Coexistence of TERT promoter and BRAF mutations in cutaneous melanoma is associated with more clinicopathological features of aggressiveness

Association of ADC of hyperintense lesions on FLAIR images with TERT promoter mutation status in glioblastoma IDH wild type

Background

Although mutations in telomerase reverse transcriptase (TERT) promoter (TERTp) are the most common alterations in glioblastoma (GBM), predicting TERTp mutation status by preoperative imaging is difficult. We determined whether tumour-surrounding hyperintense lesions on fluid-attenuated inversion recovery (FLAIR) were superior to those of contrast-enhanced lesions (CELs) in assessing TERTp mutation status using magnetic resonance imaging (MRI).

Methods

This retrospective study included 114 consecutive patients with primary isocitrate dehydrogenase (IDH)-wild-type GBM. The apparent diffusion coefficient (ADC) and volume of CELs and FLAIR hyperintense lesions (FHLs) were determined, and the correlation between MRI features and TERTp mutation status was analyzed. In a subset of cases, FHLs were histopathologically analyzed to determine the correlation between tumor cell density and ADC.

Results

TERTp mutations were present in 77 (67.5%) patients. The minimum ADC of FHLs was significantly lower in the TERTp-mutant group than in the TERTp-wild-type group (mean, 958.9 × 10-3 and 1092.1 × 10-3 mm2/s, respectively, P < 0.01). However, other MRI features, such as CEL and FHL volumes, minimum ADC of CELs, and FHL/CEL ratio, were not significantly different between the two groups. Histopathologic analysis indicated high tumor cell density in FHLs with low ADC.

Conclusion

The ADC of FHLs was significantly lower in IDH-wild-type GBM with TERTp mutations, suggesting that determining the ADC of FHLs on preoperative MRI might be helpful in predicting TERTp mutation status and surgical planning.

Diagnosing Cutaneous Melanocytic Tumors in the Molecular Era: Updates and Review of Literature

Over the past decade, molecular and genomic discoveries have experienced unprecedented growth, fundamentally reshaping our comprehension of melanocytic tumors. This review comprises three main sections. The first part gives an overview of the current genomic landscape of cutaneous melanocytic tumors. The second part provides an update on the associated molecular tests and immunohistochemical stains that are helpful for diagnostic purposes. The third section briefly outlines the diverse molecular pathways now utilized for the classification of cutaneous melanomas. The primary goal of this review is to provide a succinct overview of the molecular pathways involved in melanocytic tumors and demonstrate their practical integration into the realm of diagnostic aids. As the molecular and genomic knowledge base continues to expand, this review hopes to serve as a valuable resource for healthcare professionals, offering insight into the evolving molecular landscape of cutaneous melanocytic tumors and its implications for patient care.

Programmed Cell Death Ligand 1 Immunohistochemical Expression and Cutaneous Melanoma: A Controversial Relationship

Cutaneous melanoma (CM) is traditionally considered one of the most "immunogenic" tumors, eliciting a high immune response. However, despite the presence of tumor-infiltrating lymphocytes (TILs), melanoma cells use strategies to suppress antitumor immunity and avoid being eliminated by immune surveillance. The PD-1 (programmed death-1)/PD-L1 (programmed death-ligand 1) axis is a well-known immune escape system adopted by neoplastic cells. Therefore, immunotherapy with PD-1 and PD-L1 inhibitors is quickly becoming the main treatment approach for metastatic melanoma patients. However, the clinical utility of PD-L1 expression assessment in CM is controversial, and the interpretation of PD-L1 scores in clinical practice is still a matter of debate. Nonetheless, the recent literature data show that by adopting specific PD-L1 assessment methods in melanoma samples, a correlation between the expression of such a biomarker and a positive response to PD-1-based immunotherapy can be seen. Our review aims to describe the state-of-the-art knowledge regarding the prognostic and predictive role of PD-L1 expression in CM while also referring to possible biological explanations for the variability in its expressions and related treatment responses.

UV-radiation and MC1R germline mutations are risk factors for the development of conventional and spitzoid melanomas in children and adolescents

BACKGROUND

Genomic characterisation has led to an improved understanding of adult melanoma. However, the aetiology of melanoma in children is still unclear and identifying the correct diagnosis and therapeutic strategies remains challenging.

METHODS

Exome sequencing of matched tumour-normal pairs from 26 paediatric patients was performed to study the mutational spectrum of melanomas. The cohort was grouped into different categories: spitzoid melanoma (SM), conventional melanoma (CM), and other melanomas (OT).

FINDINGS

In all patients with CM (n = 10) germline variants associated with melanoma were found in low to moderate melanoma risk genes: in 8 patients MC1R variants, in 2 patients variants in MITF, PTEN and BRCA2. Somatic BRAF mutations were detected in 60% of CMs, homozygous deletions of CDKN2A in 20%, TERTp mutations in 30%. In the SM group (n = 12), 5 patients carried at least one MC1R variant; somatic BRAF mutations were detected in 8.3%, fusions in 25% of the cases. No SM showed a homozygous CDKN2A deletion nor a TERTp mutation. In 81.8% of the CM/SM cases the UV damage signatures SBS7 and/or DBS1 were detected. The patient with melanoma arising in giant congenital nevus (CNM) demonstrated the characteristic NRAS Q61K mutation.

INTERPRETATION

UV-radiation and MC1R germline variants are risk factors in the development of conventional and spitzoid paediatric melanomas. Paediatric CMs share genomic similarities with adult CMs while the SMs differ genetically from the CM group. Consistent genetic characterization of all paediatric melanomas will potentially lead to better subtype differentiation, treatment, and prevention in the future.

FUNDING

Found in Acknowledgement.

pTERT C250T mutation: A potential biomarker of poor prognosis in metastatic melanoma

Melanoma is the most aggressive form of skin cancer and the leading cause of death from cutaneous tumors. Several studies have associated alterations in the TERT promoter region (pTERT) with gene overexpression, aggressiveness and poor prognosis of the disease. The aim of this study was to clarify the role of pTERT molecular status in paired samples of primary melanoma and metastasis using tissue and plasma to establish a correlation with disease progression and survival. A total of 88 FFPE tissue samples from 53 patients with advanced melanoma were analyzed. Of these, 35 had paired samples. We also examined cfDNA samples from plasma of 25 patients. We detected a good correlation between primary tumors and metastases in pTERT mutation and methylation status. We were also able to identify pTERT mutations in plasma samples that correlated with mutational status in tissue samples. Interestingly, the C250T mutation was associated with worse survival and higher TERT mRNA expression, compared to the other most common mutation: C228T. In addition, hyper-methylation of the promoter region seems to be related to the progression of pTERT wild type (WT) patients. These results suggest that TERT gene alterations plays an important role during tumor progression, with the detection of the C250T mutation in tissue and plasma as a potential biomarker of poor prognosis in patients with advanced melanoma.

Interrogation of TERT promoter hotspot mutations in ameloblastoma and ameloblastic carcinoma

BACKGROUND

TERT promoter mutations increase telomerase activity, conferring cell immortality. The coexistence of TERT promoter mutations with BRAFV600E is associated with aggressiveness. Ameloblastoma and ameloblastic carcinoma are infiltrative neoplasms that harbor BRAFV600E; however, it remains unknown if these odontogenic tumors also show TERT promoter mutations.

METHODS

Genomic DNA of paraffin-embedded ameloblastomas (n = 6) and ameloblastic carcinomas (n = 3) were Sanger-sequenced to assess the hotspot TERT promoter mutations C228T and C250T. BRAFV600E status was screened by TaqMan allele-specific quantitative polymerase chain reaction.

RESULTS

None of the samples harbored TERT promoter mutations. The BRAFV600E mutation was positive in 3 of 6 of ameloblastomas and in 1 of 3 of ameloblastic carcinomas.

CONCLUSION

The absence of TERT promoter mutation in the samples indicates that this molecular event is not relevant to the tumors' pathogenesis. Further studies are necessary to explore undefined genetic or epigenetic mechanisms related to TERT-upregulation in ameloblastoma, and the telomerase activity in ameloblastic carcinoma.

Molecular testing in melanoma for the surgical pathologist

The diagnostic work-up of melanocytic tumours has undergone significant changes in the last years following the exponential growth of molecular assays. For the practising pathologist it is often difficult to sort through the multitude of different tests that are currently available for clinical use. The molecular tests used in melanocytic pathology can be broadly divided into four categories: (1) tests that predict response to systemic therapy in melanoma; (2) tests that predict prognosis in melanoma; (3) tests useful in determining the type or class of melanocytic tumour; and (4) tests useful in the differential diagnosis of naevus versus melanoma (primarily used as an aid in the diagnosis of histologically ambiguous melanocytic lesions). This review will present an updated synopsis of major molecular ancillary tests used in clinical practice.

