Telomerase Reverse Transcriptase Gene Promoter Research Articles

Evaluation of a Cytology-Molecular Co-Test in Liquid-Based Cytology-Processed Urine for Defining Indeterminate Categories of the Paris System

Introduction: Urine cytology using the Paris system (TPS) classification is useful for the detection and monitoring of bladder urothelial carcinoma (UC). However, the categories “atypical urothelial cells” (AUCs) and “suspicious for high-grade urothelial carcinoma” (SHGUC) do not establish a clear diagnosis. This pilot study aimed to investigate whether the presence of mutations in fibroblast growth factor receptor 3 (FGFR3) and telomerase reverse transcriptase (TERT) genes, in urine processed with liquid-based cytology (LBC) could enhance the diagnostic performance of cytology, particularly in defining the indeterminate categories of AUC and SHGUC. Methods: Urine samples from 82 UC patients with primary tumors or under surveillance and 10 healthy individuals were examined. The ThinPrep method was used for cytology followed by DNA isolation from urine sediments. Targeted molecular analysis was achieved in 70 cases (63 patients and 7 controls) for exons 7 and 10 of the FGFR3 gene and the TERT gene promoter (pTERT), using PCR and Sanger sequencing. Molecular results were correlated with TPS cytology categories and validated by histopathological findings following cystoscopy. Results: In healthy subjects, cytology was negative for high-grade urothelial carcinoma (NHGUC) and no mutations were found. No mutations were found in patients with NHGUC cytology, except for one case with equivocal cystoscopy that carried a pTERT mutation. In high-grade urothelial carcinoma cytology (HGUC) (15/20, 75%) of the cases with histologically confirmed UC, molecular analysis revealed the presence of pTERT without FGFR3 mutations. In SHGUC and AUC cytology, FGFR3 and/or pTERT mutations were detected in 3/4 (75%) and 4/4 (100%) histologically confirmed UC cases, respectively. Cytology sensitivity was 85.7% increasing to 100% with the combined cytology-molecular test, whereas specificity remained unchanged at 86.3%. Conclusions: This pilot study suggests that the incorporation of FGFR3/pTERT molecular testing in urine LBC could enhance the diagnostic value of cytology by diagnosing bladder urothelial carcinoma in indeterminate cytology categories.

Syngeneic mesenchymal stem cells loaded with telomerase-dependent oncolytic adenoviruses enhance anti-metastatic efficacy.

Oncolytic adenoviruses have emerged as a promising therapeutic approach for cancer therapy. However, systemic delivery of the viruses to metastatic tumors remains a major challenge. Mesenchymal stem cells (MSCs) possess tumor tropism property and can be used as cellular vehicles for delivering oncolytic adenoviruses to tumor sites. Since telomerase activity is found in ~90% of human carcinomas, but undetected in normal adult cells, the human telomerase reverse transcriptase gene (TERT) promoter can be exploited for regulating the replication of oncolytic adenoviruses. Here, we evaluated the antitumor effects of syngeneic murine MSCs loaded with the luciferase-expressing, telomerase-dependent oncolytic adenovirus Ad.GS2 (MSC-Ad.GS2) and Ad.GS2 alone on metastatic MBT-2 bladder tumors. MSCs supported a low degree of Ad.GS2 replication, which could be augmented by coculture with MBT-2 cells or tumor-conditioned medium (TCM), suggesting that viral replication is increased when MSC-Ad.GS2 migrates to tumor sites. MBT-2 cells and TCM enhanced viral replication in Ad.GS2-infected MSCs. SDF-1 is a stem cell homing factor. Our results suggest that the SDF-1/STAT3/TERT signaling axis in MSCs in response to the tumor microenvironment may contribute to the enhanced replication of Ad.GS2 carried by MSCs. Notably, we demonstrate the potent therapeutic efficacy of systemically delivered MSC-Ad.GS2 in pleural disseminated tumor and experimental metastasis models using intrapleural and tail vein injection of MBT-2 cells, respectively. Treatment with MSC-Ad.GS2 significantly reduced tumor growth and prolonged the survival of mice bearing metastatic bladder tumors. Since telomerase is expressed in a broad spectrum of cancers, this therapeutic strategy may be broadly applicable.

Telomerase Reverse Transcriptase-Promoter Mutation in Young Patients with Bladder Tumors.

