Telomere Length in Peripheral Blood Predicts Survival in Clear Cell Renal Cell Carcinoma

Higher peripheral blood mitochondrial DNA copy number and relative telomere length in under 48 years Indonesian breast cancer patients

OBJECTIVE

Breast cancer is the leading cause of cancer incidence and mortality among Indonesian women. A comprehensive investigation is required to enhance the early detection of this disease. Mitochondrial DNA copy number (mtDNA-CN) and relative telomere length (RTL) have been proposed as potential biomarkers for several cancer risks, as they are linked through oxidative stress mechanisms. We conducted a case-control study to examine peripheral blood mtDNA-CN and RTL patterns in Indonesian breast cancer patients (n = 175) and healthy individuals (n = 181). The relative ratios of mtDNA-CN and RTL were determined using quantitative real-time PCR (qPCR).

RESULTS

Median values of mtDNA-CN and RTL were 1.62 and 0.70 in healthy subjects and 1.79 and 0.73 in breast cancer patients, respectively. We found a positive association between peripheral blood mtDNA-CN and RTL (p < 0.001). In under 48 years old breast cancer patients, higher peripheral blood mtDNA-CN (mtDNA-CN ≥ 1.73 (median), p = 0.009) and RTL (continuous variable, p = 0.010) were observed, compared to the corresponding healthy subjects. We also found a significantly higher 'High-High' pattern of mtDNA-CN and RTL in breast cancer patients under 48 years old (p = 0.011). Our findings suggest that peripheral blood mtDNA-CN and RTL could serve as additional minimally invasive biomarkers for breast cancer risk evaluation.

Role of telomere length in human carcinogenesis (Review)

Cancer is considered the most important clinical, social and economic issue regarding cause‑specific disability‑adjusted life years among all human pathologies. Exogenous, endogenous and individual factors, including genetic predisposition, participate in cancer triggering. Telomeres are specific DNA structures positioned at the end of chromosomes and consist of repetitive nucleotide sequences, which, together with shelterin proteins, facilitate the maintenance of chromosome stability, while protecting them from genomic erosion. Even though the connection between telomere status and carcinogenesis has been identified, the absence of a universal or even a cancer‑specific trend renders consent even more complex. It is indicative that both short and long telomere lengths have been associated with a high risk of cancer incidence. When evaluating risk associations between cancer and telomere length, a disparity appears to emerge. Even though shorter telomeres have been adopted as a marker of poorer health status and an older biological age, longer telomeres due to increased cell growth potential are associated with the acquirement of cancer‑initiating somatic mutations. Therefore, the present review aimed to comprehensively present the multifaceted pattern of telomere length and cancer incidence association.

Impact of baseline telomere length on survival and chemotherapy related toxicity in breast cancer patients receiving (neo)adjuvant anthracycline containing chemotherapy

PURPOSE

The aim of this study is to assess baseline mean leukocyte telomere length (TL) as a potential predictive factor for chemotherapy toxicity and a prognostic marker for long-term outcome in early breast cancer (BC) patients.

METHODS

445 BC patients were selected, diagnosed between 2007 and 2010 with early BC and treated with (neo)adjuvant fluorouracil, epirubicin and cyclophosphamide (FEC) or with FEC and Docetaxel (FEC-D). RT-qPCR was performed on germline DNA samples collected at diagnosis before any treatment, to measure mean leukocyte TL. Uni- and multivariable logistic regression or Cox proportional hazard regression analyses were carried out to assess correlation between baseline TL and toxicity parameters (derived from the medical chart) or longer-term outcome.

RESULTS

Baseline TL correlated with age as expected (p = 0.005), but not with febrile neutropenia (n = 97), left ventricular ejection fraction >10% decrease (n = 17) nor other toxicity endpoints measured (all p > 0.05). TL was neither associated with overall survival, breast cancer specific survival or distant disease-free survival (all p > 0.05).

CONCLUSIONS

Baseline TL is not associated with chemotherapy-related toxicity nor long-term outcome in BC patients.