Melanoma and Glioblastoma-Not a Serendipitous Association

Recently, we came across a patient with malignant melanoma and primary glioblastoma. Given this, we parsed the literature to ascertain the relationship, if any, between these 2 malignancies. We begin with a brief overview of melanoma and glioma in isolation followed by a chronologic overview of case reports and epidemiologic studies documenting both neoplasms. This is followed by studies detailing genetic abnormalities common to both malignancies with a view to identifying unifying genetic targets for therapeutic strategies as well as to explore the possibility of a putative association and an inherited cancer susceptibility trait. From a scientific perspective, we believe we have provided evidence favoring an association between melanoma and glioma. Future studies that include documentation of additional cases, as well as a detailed molecular analyses, will lend credence to our hypothesis that the co-occurrence of these 2 conditions is likely not serendipitous.

UV-Induced Somatic Mutations Driving Clonal Evolution in Healthy Skin, Nevus, and Cutaneous Melanoma

Introduction: Due to its aggressiveness, cutaneous melanoma (CM) is responsible for most skin cancer-related deaths worldwide. The origin of CM is closely linked to the appearance of UV-induced somatic mutations in melanocytes present in normal skin or in CM precursor lesions (nevi or dysplastic nevi). In recent years, new NGS studies performed on CM tissue have increased the understanding of the genetic somatic changes underlying melanomagenesis and CM tumor progression. Methods: We reviewed the literature using all important scientific databases. All articles related to genomic mutations in CM as well as normal skin and nevi were included, in particular those related to somatic mutations produced by UV radiation. Conclusions: CM development and progression are strongly associated with exposure to UV radiation, although each melanoma subtype has different characteristic genetic alterations and evolutionary trajectories. While BRAF and NRAS mutations are common in the early stages of tumor development for most CM subtypes, changes in CDKN2A, TP53 and PTEN, together with TERT promoter mutations, are especially common in advanced stages. Additionally, large genome duplications, loss of heterozygosity, and copy number variations are hallmarks of metastatic disease. Finally, the mutations driving melanoma targeted-therapy drug resistance are also summarized. The complete sequential stages of clonal evolution leading to CM onset from normal skin or nevi are still unknown, so further studies are needed in this field to shed light on the molecular pathways involved in CM malignant transformation and in melanoma acquired drug resistance.

Case report: response to the ERK1/2 inhibitor ulixertinib in BRAF D594G cutaneous melanoma

Melanoma is characterized by oncogenic mutations in pathways regulating cell growth, proliferation, and metabolism. Greater than 80% of primary melanoma cases harbor aberrant activation of the mitogen-activated protein kinase kinase/extracellular-signal-regulated kinase (MEK/ERK) pathway, with oncogenic mutations in BRAF, most notably BRAF V600E, being the most common. Significant progress has been made in BRAF-mutant melanoma using BRAF and MEK inhibitors; however, non-V600 BRAF mutations remain a challenge with limited treatment options. We report the case of an individual diagnosed with stage III BRAF D594G-mutant melanoma who experienced an extraordinary response to the ERK1/2 inhibitor ulixertinib as fourth-line therapy. Ulixertinib was obtained via an intermediate expanded access protocol with unique flexibility to permit both single-agent and combination treatments, dose adjustments, breaks in treatment to undergo surgery, and long-term preventive treatment following surgical resection offering this patient the potential for curative treatment.

Telomere length and Wnt/β-catenin pathway in adamantinomatous craniopharyngiomas

OBJECTIVES

To evaluate how telomere length behaves in adamantinomtous craniopharyngioma (aCP) and if it contributes to the pathogenesis of aCPs with and without CTNNB1 mutations.

DESIGN

Retrospective cross-sectional study enrolling 42 aCP patients from 2 tertiary institutions.

METHODS

Clinicopathological features were retrieved from the patient's charts. Fresh frozen tumors were used for RNA and DNA analyses. Telomere length was evaluated by qPCR (T/S ratio). Somatic mutations in TERT promoter (TERTp) and CTNNB1 were detected by Sanger and/or whole-exome sequencing. We performed RNA-Seq to identify differentially expressed genes in aCPs presenting with shorter or longer telomere lengths.

RESULTS

Mutations in CTNNB1 were detected in 29 (69%) tumors. There was higher frequency of CTNNB1 mutations in aCPs from patients diagnosed under the age of 15 years (85% vs 15%; P = 0.04) and a trend to recurrent disease (76% vs 24%; P = 0.1). No mutation was detected in the TERTp region. The telomeres were shorter in CTNNB1-mutated aCPs (0.441, IQR: 0.297-0.597vs 0.607, IQR: 0.445-0.778; P = 0.04), but it was neither associated with clinicopathological features nor with recurrence. RNAseq identified a total of 387 differentially expressed genes, generating two clusters, being one enriched for short telomeres and CTNNB1-mutated aCPs.

CONCLUSIONS: CTNNB1

mutations are more frequent in children and adolescents and appear to associate with progressive disease. CTNNB1-mutated aCPs have shorter telomeres, demonstrating a relationship between the Wnt/β-catenin pathway and telomere biology in the pathogenesis of aCPs.

Mechanistic Translation of Melanoma Genetic Landscape in Enriched Pathways and Oncogenic Protein-Protein Interactions

BACKGROUND/AIM

Malignant melanoma is a skin cancer originating from the oncogenic transformation of melanocytes located in the epidermal layers. Usually, the patient's prognosis depends on timing of disease detection and molecular and genetic profiling, which may all significantly influence mortality rates. Genetic analyses often detect somatic BRAF, NRAS and cKIT mutations, germline substitutions in CDKN2A, and alterations of the PI3K-AKT-PTEN pathway. A peculiar molecular future of melanoma is its high immunogenicity, making this tumor targetable by programmed cell death protein 1-specific antibodies.

MATERIALS AND METHODS

Ten formalin-fixed paraffin embedded samples derived from melanoma patients were subjected to next-generation sequencing (NGS) analysis using the FDA-approved FoundationOne CDx™ test. The molecular features of each case were then analyzed employing several in silico prediction tools.

RESULTS

We analyzed the mutational landscape of patients with metastatic or relapsed cutaneous melanoma to define enriched pathways and protein-protein interactions. The analysis showed that both known genetic alterations and variants of unknown significance rely on redundant signaling converging on similar gene ontology biological processes. Complex informatics analyses of NGS-based genetic results identified pivotal signaling pathways that could provide additional targets for cancer treatment.

CONCLUSION

Our data suggest an additional role for NGS in melanoma, as analysis of comprehensive genetic findings using innovative informatic tools may lengthen the list of druggable molecular targets that impact patient outcome.

Direct comparison of the next-generation sequencing and iTERT PCR methods for the diagnosis of TERT hotspot mutations in advanced solid cancers

Background

Mutations in the telomerase reverse transcriptase (TERT) promoter region have been proposed as novel mechanisms for the transcriptional activation of telomerase. Two recurrent mutations in the TERT promoter, C228T and C250T, are prognostic biomarkers. Herein, we directly compared the commercially available iTERT PCR kit with NGS-based deep sequencing to validate the NGS results and determine the analytical sensitivity of the PCR kit.

Methods

Of the 2032 advanced solid tumors diagnosed using the TruSight Oncology 500 NGS test, mutations in the TERT promoter region were detected in 103 cases, with 79 cases of C228T, 22 cases of C250T, and 2 cases of C228A hotspot mutations. TERT promoter mutations were detected from 31 urinary bladder, 19 pancreato-biliary, 22 hepatic, 12 malignant melanoma, and 12 other tumor samples.

Results

In all 103 TERT-mutated cases detected using NGS, the same DNA samples were also tested with the iTERT PCR/Sanger sequencing. PCR successfully verified the presence of the same mutations in all cases with 100% agreement. The average read depth of the TERT promoter region was 320.4, which was significantly lower than that of the other genes (mean, 743.5). Interestingly, NGS read depth was significantly higher at C250 compared to C228 (p < 0.001).

Conclusions

The NGS test results were validated by a PCR test and iTERT PCR/Sanger sequencing is sensitive for the identification of the TERT promoter mutations.

A biomarker panel predicts recurrence-free survival in ulcerated primary cutaneous melanoma

BACKGROUND

Ulceration is an independent adverse prognostic factor in cutaneous malignant melanoma (CMM). There is, however, a need for additional prognostic markers to identify patients with ulcerated stage I-II CMM who have a high-risk for recurrence. The aim of this study was to examine the prognostic impact of BRAF mutation, proliferation and presence of tumour infiltrating lymphocytes (TILs) in primary ulcerated CMM.

