TERT polymorphisms modify the risk of acute lymphoblastic leukemia in Chinese children

Genetic association study of TERT gene variants with chronic kidney disease susceptibility in the Chinese population

The incidence and mortality of chronic kidney disease (CKD) are increasing globally. Studies have demonstrated the significance of genetic risk factors in the progression of CKD. Telomerase reverse transcriptase (TERT) may be implicated in the development of CKD. This study aimed to investigate the correlation between TERT gene variants and susceptibility to CKD in the Chinese population. A total of 507 patients with CKD and 510 healthy controls were recruited for this case-control study. Four candidate loci were identified using the MassARRAY platform. Logistic regression analysis was employed to assess the association between TERT gene variants and the risk of CKD. The false positive reporting probability (FPRP) method was utilized to evaluate the validity of statistically significant associations. The multifactorial dimensionality reduction (MDR) method was used to evaluate the interaction between SNPs and the risk of CKD. Furthermore, discrepancies in the clinical features of subjects with diverse genotypes were evaluated using one-way analysis of variance (ANOVA). Our findings revealed a correlation between rs2735940 and rs4635969 and an increased risk of CKD. Stratification analysis indicated that rs4635969 was related to an increased risk of CKD in different subgroups (age ≤ 50 years and male). MDR analysis indicated that the two-site model (rs2735940 and rs4635969) was the best prediction model. Furthermore, the rs2735940 GG genotype was found to be linked to an increased level of microalbuminuria (MAU) in patients with CKD. Our study is the first to reveal a connection between TERT gene variants and susceptibility to CKD, providing new insights into the field of nephrology.

Telomere length and hTERT genetic variants as potential prognostic markers in multiple myeloma

Telomere dysfunction is a notable event observed in many cancers contributing to their genomic instability. A major factor controlling telomere stability is the human telomerase reverse transcriptase catalytic subunit (hTERT). Telomere shortening has been observed in multiple myeloma (MM), a plasma cell malignancy with a complex and heterogeneous genetic background. In the present study, we aimed to analyse telomere length and hTERT genetic variants as potential markers of risk and survival in 251 MM patients. We found that telomere length was significantly shorter in MM patients than in healthy individuals, and patients with more advanced disease (stage III according to the International Staging System) had shorter telomeres than patients with less advanced disease. MM patients with hTERT allele rs2736100 T were characterized with significantly shorter progression-free survival (PFS). Moreover, allele rs2736100 T was also found to be less common in patients with disease progression in response to treatment. hTERT rs2853690 T was associated with higher haemoglobin blood levels and lower C-reactive protein. In conclusion, our results suggest that telomere length and hTERT genetic variability may affect MM development and can be potential prognostic markers in this disease.

Genetic Variants in Telomerase Reverse Transcriptase Contribute to Solar Lentigines

Solar lentigines (SLs) are a hallmark of human skin aging. They result from chronic exposure to sunlight and other environmental stressors. Recent studies also imply genetic factors, but findings are partially conflicting and lack of replication. Through a multi-trait based analysis strategy, we discovered that genetic variants in telomerase reverse transcriptase were significantly associated with non-facial SL in two East Asian (Taizhou longitudinal cohort, n = 2,964 and National Survey of Physical Traits, n = 2,954) and one Caucasian population (SALIA, n = 462), top SNP rs2853672 (P-value for Taizhou longitudinal cohort = 1.32 × 10^‒28 and P-value for National Survey of Physical Traits = 3.66 × 10^‒17 and P-value for SALIA = 0.0007 and P_meta = 4.93 × 10^‒44). The same variants were nominally associated with facial SL but not with other skin aging or skin pigmentation traits. The SL-enhanced allele/haplotype upregulated the transcription of the telomerase reverse transcriptase gene. Of note, well-known telomerase reverse transcriptase‒related aging markers such as leukocyte telomere length and intrinsic epigenetic age acceleration were not associated with SL. Our results indicate a previously unrecognized role of telomerase reverse transcriptase in skin aging‒related lentigines formation.

The landscape of GWAS validation; systematic review identifying 309 validated non-coding variants across 130 human diseases

Background

The remarkable growth of genome-wide association studies (GWAS) has created a critical need to experimentally validate the disease-associated variants, 90% of which involve non-coding variants.

Methods

To determine how the field is addressing this urgent need, we performed a comprehensive literature review identifying 36,676 articles. These were reduced to 1454 articles through a set of filters using natural language processing and ontology-based text-mining. This was followed by manual curation and cross-referencing against the GWAS catalog, yielding a final set of 286 articles.

Results

We identified 309 experimentally validated non-coding GWAS variants, regulating 252 genes across 130 human disease traits. These variants covered a variety of regulatory mechanisms. Interestingly, 70% (215/309) acted through cis-regulatory elements, with the remaining through promoters (22%, 70/309) or non-coding RNAs (8%, 24/309). Several validation approaches were utilized in these studies, including gene expression (n = 272), transcription factor binding (n = 175), reporter assays (n = 171), in vivo models (n = 104), genome editing (n = 96) and chromatin interaction (n = 33).

Conclusions

This review of the literature is the first to systematically evaluate the status and the landscape of experimentation being used to validate non-coding GWAS-identified variants. Our results clearly underscore the multifaceted approach needed for experimental validation, have practical implications on variant prioritization and considerations of target gene nomination. While the field has a long way to go to validate the thousands of GWAS associations, we show that progress is being made and provide exemplars of validation studies covering a wide variety of mechanisms, target genes, and disease areas.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01216-w.

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.

More Related Gene Pathways to Vincristine-Induced Death Events in a Human T-Acute Lymphoblastic Leukemia Cell Line

BACKGROUND

Acute lymphoblastic leukemia (ALL) is common in children but rare in adults. Vincristine (VCR) is one of the drugs used at the beginning of treatment. Some genes are resistant to VCR in B-ALL.

