplastic anemia thus suggesting that marrow failure with shortened telomere length be considered in the initial work up of unexplained mild to moderate thrombocytopenia and megaloblastic anemia.Patients: A family is described where 3 of 4 children developed aplastic anemia, of varying intensity, over a period of 5-6 years starting at age 10 years. The onset was slow initially with the two oldest children presenting with only mild thrombocytopenia initially (30-40,000 ul/ml) picked up on routine screening at ages 10 yr, female, and 12y, male siblings . They remained stable for a period of two–three years, however with monitoring it became evident that they were developing a mild megaloblastic anemia after 5 years The whole family was screened and an additional child was found to have mild megaloblastic changes and a platelet count of 100,000 ul/ml (9 yr Male). All three affected children demonstrated tri-lineage failure on bone marrow biopsy, but cytogenetic studies and breakage studies were all normal. The parents and a younger sister had normal complete blood counts. There was no history of consanguinity, but detailed family history revealed premature greying of the hair, and pulmonary fibrosis on the paternal side in three generations, although the father is currently unaffected. On the maternal side of the family there is a history of bleeding in maternal aunts, uncles and grandfather, but the mother only has a history of anemia with pregnancy or dieting. On physical exam all patients with aplastic anemia have premature greying of the hair in their twenties but are otherwise normal in appearance without dysmorphic features or skeletal abnormalities.Genetic and Telomere Analysis: Initial workup included analysis for inherited aplastic anemia including Fanconi, Shwachmann Diamond variants, Dyskeratosis Congenita, and Congenital Amegakaryocytosis all of which were negative. With Telomere length (TL) analysis, all three affected patients were found to have Telomere Lengths far less than the first percentile, while the parents and the unaffected sibling were normal for age (Repeat Diagnostics, Vancouver). Additional gene sequencing of WRAP 53, DKC1, NHP2, NOP10, TERC, and TERT was performed on the index case (Ambrey Genetics, Aliso Viejo, CA), and all genes were normal except for TERT, where he was found to be compound heterozygote for two novel TERT mutations in exon 2 at codons F101L and R312W. Family studies revealed that the mother carried the codon R312W mutation, and the father carried the F101L variant. All affected aplastic anemia siblings were also compound heterozygotes and the unaffected sibling had neither mutation. Familial testing confirms that these alterations are on opposite chromosomes (in trans). The codon F101L variant located in exon 2 of the TERT gene, results in phenylalanine being replaced by leucine, an amino acid with highly similar properties. The codon R312W variant is also located in exon 2 of the TERT gene. In this mutation, the arginine at codon 312 is replaced by tryptophan, an amino acid with very dissimilar properties. Neither variant has been previously reported in population based cohorts including: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. Both mutations are predicted to be deleterious by SIFT in silico analyses. Additional analysis using our qPCR based Telomere Length assay and Telomerase activity confirm the diagnosis and are used to screen for similar TL abnormalities in patients with marrow failure.Conclusion: Although neither variant alone results in anemia in the carrier parent, in combination, these mutations appear to result in aplastic anemia in offspring who are compound heterozygotes. Previous reports of other mutations in exon 2 of the TERT gene can also result in marrow failure. Whole genome analysis and telomerase expression studies currently underway will help to elucidate the presence of modifying genes which may impact the variable phenotype between affected siblings in this family. DisclosuresNo relevant conflicts of interest to declare.

Telomerase in differentiated thyroid cancer: Promoter mutations, expression and localization

Telomerase-reverse-transcriptase (TERT) promoter mutations have been recently described in tumors. In the present large series, TERT mutations were found in 12% of papillary thyroid cancers (PTCs) and in 14% of follicular thyroid cancers (FTCs), and were found to significantly correlate with older age at diagnosis and poorer outcome. Interestingly, the prognostic value of TERT mutations resulted to be significantly stronger than that of BRAFV600E. Moreover, the outcome was not different among tumors with isolated TERT mutation and those with coexistent mutations (TERT/BRAF in PTCs or TERT/RAS in FTCs). TERT rs2853669 polymorphism was found in 44.4% of tumors. At WB, TERT was significantly more expressed in tumors than in normal samples, being the highest levels of expression recorded in TERT mutated cases. At IHC, in tumors and in metastatic lymph-nodes TERT staining was significantly higher in the cytoplasm than in the nucleus, whereas in normal tissue the degree of staining did not differ in the two cellular compartments.In conclusion, TERT mutations were shown to strongly correlate with a poorer outcome in differentiated thyroid tumors, and neither BRAF nor RAS mutation were found to confer an additional effect in the disease persistence. TERT protein was found to be more expressed in neoplastic than in normal tissues, and to display a different cellular localization, suggesting that it could contribute to thyroid cancer progression by mechanisms taking place in the cytoplasm.