MATERIAL AND METHODS

We have used a consecutive cohort consisting of 71 primary ulcerated CMM (T1b-T4b). BRAF mutation was detected using Cobas test and pyrosequencing. Protein expression of the proliferation marker Ki67 was analysed using immunohistochemistry. Presence of TILs was evaluated in representative hematoxylin-eosin stained formalin-fixed paraffin-embedded tumour sections.

RESULTS

Proportion of BRAF mutated alleles, proliferation and presence of TILs all had a statistically significant impact on recurrence free survival in univariate analyses (HR 2.44, 95% CI 1.23-4.84, p = 0.011; HR 2.66, 95% CI 1.32-5.35, p = 0.006 respectively HR 0.48, 95% CI 0.24-0.98, p = 0.045). A trend test found a statistically significant decrease in the proportion of recurrence by including the three favourable factors (BRAF wildtype/low proportion of BRAF mutated alleles, low proliferation and high presence of TILs) (p = 0.0004). When at least two out of three factors were present there was a statistically significant association with longer recurrence free survival in the multivariate analysis (HR 0.30, 95% CI 0.15-0.61, p = 0.001) when adjusted for Breslow thickness, an established independent prognostic marker for CMM.

CONCLUSION

Thus, this panel of markers could be an interesting novel concept for predicting the clinical outcome in patients with high-risk stage I-II ulcerated CMM.

Clinical-Pathological Features and Treatment Outcome of Patients With Hobnail Variant Papillary Thyroid Carcinoma

Papillary thyroid carcinoma (PTC) with hobnail areas above 30% is classified as hobnail variant (HVPTC). Although it is widely accepted that HVPTC has a worse outcome than classical PTC, it is unclear whether PTC with hobnail features below 30% is as aggressive as HVPTC. We gathered the largest mono-institutional series of PTC with hobnail areas and HVPTC to evaluate differences in terms of pathological features of aggressiveness, molecular profile, and treatment outcome. A total of 99 PTC with hobnail features above 5% were retrospectively selected; 34 of them met the criteria for HVPTC (0.4% of all PTC diagnosed at our institution). All tumors showed high rates of extra-thyroidal extension (40.4%), lymph node metastasis (68.1% of patients with lymphadenectomy), and vascular emboli (49.5%), with no differences according to the 30% cutoff. On the other hand, distant metastases were present in HVPTC only (9.4%). Also, advanced age, advanced disease stage, and TERT promoter mutation were associated with HVPTC. More than half of the patients with follow-up had structural or biochemical persistence after 1 year from surgery. Structural persistence was significantly more common in patients with HVPTC (37.5% vs. 8.7%), while no differences were observed considering structural and biochemical persistence together. The presence of hobnail features identifies locally aggressive tumors, and, consequently, it should be always acknowledged in the pathological report. However, tumors with more than 30% hobnail areas frequently present TERT promoter mutations, advanced disease stage, and structural persistence after radioiodine ablation.

Molecular Genetics of Conjunctival Melanoma and Prognostic Value of TERT Promoter Mutation Analysis

The aim of this study was exploration of the genetic background of conjunctival melanoma (CM) and correlation with recurrent and metastatic disease. Twenty-eight CM from the Rotterdam Ocular Melanoma Study group were collected and DNA was isolated from the formalin-fixed paraffin embedded tissue. Targeted next-generation sequencing was performed using a panel covering GNAQ, GNA11, EIF1AX, BAP1, BRAF, NRAS, c-KIT, PTEN, SF3B1, and TERT genes. Recurrences and metastasis were present in eight (29%) and nine (32%) CM cases, respectively. TERT promoter mutations were most common (54%), but BRAF (46%), NRAS (21%), BAP1 (18%), PTEN (14%), c-KIT (7%), and SF3B1 (4%) mutations were also observed. No mutations in GNAQ, GNA11, and EIF1AX were found. None of the mutations was significantly associated with recurrent disease. Presence of a TERT promoter mutation was associated with metastatic disease (p-value = 0.008). Based on our molecular findings, CM comprises a separate entity within melanoma, although there are overlapping molecular features with uveal melanoma, such as the presence of BAP1 and SF3B1 mutations. This warrants careful interpretation of molecular data, in the light of clinical findings. About three quarter of CM contain drug-targetable mutations, and TERT promoter mutations are correlated to metastatic disease in CM.

TERT promoter mutations in penile squamous cell carcinoma: high frequency in non-HPV-related type and association with favorable clinicopathologic features

Purpose

Penile carcinoma is a rare malignant neoplasm with a largely unknown molecular pathogenesis. Telomerase reverse transcriptase promoter (TERT-p) mutations have been detected in several types of human malignancies. The aim of this study was to investigate the presence of TERT-p mutations in penile squamous cell carcinomas (SCCs) and their associations with clinicopathologic features.

Methods

In this retrospective study, Sanger sequencing was performed to detect TERT-p mutations in formalin-fixed paraffin-embedded tissue samples from 37 patients with penile SCC, 16 patients with cutaneous SCC, and 4 patients with non-neoplastic penile/skin tissue. The expression of p16^INK4a and Ki-67 was investigated via immunohistochemistry. Associations of TERT-p mutation with clinicopathological factors, immunohistochemical results, and clinical outcome were statistically analyzed.

Results

Recurrent TERT-p mutations were identified in 18 out of 37 (48.6%) penile SCCs, including all 3 carcinoma in situ cases. TERT-p mutations were significantly more frequent in non-human papilloma virus (HPV)-related penile SCC types than in non-HPV-related penile SCC based on both histologic classification and p16^INK4a immunoreactivity. Furthermore, TERT-p mutation was associated with a low histologic grade, low mitotic count, absence of necrosis, low Ki-67/MIB-1 labeling index, and absence of lymph node or distant metastasis.

Conclusion

Our study shows TERT-p mutations are the most frequent somatic mutations in penile SCC. In addition, TERT-p mutations are far more frequent in non-HPV-related penile SCC than in HPV-related penile SCC, indicating TERT-p mutations may have a role in tumorigenesis distinct from HPV-related penile SCC.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-021-03514-9.

TERT promoter mutation associated with multifocal phenotype and poor prognosis in patients with IDH wild-type glioblastoma

Background

Although mutations in the promoter region of the telomerase reverse transcriptase (TERTp) gene are the most common alterations in glioblastoma (GBM), their clinical significance remains unclear. Therefore, we investigated the impact of TERTp status on patient outcome and clinicopathological features in patients with GBM over a long period of follow-up.

Methods

We retrospectively analyzed 153 cases of GBM. Six patients with isocitrate dehydrogenase 1 (IDH1) or H3F3A gene mutations were excluded from this study. Among the 147 cases of IDH wild-type GBM, 92 (62.6%) had the TERTp mutation. Clinical, immunohistochemical, and genetic factors (BRAF, TP53 gene mutation, CD133, ATRX expression, O⁶-methylguanine-DNA methyltransferase [MGMT] promoter methylation) and copy number alterations (CNAs) were investigated.

Results

GBM patients with the TERTp mutation were older at first diagnosis versus those with TERTp wild type (66.0 vs. 60.0 years, respectively, P = .034), and had shorter progression-free survival (7 vs. 10 months, respectively, P = .015) and overall survival (16 vs. 24 months, respectively, P = .017). Notably, magnetic resonance imaging performed showed that TERTp-mutant GBM was strongly associated with multifocal/distant lesions (P = .004). According to the CNA analysis, TERTp mutations were positively correlated with EGFR amp/gain, CDKN2A deletion, and PTEN deletion; however, these mutations were negatively correlated with PDGFR amp/gain, CDK4 gain, and TP53 deletion.

Conclusions

TERTp mutations were strongly correlated with multifocal/distant lesions and poor prognosis in patients with IDH wild-type GBM. Less aggressive GBM with TERTp wild type may be a distinct clinical and molecular subtype of IDH wild-type GBM.

Mechanisms of TERT Reactivation and Its Interaction with BRAFV600E

The telomerase reverse transcriptase (TERT) gene, which is repressed in most differentiated human cells, can be reactivated by somatic TERT alterations and epigenetic modulations. Moreover, the recruitment, accessibility, and binding of transcription factors also affect the regulation of TERT expression. Reactivated TERT contributes to the development and progression of cancer through telomere lengthening-dependent and independent ways. In particular, because of recent advances in high-throughput sequencing technologies, studies on genomic alterations in various cancers that cause increased TERT transcriptional activity have been actively conducted. TERT reactivation has been reported to be associated with poor prognosis in several cancers, and TERT promoter mutations are among the most potent prognostic markers in thyroid cancer. In particular, when a TERT promoter mutation coexists with the BRAFV600E mutation, these mutations exert synergistic effects on a poor prognosis. Efforts have been made to uncover the mechanisms of these synergistic interactions. In this review, we discuss the role of TERT reactivation in tumorigenesis, the mechanisms of TERT reactivation across all human cancers and in thyroid cancer, and the mechanisms of interactions between BRAFV600E and TERT promoter mutations.

