Telomere Length Recovery: A Strong Predictor of Overall Survival in Acute Promyelocytic Leukemia

Meta-hallmarks of aging and cancer

Both aging and cancer are characterized by a series of partially overlapping "hallmarks" that we subject here to a meta-analysis. Several hallmarks of aging (i.e., genomic instability, epigenetic alterations, chronic inflammation, and dysbiosis) are very similar to specific cancer hallmarks and hence constitute common "meta-hallmarks," while other features of aging (i.e., telomere attrition and stem cell exhaustion) act likely to suppress oncogenesis and hence can be viewed as preponderantly "antagonistic hallmarks." Disabled macroautophagy and cellular senescence are two hallmarks of aging that exert context-dependent oncosuppressive and pro-tumorigenic effects. Similarly, the equivalence or antagonism between aging-associated deregulated nutrient-sensing and cancer-relevant alterations of cellular metabolism is complex. The agonistic and antagonistic relationship between the processes that drive aging and cancer has bearings for the age-related increase and oldest age-related decrease of cancer morbidity and mortality, as well as for the therapeutic management of malignant disease in the elderly.

Genetic Variants of the TERT Gene and Telomere Length in Obstructive Sleep Apnea

Introduction: Obstructive sleep apnea (OSA) is a worldwide breathing disorder that has been diagnosed globally in almost 1 billion individuals aged 30−69 years. It is characterized by repeated upper airway collapses during sleep. Telomerase reverse transcriptase (TERT) is involved in the prevention of telomere shortening. This prospective, observational study aimed to investigate the relationship between single nucleotide polymorphisms (SNPs) of TERT and the severity of OSA, taking into account hypertension and diabetes prevalence. Methods: A total of 149 patients with OSA were diagnosed using one-night video-polysomnography based on the American Academy of Sleep Medicine guidelines. The TERT SNPs and telomere length (TL) were detected using real-time quantitative polymerase chain reaction. Results: Statistical analysis showed that there is no relationship between the rs2853669 and rs2736100 polymorphisms of TERT, and the severity of OSA (p > 0.05). Moreover, no relationship between TL and the severity of OSA was observed. The G allele in the locus of rs2736100 TERT was associated with hypertension prevalence and was more prevalent in hypertensives patients (46.00% vs. 24.49%, p = 0.011). The prevalence of hypertension was higher in patients with the C allele in the locus of rs2853669 than in patients without this allele (50.79% vs. 30.23%, p = 0.010). Moreover, a lower prevalence of diabetes was observed in homozygotes of rs2736100 TERT than in heterozygotes (5.63% vs. 15.38%, p = 0.039). Conclusion: This study showed no relationship between OSA and TERT SNPs. However, SNPs of the TERT gene (rs2736100 and rs2853669) were found to affect arterial hypertension and diabetes prevalence.

A study of TERT rare variants in myeloid neoplasia

Telomere dysfunctions are associated with several hematopoietic stem cell (HSC) malignancies. Recent findings have indicated that the occurrence of rare variants of unknown significance (VUS) in the Telomerase Reverse Transcriptase (TERT) gene influences the outcomes of patients with myelodysplastic syndromes undergoing allogeneic HSC transplantation. However, the role of TERT variants has been historically controversial as initially considered pathogenic variants (H412Y, A202T) presenting functional consequences, were found very frequent in general population questioning their pathogenicity and risk allele significance. Herein, we show that overall TERT VUS are non-recurrent in myeloid disorders and cannot be considered risk alleles individually nor can their biological impact. This article is protected by copyright. All rights reserved.

TERT rs2853669 as a predictor for overall survival in patients with acute myeloid leukaemia

INTRODUCTION

the aim of the study was to investigate the contribution of TERT rs2736100 and rs2853669 gene polymorphisms in defining the genetic predisposition to acute myeloid leukaemia (AML), their association with different prognostic markers, and their impact on survival, outcome, and the prognosis of affected patients. Also, we investigated the association of TERT SNPs in AML in the presence or absence of DNMT3A (R882), NPM1, and FLT3 mutations.

MATERIAL AND METHODS

A total of 509 participants were enrolled in our study, consisting of 146 AML patients and 363 healthy participants, with no history of malignancy. TERT rs2736100 and rs2853669 polymorphisms were genotyped by using TaqMan SNP genotyping assay FLT3 (ITD, D835), DNMT3A (R882), and NPM1 c.863_864insTCTG (type A) mutations were analised in each AML case.