METHODS

Here, we examined the effect of VCR on gene expression changes in a T-ALL cell line, Jurkat. The MTT method was used to determine the IC₅₀ in Jurkat cells treated with different concentrations of VCR for 48 and 72 hours. Total RNA was isolated from the cells and cDNA was prepared. The Human Cancer Drug Target PCR Array kit was used to evaluate the 84 gene expression changes in Jurkat cells. Protein-protein interaction was analyzed by STRING software.

RESULTS

We identified 66 differentially expressed genes as comparison to untreated cells. The response to VCR-induced apoptotic events was remarkable in the pathways of heat shock protein, topoisomerases, protein kinases, cathepsins and cell cycle. In other pathways, there were resistant genes as well as sensitive genes to VCR treatment. Some proteins like HSP90AA1 and ESR1 had determining associations with other proteins.

CONCLUSION

The results suggest VCR target genes in T-ALL cells may be beneficial biomarkers for ALL treatment and can be used to select appropriate synergistic drugs for VCR.

Mechanism of Human Telomerase Reverse Transcriptase (hTERT) Regulation and Clinical Impacts in Leukemia

The proliferative capacity and continuous survival of cells are highly dependent on telomerase expression and the maintenance of telomere length. For this reason, elevated expression of telomerase has been identified in virtually all cancers, including leukemias; however, it should be noted that expression of telomerase is sometimes observed later in malignant development. This time point of activation is highly dependent on the type of leukemia and its causative factors. Many recent studies in this field have contributed to the elucidation of the mechanisms by which the various forms of leukemias increase telomerase activity. These include the dysregulation of telomerase reverse transcriptase (TERT) at various levels which include transcriptional, post-transcriptional, and post-translational stages. The pathways and biological molecules involved in these processes are also being deciphered with the advent of enabling technologies such as next-generation sequencing (NGS), ribonucleic acid sequencing (RNA-Seq), liquid chromatography-mass spectrometry (LCMS/MS), and many others. It has also been established that TERT possess diagnostic value as most adult cells do not express high levels of telomerase. Indeed, studies have shown that prognosis is not favorable in patients who have leukemias expressing high levels of telomerase. Recent research has indicated that targeting of this gene is able to control the survival of malignant cells and therefore offers a potential treatment for TERT-dependent leukemias. Here we review the mechanisms of hTERT regulation and deliberate their association in malignant states of leukemic cells. Further, we also cover the clinical implications of this gene including its use in diagnostic, prognostic, and therapeutic discoveries.

TERT Gene rs2736100 and rs2736098 Polymorphisms are Associated with Increased Cancer Risk: A Meta-Analysis

Abnormal telomerase activity plays a key role in the development of carcinogenesis. The variants rs2736100 and rs2736098 of the telomerase reverse transcriptase (TERT) gene, which encodes the telomerase catalytic subunit, are associated with the risk of different types of cancers. However, the results remain controversy. We conducted a meta-analysis to more precisely assess this association. We comprehensively searched the PubMed and Web of Science databases up to June 1, 2020, and retrieved a total of 103 studies in 82 articles, including 89,320 cases and 121,654 controls. Among these studies, 69 published studies including 75,274 cases and 10,3248 controls were focused on rs2736100, and 34 published studies including 14,046 cases and 18,362 controls were focused on rs2736098. The results showed a strong association between variant rs2736100 and cancer risk in all populations. (G vs. T: OR 1.18, 95% CI 1.12-1.24; TG+GG vs. TT: OR 1.23, 95% CI 1.15-1.31; GG vs. TG+TT: OR 1.25, 95% CI 1.16-1.36); the variant rs2736098 was associated with cancer risk in all populations as well (A vs. G: OR 1.13, 95% CI 1.05-1.22; GA+AA vs. GG: OR 1.15, 95% CI 1.04-1.27; AA vs. GA+GG: OR 1.22, 95% CI 1.10-1.38). Stratified analysis based on the cancer type indicated that rs2736100 was associated with an increased risk of thyroid cancer, bladder cancer, lung cancer, glioma, and myeloproliferative neoplasms. rs2736098 only increased the risk of bladder cancer and lung cancer. Moreover, the TERT variants rs2736100 and rs2736098 were associated with a decreased risk of breast cancer and colorectal cancer. The variants rs2736098 and rs2736100 located in 5p15.33 around TERT were associated with increased cancer risk in all populations. These two variants had bidirectional effects in different tumors.

Evaluation of 17 genetic variants in association with leukemia in the north Indian population using MassARRAY Sequenom

Leukemia is a heterogeneous disorder, characterized by elevated proliferation of white blood cells. In this study, we explored the association of 17 genetic variants with leukemia patients in the Jammu and Kashmir region of north India. The variants were genotyped by using a high-throughput Agena MassARRAY platform in 758 individuals (166 cases and 592 controls). Of the 17 single-nucleotide polymorphisms (SNPs) studied, five SNPs were showing significant association with the high risk of leukemia in the north Indian population, which includes rs10069690 of telomere reverse transcriptase (TERT) with OR = 0.34 (95% CI, 0.20-0.58; p = .0008), rs2972392 (​​​PSCA) with OR 1.86 (95% CI, 1.04-3.81; p = .035), rs4986764 (BRIP1) with OR 1.34 (95% CI, 1.00-1.80; p = .04), rs6990097 (TNKS) with OR 1.81 (95% CI, 1.2-2.6; p = .001) and rs12190287 (TCF21) with OR 2.87 (95% CI, 1.72-4.7; p = .0001) by allelic association using Plink and analyzed by SPSS. This is the first study to explore these variants with leukemia in the studied population.

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.