TERT Promoter Mutation as an Independent Prognostic Marker for Poor Prognosis MAPK Inhibitors-Treated Melanoma

Although the development of mitogen-activated protein kinase (MAPK) inhibitors has greatly improved the prognosis of BRAFV600 cutaneous melanomas, the identification of molecular indicators for mutated patients at risk of early progression remains a major issue. Using an amplicon-based next-generation-sequencing (NGS) assay that targets cancer-related genes, we investigated co-occurring alterations in 89 melanoma samples. We analyzed both their association with clinicopathological variables and clinical significance in terms of progression-free survival (PFS) and overall survival (OS) according to BRAF genotyping. Among co-occurring mutations, TERT promoter was the most frequently mutated gene. Although no significant difference in PFS was observed in the presence or absence of co-occurring alterations to BRAFV600, there was a trend of longer PFS for patients harboring TERT c.-124C>T mutation. Of most interest, this mutation is an independent marker of good prognosis in subgroups of patients with poor prognosis (presence of brain metastasis and elevated level of lactate dehydrogenase, LDH). Moreover, combination of elevated LDH level, presence of brain metastasis, and TERT c.-124C>T mutation was identified as the best fit model for predicting clinical outcome. Our work revealed the potential interest of c.-124C>T status determination in order to refine the prognosis of BRAFV600 melanoma under mitogen-activated protein kinase (MAPK) inhibitors.

TERT and TERT promoter in melanocytic neoplasms: Current concepts in pathogenesis, diagnosis, and prognosis

BACKGROUND AND OBJECTIVE

Located on chromosome locus 5p15.33, telomerase reverse transcriptase (TERT or hTERT) encodes the catalytic subunit of telomerase which permits lengthening and preservation of telomeres following mitosis. Mutations in TERT promoter (TERT-p) upregulate expression of TERT, allowing survival of malignant cells and tumor progression in wide variety of malignancies including melanoma. The objective of this review is to examine the roles of TERT and TERT-p in the pathogenesis, diagnosis, and prognostication of cutaneous melanoma.

METHODS

All studies of TERT or TERT-p in cutaneous melanocytic neoplasms with the following inclusion criteria were reviewed: publication date between 2010 and 2019, English language, and series of ≥3 cases were reviewed for evidence supporting the role of TERT in pathogenesis, diagnosis, and prognosis. Studies with <3 cases or focused primarily on mucosal or uveal melanocytic tumors were excluded.

RESULTS AND CONCLUSION

TERT-p mutations are frequent in chronic and non-chronic sun damage melanoma and correlate with adverse prognosis, inform pathogenesis, and may provide diagnostic support. While TERT-p mutations are uncommon in acral melanoma, TERT copy number gains and gene amplification predict reduced survival. Among atypical spitzoid neoplasms, TERT-p mutations identify biologically aggressive tumors and support the diagnosis of spitzoid melanoma. TERT-p methylation may have prognostic value in pediatric conventional melanoma and drive tumorigenesis in melanoma arising within congenital nevi. Finally, TERT-p mutations may aid in the differentiation of recurrent nevi from recurrent melanoma.

TERT promoter mutation determines apoptotic and therapeutic responses of BRAF-mutant cancers to BRAF and MEK inhibitors: Achilles Heel

Combination use of BRAF V600E inhibitor dabrafenib and MEK inhibitor trametinib has become a standard treatment for human cancers harboring BRAF V600E. Its anticancer efficacies vary, however, with dramatic efficacy in some patients and drug resistance/tumor recurrence in others, which is poorly understood. Using thyroid cancer, melanoma, and colon cancer cell models, we showed that dabrafenib and trametinib induced robust apoptosis of cancer cells harboring both BRAF V600E and TERT promoter mutations but had little proapoptotic effect in cells harboring only BRAF V600E. Correspondingly, the inhibitors nearly completely abolished the growth of in vivo tumors harboring both mutations but had little effect on tumors harboring only BRAF V600E. Upon drug withdrawal, tumors harboring both mutations remained hardly measurable but tumors harboring only BRAF V600E regrew rapidly. BRAF V600E/MAP kinase pathway is known to robustly activate mutant promoter of TERT, a strong apoptosis suppressor. Thus, for survival, cancer cells harboring both mutations may have evolved to rely on BRAF V600E-promoted and high-TERT expression-mediated suppression of apoptosis. As such, inhibition of BRAF/MEK can trigger strong apoptosis-induced cell death and hence tumor abolishment. This does not happen in cells harboring only BRAF V600E as they have not developed reliance on TERT-mediated suppression of apoptosis due to the lack of mutant promoter-driven high-TERT expression. TERT promoter mutation governs BRAF-mutant cancer cells' apoptotic and hence therapeutic responses to BRAF/MEK inhibitors. Thus, the genetic duet of BRAF V600E and TERT promoter mutation represents an Achilles Heel for effective therapeutic targeting and response prediction in cancer.

Telomeres and telomerase in oncogenesis

Telomeres are located at the ends of chromosomes and protect them from degradation. Suppressing the activity of telomerase, a telomere-synthesizing enzyme, and maintaining short telomeres is a protective mechanism against cancer in humans. In most human somatic cells, the expression of telomerase reverse transcriptase (TERT) is repressed and telomerase activity is inhibited. This leads to the progressive shortening of telomeres and inhibition of cell growth in a process called replicative senescence. Most types of primary cancer exhibit telomerase activation, which allows uncontrolled cell proliferation. Previous research indicates that TERT activation also affects cancer development through activities other than the canonical function of mediating telomere elongation. Recent studies have improved the understanding of the structure and function of telomeres and telomerase as well as key mechanisms underlying the activation of TERT and its role in oncogenesis. These advances led to a search for drugs that inhibit telomerase as a target for cancer therapy. The present review article summarizes the organization and function of telomeres, their role in carcinogenesis, and advances in telomerase-targeted therapy.

Mutational Profile of Driver Genes in Brazilian Melanomas

PURPOSE

Mutation testing of the key genes involved in melanoma oncogenesis is now mandatory for the application of targeted therapeutics. However, knowledge of the mutational profile of melanoma remains largely unknown in Brazil.

PATIENTS AND METHODS

In this study, we assessed the mutation status of melanoma driver genes BRAF, NRAS, TERT, KIT, and PDGFRA in a cohort of 459 patients attended at Barretos Cancer Hospital between 2001 and 2012. We used polymerase chain reaction followed by Sanger sequencing to analyze the hot spot mutations of BRAF exon 15 (V600E), NRAS (codons 12/13 and 61), TERT (promoter region), KIT (exons 9, 11, 13, and 17), and PDGFRA (exons 12, 14, and 18) in tumors. The mutational profile was investigated for associations with demographic, histopathologic, and clinical features of the disease.

RESULTS

The nodular subtype was most frequent (38.9%) followed by the superficial spreading subtype (34.4%). The most frequent tumor location was in the limbs (50.0%). The mutation rates were 34.3% for TERT and 34.1% for BRAF followed by NRAS (7.9%), KIT (6.2%), and PDGFRA (2.9%). The BRAF (P = .014) and TERT (P = .006) mutations were associated with younger patients and with different anatomic locations, particularly in the trunk, for the superficial spreading and nodular subtypes, respectively (P = .0001 for both). PDGFRA mutations were associated with black skin color (P = .023) and TERT promoter mutations with an absence of ulceration (P = .037) and lower levels of lactate dehydrogenase. There was no association between patient survival rates and mutational status.

CONCLUSION

The similar mutational profile we observe in melanomas in Brazil compared with other populations will help to guide precision medicine in this country.

Prevalence of NRAS Mutation, PD-L1 Expression and Amplification, and Overall Survival Analysis in 36 Primary Vaginal Melanomas

Background

Primary vaginal melanomas are uncommon and aggressive tumors with poor prognosis, and the development of new targeted therapies is essential. This study aimed to identify the molecular markers occurring in these patients and potentially improve treatment strategies.

Materials and Methods

The clinicopathological characteristics of 36 patients with primary vaginal melanomas were reviewed. Oncogenic mutations in BRAF, KIT, NRAS, GNAQ and GNA11 and the promoter region of telomerase reverse transcriptase (TERT) were investigated using the Sanger sequencing. The expression and copy number of programmed death‐ligand 1 (PD‐L1) were also assessed.