Telomerase gene mutations and telomere length shortening in patients with idiopathic pulmonary fibrosis in a Chinese population.

Idiopathic pulmonary fibrosis (IPF) is an age-related disease and the most common manifestation of telomere-mediated disorders. We collected detailed medical histories and DNA samples from 100 IPF patients seen at Nanjing Drum Tower Hospital Affiliated to Medical School of Nanjing University. All patients had sporadic IPF, with no family history reported. We screened all patients for telomerase reverse transcriptase (TERT) and telomerase RNA component (TERC) variants, and measured their telomere lengths in lymphocytes. Six novel telomerase gene mutations were identified in six IPF patients enrolled in the studies. They were two heterozygous mutations in TERC (257 G>A and 108 C>T) and four in TERT (R622H, T644M, V777L and F1032I). IPF patients with TERT/TERC mutations had significant thrombocytopaenia (160.167 ± 28.089 × 10(9)) compared with the non-mutation groups (191.018 ± 71.187 × 10(9), P = 0.047). All IPF patients with TERT/TERC mutations had shortened telomeres (0.656 ± 0.125) compared with the patients lacking TERT/TERC mutations (1.080 ± 0.6819, P = 0.0184). IPF patients lacking TERT or TERC mutations (1.080 ± 0.6819) had significantly shorter telomeres compared with age-matched healthy controls (1.244 ± 0.5890, P = 0.0355). Six novel mutations in the telomerase genes were identified for the first time in individuals diagnosed with sporadic IPF in a Chinese Han population. Shorter telomeres and mild thrombocytopaenia could be clues to association with telomerase gene mutation and sporadic IPF.

Abstract 3420: TERT promoter mutations are rare in uveal melanoma

Abstract Uveal melanoma is the most frequent primary tumor of the eye. It is molecularly clearly distinct from cutaneous melanoma and shows a different pattern of driver mutations. The influence of sunlight UV-exposure on the etiology of uveal melanoma is matter of debate. The recent identification of driver mutations in the promoter of the telomerase reverse transcriptase (TERT) gene with UV induced cytidine-to-thymidine transitions in cutaneous melanoma prompted us to investigate whether these mutations also occur in uveal melanoma. We also analyzed the frequency of other recently discovered uveal melanoma specific mutations in the genes GNAQ, GNA11, BAP1, SF3B1, and EIFAX1, and we analyzed the association of these mutation with histopathological and clinical features including progression free survival. Finally, we analyzed TERT expression in these tumors. The mutation frequencies observed confirmed the prevalence of GNAQ mutations in cases with disomy of chromosome 3 that have a better prognosis whereas GNA11 was more frequent in monosomic cases. Together these two mutations account for more than 85% of the cases. BAP1 mutations are associated with chromosome 3 monosomy but not with progression free survival. SF3B1 and EIF1AX mutations occur in 10.3 and 22.5% of uveal melanomas, in disomic cases only. We detected a TERT mutation in only one case of a 57-year old white male with clinical and histo-pathological features typical for uveal melanoma. The tumor showed mutations in GNA11 and EIF1AX. No mutations were detected in GNAQ, BAP1, and SF3B1. Both copies of chromosome 3 were retained. Several tumors among which the one carrying the TERT promoter mutation showed elevated TERT expression. These data indicate that TERT mutations are rare in uveal melanoma, consistent with a reduced etiological influence of sunlight. No conclusion can be drawn on the potential influence of TERT mutations on tumor progression. Citation Format: Adriana Agnese AMARO, Marina Gualco, Maria Dono, Ulrich Pfeffer, Irena Maric, Carlo Mosci. TERT promoter mutations are rare in uveal melanoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3420. doi:10.1158/1538-7445.AM2014-3420