RESULTS

TERT rs2736100 and rs2853669 were not associated with AML risk in the codominant, dominant, recessive, or allelic models. Multivariate Cox regression showed that TERT rs2853669 was a significant predictor for overall survival in AML patients. After adjusting for age, gender, cytogenetic risk group, ECOG status, FLT3, DNMT3A, NPM1 mutation, AML subtype, and treatment, the estimated adjusted hazard ratio (HR adjusted = 1.54, 95% CI: 1.01-2.35) showed that the TERT rs2853669 variant genotype had a negative influence on survival time.

CONCLUSIONS

TERT rs2853669 and rs2736100 polymorphisms were not risk factors for developing AML in the Romanian population, but the TERT rs2853669 variant genotype had a negative effect on AML patients' overall survival in the presence of other known prognostic factors.

Evaluation of pretreatment telomere length as a prognostic marker in intermediate-risk acute myeloid leukemia

INTRODUCTION

The current framework for risk stratification is still insufficient for highly heterogeneous intermediate-risk acute myeloid leukemia (IRC-AML), which lacks specific genomic abnormalities.

METHODS

In order to incorporate novel biomarkers to refine current risk stratification strategies for patients with this subtype, we investigated pretreatment telomere length (TL), which is essential for maintaining genomic stability, in 204 adults with de novo AML (non-acute promyelocytic leukemia).

RESULTS

We found that TL measured at diagnosis did not decrease with advancing age in 204 patients with AML (R²  = 0.001, P = .695). A multivariate analysis demonstrated that short TL was independently associated with an inferior relapse-free survival (hazard ratio [HR] 3.08, 95% confidence interval [CI] 1.48-6.41, P = .003); event-free survival (HR 2.14, 95% CI 1.12-4.08, P = .021); and overall survival (HR 2.26, 95% CI 1.09-4.67, P = .028) in IRC-AML patients. In addition, IRC-AML patients with short TL also exhibited an increased cumulative incidence of hematologic relapse (HR 2.32, 95% CI 1.08-5.26, P = .032).

CONCLUSION

Short TL is an independent prognostic factor for poor prognosis in patients with IRC-AML and may represent a novel mechanism that links genomic stability and disease progression.

Differentiation syndrome with lower-intensity treatments for acute myeloid leukemia

Differentiation Syndrome (DS) has been identified in a subset of patients undergoing treatment with novel classes of differentiating therapies for acute myeloid leukemia (AML) such as IDH and FLT3 inhibitors. While DS is a well-known treatment-related complication in acute promyelocytic leukemia (APL), efforts are still ongoing to standardize diagnostic and treatment parameters for DS in AML. Though the rates of incidence vary, many of the signs and symptoms of DS are common between APL and AML. So, DS can lead to fatal complications in AML, but prompt management is usually effective and rarely necessitates interruption or discontinuation of AML therapy.

Telomere Length and Hematological Disorders: A Review

Telomeres compose the end portions of human chromosomes, and their main function is to protect the genome. In hematological disorders, telomeres are shortened, predisposing to genetic instability that may cause DNA damage and chromosomal rearrangements, inducing a poor clinical outcome. Studies from 2010 to 2019 were compiled and experimental studies using samples of patients diagnosed with hematological malignancies that reported the size of the telomeres were described. Abnormal telomere shortening is described in cancer, but in hematological neoplasms, telomeres are still shortened even after telomerase reactivation. In this study, we compared the sizes of telomeres in leukemias, myelodysplastic syndrome and lymphomas, identifying that the smallest telomeres are present in patients at relapse. In conclusion, the experimental and clinical data analyzed in this review demonstrate that excessive telomere shortening is present in major hematological malignancies and its analysis and measurement is a crucial step in determining patient prognosis, predicting disease risk and assisting in the decision for targeted therapeutic strategies.

Bone marrow mononuclear cell telomere length in acute myeloid leukaemia and high-risk myelodysplastic syndrome

OBJECTIVE

Short telomere length is a known risk factor for developing clonal haematopoietic stem cell disorders, probably due to chromosomal instability. We tested the hypotheses that bone marrow mononuclear cell telomere length change from diagnosis through chemotherapy-induced remission and relapse, and that long telomere length is associated with low risk of relapse and all-cause mortality in patients with acute myeloid leukaemia or high-risk myelodysplastic syndrome.

METHODS

We measured telomere length in bone marrow mononuclear cells from 233 patients at diagnosis, 112 patients at chemotherapy-induced remission and 58 patients at relapse of disease.