Genetic Variants of the TERT Gene, Telomere Length, and Circulating TERT as Prognostic Markers in Rectal Cancer Patients

Single-nucleotide polymorphisms (SNPs) in the TERT gene can affect telomere length and TERT expression and have been associated with risk and/or outcome for several tumors, but very few data are available about their impact on rectal cancer. Eight SNPs (rs2736108, rs2735940, rs2736098, rs2736100, rs35241335, rs11742908, rs2736122 and rs2853690), mapping in regulatory and coding regions of the TERT gene, were studied in 194 rectal cancer patients to evaluate their association with constitutive telomere length, circulating TERT mRNA levels, response to neoadjuvant chemoradiotherapy (CRT) and disease outcome. At diagnosis, the rs2736100CC genotype was associated with longer telomeres measured pre-CRT, while the rs2736100CC, rs2736108TT and rs2735940AA were associated with greater telomere erosion evaluated post-CRT. The rs2736108CC and rs2853690AA/GG genotypes, respectively associated with lower telomere erosion and lower levels of circulating TERT post-CRT, were also independently associated with a better response to therapy [OR 4.6(1.1-19.1) and 3.0(1.3-6.9)]. Overall, post-CRT, low levels (≤ median value) of circulating TERT and its stable/decreasing levels compared to those pre-CRT, were independently associated with a better response to therapy [OR 5.8(1.9-17.8) and 5.3(1.4-19.4), respectively]. Furthermore, post-CRT, patients with long telomeres (>median value) and low levels of circulating TERT had a significantly lower risk of disease progression [HR 0.4(0.1-0.9) and 0.3(0.1-0.8), respectively]. These findings suggest that TERT SNPs could be a useful tool for improving the selection of patients who could benefit from CRT and support the role of telomere length and circulating TERT mRNA levels as useful markers for monitoring the response to therapy and disease outcome in rectal cancer patients.

TERT rs10069690 polymorphism and cancers risk: A meta-analysis

BACKGROUND

Studies have identified that the telomerase reverse transcriptase (TERT) gene polymorphism rs10069690 (C>T) is associated with cancer risk, but the results remain inconclusive.

METHODS

To provide a more precise estimation of the relationship, we performed a meta-analysis of 45 published studies including 329,035 cases and 730,940 controls. We conducted a search in PubMed, Google Scholar and Web of Science to select studies on the association between rs10069690 and cancer risk. Stratification by ethnicity, cancer type, cancers' classification, source of control, sample size, and genotype method was used to explore the source of heterogeneity. The pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were evaluated using random effects models. Sensitivity, publication bias, false-positive report probability (FPRP) and statistical power were also assessed.

RESULTS

The result demonstrated that rs10069690 was significantly associated with an increased risk of cancer overall (OR = 1.09, 95% CI: 1.06-1.12, p < .001) under the allele model. Stratification analysis revealed an increased cancer risk in subgroups of breast cancer, ovarian cancer, lung cancer, thyroid cancer, and renal cell carcinoma (RCC). However, a significantly decreased association was observed in pancreatic cancer in the European population (OR = 0.93,95% CI: 0.87-0.99, p = .031). In the subgroup analysis based on cancer type, no significant association was found in prostate cancer, leukemia, colorectal cancer and glioma.

CONCLUSIONS

This meta-analysis suggested that the TERT rs10069690 polymorphism may be a risk factor for cancer, especially breast cancer, ovarian cancer, lung cancer, thyroid cancer, and RCC. Further functional studies are warranted to reveal the role of the polymorphism in carcinogenesis.

Association between hTERT Polymorphisms and Female Papillary Thyroid Carcinoma

BACKGROUND

A previous genome-wide association study showed that hTERT rs10069690 and rs2736100 polymorphisms were associated with thyroid cancer risk.

OBJECTIVE

This study further investigated the association between increased risk and clinicopathologic characteristics for Papillary Thyroid Carcinoma (PTC) and hTERT polymorphisms rs10069690 or rs2736100 in a Chinese female population.

METHODS

The hTERT genotypes of 276 PTC patients and 345 healthy subjects were determined with regard to SNPs rs10069690 and rs2736100. The association between these SNPs and the risk of PTC and clinicopathologic characteristics was investigated by logistic regression.

RESULTS

We found a significant difference between PTC and rs10069690 (Odds Ratio (OR) = 1.515; P = 0.005), but not between PTC and rs2736100. When the analysis was limited to females, rs10069690 and rs2736100 were both associated with increased risk for PTC in female individuals (OR = 1.647, P = 0.007; OR = 1.339, P = 0.041, respectively). Further haplotype analysis revealed a stimulative effect of haplotypes TC and CA of TERT rs10069690-rs2736100, which increased risk for PTC in female individuals (OR = 1.579, P = 0.014; OR = 0.726, P = 0.025, respectively). Furthermore, the heterozygote A/C of rs2736100 showed significant difference for age (OR = 0.514, P = 0.047).

CONCLUSION

Our finding suggests that hTERT polymorphisms rs10069690 and rs2736100 are associated with increased risk for PTC in Chinese female population and rs2736100 may be related to age. Consistent with US20170360914 and US20170232075, they are expected to be a potential molecular target for anti-cancer therapy.