Tieing together loose ends: telomere instability in cancer and aging

Telomere maintenance is essential for maintaining genome integrity in both normal and cancer cells. Without functional telomeres, chromosomes lose their protective structure and undergo fusion and breakage events that drive further genome instability, including cell arrest or death. One means by which this loss can be overcome in stem cells and cancer cells is via re-addition of G-rich telomeric repeats by the telomerase reverse transcriptase (TERT). During aging of somatic tissues, however, insufficient telomerase expression leads to a proliferative arrest called replicative senescence, which is triggered when telomeres reach a critically short threshold that induces a DNA damage response. Cancer cells express telomerase but do not entirely escape telomere instability as they often possess short telomeres; hence there is often selection for genetic alterations in the TERT promoter that result in increased telomerase expression. In this review, we discuss our current understanding of the consequences of telomere instability in cancer and aging, and outline the opportunities and challenges that lie ahead in exploiting the reliance of cells on telomere maintenance for preserving genome stability.

Association Between Baseline Buccal Telomere Length and Progression of Kidney Function: The Health and Retirement Study

We aimed to evaluate associations of baseline telomere length with overall and annual change in estimated glomerular filtration rate (eGFR) and trajectory of kidney function during an 8-year follow-up. A total of 3 964 participants of the Health and Retirement Study were included. We identified 3 trajectory groups of kidney function: consistently normal (n = 1 163 or 29.3%), normal to impaired (n = 2 306 or 58.2%), and consistently impaired groups (n = 495 or 12.5%). After controlling for age, sex, race, education, smoking, drinking, diabetes, heart disease, blood pressure, body mass index, total cholesterol, and hemoglobin A1c, participants with longer telomere length were 20% less likely (odds ratio = 0.80, 95% confidence interval: 0.69-0.93, p = .003) to have a normal to impaired kidney function trajectory than a consistently normal function trajectory. Telomere length was not associated with changing rate of eGFR over 8 years (p = .45). Participants with longer telomere length were more likely to have consistently normal kidney function.

Shorter Leukocyte Telomere Length Is Associated with Worse Survival of Patients with Bladder Cancer and Renal Cell Carcinoma

BACKGROUND

Telomeres are protein-DNA complexes at the tips of linear chromosomes. They protect the DNA from end-to-end fusion and exonucleolytic degradation. Shortening of telomeric DNA during aging can generate dysfunctional telomeres, promoting tumorigenesis. More recent data indicate that both short and long telomeres of peripheral blood leukocyte (PBL) cells can serve as prognostic biomarkers for cancer risk and may be associated with survival of patients with solid cancers. Telomere length in PBL cells could also be a potential prognostic biomarker for survival in bladder cancer (BC) or renal cell carcinoma (RCC).

METHODS

The relative telomere length (RTL) of PBL cells was assessed in patients with BC (n = 144) and RCC (n = 144) by using qPCR. A control population of patients without malignant disease (NC, n = 73) was included for comparison. The correlation and association of RTL with histopathological parameters and overall survival (OS) were evaluated.

RESULTS

Patients with BC and RCC had significantly shorter telomeres compared to patients without malignant disease. Within the cancer cohorts, multivariate analysis revealed that short RTL is an independent predictor of worse survival in BC (p = 0.039) and RCC (p = 0.041).

CONCLUSION

Patients with BC and RCC had significantly shorter telomeres compared to the normal population. Shorter RTL in BC and RCC was an independent predictor of reduced survival.

Does Subtelomeric Position of COMMD5 Influence Cancer Progression?