The TERT (Telomerase Reverse Transcriptase) gene promoter mutation is one of the most prevalent mutations in urothelial bladder tumors and this mutation is related to bladder tumor progression. Our purpose was to evaluate the presence of this mutation in a population of patients who were first diagnosed at age ≤ 40 years and to examine its relationship with tumor characteristics and progression. A molecular study was performed to detect the two most prevalent mutations in the TERT promoter (C228T and C250T). The study included 29 patients, with a mean follow-up of 152 months. There were no statistically significant differences in the clinical or tumor characteristics according to the presence or absence of the mutation. Although the mutation group showed poorer recurrence-free survival (RFS), there was no statistically significant difference and there was no difference in progression-free survival by group (p > 0.05). The pTERT mutations in bladder tumor cells occurred less frequently in younger patients than in older patients, a finding that could indicate different mechanisms of carcinogenesis. The trend towards lower RFS in patients with mutated pTERT needs to be confirmed by further studies, given the small number of patients included in these studies due to the low incidence of bladder tumors in this age group.

Initial safety assessment of the endoscopically injected oncolytic virus OBP-301 in medically inoperable esophageal cancer: NRG-GI007.

341 Background: Definitive chemoradiation (CRT) is a standard-of-care for patients (Pts) with medically inoperable esophageal cancer (EC). The NRG/RTOG 0436 study of cisplatin/paclitaxel and RT (+/- cetuximab) as definitive therapy showed that about half of Pts have locally persistent disease. OBP-301 is a conditionally restricted, replication-competent adenovirus derived from human adenovirus type 5 that adds a human Telomerase Reverse Transcriptase (hTERT) gene promoter, replicating only in tumor cells to cause lysis. It may cause immunogenic cell death, enhance RT, and improve local control. OBP-301 was previously studied with RT in Japanese esophageal cancer Pts and shown to be safe and has promising activity.1 Methods: In NRG-GI007, a phase 1 study (NCT04391049), OBP-301 is added to weekly carboplatin/paclitaxel and RT (50.4 Gy/28 fractions) for Pts with medically inoperable EC. Pts receive 1-2mL of intratumoral OBP-301 1×1012virus particles/ml via endoscopy 3 days prior to and then at days 12 and 26 of CRT. The primary endpoint is dose-limiting toxicity (DLT), defined as adverse events (AEs, by CTCAE v5) definitely or probably attributed to OBP-301 that meet either of the following: (1) leading to a >14-day cumulative delay in CRT or (2) any grade ≥ 3 AE EXCEPT: grade 3 nausea/vomiting, grade 3 esophagitis or dehydration, first occurrence of grade 3/4 neutropenia, or grade 3/4 lymphopenia. Initially, 6 evaluable Pts (eligible and started protocol treatment) are enrolled. If protocol defined DLT occurs in ≤1 of 6 Pts, the dose will be deemed safe and an expansion cohort of 9 more will be enrolled to further assess safety and obtain a preliminary assessment of clinical complete response. If ≥2 Pts have a DLT then one de-escalated OBP-301 dose will be assessed. Results: From June 2020 to April 2023, 6 evaluable Pts were enrolled. Median age was 73.5 years, all male. Five Pts had adenocarcinoma and 1 had squamous cell carcinoma; 3 Pts had node-positive disease. All Pts received all planned OBP-301 injections, along with 50.4 Gy RT. Four out of 6 Pts received all 5 weekly doses of chemo for > 85% of planned total dose, and 2 got 4 weekly doses for > 70% of planned total dose. No Pt experienced ³7 day treatment delay. The following treatment-related (attributed as definitely, probably, or possibly related to CRT and/or OBP-301) grade 3 AEs were reported across 5 Pts: decreased neutrophil count (3 Pts), decreased lymphocyte count (2 Pts), decreased WBC (2 Pts), and fever and fatigue (1 Pt each). There were 4 Pts with AEs reported as definitely or probably related to OBP-301, all grade ≤2. No DLT occurred. Conclusions: No DLTs in the 6 evaluable Pts were observed and it is concluded that the initial OBP-301 dose level is safe. NRG-GI007 was reopened on August 7, 2023 to the expansion cohort. Full toxicity and treatment data will be presented. 1. Eur J Cancer 2021;153:98. Clinical trial information: NCT04391049 .

Identification of IDH and TERTp mutations using dynamic susceptibility contrast MRI with deep learning in 162 gliomas