Leukocyte Telomere Length Shortening, hTERT Genetic Polymorphisms and Risk of Childhood Acute Lymphoblastic Leukemia

Background: Telomeres are involved in chromosomal stability, cellular immortality and tumorigenesis. Human telomerase reverse transcriptase (TERT) is essential for the maintenance of telomere DNA length. Recently, a variable tandem-repeats polymorphism, MNS16A, located in the downstream region of the TERT gene, was reported to have an effect on TERT expression and telomerase activity. Previous studies have linked both relative telomere length (RTL) and TERT variants with cancer. Therefore, we evaluated associations between RTL, TERT gene polymorphisms (hTERT, rs2735940 C/T and MNS16A Ins/Del) and risk of childhood acute lymphoblastic leukemia (ALL) in an Iranian population. Methods: RTL was determined by a multiplex quantitative PCR-based method, and variants of the hTERT, rs2735940 C/T and MNS16A Ins/Del, were genotyped by amplification refractory mutation system PCR (ARMS-PCR), and PCR, respectively. Results: Our results indicated that RTL was shorter in ALL patients (1.53±0.12) compared to the control group (2.04±0.19) (P=0.029). However, no associations between hTERT gene variants or haplotypes and the risk of childhood ALL were observed (P>0.05). Also hTERT polymorphisms were not associated with RTL or patient clinicopathological characteristics, including age (P=0.304), sex (P=0.061) organomegally (P=0.212) CSF involvement (P=0.966) or response to treatment (P=0.58). Conclusions: We found that telomere attrition may be related to the pathogenesis of childhood ALL, irrespective to TERT variants.

The TERT rs2736100 polymorphism increases cancer risk: A meta-analysis

Abnormal telomerase activity is implicated in cancer initiation and development. The rs2736100 T > G polymorphism in the telomerase reverse transcriptase (TERT) gene, which encodes the telomerase catalytic subunit, has been associated with increased cancer risk. We conducted a meta-analysis to more precisely assess this association. After a comprehensive literature search of the PubMed and EMBASE databases up to November 1, 2016, 61 articles with 72 studies comprising 108,248 cases and 161,472 controls were included in our meta-analysis. Studies were conducted on various cancer types. The TERT rs2736100 polymorphism was associated with increased overall cancer risk in five genetic models [homozygous model (GG vs. TT): odds ratio (OR) = 1.39, 95% confidence interval (95% CI) = 1.26-1.54, P < 0.001; heterozygous model (TG vs. TT): OR = 1.16, 95% CI = 1.11-1.23, P < 0.001; dominant model (TG + GG vs. TT): OR = 1.23, 95% CI = 1.15-1.31, P < 0.001; recessive model (GG vs. TG + TT): OR = 1.25, 95% CI = 1.16-1.35, P < 0.001; and allele contrast model (G vs. T): OR = 1.17, 95% CI = 1.12-1.23, P < 0.001]. A stratified analysis based on cancer type associated the polymorphism with elevated risk of thyroid cancer, bladder cancer, lung cancer, glioma, myeloproliferative neoplasms, and acute myeloid leukemia. Our results confirm that the TERT rs2736100 polymorphism confers increased overall cancer risk.

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.

Telomerase Reverse Transcriptase Polymorphism rs2736100: A Balancing Act between Cancer and Non-Cancer Disease, a Meta-Analysis

The enzyme telomerase reverse transcriptase (TERT) is essential for telomere maintenance. In replicating cells, maintenance of telomere length is important for the preservation of vital genetic information and prevention of genomic instability. A common genetic variant in TERT, rs2736100 C/A, is associated with both telomere length and multiple diseases. Carriage of the C allele is associated with longer telomere length, while carriage of the A allele is associated with shorter telomere length. Furthermore, some diseases have a positive association with the C and some with the A allele. In this study, meta-analyses were performed for two groups of diseases, cancerous diseases, e.g., lung cancer and non-cancerous diseases, e.g., pulmonary fibrosis, using data from genome-wide association studies and case-control studies. In the meta-analysis it was found that cancer positively associated with the C allele (pooled OR 1.16 [95% CI 1.09–1.23]) and non-cancerous diseases negatively associated with the C allele (pooled OR 0.81 [95% CI 0.65–0.99]). This observation illustrates that the ambiguous role of telomere maintenance in disease hinges, at least in part, on a single locus in telomerase genes. The dual role of this single nucleotide polymorphism also emphasizes that therapeutic agents aimed at influencing telomere maintenance should be used with caution.

Association of TERT polymorphisms with chronic hepatitis B in a Chinese Han population

In this study, we investigated the association between the polymorphisms of telomerase reverse transcriptase (TERT) gene and the risk of chronic hepatitis B (CHB) in a Chinese Han population. Four single nucleotide polymorphisms (SNPs) in TERT (rs10069690, rs2242652, rs2853677 and rs2853676) were genotyped from 224 CHB patients and 300 healthy controls using the Sequenom Mass-ARRAY platform. We used genetic model, haplotype analyses, chi-square test, logistic regression analysis to evaluate the association between SNPs and CHB risk. The relative risk was estimated by odd ratios (ORs) and 95% confidence intervals (CIs). We found that rs10069690 was significantly associated with an increased CHB risk in the dominant model (adjusted OR = 1.70, 95% CI: 1.06–2.71, P = 0.031) and additive model (adjusted OR = 1.62, 95% CI: 1.09–2.41, P = 0.018). The haplotype “TA” (rs10069690 and rs2242652) was found to be associated with an increased risk of CHB (adjusted OR = 1.58, 95% CI: 1.05–2.38, P = 0.027). Our results suggested potential genetic contributes for TERT in CHB development in a Chinese Han population. Future functional and association studies with larger sample sizes are required to confirm these findings.

The association between the TERT rs2736100 AC genotype and reduced risk of upper tract urothelial carcinomas in a Han Chinese population

Upper tract urothelial carcinomas (UTUCs) are originated from urothelium, and consist of renal pelvic carcinomas (RPCs) and ureter carcinomas (UCs). Most UTUCs have already become invasive when diagnosed and there is thus a need to identify high-risk populations for preventive intervention. Recent evidence has accumulated supporting common single nucleotide polymorphisms (SNPs) to be associated with increased risk of various malignancies. However, little is known about susceptibility loci in relation to UTUC development. We genotyped telomerase reverse transcriptase (TERT) rs2736100 variants, the SNP associated with a risk of multiple-types of cancer, in patients with UTUC (n = 212) and evaluated the relationship between the rs2736100 and UTUC risk by comparing to 289 healthy controls. Neither AA nor CC genotypes differed significantly between cases and controls, while the AC-carriers were associated with a reduced risk of UTUC compared to the homozygous AA (OR = 0.583; 95% CI: 0.388 − 0.875; P = 0.012) or AA + CC genotypes (0.613; 95% CI: 0.428 − 0.879; P = 0.010). Further analyses showed that the AC variant conferred a lower risk for early stage UTUCs or those with a wt TERT promoter. When UTUCs were sub-grouped into UCs and RPCs, the AC genotype still predicts a significantly lower risk for UC (P = 0.045, OR = 0.597, 95% CI: 0.370 − 0.963), while at a border line significance for RPC (P = 0.055, OR = 0.597, 95% CI: 0.324 − 0.976). Collectively, the rs2736100 AC variant predicts a reduced risk to develop UTUC.