The COMMD proteins are a family of ten pleiotropic factors which are widely conserved throughout evolution and are involved in the regulation of many cellular and physiological processes. COMMD proteins are mainly expressed in adult tissue and their downregulation has been correlated with tumor progression and poor prognosis in cancer. Among this family, COMMD5 emerged as a versatile modulator of tumor progression. Its expression can range from being downregulated to highly up regulated in a variety of cancer types. Accordingly, two opposing functions could be proposed for COMMD5 in cancer. Our studies supported a role for COMMD5 in the establishment and maintenance of the epithelial cell phenotype, suggesting a tumor suppressor function. However, genetic alterations leading to amplification of COMMD5 proteins have also been observed in various types of cancer, suggesting an oncogenic function. Interestingly, COMMD5 is the only member of this family that is located at the extreme end of chromosome 8, near its telomere. Here, we review some data concerning expression and role of COMMD5 and propose a novel rationale for the potential link between the subtelomeric position of COMMD5 on chromosome 8 and its contrasting functions in cancer.

Roles of telomeres and telomerase in age‑related renal diseases (Review)

Age‑related renal diseases, which account for various progressive renal disorders associated with cellular and organismal senescence, are becoming a substantial public health burden. However, their aetiologies are complicated and their pathogeneses remain poorly understood. Telomeres and telomerase are known to be essential for maintaining the integrity and stability of eukaryotic genomes and serve crucial roles in numerous related signalling pathways that activate renal functions, such as repair and regeneration. Previous studies have reported that telomere dysfunction served a role in various types of age‑related kidney disease through various different molecular pathways. The present review aimed to summarise the current knowledge of the association between telomeres and ageing‑related kidney diseases and explored the contribution of dysfunctional telomeres to these diseases. The findings may help to provide novel strategies for treating patients with renal disease.

Combining epigenetic and clinicopathological variables improves specificity in prognostic prediction in clear cell renal cell carcinoma

BACKGROUND

Metastasized clear cell renal cell carcinoma (ccRCC) is associated with a poor prognosis. Almost one-third of patients with non-metastatic tumors at diagnosis will later progress with metastatic disease. These patients need to be identified already at diagnosis, to undertake closer follow up and/or adjuvant treatment. Today, clinicopathological variables are used to risk classify patients, but molecular biomarkers are needed to improve risk classification to identify the high-risk patients which will benefit most from modern adjuvant therapies. Interestingly, DNA methylation profiling has emerged as a promising prognostic biomarker in ccRCC. This study aimed to derive a model for prediction of tumor progression after nephrectomy in non-metastatic ccRCC by combining DNA methylation profiling with clinicopathological variables.

METHODS

A novel cluster analysis approach (Directed Cluster Analysis) was used to identify molecular biomarkers from genome-wide methylation array data. These novel DNA methylation biomarkers, together with previously identified CpG-site biomarkers and clinicopathological variables, were used to derive predictive classifiers for tumor progression.

RESULTS

The "triple classifier" which included both novel and previously identified DNA methylation biomarkers together with clinicopathological variables predicted tumor progression more accurately than the currently used Mayo scoring system, by increasing the specificity from 50% in Mayo to 64% in our triple classifier at 85% fixed sensitivity. The cumulative incidence of progress (_pCIP_5yr) was 7.5% in low-risk vs 44.7% in high-risk in M0 patients classified by the triple classifier at diagnosis.

CONCLUSIONS

The triple classifier panel that combines clinicopathological variables with genome-wide methylation data has the potential to improve specificity in prognosis prediction for patients with non-metastatic ccRCC.

Shorter Telomere Length in Peripheral Blood Leukocytes Is Associated with Post-Traumatic Chronic Osteomyelitis

Background: This study investigated the association between post-traumatic chronic osteomyelitis (COM) and peripheral leukocyte telomere length (PLTL) and explored factors associated with PLTL in COM. Methods: A total of 56 patients with post-traumatic COM of the extremity and 62 healthy control subjects were recruited. The PLTL was measured by real-time PCR. Binary logistic regression analysis was used to identify factors in correlation with telomere length. Sex, age, white blood cell (WBC) count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and infection duration were included as independent variables in the logistic regression model. Results: Post-traumatic COM patients had significantly shorter PLTLs (5.39 ± 0.40) than healthy control subjects (5.69 ± 0.46; p < 0.001). Binary logistic regression analysis showed that PLTL had a statistically significant association with age (B = -0.072; p = 0.013) and CRP (B = -0.061; p = 0.033). The logistic regression model was statistically significant and explained 31.4% (Nagelkerke R²) of the change in telomere length and correctly classified 69.6% of the cases. Conclusions: Patients with post-traumatic COM have shorter PLTLs than healthy subjects. The PLTL erosion of post-traumatic COM was partially explained by age and CRP.