Results

Mutations in NRAS, KIT, and TERT promoter were identified in 13.9% (5/36), 2.9% (1/34), and 5.6% (2/36) of the primary vaginal melanomas, respectively. PD‐L1 expression and amplification were observed in 27.8% (10/36) and 5.6% (2/36) of cases, respectively. PD‐L1 positive expression and/or amplification was associated with older patients (p = .008). Patients who had NRAS mutations had a poorer overall survival compared with those with a wild‐type NRAS (33.5 vs. 14.0 months; hazard ratio [HR], 3.09; 95% CI, 1.08–8.83). Strikingly, two patients with/without PD‐L1 expression receiving immune checkpoint inhibitors had a satisfying outcome. Multivariate analysis demonstrated that >10 mitoses per mm² (HR, 2.96; 95% CI, 1.03–8.51) was an independent prognostic factor.

Conclusions

NRAS mutations and PD‐L1 expression were most prevalent in our cohort of primary vaginal melanomas and can be potentially considered as therapeutic targets.

Implications for Practice

This study used the Sanger sequencing, immunohistochemistry, and fluorescence in situ hybridization methods to detect common genetic mutations and PD‐L1 expression and copy number in 36 primary vaginal melanomas. NRAS mutations and PD‐L1 expression were the most prevalent, but KIT and TERT mutations occurred at a lower occurrence in this rare malignancy. Two patients receiving immune checkpoint inhibitors had a satisfying outcome, signifying that the PD‐L1 expression and amplification can be a possible predictive marker of clinical response. This study highlights the possible prospects of biomarkers that can be used for patient selection in clinical trials involving treatments with novel targeted therapies based on these molecular aberrations.

Little is known about the molecular characteristics of primary vaginal melanoma. This article reports on the molecular markers of this rare and aggressive disease, focusing on improvements in treatment strategies.

Noninvasive Analysis of High-Risk Driver Mutations and Gene Expression Profiles in Primary Cutaneous Melanoma

Tools that help reduce the number of surgical biopsies performed on benign lesions have the potential to improve patient care. The pigmented lesion assay (PLA) is a noninvasive tool validated against histopathology that helps rule out melanoma and the need for surgical biopsies of atypical pigmented skin lesions. Genetic information is collected using adhesive patches and the expression of two genes, LINC and PRAME, is measured. By using genetic material collected noninvasively and to further validate the PLA, somatic hotspot mutations in genes known to be drivers of early melanoma development (BRAF other than V600E, NRAS, and the TERT promoter) can also be identified. The frequency of these hotspot mutations in samples of early melanoma was 77%, which is higher than the 14% found in nonmelanoma samples (P < 0.0001). TERT promoter mutations were the most prevalent mutation type in PLA-positive melanomas; 82% of PLA-negative lesions had no mutations, and 97% of histopathologically confirmed melanomas were PLA and/or mutation positive (cohort 1, n = 103). Mutation frequencies were similar in prospectively collected real-world PLA samples (cohort 2, n = 519), in which 88% of PLA-negative samples had no mutations. Combining gene expression and mutation analyses enhances the ability to noninvasively detect early cutaneous melanoma.

Utility of TERT Promoter Mutations for Cutaneous Primary Melanoma Diagnosis

Telomerase reverse transcriptase (TERT) promoter mutations are commonly found in malignant melanomas but rare in melanocytic nevi. To assess its potential diagnostic utility for the distinction of melanoma from nevus, we determined the TERT promoter mutation status of 86 primary melanomas, 72 melanocytic nevi, and 40 diagnostically problematic melanocytic proliferations. Of the 86 melanomas, 67 (77.9%) were TERT-positive, defined as harboring a hotspot TERT promoter mutation at positions -124C>T, -124_125CC>TT, -138_139CC>TT, or -146C>T. Of the 72 nevi, only 1 (1.4%) was TERT-positive. Of the 40 diagnostically uncertain melanocytic proliferations, 2 (5.0%) were TERT-positive. TERT positivity as a test for melanoma versus nevus had an accuracy of 87.3% [95% confidence interval (CI), 81.1-92.1], a sensitivity of 77.9% (95% CI, 68.9-85.4), a specificity of 98.6% (95% CI, 95.8-100), a positive predictive value of 98.5% (95% CI, 95.6-100), and a negative predictive value of 78.9% (95% CI, 72.6-85.4). Our results indicate that hotspot TERT promoter mutation status may be a useful ancillary parameter for the diagnosis of melanoma. In particular, the high specificity of these mutations for melanoma indicates the presence of a TERT promoter mutation in a melanocytic neoplasm associated with diagnostic controversy, or uncertainty should increase concern for a melanoma.

Telomerase reverse transcriptase promoter mutations and solar elastosis in cutaneous melanoma

The aims of this study were to assess the prognostic potential of solar elastosis grading and telomerase reverse transcriptase (TERT) promoter mutations (TERTp) in melanoma and to evaluate whether an association between solar elastosis and TERTp exists. Solar elastosis in the dermis was evaluated in hematoxylin and eosin-stained whole slides from 486 malignant melanomas. Pyrosequencing was used to detect TERTp in 189 samples. There was no association between solar elastosis and TERTp (P=0.3). Severe elastosis was associated with older age (P<0.0001), ulceration (P=0.03), and location in the head/neck region (P<0.0001). The absence of elastosis was associated with younger age (P<0.0001), benign nevus remnants (P=0.001), and a positive BRAF V600E expression (P<0.0001). Severe elastosis predicted a worse relapse-free survival (hazard ratio: 2.18; 95% confidence interval: 1.30-3.64; P=0.003). However, it was not independent of age. TERTp was not associated with any adverse prognostic or clinicopathological outcome, nor any mitogen-activated protein kinase-related protein expressions. However, at a cutoff corresponding to the sensitivity of Sanger sequencing, TERTp predicted melanoma-specific death independently of age, and was associated with Breslow thickness, ulceration, tumor stage at diagnosis, BRAF V600E oncoprotein, and absence of p16 expression. In conclusion, TERTp were not related to severe elastosis and may thus be triggered by both chronic and acute intermittent sun exposure, the latter not visible on ordinary hematoxylin and eosin-stained slides. Neither TERTp nor severe elastosis predicted an adverse outcome in melanoma. An absence of elastosis was seen in younger melanoma patients and may be used to select those melanomas originating in a nevus, which often harbors a BRAF mutation.

Coexistence of TERT Promoter Mutations and the BRAF V600E Alteration and Its Impact on Histopathological Features of Papillary Thyroid Carcinoma in a Selected Series of Polish Patients

TERT promoter (TERTp) mutations are important factors in papillary thyroid carcinomas (PTCs). They are associated with tumor aggressiveness, recurrence, and disease-specific mortality and their use in risk stratification of PTC patients has been proposed. In this study we investigated the prevalence of TERTp mutations in a cohort of Polish patients with PTCs and the association of these mutations with histopathological factors, particularly in coexistence with the BRAF V600E mutation. A total of 189 consecutive PTC specimens with known BRAF mutational status were evaluated. TERTp mutations were detected in 8.5% of cases (16/189) with the C228T mutation being the most frequent. In six of the PTC specimens (3.2%), four additional TERTp alterations were found, which included one known polymorphism (rs2735943) and three previously unreported alterations. The association analysis revealed that the TERTp hotspot mutations were highly correlated with the presence of the BRAF V600E mutation and their coexistence was significantly associated with gender, advanced patient age, advanced disease stage, presence of lymph node metastases, larger tumor size, and tumor-capsule infiltration. While correlations were identified, the possibility of TERTp mutations being key molecular modulators responsible for PTC aggressiveness requires further studies.

Concordance of somatic mutation profiles (BRAF,NRAS, and TERT) and tumoral PD-L1 in matched primary cutaneous and metastatic melanoma samples

Despite the efficacy of BRAF-targeted and PD-L1-related immune therapies in tackling metastatic melanoma, a significant number of patients exhibit resistance. Given this, the objective of the current study was to ascertain concordance of somatic mutations in BRAF/NRAS/TERT and immunohistochemical PD-L1 and CD8 in matched primary cutaneous and metastatic melanoma. A total of 43 archival paired samples with sufficient material for genetic and immunohistochemical analyses met the criteria for inclusion in the study. Immunohistochemistry was performed for PD-L1 and CD8 and direct-DNA Sanger sequencing for BRAF/NRAS/TERT promoter mutational analyses. Agreement between paired samples was assessed using Cohen κ. Poor concordance among primary and corresponding metastases was noted in BRAF (9/42 cases discordant, κ = 0.49; 95% confidence interval [CI], 0.21-0.77; P = .0013), TERT promoter mutations (13/41 cases discordant, κ = 0.33; 95% CI, 0.04-0.62; P = .033), tumoral PD-L1 immunoexpression (9/43 cases discordant, κ = 0.39; 95% CI, 0.07-0.72; P = .0099), and immunoexpression of CD8⁺ T lymphocytes (12/43 cases discordant, κ = 0.44; 95% CI, 0.19-0.69; P = .002). Although NRAS1 and NRAS2 were highly concordant (42/43 and 39/43 cases, respectively), discordant NRAS2 mutational status was associated with a median time to metastasis of 90 versus 455 days for pairs with concordant status (P = .07). Although limited by sample size, our findings suggest that consideration be given to mutational analysis of metastatic tissue rather than the primary to guide BRAF-targeted therapy and question the roles of TERT promoter mutations and PD-L1 as predictive biomarkers in malignant melanoma.