PurposeIsocitrate dehydrogenase (IDH) and telomerase reverse transcriptase gene promoter (TERTp) mutations play crucial roles in glioma biology. Such genetic information is typically obtained invasively from excised tumor tissue; however, these mutations need to be identified preoperatively for better treatment planning. The relative cerebral blood volume (rCBV) information derived from dynamic susceptibility contrast MRI (DSC-MRI) has been demonstrated to correlate with tumor vascularity, functionality, and biology, and might provide some information about the genetic alterations in gliomas before surgery. Therefore, this study aims to predict IDH and TERTp mutational subgroups in gliomas using deep learning applied to rCBV images. MethodAfter the generation of rCBV images from DSC-MRI data, classical machine learning algorithms were applied to the features obtained from the segmented tumor volumes to classify IDH and TERTp mutation subgroups. Furthermore, pre-trained convolutional neural networks (CNNs) and CNNs enhanced with attention gates were trained using rCBV images or a combination of rCBV and anatomical images to classify the mutational subgroups. ResultsThe best accuracies obtained with classical machine learning algorithms were 83 %, 68 %, and 76 % for the identification of IDH mutational, TERTp mutational, and TERTp-only subgroups, respectively. On the other hand, the best-performing CNN model achieved 88 % accuracy (86 % sensitivity, 91 % specificity) for the IDH-mutational subgroups, 70 % accuracy (73 % sensitivity and 67 % specificity) for the TERTp-mutational subgroups, and 84 % accuracy (86 % sensitivity, 81 % specificity) for the TERTp-only subgroup using attention gates. ConclusionsDSC-MRI can be utilized to noninvasively classify IDH- and TERTp-based molecular subgroups of gliomas, facilitating preoperative identification of these genetic alterations.

Abstract C058: Clinical relevance of telomerase upregulation via TERT promoter mutation or TERC amplification in high-grade ovarian cancer

Abstract Background: Increased telomerase activity confers a survival advantage to cancer cells and is considered one of the cancer hallmarks. The two main molecular mechanisms responsible for telomerase upregulation are the amplification of the telomerase RNA component gene (TERCamp) which serves as the template for telomeric repeats, and mutations in the telomerase reverse transcriptasegene promoter (TERTm), which encored the catalytic unit of telomerase. Increased telomerase activity has been detected in more than 90% of ovarian cancer (OC) but the clinical impact of this phenotype remains understudied. Methods: This retrospective analysis included all patients (pts) with high grade OC who underwent large-panel sequencing (Foundation Medicine) from National University Cancer Institute, Singapore and Institut Gustave Roussy, France. TERTm and TERCamp were correlated with clinical, pathological and molecular features as well as progression-free survival (PFS, calculated from histological diagnosis to first progression). Results: Out of the 503 pts with OC analyzed, 15 pts (3.0%) presented TERT mutation and 39 pts (7.8%) had TERC amplification. In the TERTm subgroup, only one hotspot mutation was detected (c.-124C>T). Compared to the wild-type (WT) group, there was significantly higher frequency of FIGO I/II diseases (57% vs 17%, p=0.001) and clear-cell histology (80% vs 14%, p<0.001). Consequently, there were more ARID1A and PIK3CA mutations and median loss of heterozygosity (LOH) score was significantly lower (5.3% vs 16.4%, p=0.006). Interestingly, TERTm were exclusive to P53 and BRCA1/2 mutations. With a follow-up of 64 months, the median PFS was 8.1 months, 18.7 months and 25.5 months for the TERTm, P53m and WT subgroups respectively (p=0.006). In the multivariate analysis, TERTm emerged as an independent negative prognostic biomarker. In the TERCamp subgroup, compared to WT, there was no difference in term of stage (74% of advanced stages vs 82%), or histologic type (77% of high-grade serous vs 71%). TERCamp was associated with a significantly higher tumor mutational load (6.2 mut/mbase vs 4.2, p<0.001), more P53 mutations (90% vs 72%, p=0.014), more BRCA1/2 mutations (33% vs 17%, p=0.016) and higher LOH (22% vs 15%, p=0.023). There were no statistical differences in terms of PFS. Conclusion: This study highlights intriguing heterogeneity in high-grade OC pts with telomerase upregulation. TERTm are associated with a clear-cell phenotype and TERTm and P53m define three prognostic subgroups among OC patients. On the other hand, TERCamp are detected in genomically unstable tumors presenting a higher mutational burden and copy-number alterations. These results emphasize the critical importance of the molecular mechanism underlying increased telomerase activity, which may impact the efficacy of telomerase-targeted therapy. Citation Format: Felix Blanc-Durand, Natalie Ngoi, Damien Vasseur, Patricia Pautier, Judith Michels, Kaissa Ouali, Catherine Genestie, Sophie Cotteret, Etenne Rouleau, Yi Wan Lim, Siew Eng Lim, Diana Lim, Silvana Talisa Wijaya, Alexandra Leary, David SP Tan. Clinical relevance of telomerase upregulation via TERT promoter mutation or TERC amplification in high-grade ovarian cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C058.

Prognostic Value of TSPO PET Before Radiotherapy in Newly Diagnosed IDH-Wild-Type Glioblastoma.