TERT rs2736098 (Ex2-659G>A) polymorphism and cancer susceptibility: evidence from a comprehensive meta-analysis

Increasing researches have been performed regarding the relationship between TERT rs2736098 and cancer risk, but no consensus has been reached about the relationship. Here, we conducted this updated meta-analysis, aiming to comprehensively evaluate the role of TERT rs2736098 in cancer risk. We systematically searched potential relevant articles through PubMed, EMBASE, CNKI, and WanFang database before August 2017. A total of 33 studies with 18685 cases and 23820 controls were finally included in the current meta-analysis. We then adopted odds ratios (ORs) and 95% confidence intervals (CIs) to analyze the contributions of TERT rs2736098 to cancer risk. We found that the TERT rs2736098 polymorphism was associated with risk of cancer in overall analysis (AA vs. GG: OR = 1.26, 95% CI = 1.09–1.47; AA vs. AG/GG: OR = 1.22, 95% CI = 1.09–1.36; AA/AG vs. GG: OR = 1.13, 95% CI = 1.02–1.24; A vs. G: OR = 1.11, 95% CI = 1.04–1.20). Furthermore, in analysis stratified by cancer type, ethnicity, control source, quality score, and Hardy-Weinberg equilibrium (HWE) in controls, we found increased risk of cancer among lung cancer, bladder cancer, breast cancer, colorectal cancer, other cancers, Asians, hospital-based subgroup, score > 9 group, as well as controls agreement with HWE group. Despite some limitations, the current meta-analysis represented the largest and the most comprehensive investigations, with the strongest conclusion than ever before. To further explicit the association between TERT rs2736098 and cancer risk, more well-design case-control studies with larger sample size are warranted in the future.

Telomerase Activation in Hematological Malignancies

Telomerase expression and telomere maintenance are critical for cell proliferation and survival, and they play important roles in development and cancer, including hematological malignancies. Transcriptional regulation of the rate-limiting subunit of human telomerase reverse transcriptase gen (hTERT) is a complex process, and unveiling the mechanisms behind its reactivation is an important step for the development of diagnostic and therapeutic applications. Here, we review the main mechanisms of telomerase activation and the associated hematologic malignancies.

Human Specific Regulation of the Telomerase Reverse Transcriptase Gene

Telomerase, regulated primarily by the transcription of its catalytic subunit telomerase reverse transcriptase (TERT), is critical for controlling cell proliferation and tissue homeostasis by maintaining telomere length. Although there is a high conservation between human and mouse TERT genes, the regulation of their transcription is significantly different in these two species. Whereas mTERT expression is widely detected in adult mice, hTERT is expressed at extremely low levels in most adult human tissues and cells. As a result, mice do not exhibit telomere-mediated replicative aging, but telomere shortening is a critical factor of human aging and its stabilization is essential for cancer development in humans. The chromatin environment and epigenetic modifications of the hTERT locus, the binding of transcriptional factors to its promoter, and recruitment of nucleosome modifying complexes all play essential roles in restricting its transcription in different cell types. In this review, we will discuss recent progress in understanding the molecular mechanisms of TERT regulation in human and mouse tissues and cells, and during cancer development.

Polymorphisms in human telomerase reverse transcriptase (hTERT) gene and susceptibility to gastric cancer in a Turkish population: Hospital-based case-control study

Erosion of telomeres, tandem nucleotide repeats (TTAGGG)n that cap the end of eukaryotic chromosomes, has been related with carcinogenesis. The human telomerase reverse transcriptase (hTERT) gene is encoded the rate-limiting catalytic subunit of the telomerase complexes, which is essential for the protection of telomeric DNA length and chromosomal stability. The purpose of this study was to examine the effect of four functional single nucleotide polymorphisms (SNPs) of hTERT (rs2736109 G>A, rs2735940 T>C, rs2853669 A>G and rs2736100 T>G) on susceptibility to gastric cancer (GC) in Turkish population. The genotype frequency of hTERT rs2736109 G>A, rs2735940 T>C, rs2853669 A>G and rs2736100 T>G polymorphisms were determined by using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and TaqMan methods in 104 subjects with GC and 209 healthy control subjects. We found that hTERT rs2736109 G>A (AA+AG vs. GG OR=1.68 95% CI=1.01-2.81, P=0.04), rs2735940 T>C (CC vs. CT+TT: OR=2.53 95% CI=1.01-6.13, P=0.03), and rs2736100 T>G (TT vs. TG+GG: OR=2.27 95% CI=1.23-4.17, P=0.006) polymorphisms were associated with risk of GC. In the haplotype analysis, hTERT Grs2736109/Trs2735940/Ars2853669/Grs2736100 haplotype was also related with an increased risk of GC (OR=1.75; 95% CI: 1.05-2.93, P=0.03). Because this is the first study regarding the hTERT rs2736109 G>A, rs2735940 T>C, rs2853669 A>G and rs2736100 T>G polymorphisms and the risk of GC susceptibility in the literature, further independent studies are needed to verify our results in a larger sample sizes, as well as in patients of different populations.