Leukocyte telomere length and hTERT genetic polymorphism rs2735940 influence the renal cell carcinoma clinical outcome

Aim: Analysis of the genetic hTERT-1327 C>T (rs2735940) influence on leukocyte telomere length (LTL) and tumor development, progression and overall survival in renal cell carcinoma (RCC) patients. Materials & methods: Using leukocyte DNA of RCC patients and healthy individuals, LTL measurement and allelic discrimination of rs2735940 was performed by real-time PCR. Results: RCC patients showed shorter LTL than healthy individuals and LTL increased with clinical stage. CC+TC genotypes healthy carriers' presented shorter LTL. However, no statistical association between the different genotypes and RCC risk. Nevertheless, CC homozygous presented a reduced time to disease progression and a lower overall survival. The use of hTERT-1327 single nucleotide polymorphism information increased the capacity to predict risk for RCC progression. Conclusion: In fact, in healthy individuals, hTERT-1327 CC+TC genotypes were associated with shorter LTL, and this single nucleotide polymorphism was associated with time to disease progression, being a promising potential prognosis biomarker to be used in the future.

Telomere Length in Renal Cell Carcinoma: The Jekyll and Hyde Biomarker of Ageing of the Kidney

Renal cell carcinoma (RCC) is a heterogeneous group of cancers where the clear cell (ccRCC) is the most common and the most lethal. The absence of accurate diagnostic and follow-up biomarkers along with the time-limited response to therapies may explain the lethality and shows the necessity of new sensitive and specific biomarkers. One of the most studied molecules are the telomeres: specialized ribonucleoprotein structures that keep the structural integrity of the genome. Among other features, telomere length (TL) has been widely studied in several tumor models regarding its biomarker potential, due to the easy detection and quantification. The scope of this review was to analyze all the information about this parameter in RCC. There was some disparity in the results of the studies, since some pointed to an association between short TL and risk or poor outcome of RCC; others between long TL and RCC outcome and some did not find any association. We propose some epidemiological and biological explanations to these differences. The telomeres may play a dual role during RCC carcinogenesis in the early stages, short telomeres may increase RCC risk and in late carcinogenesis, long telomeres seem to be associated with tumor prognosis. However, the controversy of the results along with the lack of specificity are some problems that need to be clarified for the usage of TL as a prognostic biomarker.

Association between ACYP2 polymorphisms and the risk of renal cell cancer

BACKGROUND

Kidney cancer is the predominant form of malignancy of the kidney and accounts for approximately 3%-4% of all cancers. Renal cell cancer (RCC) represents more than 85% of kidney cancer. It has been reported that genetic factors may predispose individuals to RCC. This study evaluated the association between Acylphosphatase 2 (ACYP2) gene polymorphisms and RCC risk in the Han Chinese population.

METHODS

Twelve single-nucleotide polymorphisms (SNPs) in ACYP2 were genotyped using the Agena MassARRAY platform from 293 RCC patients and 495 controls. The Chi-squared test, genetic models, haplotype, and stratification analyses were used to evaluate the association between SNPs and the risk of RCC. The relative risk was estimated using the odds ratio (OR) and 95% confidence interval (CI).