RESULTS

In patients with acute myeloid leukaemia or high-risk myelodysplastic syndrome, bone marrow mononuclear cell telomere length was similar at diagnosis and relapse, but increased after chemotherapy-induced remission. Furthermore, bone marrow mononuclear cell telomere length was longer in patients with higher age at diagnosis. There was no association between telomere length at diagnosis, remission or relapse and all-cause mortality, nor did we find any association between telomere length at diagnosis or remission and risk of relapse.

CONCLUSION

In patients with acute myeloid leukaemia or high-risk myelodysplastic syndrome, bone marrow mononuclear cell telomere length increased from diagnosis to remission. Furthermore, telomere length paradoxically was longer at higher age at diagnosis, even after adjusting for known risk factors of disease severity. Finally, we did not detect any prognostic information in telomere length.

Biological and clinical implications of telomere dysfunction in myeloid malignancies

Telomeres at the ends of linear chromosomes protect the genome. Telomeres shorten with each round of cell division, placing a finite limit on cell growth. Telomere attrition is associated with cell senescence and apoptosis. Telomerase, a specialized ribonucleoprotein complex, maintains telomeres homeostasis through repeat addition of telomere sequences to the 3' telomeric overhang. Telomere biology is closely related to cancer and normal aging. Upregulation of telomerase or activation of the alternative pathway of telomere lengthening is a hallmark of cancer cells, making telomerase an attractive target for cancer therapeutics. In this review, we will discuss telomere biology and the prognostic implications of telomere length in acute myeloid leukemia, and review exciting new investigational approaches using telomerase inhibitors in acute myeloid leukemia and other myeloid malignancies.

Alternative splicing of hTERT: a further mechanism for the control of active hTERT in acute myeloid leukemia

hTERT component is the key regulator of telomerase. Alternatively spliced variants of hTERT generate different telomerase activity. The goal of the study was to determine the role of different hTERT isoforms in the regulation of telomerase expression in AML patients. Among the 97 studied patients, 45 had a complex karyotype and 52 a normal karyotype. hTERT isoforms expression was determined in bone marrow samples by q-RT-PCR, using SYBR Green I. hTERT expression was lower in AML patients than controls (median 2.5 vs. 10.1, p = .003), though no difference was observed between the complex and normal karyotype (median 3.2 vs. 2.3, p = .37). High trans-dominant negative isoform expression increased the response rate by two. High expression of inactive product (-α - β) was shown to increase the risk of relapse by about three times. In conclusion, our data suggest an intriguing link between the control of hTERT isoforms expression and AML outcome.

Prognostic role of telomere length in malignancies: A meta-analysis and meta-regression

Telomere length (TL) has been associated with several health conditions including cancer. To quantify the effect of TL on outcomes in malignancies and explore the role of type of TL measurement we conducted a librarian-led systematic search of electronic databases identified publications exploring the prognostic role of TL on cancer outcomes. Overall survival (OS) was the primary outcome measure while other time-to-event endpoints were secondary outcomes. Data from studies reporting a hazard ratio (HR) with 95% confidence interval (CI) and/or p-value were pooled in a meta-analysis. HRs were weighted by generic inverse variance and computed by random effects modeling. All statistical tests were two-sided. Sixty-one studies comprising a total of 14,720 patients were included of which 41 (67%) reported OS outcomes. Overall, the pooled HR for OS was 0.88 (95%CI=0.69-1.11, p=0.28). Long (versus short) telomeres were associated with improved outcomes in chronic lymphatic leukemia (CLL) and urothelial cancer (HR=0.45, 95%CI=0.29-0.71 and HR=0.68, 95%CI=0.46-1.00, respectively), conversely worse OS was seen with hepatocellular carcinoma (HR=1.90, 95%CI=1.51-2.38). Pooled HRs (95% CI) for progression-free survival, relapse/disease-free survival, cancer-specific survival, and treatment-free survival were 0.56 (0.41-0.76), 0.76 (0.53-1.10), 0.72 (0.48-1.10), and 0.48 (0.39-0.60), respectively. There was substantial heterogeneity of tissues and methods used for TL measurement and no clear association between TL and outcome was identified in subgroups. In conclusion, there is inconsistent effect of TL on cancer outcomes possibly due to variable methods of measurement. Standardization of measurement and reporting of TL is warranted before the prognostic value of TL can be accurately assessed.