TERT copy gain predicts the outcome of high-dose interferon α-2b therapy in acral melanoma

Background

Asian populations are more likely to develop acral melanoma (AM) than Caucasians. The high-dose interferon (HD-IFN) α-2b regimen is the main adjuvant treatment for AM. TERT encodes the catalytic subunit of telomerase reverse transcriptase, which plays an important role in melanoma. Frequent TERT mutation and increased TERT gene expression have been described in AM. Our study aimed to investigate the status and the clinical significance of TERT copy number in a large cohort of patients with AM and to analyze the relationship between TERT copy number gain and the efficiency of HD-IFN.

Patients and methods

A total of 573 melanoma samples were retrospectively collected and analyzed for TERT copy number via Sanger sequencing. Clinical data of patients were also collected.

Results

TERT copy gain (copy number >2) was detected in 257 of the 573 patients with AM (44.9%). Of the 573 patients, 81 (14.1%) had a high copy gain (copy number >4). Patients with ulceration showed a significantly higher copy gain rate of TERT compared to the patients without ulceration (P=0.028). Patients with a tumor thicker than 4 mm also had a higher copy number rate of TERT than those with <4 mm (P=0.048). Our results showed that the overall survival (OS) was not significantly different between patients with and without TERT copy gain (P=0.890). However, among the 278 patients who received an HD-IFN regimen, Kaplan–Meier survival analysis demonstrated a significant correlation between TERT copy gain and relapse-free survival (RFS) (P=0.008). In addition, multivariate Cox regression assays validated TERT copy gain to be an independent prognostic factor of RFS for patients with AM undergoing HD-IFN therapy (hazard ratio =1.50; P=0.019).

Conclusion

The copy number status of TERT might be a predictor for HD-IFN efficacy, but it is not a prognostic factor of OS in patients with AM.

Telomere Maintenance Mechanisms in Cancer

Tumour cells can adopt telomere maintenance mechanisms (TMMs) to avoid telomere shortening, an inevitable process due to successive cell divisions. In most tumour cells, telomere length (TL) is maintained by reactivation of telomerase, while a small part acquires immortality through the telomerase-independent alternative lengthening of telomeres (ALT) mechanism. In the last years, a great amount of data was generated, and different TMMs were reported and explained in detail, benefiting from genome-scale studies of major importance. In this review, we address seven different TMMs in tumour cells: mutations of the TERT promoter (TERTp), amplification of the genes TERT and TERC, polymorphic variants of the TERT gene and of its promoter, rearrangements of the TERT gene, epigenetic changes, ALT, and non-defined TMM (NDTMM). We gathered information from over fifty thousand patients reported in 288 papers in the last years. This wide data collection enabled us to portray, by organ/system and histotypes, the prevalence of TERTp mutations, TERT and TERC amplifications, and ALT in human tumours. Based on this information, we discuss the putative future clinical impact of the aforementioned mechanisms on the malignant transformation process in different setups, and provide insights for screening, prognosis, and patient management stratification.

Regulation of mutant TERT by BRAF V600E/MAP kinase pathway through FOS/GABP in human cancer

The unique oncogene duet of coexisting BRAF V600E and TERT promoter mutations are widely found to be a robust genetic background promoting human cancer aggressiveness, but the mechanism is unclear. Here, we demonstrate that the BRAF V600E/MAP kinase pathway phosphorylates and activates FOS, which in turn acts as a transcription factor to bind and activate the GABPB promoter, increasing GABPB expression and driving formation of GABPA-GABPB complex; the latter selectively binds and activates mutant TERT promoter, upregulating TERT expression. Elevated TERT functions as a strong oncoprotein, robustly promoting aggressive behaviors of cancer cells and tumor development. We thus identify a molecular mechanism for the activation of mutant TERT by the BRAF V600E/MAP kinase pathway, in which FOS as a transcriptional factor of GABPB promoter plays a key role in functionally bridging the two oncogenes in cooperatively promoting oncogenesis, providing important cancer biological and clinical implications.

The mechanism of tumor progression robustly promoted by co-existing BRAF V600E and TERT promoter mutations is not known. Here, the authors show a mechanism of mutant TERT activation by BRAF V600E and MAPK pathways in which FOS, as a transcription factor of the GABPB promoter, functionally links the two oncogenes.

TERT promoter mutations and their correlation with BRAF and RAS mutations in a consecutive cohort of 145 thyroid cancer cases

Papillary thyroid carcinoma (PTC) is the most common type of endocrine malignancy and accounts for ~80% of thyroid carcinomas in adults and 90% in children. Risk stratification is important for identifying patients at higher risk and, for this reason, recent advances in molecular genetics of thyroid cancer can be applied to provide novel biomarkers useful in understanding tumor behavior. B-Raf proto-oncogene, serine/threonine kinase (BRAF) and rat sarcoma (RAS) mutations have been widely studied and appear to have an important role in thyroid tumorigenesis. Somatic telomerase reverse transcriptase (TERT) promoter mutations have been recently identified in several types of malignant tumors, including thyroid neoplasia; however, the actual role of TERT mutations in thyroid tumorigenesis is still under debate. In the present study, the mutational status of BRAF, RAS and TERT was analyzed in order to elucidate the roles of these genes in thyroid tumorigenesis. The TERT mutational analysis was also correlated with an immunohistochemical study of TERT protein expression. According to the literature, our data provide evidence of the BRAF and RAS roles in thyroid tumorigenesis, supporting an association between BRAF (V600E) mutations and the more aggressive clinical and pathological features of thyroid tumors. By contrast, TERT mutations were not significantly associated with any clinical parameters; therefore, its role in initial tumorigenesis should be further investigated.

Combining molecular and immunohistochemical analyses of key drivers in primary melanomas: interplay between germline and somatic variations

Due to the high mutational somatic burden of Cutaneous Malignant Melanoma (CMM) a thorough profiling of the driver mutations and their interplay is necessary to explain the timing of tumorigenesis or for the identification of actionable genetic events. The aim of this study was to establish the mutation rate of some of the key drivers in melanoma tumorigenesis combining molecular analyses and/or immunohistochemistry in 93 primary CMMs from an Italian cohort also characterized for germline status, and to investigate an interplay between germline and somatic variants. BRAF mutations were present in 68% of cases, while CDKN2A germline mutations were found in 16 % and p16 loss in tissue was found in 63%. TERT promoter somatic mutations were detected in 38% of cases while the TERT –245T>C polymorphism was found in 51% of cases. NRAS mutations were found in 39% of BRAF negative or undetermined cases. NF1 was expressed in all cases analysed. MC1R variations were both considered as a dichotomous variable or scored. While a positive, although not significant association between CDKN2A germline mutations, but not MC1R variants, and BRAF somatic mutation was found, we did not observe other associations between germline and somatic events. A yet undescribed inverse correlation between TERT –245T>C polymorphism and the presence of BRAF mutation was found. It is possible to hypothesize that –245T>C polymorphism could be included in those genotypes which may influence the occurrence of BRAF mutations. Further studies are needed to investigate the role of –245T>C polymorphism as a germline predictor of BRAF somatic mutation status.

Telomerase reverse transcriptase promoter alterations across cancer types as detected by next-generation sequencing: A clinical and molecular analysis of 423 patients

BACKGROUND

Telomerase reverse transcriptase (TERT) promoter mutations that may affect telomerase activity have recently been described in human malignancies. The purpose of this study was to investigate the clinical correlates of TERT promoter abnormalities in a large cohort of patients with diverse cancers.

METHODS

This study analyzed TERT promoter alterations and clinical characteristics of 423 consecutive patients for whom molecular testing by next-generation sequencing was performed between August 2014 and July 2015.

RESULTS

Of the 423 patients, 61 (14.4%) had TERT promoter mutations, and this placed TERT promoter alterations among the most prevalent aberrations after tumor protein 53 (TP53; 39%) and KRAS and cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) alterations (15% each) in this population. TERT promoter alterations were more frequent in men (P = .031) and were associated with brain cancers (P = .001), skin cancers/melanoma (P = .001), and a higher number of aberrations (P = .0001). A co-alteration analysis found that TERT promoter alterations were significantly correlated with CDKN2A/B (P = .001) and BRAF abnormalities (P = .0003). Patients harboring TERT promoter alterations or TP53 or CDKN2A/B alterations and those with 4 or more alterations demonstrated shorter survival (hazard ratio for normal TERT promoters vs aberrant ones, 0.44; P = .017). However, only a higher number of alterations remained significant in the multivariate analysis.