Association between TERT promoter polymorphisms and acute myeloid leukemia risk and prognosis

Telomerase reverse transcriptase gene (TERT) promoter mutations are identified in many malignancies but not in hematological malignancies. Here we analyzed TERT and protection of telomeres 1 gene (POT1) mutations, and four different TERT SNVs in 226 acute myeloid leukemia (AML) patients and 806 healthy individuals in a case referent design, where also overall survival was assessed. A significant association for increased risk of AML was found for TERT SNVs, rs2853669 (OR = 2.45, p = 0.00015) and rs2736100 (OR = 1.5, p = 0.03). The overall survival for patients with CC genotype of rs2853669 was significantly shorter compared to those with TT or TC genotypes (p = 0.036 and 0.029 respectively). The influence of TERT rs2853669 CC on survival was confirmed in multivariable Cox regression analysis as an independent risk biomarker in addition to high risk group, higher age and treatment. No hot spot TERT promoter mutations at -228C > T or -250C > T or POT1 mutations could be identified in this AML cohort. We show that rs2853669 CC may be a risk factor for the development of AML that may also be used as a prognostic marker to identify high risk normal karyotype-AML (NK-AML) patients, for treatment guidance.

A Common Cancer Risk-Associated Allele in the hTERT Locus Encodes a Dominant Negative Inhibitor of Telomerase

The TERT-CLPTM1L region of chromosome 5p15.33 is a multi-cancer susceptibility locus that encodes the reverse transcriptase subunit, hTERT, of the telomerase enzyme. Numerous cancer-associated single-nucleotide polymorphisms (SNPs), including rs10069690, have been identified within the hTERT gene. The minor allele (A) at rs10069690 creates an additional splice donor site in intron 4 of hTERT, and is associated with an elevated risk of multiple cancers including breast and ovarian carcinomas. We previously demonstrated that the presence of this allele resulted in co-production of full length (FL)-hTERT and an alternatively spliced, INS1b, transcript. INS1b does not encode the reverse transcriptase domain required for telomerase enzyme activity, but we show here that INS1b protein retains its ability to bind to the telomerase RNA subunit, hTR. We also show that INS1b expression results in decreased telomerase activity, telomere shortening, and an increased telomere-specific DNA damage response (DDR). We employed antisense oligonucleotides to manipulate endogenous transcript expression in favor of INS1b, which resulted in a decrease in telomerase activity. These data provide the first detailed mechanistic insights into a cancer risk-associated SNP in the hTERT locus, which causes cell type-specific expression of INS1b transcript from the presence of an additional alternative splice site created in intron 4 by the risk allele. We predict that INS1b expression levels cause subtle inadequacies in telomerase-mediated telomere maintenance, resulting in an increased risk of genetic instability and therefore of tumorigenesis.

Multiple cancer-associated single nucleotide polymorphisms (SNPs) associated with risk of a wide variety of cancers have been identified in the TERT-CLPTM1L region of 5p15.33, identifying this as a multi-cancer susceptibility locus. hTERT encodes the catalytic subunit of the enzyme telomerase, which is responsible for telomere length maintenance in the germline and in most immortalised cancer cells. To date, very little is known regarding the mechanisms by which specific hTERT SNPs predispose to cancer. In this study, we carried out detailed functional analyses on the intron 4 SNP rs10069690, which is associated with a small, but highly significant risk for many types of cancer. We show that the risk-associated minor allele of this SNP results in an hTERT mRNA splice variant, encoding a catalytically inactive protein which acts as a dominant negative inhibitor of telomerase activity and therefore decreases total telomerase activity. We propose that individuals who carry the rs10069690 minor allele have less telomerase activity in some cell types due to cell type-specific alternative splicing, which may result in slightly shorter telomeres, and hence an increased risk of genetic instability and tumorigenesis.

Association between the TERT Genetic Polymorphism rs2853676 and Cancer Risk: Meta-Analysis of 76,108 Cases and 134,215 Controls

Background

Several recent studies have identified that the TERT genetic polymorphism rs2853676 is associated with cancer risk, but presented inconsistent results. We investigated these inconclusive results by performing a meta-analysis to systematically evaluate the association.

Methods

We conducted a search in PubMed, Google Scholar and ISI Web of Science to select studies on the association between TERT rs2853676 and cancer risk. We conducted a stratified analysis using cancer type, ethnicity and source of controls. We calculated the odds ratios (OR) and 95% confidence intervals (CI). Article quality, heterogeneity, sensitivity, publication bias and statistical power were also assessed.

Results

26 articles covering 76 108 cases and 134 215 controls met our inclusion criteria. A significant association between TERT rs2853676 allele A and cancer susceptibility was demonstrated under a per-allele risk analysis (OR = 1.08, 95% CI = 1.04-1.13). Stratification analysis revealed an increased cancer risk in subgroups of glioma, lung cancer and ovarian cancer. No significant increase was found in melanoma, breast cancer, pancreatic cancer and colorectal cancer. In a subgroup analysis of lung cancer, a statistically significant increase was only observed in adenocarcinoma. Moreover, a stratified analysis performed for ethnic groups revealed that the significant increase was only observed in Caucasians, whereas a non-significant increase was found in Asians.

Conclusions

This meta-analysis suggests that the TERT genetic polymorphism rs2853676 is associated with increased risk of glioma, lung adenocarcinoma and ovarian cancer among Caucasians. Further functional studies are warranted to validate this association and investigate further.