The 18-kDa translocator protein (TSPO) is gaining recognition as a relevant target in glioblastoma imaging. However, data on the potential prognostic value of TSPO PET imaging in glioblastoma are lacking. Therefore, we investigated the association of TSPO PET imaging results with survival outcome in a homogeneous cohort of glioblastoma patients. Methods: Patients were included who had newly diagnosed, histologically confirmed isocitrate dehydrogenase (IDH)-wild-type glioblastoma with available TSPO PET before either normofractionated radiotherapy combined with temozolomide or hypofractionated radiotherapy. SUVmax on TSPO PET, TSPO binding affinity status, tumor volumes on MRI, and further clinical data, such as O 6-alkylguanine DNA methyltransferase (MGMT) and telomerase reverse transcriptase (TERT) gene promoter mutation status, were correlated with patient survival. Results: Forty-five patients (median age, 63.3 y) were included. Median SUVmax was 2.2 (range, 1.0-4.7). A TSPO PET signal was associated with survival: High uptake intensity (SUVmax > 2.2) was related to significantly shorter overall survival (OS; 8.3 vs. 17.8 mo, P = 0.037). Besides SUVmax, prognostic factors for OS were age (P = 0.046), MGMT promoter methylation status (P = 0.032), and T2-weighted MRI volume (P = 0.031). In the multivariate survival analysis, SUVmax in TSPO PET remained an independent prognostic factor for OS (P = 0.023), with a hazard ratio of 2.212 (95% CI, 1.115-4.386) for death in cases with a high TSPO PET signal (SUVmax > 2.2). Conclusion: A high TSPO PET signal before radiotherapy is associated with significantly shorter survival in patients with newly diagnosed IDH-wild-type glioblastoma. TSPO PET seems to add prognostic insights beyond established clinical parameters and might serve as an informative tool as clinicians make survival predictions for patients with glioblastoma.

Phase II study of telomelysin (OBP-301) in combination with pembrolizumab in gastroesophageal (GEA) adenocarcinoma.

4052 Background: OBP-301 is a novel, replication-selective adenoviral construct that incorporates the human telomerase reverse transcriptase gene (hTERT) promoter, which is highly expressed in tumors but not in normal, differentiated adult cells, to regulate expression of the early adenoviral genes, E1A and E1B. OBP-301 has been evaluated as a single agent, and demonstrated immune responses and clinical activity in phase I studies. We examined OBP-301 in combination with pembrolizumab in a multicenter phase II study as a novel mechanism to improve immunotherapy in advanced gastric cancer. Methods: Eligible patients had advanced GEA that had progressed on at least 2 lines of prior therapy for incurable, advanced disease. Patients were required to have adequate end-organ function, measurable disease by RECIST 1.1, and a PD-L1 CPS > 1. Patients received OBP-301 at 2x1012 viral particles via direct tumor injection every two weeks x 4 injections as well as pembrolizumab 200 mg IV every 3 weeks. The primary endpoint was objective response rate (ORR). The null hypothesis that the ORR is < 15% was tested against the Ha ORR > 30%. We used a Simon two-stage design, requiring 3 or more responses in 18 patients in the first stage to proceed to stage two. The study was closed after successfully completing stage one of the Simon’s two stage design to formally examine OBP-301 + pembrolizumab in an immunotherapy (IO) refractory GEA population. Tissue was collected for single cell RNA Sequencing to examine the tumor immune microenvironment pre- and post-OBP-301 injections. Results: From May 2019 to Oct 2022, we enrolled 16 patients, median age 65 (range 43-81), male n = 13. OBP-301 direct tumor injection was well tolerated, median OBP-301 injections 3 (range 1-5). Toxicity attributed to OBP-301 included grade 2 fatigue/weakness (25%), grade 2 fever (18.7%), and a single incidence each of grade 2 nausea, anemia, grade 3 melena, and grade 4 diabetes mellitus (6.25%). We observed 3 patients (19%) with a partial response (PR), thereby meeting the Simon two-stage threshold. The responses were durable; two patients with PR are currently without evidence of disease (one completed 2 years of pembrolizumab, one underwent resection of primary tumor after 15 months), and the 3rd patient is now in month 12 of treatment. Further, one patient with brain metastases demonstrated regression of metastatic disease following progression on immunotherapy alone. All patients were mismatch repair proficient. Conclusions: OBP-301 viral particle injection into the tumor is feasible and safe. OBP-301 with pembrolizumab has encouraging activity in GEA, with durable responses and demonstration of activity in immunotherapy refractory disease. Single Cell RNA Sequencing data of the pre- and post-injection immune effects of OBP-301 will be presented. A formal phase II study of OBP-301 + pembrolizumab in IO refractory GEA patients is underway. Clinical trial information: NCT03921021 .

Telomerase inhibition is an effective therapeutic strategy in TERT promoter-mutant glioblastoma models with low tumor volume.