CONCLUSIONS

Overall, TERT promoter alterations were among the most prevalent aberrations in this population, with very high rates in brain cancers (48% of patients) and melanomas (56% of patients). These aberrations frequently coexist with a high number of other aberrations, with the latter feature also significantly associated with poorer overall survival. Therapeutic options for targeting tumors with TERT promoter mutations are currently limited, although a variety of novel approaches are under development. Cancer 2018;124:1288-96. © 2017 American Cancer Society.

Prognostic impact and concordance of TERT promoter mutation and protein expression in matched primary and metastatic cutaneous melanoma

Background:

TERT promoter mutations are frequent in melanoma. Here we analysed the concordance and prognostic impact of TERT mutation and telomerase reverse transcriptase (TERT) protein expression in a large melanoma series.

Methods:

In 194 primary nodular melanomas with 72 matched loco-regional metastases, TERT promoter mutation status was assessed by Sanger sequencing and TERT protein expression by immunohistochemistry.

Results:

TERT mutations were found in 68% of primary melanomas and 64% of metastases, and the mutation status was discordant between primary tumour and metastasis in 24% of the cases. 6 of the 10 cases with discordant and wild-type metastases were also TERT wild type when re-tested in other intra-tumour regions, whereas 4 cases were mutation positive. TERT-mutated tumours tended to be thicker, have a higher mitotic count and higher patient age than TERT wild-type cases, but there was no significant association with reduced survival. TERT protein expression did not correlate with mutation status, but showed a similar discordancy between the primary and first metastatic lesion, and was significantly associated with reduced survival.

Conclusions:

TERT promoter mutations showed inter- and intra-tumoural discordancy, whereas only expression of TERT protein was associated with reduced patient survival.

Low frequency of TERT promoter mutations in a series of well-differentiated follicular-patterned thyroid neoplasms

The diagnostic and clinical approaches to follicular-patterned thyroid neoplasms often create dilemmas for pathologist and clinicians. The molecular analysis of these tumors could be a useful tool to overcome diagnostic limitations. The most frequent molecular alterations are point mutations of RAS family genes. Nevertheless, other molecular markers should be taken into account for their prognostic role, as BRAF mutations and the recently described telomerase reverse transcriptase (TERT) promoter mutation. We investigated the prevalence and the possible role of TERT promoter, BRAF, and RAS mutations in a series of low-risk well-differentiated follicular-patterned thyroid neoplasms. We evaluated 60 follicular adenomas (FA), 29 minimally invasive follicular carcinomas (MIFTC), 82 papillary carcinomas, follicular variant (FVPTC), and 16 noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFT-P) for the molecular status of BRAF, H-, N-, K-RAS, and TERT and correlated it with clinic-pathological parameters of tumors. Fifty-seven (30.5%) follicular neoplasms were mutated. In particular, we found 44 RAS mutated neoplasms (23.5%), specifically three FAs, 29 FVPTCs, five NIFT-Ps, and seven FTCs. BRAF mutations were found in ten FVPTCs. Finally, TERT promoter mutations were observed in three FVPTCs and three FTCs; three of them harbored also N-RAS mutations. We confirmed the absence of TERT promoter mutations in benign follicular neoplasms and found a low frequency of TERT promoter mutations in our selected cohort of low-risk follicular-patterned malignancies, speculating their role in the progression and de-differentiation of thyroid cancer.

KIF5B/RET Rearrangement in a Carcinoma of the Thyroid Gland: A Case Report of a Fatal Disease

BACKGROUND

The diffuse sclerosing variant of papillary thyroid cancer (DSV-PTC) is a rare variant of papillary thyroid cancer (PTC) with different clinicopathological features compared with conventional PTC.

CASE

An advanced DSV-PTC was diagnosed in a 39-year-old man. The radioiodine posttherapeutic whole-body-scan showed only an uptake in the central neck, whereas the computerized tomography showed multiple latero-cervical and mediastinum lymph node metastases, a single and spiculated lung lesion and multiple bilateral cerebellum metastases. The patient died after 6 months from the initial diagnosis. The histological revision of the thyroid tumor confirmed the diagnosis of DSV-PTC, and its molecular analysis revealed a KIF5B/RET rearrangement that, until now, was described only in a minority of lung adenocarcinoma. Other 18 cases of DSV-PTC were then studied for the presence of KIF5B/RET rearrangement, but all of them were negative.

CONCLUSIONS

This was a case of DSV-PTC positive for KIF5B/RET rearrangement, but considering that this alteration has been described only in lung adenocarcinoma and that the clinical course was more typical of lung carcinoma, we cannot completely rule out the possibility that this was a metastatic lesion from a lung tumor mimicking a DSV-PTC. As an alternative, we can also hypothesize that this was a case of fusion of two tumoral tissues deriving from a DSV-PTC and a metastasis of a KIF5B/RET positive lung adenocarcinoma. The question of whether the molecular findings, particularly when specifically reported only in some subtypes of human tumors, can overcome the morphological diagnosis is a matter of discussion.

Presence of immune cells, low tumor proliferation and wild type BRAF mutation status is associated with a favourable clinical outcome in stage III cutaneous melanoma

BACKGROUND

The variable prognosis in stage III cutaneous melanoma is partially due to unknown prognostic factors. Improved prognostic tools are required to define patients with an increased risk of developing metastatic disease who might benefit from adjuvant therapies. The aim was to examine if cellular immune markers in association with tumor proliferation rate and BRAF mutation status have an impact on prognosis in stage III melanoma.

METHODS

We have used two sets of case series with stage III disease: 23 patients with short survival (≤ 13 months) and 19 patients with long survival (≥ 60 months). Lymph node metastases were analyzed for Ki67, CD8 and FOXP3 protein expression using immunohistochemistry. BRAF mutation status was analyzed in a previous study on the same samples.

RESULTS

Low tumor proliferation rate was significantly associated with a better prognosis (p = 0.013). Presence of FOXP3+ T cells was not correlated to adverse clinical outcome. A highly significant trend for a longer survival was found in the presence of an increasing number of markers; CD8+ and FOXP3+ T cells, low tumor proliferation and BRAF wildtype status (p = 0.003). Presence of at least three of these four markers was found to be an independent favorable prognostic factor (OR 19.4, 95% CI 1.9-197, p = 0.012), when adjusting for ulceration and number of lymph node metastases. Proliferation alone remained significant in multivariate analyses (OR 26.1, 95% CI 2.0-344, p = 0.013) but with a wider confidence interval. This panel still remained independent when also adjusting for a previously identified prognostic glycolytic-pigment panel.

CONCLUSIONS

We have demonstrated that presence of immune cells in association with tumor proliferation and BRAF mutation status may further contribute to identify stage III melanoma patients with high risk of relapse.

MAPK Pathway and TERT Promoter Gene Mutation Pattern and Its Prognostic Value in Melanoma Patients: A Retrospective Study of 2,793 Cases

Purpose: Ethnic differences are conspicuous in melanoma. This study is to obtain a comprehensive view of a genomic landscape and a better understanding of the correlations of gene mutation status with clinicopathologic characteristics and disease prognosis in the Asian population.Experimental Design: A total of 2,793 melanoma patient samples were retrospectively collected and analyzed for mutations in C-KIT, BRAF, NRAS, and PDGFRA coding regions and telomerase reverse transcriptase (TERT) promoter region by Sanger sequencing. Mutations were correlated to clinicopathologic features and overall survival.Results: The incidences of somatic mutations within the BRAF, NRAS, C-KIT, TERT-228, TERT-250, and PDGFRA genes were 23.7%, 10.4%, 8.0%, 5.9%, 5.5%, and 1.4%, respectively. Hotspot mutations accounted for 95.8% and 87.2% of BRAF and NRAS mutations, respectively; meanwhile, C-KIT and PDGFRA mutations showed more heterogeneity. BRAF, C-KIT, and NRAS mutations were mutually exclusive. BRAF, C-KIT, NRAS, and numbers of gene mutations of the MAPK pathway were all independent negative prognostic factors (P = 0.007, other P < 0.001, respectively). In acral melanoma, BRAF, C-KIT, and NRAS mutations were all independent prognostic factors of worse overall survival (all P < 0.001), whereas in mucosal melanoma, only C-KIT was (P = 0.006). Although correlated with BRAF mutations (P = 0.001 and P < 0.001 for C228T and C250T, respectively), TERT promoter gene mutations were not correlated with overall survival (P = 0.406 and 0.256, respectively).Conclusions: The MAPK pathway and TERT promoter gene mutations are differentially represented in the Asian population. Mutations in BRAF, C-KIT, and NRAS have prognostic values that vary by melanoma subtypes. Clinical treatment targeting these critical pathways should be aimed directly at these poor-prognosis subpopulations for maximum potential impact. Clin Cancer Res; 23(20); 6120-7. ©2017 AACR.