O8.06 * ATRX AND TERT EXPRESSION IN RELAPSING LOW GRADE GLIOMA

Mechanisms responsible for telomere maintenance are been recently elucidated: many cancers harbor mutations in alpha thalassemia/mental retardation syndrome X-linked (ATRX) gene resulting in a phenomenon known as alternative lengthening of telomeres (ALT) or point mutations in the promoter of the telomerase reverse transcriptase (TERT) gene leading to an increased telomerase expression. ATRX and TERT mutations have been recently identified also in brain tumors. In gliomas, a molecular stratification based on IDH and ATRX mutational status and 1p/19q codeletion has been suggested. ATRX mutations have been observed mainly in astrocytic tumors and TERT promoter mutations mainly in oligodendroglial tumors. Aim of our study was to evaluate the expression of both ATRX and TERT in WHO grade II gliomas and in their resected recurrences, related to a set of confirmed molecular markers and to clinical data. We performed an immunohistochemical analysis of ATRX and TERT expression in 30 grade II gliomas (astrocytomas, oligoastrocytomas and oligodendroglioma) and in their respective recurrences (grade III-IV). Also evaluation of IDH1 and p53 status and 1p/19q LOH were carried out. Loss of expression of ATRX protein has been associated to the mutated gene and ALT phenotype, while expression of TERT protein could be related to TERT promoter mutations. We found a loss of ATRX expression in 70% of cases; recurrences showed the same pattern of ATRX expression. In the most part of cases ATRX loss was associated to IDH1 and p53 mutation and intact 1p/19q, as previously observed. In the major part of cases with ATRX loss of expression TERT was not detected. TERT high expression was observed in about 30% of grade II gliomas at the first surgery, minor expression of TERT was found in grade III-IV recurrent tumors. In most case high expression of TERT was associated to 1p/19q deletion. We observed a statistically significant correlation between TERT high expression and a better outcome. Our study of protein expression of both ATRX and TERT in low grade gliomas and in their recurrences in relationship with established molecular markers and follow-up data, confirm the possibility of using immunohistochemistry in routine diagnostic procedures for better define this subset of neoplasm.

The genomic landscape of hepatoblastoma and their progenies with HCC-like features

Hepatoblastoma (HB) is the most common childhood liver cancer and occasionally presents with histological and clinical features reminiscent of hepatocellular carcinoma (HCC). Identification of molecular mechanisms that drive the neoplastic continuation towards more aggressive HCC phenotypes may help to guide the new stage of targeted therapies. We performed comprehensive studies on genetic and chromosomal alterations as well as candidate gene function and their clinical relevance. Whole-exome sequencing identified HB as a genetically very simple tumour (2.9 mutations per tumour) with recurrent mutations in ß-catenin (CTNNB1) (12/15 cases) and the transcription factor NFE2L2 (2/15 cases). Their HCC-like progenies share the common CTNNB1 mutation, but additionally exhibit a significantly increased mutation number and chromosomal instability due to deletions of the genome guardians RAD17 and TP53, accompanied by telomerase reverse-transcriptase (TERT) promoter mutations. Targeted genotyping of 33 primary tumours and cell lines revealed CTNNB1, NFE2L2, and TERT mutations in 72.5%, 9.8%, and 5.9% of cases, respectively. All NFE2L2 mutations affected residues of the NFE2L2 protein that are recognized by the KEAP1/CUL3 complex for proteasomal degradation. Consequently, cells transfected with mutant NFE2L2 were insensitive to KEAP1-mediated downregulation of NFE2L2 signalling. Clinically, overexpression of the NFE2L2 target gene NQO1 in tumours was significantly associated with metastasis, vascular invasion, the adverse prognostic C2 gene signature, as well as poor outcome. Our study demonstrates the importance of CTNNB1 mutations and NFE2L2-KEAP1 pathway activation in HB development and defines loss of genomic stability and TERT promoter mutations as prominent characteristics of aggressive HB with HCC features.

Telomerase reverse transcriptase (TERT) A1062T mutation as a prognostic factor in Egyptian patients with acute myeloid leukemia (AML).

This study aimed to evaluate the incidence and clinical and prognostic impact of TERT A1062T mutation in AML patients treated at Mansoura Oncology Center. Screening for TERT A1062T mutation in exon 15 of the TERT gene was performed on diagnostic DNA samples from 153 AML patients and 197 healthy subjects as a control group by using sequence-specific primers. TERT A1062T mutation was detected in 18 cases out of 153 patients (11.8 %) and in one out of 197 control group subjects (0.51 %). The achievement of complete remission was significantly higher in AML group with wild type as compared to that in the mutant one (53.3 vs 16.7 %, respectively). In addition, the relapse rate was significantly higher in the mutant patients as compared to those with wild type (62.5 vs 28.2 %, respectively). The AML patients with TERT (A1062T) mutation had shorter overall survival than patients with wild type (P = 0.001). In a multivariable analysis, TERT (A1062T) mutational status is independently worse predictor factor (P = 0.007) when controlling for cytogenetic status (P = <0.001), performance status (P = <0.001) and bone marrow blast cells (P = 0.001). In conclusion, TERT A1062T mutation is an independent negative prognostic factor in AML patients. Therefore, molecular testing for TERT A1062T mutation in patients with AML is recommended in order to delineate their prognostic status.