RESULTS

We observed that the rs6713088 allele G (OR = 1.26, 95% CI: 1.03-1.53, p = .023) and rs843711 allele T (OR = 1.29, 95% CI: 1.06-1.57, p = .010) were associated with increased RCC risk. Genetic model analyses found that rs843711 was significantly associated with an increased RCC risk under the recessive model and log-additive model after adjusting for age and gender. Haplotype analysis showed that the haplotype "TTCTCGCC" (OR = 0.67, 95% CI: 0.48-0.94, p = .021) was associated with a decreased risk of RCC in the Han Chinese population. Stratification analysis also found that rs6713088 and rs843711 were significantly associated with increased RCC risk.

CONCLUSION

In summary, the results suggested that ACYP2 polymorphisms could be used as a genetic marker for RCC. Additional functional and association studies are required to validate our results.

Interactions between TGF-β type I receptor and hypoxia-inducible factor-α mediates a synergistic crosstalk leading to poor prognosis for patients with clear cell renal cell carcinoma

To investigate the significance of expression of HIF-1α, HIF-2α, and SNAIL1 proteins; and TGF-β signaling pathway proteins in ccRCC, their relation with clinicopathological parameters and patient's survival were examined. We also investigated potential crosstalk between HIF-α and TGF-β signaling pathway, including the TGF-β type 1 receptor (ALK5-FL) and the intracellular domain of ALK5 (ALK5-ICD). Tissue samples from 154 ccRCC patients and comparable adjacent kidney cortex samples from 38 patients were analyzed for HIF-1α/2α, TGF-β signaling components, and SNAIL1 proteins by immunoblot. Protein expression of HIF-1α and HIF-2α were significantly higher, while SNAIL1 had similar expression levels in ccRCC compared with the kidney cortex. HIF-2α associated with poor cancer-specific survival, while HIF-1α and SNAIL1 did not associate with survival. Moreover, HIF-2α positively correlated with ALK5-ICD, pSMAD2/3, and PAI-1; HIF-1α positively correlated with pSMAD2/3; SNAIL1 positively correlated with ALK5-FL, ALK5-ICD, pSMAD2/3, PAI-1, and HIF-2α. Intriguingly, in vitro experiments performed under normoxic conditions revealed that ALK5 interacts with HIF-1α and HIF-2α, and promotes their expression and the expression of their target genes GLUT1 and CA9, in a VHL dependent manner. We found that ALK5 induces expression of HIF-1α and HIF-2α, through its kinase activity. Under hypoxic conditions, HIF-α proteins correlated with the activated TGF-β signaling pathway. In conclusion, we reveal that ALK5 plays a pivotal role in synergistic crosstalk between TGF-β signaling and hypoxia pathway, and that the interaction between ALK5 and HIF-α contributes to tumor progression.

Telomere length and cancer mortality in American Indians: the Strong Heart Study

The objective of this study was to investigate whether leukocyte telomere length (LTL) predicts the risk for cancer mortality among American Indians participating in the Strong Heart Study (1989-1991). Participants (aged 45-74 years) were followed annually until December 2015 to collect information on morbidity/mortality. LTL was measured by qPCR using genomic DNA isolated from peripheral blood. The association between LTL and risk for cancer mortality was examined using a multivariable Cox proportional hazard model, adjusting for age, gender, education, study site, smoking, alcohol use, physical activity, systolic blood pressure, fasting blood glucose, obesity, and low- and high-density lipoprotein. Of 1945 participants (mean age 56.10 ± 8.17 at baseline, 57% women) followed for an average 20.5 years, 220 died of cancer. Results showed that longer LTL at baseline significantly predicts an increased risk of cancer death among females (HR 1.57, 95% CI 1.08-2.30), but not males (HR 0.74, 95% CI 0.49-1.12) (p for interaction 0.009). Specifically, compared with the women with the longest LTL (fourth quartile), those in the third, second, and first quartiles showed 53%, 41%, and 44% reduced risk for cancer death, respectively. The findings highlight the importance of sex-specific analysis in future telomere research.