Management of intracranial melanomas in the era of precision medicine

Melanoma is the most lethal of skin cancers, in part because of its proclivity for rapid and distant metastasis. It is also potentially the most neurotropic cancer in terms of probability of CNS metastasis from the primary lesion. Despite surgical resection and radiotherapy, prognosis remains guarded for patients with brain metastases. Over the past five years, a new domain of personalized therapy has emerged for advanced melanoma patients with the introduction of BRAF and other MAP kinase pathway inhibitors, immunotherapy, and combinatory therapeutic strategies. By targeting critical cellular signaling pathways and unleashing the adaptive immune response against tumor antigens, a subset of melanoma patients have demonstrated remarkable responses to these treatments. Over time, acquired resistance to these modalities inexorably develops, providing new challenges to overcome. We review the rapidly evolving terrain for intracranial melanoma treatment, address likely and potential mechanisms of resistance, as well as evaluate promising future therapeutic approaches currently under clinical investigation.

Genetic and Epigenetic Alterations of TERT Are Associated with Inferior Outcome in Adolescent and Young Adult Patients with Melanoma

Progression of melanoma to distant sites in adolescents and young adults (AYAs) is not reliably predicted by clinicopathologic criteria. TERT promoter mutations when combined with BRAF/NRAS mutations correlate with adverse outcome in adult melanoma. To determine the prognostic value of TERT alterations in AYA melanoma, we investigated the association of TERT promoter mutations, as well as promoter methylation, an epigenetic alteration also linked to TERT upregulation, with TERT mRNA expression and outcome using a well-characterized cohort of 27 patients with melanoma (ages 8–25, mean 20). TERT mRNA expression levels were significantly higher in tumors harboring TERT promoter mutation and/or hypermethylation than those without either aberration (P = 0.046). TERT promoter mutations alone did not predict adverse outcomes (P = 0.50), but the presence of TERT promoter methylation, alone or concurrent with promoter mutations, correlated with reduced recurrence-free survival (P = 0.001). These data suggest that genetic and epigenetic alterations of TERT are associated with TERT upregulation and may predict clinical outcomes in AYA melanoma. A more exhaustive understanding of the different molecular mechanisms leading to increased TERT expression may guide development of prognostic assays to stratify AYA melanoma patients according to clinical risk.

TERT biology and function in cancer: beyond immortalisation

Evasion of replicative senescence and proliferation without restriction, sometimes designated as immortalisation, is one of the hallmarks of cancer that may be attained through reactivation of telomerase in somatic cells. In contrast to most normal cells in which there is lack of telomerase activity, upregulation of TERT transcription/activity is detected in 80-90% of malignant tumours. In several types of cancer, there is a relationship between the presence of TERT promoter mutations, TERT mRNA expression and clinicopathological features, but the biological bridge between the occurrence of TERT promoter mutations and the aggressive/invasive features displayed by the tumours remains unidentified. We and others have associated the presence of TERT promoter mutations with metastisation/survival in several types of cancer. In follicular cell-derived thyroid cancer, such mutations are associated with worse prognostic features (age of patients, tumour size and tumour stage) as well as with distant metastases, worse response to treatment and poorer survival. In this review, we analyse the data reported in several studies that imply TERT transcription reactivation/activity with cell proliferation, tumour invasion and metastisation. A particular attention is given to the putative connections between TERT transcriptional reactivation and signalling pathways frequently altered in cancer, such as c-MYC, NF-κB and B-Catenin.

Systemic BRAF/MEK Inhibitors as a Potential Treatment Option in Metastatic Conjunctival Melanoma

AIM

In this review, we outline similarities between conjunctival and skin melanoma as well as the effectiveness of combined BRAF/MEK inhibition in melanoma, and discuss the applicability of these agents in conjunctival melanoma.

METHODS

The study provides a PubMed literature review.

RESULTS

Conjunctival melanoma and skin melanoma are genetically and phenotypically related. Both tumors typically harbor BRAF mutations in more than 50% of cases. New targeted therapies in metastatic skin melanoma include selective inhibition of BRAF and MEK. Combined BRAF/MEK inhibition has revolutionized the treatment of metastatic skin melanoma, significantly improving patients' prognoses. While these new substances have been investigated extensively in the treatment of skin melanoma, comparable studies in conjunctival melanoma do not exist owing to the rarity of the malignancy.

CONCLUSIONS

The application of combined BRAF/MEK inhibition in metastatic or unresectable conjunctival melanoma shows great potential for improving patients' prognoses. Future studies are needed to investigate the assumed benefit.

TERT promoter mutations in telomere biology

Telomere repeats at chromosomal ends, critical to genome integrity, are maintained through an elaborate network of proteins and pathways. Shelterin complex proteins shield telomeres from induction of DNA damage response to overcome end protection problem. A specialized ribonucleic protein, telomerase, maintains telomere homeostasis through repeat addition to counter intrinsic shortcomings of DNA replication that leads to gradual sequence shortening in successive mitoses. The biogenesis and recruitment of telomerase composed of telomerase reverse transcriptase (TERT) subunit and an RNA component, takes place through the intricate machinery that involves an elaborate number of molecules. The synthesis of telomeres remains a controlled and limited process. Inherited mutations in the molecules involved in the process directly or indirectly cause telomeropathies. Telomerase, while present in stem cells, is deactivated due to epigenetic silencing of the rate-limiting TERT upon differentiation in most of somatic cells with a few exceptions. However, in most of the cancer cells telomerase reactivation remains a ubiquitous process and constitutes one of the major hallmarks. Discovery of mutations within the core promoter of the TERT gene that create de novo binding sites for E-twenty-six (ETS) transcription factors provided a mechanism for cancer-specific telomerase reactivation. The TERT promoter mutations occur mainly in tumors from tissues with low rates of self-renewal. In melanoma, glioma, hepatocellular carcinoma, urothelial carcinoma and others, the promoter mutations have been shown to define subsets of patients with adverse disease outcomes, associate with increased transcription of TERT, telomerase reactivation and affect telomere length; in stem cells the mutations inhibit TERT silencing following differentiation into adult cells. The TERT promoter mutations cause an epigenetic switch on the mutant allele along with recruitment of pol II following the binding of GABPA/B1 complex that leads to mono-allelic expression. Thus, the TERT promoter mutations hold potential as biomarkers as well as future therapeutic targets.

Activation of mutant TERT promoter by RAS-ERK signaling is a key step in malignant progression of BRAF-mutant human melanomas

Although activating BRAF/NRAS mutations are frequently seen in melanomas, they are not sufficient to drive malignant transformation and require additional events. Frequent co-occurrence of mutations in the promoter for telomerase reverse transcriptase (TERT), along with BRAF alterations, has recently been noted and correlated with poorer prognosis, implicating a functional link between BRAF signaling and telomerase reactivation in melanomas. Here, we report that RAS-ERK signaling in BRAF mutant melanomas is critical for regulating active chromatin state and recruitment of RNA polymerase II at mutant TERT promoters. Our study provides evidence that the mutant TERT promoter is a key substrate downstream of the RAS-ERK pathway. Reactivating TERT and hence reconstituting telomerase is an important step in melanoma progression from nonmalignant nevi with BRAF mutations. Hence, combined targeting of RAS-ERK and TERT promoter remodeling is a promising avenue to limit long-term survival of a majority of melanomas that harbor these two mutations.

Transcription Regulation of the Human Telomerase Reverse Transcriptase (hTERT) Gene

Embryonic stem cells and induced pluripotent stem cells have the ability to maintain their telomere length via expression of an enzymatic complex called telomerase. Similarly, more than 85%–90% of cancer cells are found to upregulate the expression of telomerase, conferring them with the potential to proliferate indefinitely. Telomerase Reverse Transcriptase (TERT), the catalytic subunit of telomerase holoenzyme, is the rate-limiting factor in reconstituting telomerase activity in vivo. To date, the expression and function of the human Telomerase Reverse Transcriptase (hTERT) gene are known to be regulated at various molecular levels (including genetic, mRNA, protein and subcellular localization) by a number of diverse factors. Among these means of regulation, transcription modulation is the most important, as evident in its tight regulation in cancer cell survival as well as pluripotent stem cell maintenance and differentiation. Here, we discuss how hTERT gene transcription is regulated, mainly focusing on the contribution of trans-acting factors such as transcription factors and epigenetic modifiers, as well as genetic alterations in hTERT proximal promoter.