Glioblastoma is one of the most lethal forms of cancer, with 5-year survival rates of only 6%. Glioblastoma-targeted therapeutics have been challenging to develop due to significant inter- and intra-tumoral heterogeneity. Telomerase reverse transcriptase gene (TERT) promoter mutations are the most common known clonal oncogenic mutations in glioblastoma. Telomerase is therefore considered to be a promising therapeutic target against this tumor. However, an important limitation of this strategy is that cell death does not occur immediately after telomerase ablation, but rather after several cell divisions required to reach critically short telomeres. We, therefore, hypothesize that telomerase inhibition would only be effective in glioblastomas with low tumor burden. We used CRISPR interference to knock down TERT expression in TERT promoter-mutant glioblastoma cell lines and patient-derived models. We then measured viability using serial proliferation assays. We also assessed for features of telomere crisis by measuring telomere length and chromatin bridge formation. Finally, we used a doxycycline-inducible CRISPR interference system to knock down TERT expression in vivo early and late in tumor development. Upon TERT inactivation, glioblastoma cells lose their proliferative ability over time and exhibit telomere shortening and chromatin bridge formation. In vivo, survival is only prolonged when TERT knockdown is induced shortly after tumor implantation, but not when the tumor burden is high. Our results support the idea that telomerase inhibition would be most effective at treating glioblastomas with low tumor burden, for example in the adjuvant setting after surgical debulking and chemoradiation.

The TERT Promoter: A Key Player in the Fight for Cancer Cell Immortality

The review describes the role of telomeres and telomerase in tumor progression, as well as various mechanisms of the activation of telomerase reverse transcriptase (TERT) expression in CNS tumors and other cancers. The main mechanism of TERT activation involves acquisition of somatic mutations by the TERT gene promoter (TERTp). The article presents information on the TERTp structure and transcription factors directly interacting with TERTp and regulating its transcription. The prospects of using the mutational status of TERTp as a prognostic marker of CNS malignancies and other tumors with a common profile of TERTp mutations are discussed.

Radiomic study on preoperative multi-modal magnetic resonance images identifies IDH-mutant TERT promoter-mutant gliomas.

Gliomas with comutations of isocitrate dehydrogenase (IDH) genes and telomerase reverse transcriptase (TERT) gene promoter (IDHmut pTERTmut) show distinct biological features and respond to first-line treatment differently in comparison with other gliomas. This study aimed to characterize the IDHmut pTERTmut gliomas in multimodal MRI using the radiomic method and establish a precise diagnostic model identifying this group of gliomas. A total of 140 patients with untreated primary gliomas were admitted between 2016 and 2020 to West China Hospital as a discovery cohort, including 22 IDHmut pTERTmut patients. Thirty-four additional cases from a different hospital were included in the study as an independent validation cohort. A total of 3654 radiomic features were extracted from the preoperative multimodal MRI images (T1c, FLAIR, and ADC maps) and filtered in a data-driven approach. The discovery cohort was split into training and test sets by a 4:1 ratio. A diagnostic model (multilayer perceptron classifier) for detecting the IDHmut pTERTmut gliomas was trained using an automatic machine-learning algorithm named tree-based pipeline optimization tool (TPOT). The most critical radiomic features in the model were identified and visualized. The model achieved an area under the receiver-operating curve (AUROC) of 0.971 (95% CI, 0.902-1.000), the sensitivity of 0.833 (95% CI, 0.333-1.000), and the specificity of 0.966 (95% CI, 0.931-1.000) in the test set. The area under the precision-recall curve (AUCPR) was 0.754 (95% CI, 0.572-0.833) and the F1 score was 0.833 (95% CI, 0.500-1.000). In the independent validation set, the model reached 0.952 AUROC, 0.714 sensitivity, 0.963 specificity, 0.841 AUCPR, and 0.769 F1 score. MR radiomic features of the IDHmut pTERTmut gliomas represented homogenous low-complexity texture in three modalities. An accurate diagnostic model was constructed for detecting IDHmut pTERTmut gliomas using multimodal radiomic features. The most important features were associated with the homogenous simple texture of IDHmut pTERTmut gliomas in MRI images transformed using Laplacian of Gaussian and wavelet filters.

Human TERT Promoter Mutations in Atypical and Anaplastic Meningiomas.

Background: The role of telomerase reverse transcriptase (TERT) gene promoter mutations (pTERT) in atypical and anaplastic meningiomas remains controversial. This study aimed to evaluate their impact on the histologic diagnosis and prognosis in a retrospective series of 74 patients with atypical and anaplastic meningioma, including disease progression and relapse. A supplementary panel of 21 benign tumours was used as a control cohort. Materials and Methods: The mutation rate of the pTERT gene was assessed by Sanger sequencing. ATRX protein expression was detected by immunohistochemistry. The phenotypic and genotypic intra-tumour heterogeneity was studied in a sub-group of 12 cases using a Molecular Machines & Industries (MMI) CellCut laser microdissection (LMD) system. Results: pTERT mutations were detected in 12/74 (17.6%) malignant meningiomas. The mutation rate was significantly higher in anaplastic meningiomas (7/23, 30.4%) compared to atypical tumours (5/48, 10.4%) (p = 0.0443). In contrast, the mutation rate was < 5% in benign tumours. All pTERT mutant cases retained nuclear ATRX immunoreactivity. pTERT mutations were significantly associated with the histologic grade (p = 0.0443) and were adverse prognostic factors for anaplastic tumours (p = 0.06). Conclusion: We reported on the pTERT mutation spectrum in malignant meningiomas, supporting their use in the prognostic classification.