DNA methylation associates with survival in non-metastatic clear cell renal cell carcinoma

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is the most common subtype among renal cancer and is associated with poor prognosis if metastasized. Up to one third of patients with local disease at diagnosis will develop metastasis after nephrectomy, and there is a need for new molecular markers to identify patients with high risk of tumor progression. In the present study, we performed genome-wide promoter DNA methylation analysis at diagnosis to identify DNA methylation profiles associated with risk for progress.

METHOD

Diagnostic tissue samples from 115 ccRCC patients were analysed by Illumina HumanMethylation450K arrays and methylation status of 155,931 promoter associated CpGs were related to genetic aberrations, gene expression and clinicopathological parameters.

RESULTS

The ccRCC samples separated into two clusters (cluster A/B) based on genome-wide promoter methylation status. The samples in these clusters differed in tumor diameter (p < 0.001), TNM stage (p < 0.001), morphological grade (p < 0.001), and patients outcome (5 year cancer specific survival (pCSS5yr) p < 0.001 and cumulative incidence of progress (pCIP5yr) p < 0.001. An integrated genomic and epigenomic analysis in the ccRCCs, revealed significant correlations between the total number of genetic aberrations and total number of hypermethylated CpGs (R = 0.435, p < 0.001), and predicted mitotic age (R = 0.407, p < 0.001). We identified a promoter methylation classifier (PMC) panel consisting of 172 differently methylated CpGs accompanying progress of disease. Classifying non-metastatic patients using the PMC panel showed that PMC high tumors had a worse prognosis compared with the PMC low tumors (pCIP5yr 38% vs. 8%, p = 0.001), which was confirmed in non-metastatic ccRCCs in the publically available TCGA-KIRC dataset (pCIP5yr 39% vs. 16%, p < 0.001).

CONCLUSION

DNA methylation analysis at diagnosis in ccRCC has the potential to improve outcome-prediction in non-metastatic patients at diagnosis.

The association between longer relative leukocyte telomere length and risk of glioma is independent of the potentially confounding factors allergy, BMI, and smoking

PURPOSE

Previous studies have suggested an association between relative leukocyte telomere length (rLTL) and glioma risk. This association may be influenced by several factors, including allergies, BMI, and smoking. Previous studies have shown that individuals with asthma and allergy have shortened relative telomere length, and decreased risk of glioma. Though, the details and the interplay between rLTL, asthma and allergies, and glioma molecular phenotype is largely unknown.

METHODS

rLTL was measured by qPCR in a Swedish population-based glioma case-control cohort (421 cases and 671 controls). rLTL was related to glioma risk and health parameters associated with asthma and allergy, as well as molecular events in glioma including IDH1 mutation, 1p/19q co-deletion, and EGFR amplification.

RESULTS

Longer rLTL was associated with increased risk of glioma (OR = 1.16; 95% CI 1.02-1.31). Similar to previous reports, there was an inverse association between allergy and glioma risk. Specific, allergy symptoms including watery eyes was most strongly associated with glioma risk. High body mass index (BMI) a year prior diagnosis was significantly protective against glioma in our population. Adjusting for allergy, asthma, BMI, and smoking did not markedly change the association between longer rLTL and glioma risk. rLTL among cases was not associated with IDH1 mutation, 1p/19q co-deletion, or EGFR amplification, after adjusting for age at diagnosis and sex.

CONCLUSIONS

In this Swedish glioma case-control cohort, we identified that long rLTL increases the risk of glioma, an association not confounded by allergy, BMI, or smoking. This highlights the complex interplay of the immune system, rLTL and cancer risk.