Genetic susceptibility in childhood acute leukaemias: a systematic review

Acute leukaemias (AL) correspond to 25-35% of all cancer cases in children. The aetiology is still sheltered, although several factors are implicated in causality of AL subtypes. Childhood acute leukaemias are associated with genetic syndromes (5%) and ionising radiation as risk factors. Somatic genomic alterations occur during fetal life and are initiating events to childhood leukaemia. Genetic susceptibility has been explored as a risk factor, since environmental exposure of the child to xenobiotics, direct or indirectly, can contribute to the accumulation of somatic mutations. Hence, a systematic review was conducted in order to understand the association between gene polymorphisms and childhood leukaemia risk. The search was performed in the electronic databases PubMed, Lilacs, and Scielo, selecting articles published between 1995 and 2013. This review included 90 case-control publications, which were classified into four groups: xenobiotic system (n = 50), DNA repair (n = 16), regulatory genes (n = 15), and genome wide association studies (GWAS) (n = 9). We observed that the most frequently investigated genes were: NQO1, GSTM1, GSTT1, GSTP1, CYP1A1, NAT2, CYP2D6, CYP2E1, MDR1 (ABCB1), XRCC1, ARID5B, and IKZF1. The collected evidence suggests that genetic polymorphisms in CYP2E1, GSTM1, NQO1, NAT2, MDR1, and XRCC1 are capable of modulating leukaemia risk, mainly when associated with environmental exposures, such as domestic pesticides and insecticides, smoking, trihalomethanes, alcohol consumption, and x-rays. More recently, genome wide association studies identified significant associations between genetic polymorphisms in ARID5B e IKZF1 and acute lymphoblastic leukaemia, but only a few studies have replicated these results until now. In conclusion, genetic susceptibility contributes to the risk of childhood leukaemia through the effects of gene-gene and gene-environment interactions.

Association of genetic polymorphisms in the telomerase reverse transcriptase gene with prostate cancer aggressiveness

Telomerase reverse transcriptase (TERT), encoded by the TERT gene, is an essential component of telomerase, essential for the maintenance of telomere DNA length, chromosomal stability and cellular immortality. The aim of the present study was to evaluate the association between common genetic variations across the TERT gene region and prostate cancer (PCa) aggressiveness in a Chinese population. A total of 12 TERT tagging single-nucleotide polymorphisms (SNPs) were genotyped on the Sequenom Mass-ARRAY iPLEX® platform in a case-case study with 1,210 Chinese patients with PCa. Unconditional logistic regression was used to investigate the association of genotypes with PCa aggressiveness, Gleason grade and risk of developing early-onset PCa. It was observed that the C allele of the TERT intron 2 SNP (rs2736100) was significantly associated with reduced risk of PCa aggressiveness [odds ratio (OR)=0.81; 95% confidence interval (CI): 0.66-0.99; P=0.037]. This allele was also significantly correlated with a reduced risk of developing a tumor with a high Gleason score (>7; OR=0.83; 95% CI: 0.70-0.99; P=0.039). The T allele of the intron 4 SNP (rs10069690) was found to be significantly associated with a decreased risk for an aggressive form of PCa (OR=0.76; 95% CI: 0.59-0.97; P=0.030). In addition, the A allele of rs10078761 located at the 3' end of the TERT gene exhibited a statistically significant association with the reduced risk of developing a higher grade disease (OR=0.48; 95% CI: 0.28-0.81; P=0.006). However, no association between TERT polymorphisms and age at diagnosis was observed in the present study. The present findings demonstrated for the first time, to the best of our knowledge, that genetic variations across the TERT gene are associated with PCa aggressiveness in a Chinese Han population.

Telomere reverse transcriptase (TERT) rs2735940 increases cancer risk

Background

Telomerase reverse transcriptase (TERT) rs2735940 polymorphism was found to be associated with increased cancer risk. However, recent studies reported controversial results. The aim of our study was to detect its relationship with cancer risk.

Material/Methods

EMBASE and PubMed databases were searched for all publications until October 2014. ORs and 95% CIs were applied to investigate the association in the random-effects model.

Results

Thirteen case-control studies with 19385 cases and 17558 controls were included in this study. We found a significant association between cancer risk and TERT rs2735940 polymorphism (OR=1.06, 95% CI 1.02–1.11, P=0.005). In the subgroup analysis by ethnicity, a marginal association was found in Caucasians (OR=1.05, 95% CI 1.00–1.10, P=0.05), but not in Asians (OR=1.01, 95% CI 0.82–1.24, P=0.93). In the subgroup analysis by cancer site, this polymorphism was significantly associated with lung cancer risk (OR=1.08, 95% CI 1.02–1.13, P=0.004).

Conclusions

TERT rs2735940 polymorphism was significantly associated with cancer risk, especially lung cancer.

TERT polymorphisms rs2853669 and rs7726159 influence on prostate cancer risk in Russian population

Telomere length and telomerase activity have been hypothesized to play a role in cancer development. The aim of our study was to investigate the association of allelic variants of three functional polymorphisms rs2853669, rs2736100, and rs7726159 in the telomerase reverse transcriptase (TERT) gene with the risk of the breast cancer and prostate cancer in Russian population. Six hundred sixty women with breast cancer, 372 men with prostate cancer, and corresponding control groups of 523 women and 363 men were included in the present case-control study. We observed an association of allele rs2853669 C with increased risk of prostate cancer (co-dominant model TC vs. TT OR = 1.65, P = 0.002; additive model OR = 1.42, P = 0.005; dominant model: OR = 1.64, P = 0.001) and allele rs7726159 A with reduced risk of this malignancy (сo-dominant model: AA vs. CC OR = 0.42, P = 0.002; additive model: OR = 0.69, P = 0.002; dominant model: OR = 0.67, P = 0.01; recessive model: OR = 0.48, P = 0.005). None of the studied polymorphisms showed an association with the risk of breast cancer. Our results provide evidence that the TERT gene variability modulate prostate cancer predisposition in ethnical Russians.