940P Dose-escalation trial of OBP-301, novel telomerase-specific oncolytic virus in advanced hepatocellular carcinoma

OBP-301 is a novel, human telomerase reverse transcriptase gene (hTERT) promoter regulated replication-competent adenovirus. Its replication, oncolysis and dissemination are restricted to cells that express the hTERT promoter, which is highly expressed in a variety of human cancers including liver cancer. We assessed the safety and efficacy of intratumoral (IT) injection of OBP-301 in advanced hepatocellular carcinoma (HCC).

Molecular pathogenesis of pediatric thyroid carcinoma.

ABSTRACTThere has been little understanding of the molecular pathogenesis of pediatric thyroid cancers. Most of them are histologically classified as papillary thyroid carcinoma (PTC). Ionizing radiation is the most important environmental factor to induce PTC, especially in children. Particularly, radiation-related pediatric PTCs after the Chernobyl accident provided invaluable information. In addition, the recent accumulation of sporadic pediatric PTC cases, partly due to advances in diagnostic imaging, has also provided insight into their general pathogenesis. In PTC development, basically two types of genetic alterations, fusion oncogenes, mainly RET/PTC, and a point mutation, mainly BRAFV600E, are thought to play a key role as driver oncogenes. Their frequencies vary depending on patient age. The younger the age, the more prevalent the fusion oncogenes are. Higher incidence of fusion oncogenes was also observed in cases exposed to radiation. In short, fusion oncogenes are associated with both age and radiation and are not evidence of radiation exposure. The type of driver oncogene is shifted toward BRAFV600E during adolescence in sporadic PTCs. However, until about this age, fusion oncogenes seem to still confer dominant growth advantages, which may lead to the higher discovery rate of the fusion oncogenes. It has been postulated that RET/PTC in radiation-induced PTC is generated by ionizing radiation; however, there is an interesting hypothesis that thyroid follicular cell clones with pre-existing RET/PTC were already present, and radiation may play a role as a promoter/progressor but not initiator. Telomerase reverse transcriptase gene (TERT) promoter mutations, which are the strongest marker of tumor aggressiveness in adult PTC cases, have not been detected in pediatric cases; however, TERT expression without the mutations may play a role in tumor aggressiveness. In this paper, the recent information regarding molecular findings in sporadic and radiation-associated pediatric PTCs is summarized.

TERT-Promoter Mutational Status in Glioblastoma - Is There an Association With Amino Acid Uptake on Dynamic 18F-FET PET?

ObjectiveThe mutation of the ‘telomerase reverse transcriptase gene promoter’ (TERTp) has been identified as an important factor for individual prognostication and tumorigenesis and will be implemented in upcoming glioma classifications. Uptake characteristics on dynamic 18F-FET PET have been shown to serve as additional imaging biomarker for prognosis. However, data on the correlation of TERTp-mutational status and amino acid uptake on dynamic 18F-FET PET are missing. Therefore, we aimed to analyze whether static and dynamic 18F-FET PET parameters are associated with the TERTp-mutational status in de-novo IDH-wildtype glioblastoma and whether a TERTp-mutation can be predicted by dynamic 18F-FET PET.MethodsPatients with de-novo IDH-wildtype glioblastoma, WHO grade IV, available TERTp-mutational status and dynamic 18F-FET PET scan prior to any therapy were included. Here, established clinical parameters maximal and mean tumor-to-background-ratios (TBRmax/TBRmean), the biological-tumor-volume (BTV) and minimal-time-to-peak (TTPmin) on dynamic PET were analyzed and correlated with the TERTp-mutational status.ResultsOne hundred IDH-wildtype glioblastoma patients were evaluated; 85/100 of the analyzed tumors showed a TERTp-mutation (C228T or C250T), 15/100 were classified as TERTp-wildtype. None of the static PET parameters was associated with the TERTp-mutational status (median TBRmax 3.41 vs. 3.32 (p=0.362), TBRmean 2.09 vs. 2.02 (p=0.349) and BTV 26.1 vs. 22.4 ml (p=0.377)). Also, the dynamic PET parameter TTPmin did not differ in both groups (12.5 vs. 12.5 min, p=0.411). Within the TERTp-mutant subgroups (i.e., C228T (n=23) & C250T (n=62)), the median TBRmax (3.33 vs. 3.69, p=0.095), TBRmean (2.08 vs. 2.09, p=0.352), BTV (25.4 vs. 30.0 ml, p=0.130) and TTPmin (12.5 vs. 12.5 min, p=0.190) were comparable, too.ConclusionUptake characteristics on dynamic 18F-FET PET are not associated with the TERTp-mutational status in glioblastoma However, as both, dynamic 18F-FET PET parameters as well as the TERTp-mutation status are well-known prognostic biomarkers, future studies should investigate the complementary and independent prognostic value of both factors in order to further stratify patients into risk groups.