TERT PROMOTER MUTATIONS OCCUR FREQUENTLY IN GLIOMAS AND A SUBSET OF TUMORS DERIVED FROM CELLS WITH LOW RATES OF SELF-RENEWAL

c Neurosurgery, d Otolaryngology—Head and Neck Surgery, h Pathology, l Urology, and m Malignant cells, like all actively growing cells, must maintain their telomeres, but genetic mechanisms responsible for telomere main- tenance in tumors have only recently been discovered. In particular, mutations of the telomere binding proteins alpha thalassemia/ mental retardation syndrome X-linked (ATRX )o rdeath-domain associated protein (DAXX) have been shown to underlie a telomere maintenance mechanism not involving telomerase (alternative lengthening of telomeres), and point mutations in the promoter of the telomerase reverse transcriptase (TERT) gene increase telo- merase expression and have been shown to occur in melanomas and a small number of other tumors. To further define the tumor types in which this latter mechanism plays a role, we surveyed 1,230 tumors of 60 different types. We found that tumors could be divided into types with low (<15%) and high (≥15%) frequen- cies of TERT promoter mutations. The nine TERT-high tumor types almost always originated in tissues with relatively low rates of self renewal, including melanomas, liposarcomas, hepatocellular carci- nomas, urothelial carcinomas, squamous cell carcinomas of the tongue, medulloblastomas, and subtypes of gliomas (including 83% of primary glioblastoma, the most common brain tumor type). TERT and ATRX mutations were mutually exclusive, suggest- ing that these two genetic mechanisms confer equivalent selective growth advantages. In addition to their implications for under- standing the relationship between telomeres and tumorigenesis, TERT mutations provide a biomarker that may be useful for the early detection of urinary tract and liver tumors and aid in the classification and prognostication of brain tumors.

TERT promoter mutation as an early genetic event activating telomerase in follicular thyroid adenoma (FTA) and atypical FTA.

The telomerase reverse transcriptase (TERT) promoter mutations C228T and C250T have been found in many malignancies, including in thyroid carcinomas. However, it is unclear how early these mutations occur in thyroid tumorigenesis. The study included primary tumors from 58 patients initially diagnosed with follicular thyroid adenoma (FTA), a benign entity, 18 with atypical FTA (AFTA) having an uncertain malignant potential, and 52 with follicular thyroid carcinoma (FTC). Sanger sequencing was used to investigate the mutational status of the TERT promoter. Telomere length and TERT messenger RNA (mRNA) expression were determined using quantitative polymerase chain reaction (PCR). Telomerase activity was assessed using a Telomerase PCR enzyme-linked immunosorbent assay kit. The C228T mutation was identified in 1 of 58 FTA (2%) and 3 of 18 AFTA (17%) samples. These 4 tumors all expressed TERT mRNA and telomerase activity, whereas the majority of C228T-negative adenomas lacked TERT expression (C228T versus wild-type, P = .008). The C228T mutation was associated with NRAS gene mutations (P = .016). The patient with C228T-mutated FTA later developed a scar recurrence and died of FTC, whereas none of the remaining 57 patients with FTA had recurrence. No recurrence occurred in 3 patients with AFTA who carried C228T during the follow-up period (36-285 months). Nine of the 52 FTCs (17%) exhibited the TERT mutation (8 of 9 C228T and 1 of 9 C250T), and the presence of the mutation was associated with shorter patient survival. TERT promoter mutations may occur as an early genetic event in thyroid follicular tumors that have not developed malignant features on routine histopathological workup.

TERTPromoter Mutations and Their Association withBRAFV600E Mutation and Aggressive Clinicopathological Characteristics of Thyroid Cancer

Promoter mutations chr5:1,295,228C>T and chr5:1,295,250C>T (termed C228T and C250T, respectively) in the gene for telomerase reverse transcriptase (TERT) have been reported in various cancers and need to be further investigated in thyroid cancer. The aim of the study was to explore TERT promoter mutations in various thyroid tumors and examine their relationship with BRAF V600E mutation, iodine intake, and clinicopathological behaviors of thyroid cancer. TERT promoter and BRAF mutations were identified by sequencing genomic DNA of primary thyroid tumors from normal- and high-iodine regions in China, and clinicopathological correlation was analyzed. The C228T mutation was found in 9.6% (39 of 408) of papillary thyroid cancer (PTC), C250T was found in 1.7% (7 of 408) of PTC, and they were collectively found in 11.3% (46 of 408) of PTC. C228T was found in 31.8% (7 of 22) and C250T in 4.6% (1 of 22) of follicular thyroid cancer (FTC), and they were collectively found in 36.4% (8 of 22) of FTC. No TERT mutation was found in 44 benign thyroid tumors. The two mutations occurred in 3.8% (6 of 158) of BRAF mutation-negative PTC vs 16.0% (40 of 250) of BRAF mutation-positive PTC (P = 5.87 × 10(-4)), demonstrating their association. Unlike BRAF mutation, TERT promoter mutations were not associated with high iodine intake, but they were associated with older patient age, larger tumor size, extrathyroidal invasion, and advanced stages III/IV of PTC. Coexisting TERT and BRAF mutations were even more commonly and more significantly associated with clinicopathological aggressiveness. In this large cohort, we found TERT promoter mutations to be common, particularly in FTC and BRAF mutation-positive PTC, and associated with aggressive clinicopathological characteristics.