Functional annotation of putative regulatory elements at cancer susceptibility Loci

Most cancer-associated genetic variants identified from genome-wide association studies (GWAS) do not obviously change protein structure, leading to the hypothesis that the associations are attributable to regulatory polymorphisms. Translating genetic associations into mechanistic insights can be facilitated by knowledge of the causal regulatory variant (or variants) responsible for the statistical signal. Experimental validation of candidate functional variants is onerous, making bioinformatic approaches necessary to prioritize candidates for laboratory analysis. Thus, a systematic approach for recognizing functional (and, therefore, likely causal) variants in noncoding regions is an important step toward interpreting cancer risk loci. This review provides a detailed introduction to current regulatory variant annotations, followed by an overview of how to leverage these resources to prioritize candidate functional polymorphisms in regulatory regions.

Hsa-miR-196a2 polymorphism increases the risk of acute lymphoblastic leukemia in Chinese children

Acute lymphoblastic leukemia (ALL) is a major cause of mortality and morbidity in childhood, and the causes of ALL are not completely understood. microRNAs (miRNAs) regulate various biological processes including organ development, cell growth regulation, cell differentiation, apoptosis, and tumorigenesis. We performed a case-control study with 570 childhood ALL cases and 673 cancer-free controls to investigate the association between hsa-miR-196a2 rs11614913 T>C polymorphism and ALL risk. The bioinformatics was used to estimate the potential target of hsa-miR-196a2. In the present study, the hsa-miR-196a2 variant TC heterozygote, and CC/TC genotypes were found to be associated with a significantly increased childhood ALL risk, compared with the TT wild-type homozygote (adjusted OR=1.50, 95% CI=1.15-1.95 for TC and OR=1.40, 95% CI=1.09-1.79 for CC/TC). Further, the difference was pronounced in younger (≤6) subjects or parental non-drinker. The significance of the increased risk is more obvious than the higher treatment branch. Additionally, we found that the rs11614913 TC genotype can increase B-phenotype ALL risk (OR=1.37, 95% CI=1.07-1.76). Finally, combination of three bioinformatics approaches revealed that HOXC8 may be the target gene of hsa-miR-196a2. Taken together, our finding suggested that hsa-miR-196a2 rs11614913 T>C may increase the risk of childhood ALL. Large studies with the function of hsa-miR-196a2 are needed in the further study.

Association between the telomerase reverse transcriptase (TERT) rs2736098 polymorphism and cancer risk: evidence from a case-control study of non-small-cell lung cancer and a meta-analysis

Background

A common genetic variant, telomerase reverse transcriptase (TERT) rs2736098, was recently reported to be associated with lung cancer risk in Caucasians. In addition, many studies have investigated the role of this polymorphism in the etiology of cancer of various organs. Nevertheless, the results of related case-control studies remain inconsistent.

Methods

We hypothesized that the genetic risk variant identified in Caucasians may potentially influence the susceptibility to lung cancer in the Chinese population. To test this hypothesis, a case-control study including 539 non-small-cell lung cancer (NSCLC) cases and 627 cancer-free controls was conducted. Furthermore, to investigate the association between rs2736098 and cancer risk, a meta-analysis based on previously published studies and our case-control study was also performed.

Results

Multivariate logistic regression demonstrated that individuals carrying the A allele or the AA genotype exhibited a significantly elevated risk of NSCLC compared with those carrying the G allele or GG genotype (A vs. G: OR = 1.21, 95% CI = 1.02–1.43, P = 0.028; AA vs. GG: OR = 1.48, 95% CI = 1.05–2.09, P = 0.025). Additionally, this association was stronger among adenocarcinoma cases (AA vs. GG: OR = 1.67, 95% CI = 1.12–2.50, P = 0.013; A vs. G: OR = 1.28, 95% CI = 1.05–1.57, P = 0.016). In the meta-analysis, a borderline significant association between the rs2736098 polymorphism and overall cancer risk was observed (AA vs. GG: OR = 1.25, 95% CI = 1.07–1.46; AA vs. AG+GG: OR = 1.22, 95% CI = 1.06–1.41; additive model: OR = 1.10, 95% CI = 1.02–1.18), and further stratifications demonstrated a moderately increased risk for lung and bladder cancer, Asian ethnicity and hospital-based studies.

Conclusions

Our results suggest that the rs2736098 polymorphism may contribute to the risk of lung cancer, especially adenocarcinoma, in the Chinese population. In addition, the current meta-analysis indicates that this genetic variant is only weakly associated with overall cancer risk. However, the rs2736098 polymorphism may affect individual susceptibility to lung and bladder cancer. Further studies are needed to validate our findings.

Genome-wide association study identifies multiple risk loci for chronic lymphocytic leukemia

Genome-wide association studies (GWAS) have previously identified 13 loci associated with risk of chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL). To identify additional CLL susceptibility loci, we conducted the largest meta-analysis for CLL thus far, including four GWAS with a total of 3,100 individuals with CLL (cases) and 7,667 controls. In the meta-analysis, we identified ten independent associated SNPs in nine new loci at 10q23.31 (ACTA2 or FAS (ACTA2/FAS), P=1.22×10(-14)), 18q21.33 (BCL2, P=7.76×10(-11)), 11p15.5 (C11orf21, P=2.15×10(-10)), 4q25 (LEF1, P=4.24×10(-10)), 2q33.1 (CASP10 or CASP8 (CASP10/CASP8), P=2.50×10(-9)), 9p21.3 (CDKN2B-AS1, P=1.27×10(-8)), 18q21.32 (PMAIP1, P=2.51×10(-8)), 15q15.1 (BMF, P=2.71×10(-10)) and 2p22.2 (QPCT, P=1.68×10(-8)), as well as an independent signal at an established locus (2q13, ACOXL, P=2.08×10(-18)). We also found evidence for two additional promising loci below genome-wide significance at 8q22.3 (ODF1, P=5.40×10(-8)) and 5p15.33 (TERT, P=1.92×10(-7)). Although further studies are required, the proximity of several of these loci to genes involved in apoptosis suggests a plausible underlying biological mechanism.