Human TERT promoter polymorphism rs2853669 is associated with cancers: an updated meta-analysis.

The polymorphism rs2853669 in the telomerase reverse transcriptase gene (TERT) promoter region is widely investigated for the risk of different cancers. However, previous results remained inconclusive. Thus, we performed this updated meta-analysis to comprehensively evaluate the association between rs2853669 and the susceptibility of human cancer. A systematic literature search via PubMed, EMBASE, Cochrane Library, and Web of Science databases was conducted that produced a total of 19 eligible studies containing 23,085 subjects. The relationship was calculated with the odds ratio (OR) and 95% confidence intervals (CIs). Statistical analyses were performed using the RevMan 5.4 software. The analysis indicated that rs2853669 is associated with an enhanced risk of overall cancer risk. From subgroup analysis, a significantly increased association in five genetic models (p < 0.05) was found among Asians, but no association was observed in Caucasians. Although we did not find any significant correlation between rs2853669 and breast cancer, an increased and statistically significant association was found for both lung cancer and acute myeloid leukemia. We did not find any association in other cancer types during stratified analysis. Our meta-analysis suggests that rs2853669 polymorphism in TERT gene is associated with an increased risk of overall cancer susceptibility, particularly in the Asian population. Moreover, rs2853669 is significantly associated with lung cancer and acute myeloid lymphoma. However, large-scale studies are needed to confirm our findings.

NRG Oncology NRG-GI007 trial-in-progress: Phase I study of OBP-301 (Telomelysin) and definitive chemoradiation (CRT) for patients with locally advanced esophageal and gastroesophageal adenocarcinoma who are not candidates for surgery.

TPS262 Background: Definitive CRT is a standard-of-care for patients with medically inoperable esophageal cancer (EC, NEJM 326:1593). The NRG/RTOG 0436 study of cisplatin/paclitaxel and RT (+/- cetuximab) as definitive therapy showed that about ½ of patients have locally persistent disease (JAMA Oncol 3:1520). OBP-301 is a conditionally-restricted, replication-competent adenovirus derived from human adenovirus type 5 (Ad-5) that adds a human Telomerase Reverse Transcriptase (hTERT) gene promoter; it replicates only in tumor cells to cause lysis. It may enhance RT and may cause immunogenic cell death. A phase I study with RT in Japanese patients with inoperable EC showed tolerability and activity. Methods: In NRG-GI007, OBP-301 is added to weekly carboplatin/paclitaxel and RT to 50.4 Gy (1.8 Gy/fx ×28 fx) for patients with medically inoperable esophageal or gastroesophageal junction (GEJ) adenocarcinoma. Patients receive intratumoral OBP-301 1×1012 virus particles (vp)/ml via endoscopy (EGD) 3 days prior to CRT, then at days 12 and 26 of CRT, for a total of 3 doses. Restaging with PET and EGD occur 6-8 weeks later. Blood and tumor tissue are collected for immune- and viral-based correlative assays. Patients must be assessed to be medically inoperable and have ECOG performance status &lt;1. The primary endpoint is safety, and clinical complete response (cCR) rate is a secondary endpoint. Initially, 6 patients are enrolled. If protocol-defined dose-limiting toxicity (DLT) occurs in &lt;1 of 6 patients, the dose will be deemed to be safe and 9 more will be enrolled to further assess safety and obtain a preliminary assessment of cCR rate. If &gt;2 of 6 patients have DLT, the dose of OBP-301 is reduced to 1×1011 vp/ml and another 6 patients will be treated. If &lt;1 of 6 patients has a DLT at the lower dose, that dose will be deemed to be safe and 9 more will be enrolled. If &gt;2 of 6 patients have DLT, then neither dose level will have met the safety rule and the trial will be ended. This trial opened to accrual on June 29, 2020. Clinicaltrials.gov NCT04391049. Funding: This project was supported by grants U10CA180868 (NRG Oncology Operations), U10CA180822 (NRG Oncology SDMC), U24CA180803 (IROC), from the National Cancer Institute (NCI) and Oncolys BioPharma. Clinical trial information: NCT04391049.

Negative Prognostic Implication of TERT Promoter Mutations in Human Papillomavirus\u2013Negative Tonsillar Squamous Cell Carcinoma Under the New 8th AJCC Staging System

Telomerase reverse transcriptase gene promoter (TERTp) mutation is a potential candidate for pathogenesis and therapeutic target of tonsillar squamous cell carcinomas (TSCCs) in association with human papillomavirus (HPV). Their clinical relevance has not been validated under the new 8th American Joint Committee on Cancer (AJCC) staging system. We analyzed real-time peptide nucleic acid–mediated PCR and sequencing methods (TERTp mutation) and real-time PCR-based assay (HPV) in 80 surgically resected TSCCs. The 8th edition staging system improved the stratification of the early and advanced stages and between T or N categories for overall survival over the 7th edition. TERTp mutation was found in 7.5%, and HPV in 80.0% of the patients. The majority (83.3%) of TERTp mutation cases were HPV-positive TSCCs. Applying the 8th edition staging system, TERTp mutation was an independent factor of poor prognosis for disease-free survival (DFS) in TSCC patients, supporting the clinical significance of TERTp mutation in tonsil cancer. TERTp mutations were also negatively correlated with overall survival and DFS in HPV-negative TSCCs. Conclusively, TERTp mutation provides negative prognostic impact on survival of surgically managed tonsil cancers staged with the AJCC 8th edition.

Telomerase Reverse Transcriptase Promoter Mutations Identify a Genomically Defined and Highly Aggressive Human Pleural Mesothelioma Subgroup.

Human malignant pleural mesothelioma (MPM) is characterized by dismal prognosis. Consequently, dissection of molecular mechanisms driving malignancy is of key importance. Here we investigate whether activating mutations in the telomerase reverse transcriptase (TERT) gene promoter are present in MPM and associated with disease progression, cell immortalization, and genomic alteration patterns. TERT promoters were sequenced in 182 MPM samples and compared with clinicopathologic characteristics. Surgical specimens from 45 patients with MPM were tested for in vitro immortalization. The respective MPM cell models (N = 22) were analyzed by array comparative genomic hybridization, gene expression profiling, exome sequencing as well as TRAP, telomere length, and luciferase promoter assays. TERT promoter mutations were detected in 19 of 182 (10.4%) MPM cases and significantly associated with advanced disease and nonepithelioid histology. Mutations independently predicted shorter overall survival in both histologic MPM subtypes. Moreover, 9 of 9 (100%) mutated but only 13 of 36 (36.1%) wild-type samples formed immortalized cell lines. TERT promoter mutations were associated with enforced promoter activity and TERT mRNA expression, while neither telomerase activity nor telomere lengths were significantly altered. TERT promoter-mutated MPM cases exhibited distinctly reduced chromosomal alterations and specific mutation patterns. While BAP1 mutations/deletions were exclusive with TERT promoter mutations, homozygous deletions at the RBFOX1 and the GSTT1 loci were clearly enriched in mutated cases. TERT promoter mutations independently predict a dismal course of disease in human MPM. The altered genomic aberration pattern indicates that TERT promoter mutations identify a novel, highly aggressive MPM subtype presumably based on a specific malignant transformation process.

Human Telomerase Reverse Transcriptase Gene Promoter Mutation in Serum of Patients with Hepatocellular Carcinoma

Background: Mutations in the human telomerase reverse transcriptase (hTERT) gene promoter have been reported in hepatocellular carcinoma (HCC); however, analyses of these mutations in liquid biopsies have been technically difficult because of the high GC content of the regions of interest within this promoter. We evaluated the feasibility and prognostic value of hTERT promoter mutations identified in circulating cell-free DNA (cfDNA) from the serum of patients with HCC. Objective: A cohort of HCC patients (n = 36) who were curatively treated by surgical resection between June 2003 and September 2014 were enrolled in this study. Methods: The presence of hTERT promoter mutations in cfDNA from the patients’ serum was analyzed via modified droplet digital polymerase chain reaction, and associations were sought between specific promoter mutations and patients’ disease-free survival (DFS). Results: The G>A hTERT mutation at –124 bp was detected in the serum of 25 patients (69%). Although no marked differences were observed between the characteristics of the serum mutation-positive and serum mutation-negative patient groups, the DFS of patients with the mutation was significantly shorter than that of the serum mutation-negative patients (p = 0.02). Among 18 clinicopathologic and background liver factors examined, the presence of the –124 bp G>A mutation was an independent and significant predictor of patients’ DFS (hazard ratio = 3.01, 95% confidence interval 1.11–10.5, p = 0.03) in multivariate analyses. Conclusions: The –124 bp G>A hTERT promoter mutation was observed in the serum of 69% of HCC patients who underwent surgical resection and was an independent predictor of disease progression in HCC.