Leukocyte Telomere Length and Clinical Outcomes of Advanced Lung Adenocarcinoma Patients with Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors Treatment

Gefitinib is currently one of the mostly used epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) recommended for treating nonsmall cell lung cancer. However, drug resistance is observed among the majority of patients after initial treatment. Factors that predict treatment prognosis and drug resistance to EGFR-TKIs remain elusive. The objective of this study is to investigate whether leukocyte relative telomere length (RTL) can be used as a prognostic biomarker of EGFR-TKIs therapy. In this study, 369 patients with stage IIIB or IV lung adenocarcinoma were recruited and treated with gefitinib as first-line monotherapy. Leukocyte RTL of each patient was measured using quantitative polymerase chain reaction protocol and calculated according to Cawthon's formula. Finally, we examined the association between leukocyte RTL and prognosis or drug resistance of advanced lung adenocarcinoma to gefitinib treatment. Our results indicated that compared with long RTL, short leukocyte RTL was significantly associated with poor prognosis in all patients after gefitinib treatment (overall survival [OS]: 12.9 months vs. 17.8 months, p = 1.2 × 10^-4; progression-free survival: 7.8 months vs. 13.0 months, p = 0.043). In addition, statistically significant association between short leukocyte RTL and short OS still existed among the EGFR mutant patients (hazards ratio [HR] = 1.65, 95% confidence interval [CI] = 1.28-2.12; p = 0.006). Besides EGFR mutation status, short RTL also contributed to remarkably elevated risk of gefitinib primary resistance (HR = 1.50, 95% CI = 1.05-2.15, p = 0.027). Our results highlight the clinical potential of leukocyte RTL as a novel biomarker in advanced lung adenocarcinoma treated with EGFR-TKIs.

Leukocyte telomere length associates with nasopharyngeal carcinoma risk and survival in Hong Kong Chinese

Telomere shortening occurs as an early event in tumorigenesis. The TERT-CLPTM1L locus associates with nasopharyngeal carcinoma (NPC) risk. It remains unknown if leukocyte telomere length (LTL) associates with NPC risk and survival. The relative LTL (rLTL) was measured by quantitative-PCR in 2,996 individuals comprised of 1,284 NPC cases and 1712 matched controls. The odds ratio (OR) and 95% confidence intervals (CI) were calculated by logistic regression. The hazard ratio (HR) and 95% CI were calculated by Cox regression for survival analysis with rLTL and other clinical parameters in 1,243 NPC with a minimum follow-up period of 25 months. NPC patients had significantly shorter telomere length than controls. Shorter rLTL significantly associated with increased NPC risk, when the individuals were dichotomized into long and short telomeres based on median-split rLTL in the control group (OR = 2.317; 95% CI = 1.989-2.700, p = 4.10 × 10^-27 ). We observed a significant dose-response association (p_trend  = 3.26 × 10^-34 ) between rLTL and NPC risk with OR being 3.555 (95% CI = 2.853-4.429) for the individuals in the first quartile (shortest) compared with normal individuals in the fourth quartile (longest). A multivariate Cox regression analysis adjusted by age demonstrated an independent effect of rLTL on NPC survival for late-stage NPC patients, when the individuals were categorized into suboptimal rLTL versus the medium rLTL based on a threshold set from normal (HR = 1.471, 95% CI = 1.056-2.048, p = 0.022). Shorter blood telomeres may be markers for higher susceptibility for NPC risk. Suboptimal rLTL may be a poor prognostic factor for advanced NPC patients, as it associates independently with poor survival.

Relative telomere length and prostate cancer mortality

PURPOSE

Telomeres are essential for the maintenance of chromosomal integrity and telomere length has been associated with cancer risk and development. Aim of the present study was to analyze the prognostic value of leukocyte relative telomere (RTL) length in long-term prostate cancer (PCa) mortality.

METHODS

Blood samples of PCa patients were obtained before initiation of radiotherapy. RTL of peripheral blood leukocytes was determined by a quantitative polymerase chain reaction method in 533 patients with PCa. Main outcome was overall mortality.

RESULTS

During a median follow-up time of 149 months, 188 (35.3%) patients died. In a univariate Cox regression analysis, RTL quartiles (longer RTL) were significantly associated with higher overall mortality (hazard ration (HR) = 1.20; 95% confidence interval (CI): 1.05-1.36; p = 0.006). In a multivariate Cox regression model including age at diagnosis, androgen deprivation therapy, and risk group (based on PSA level, GS, and T stage), RTL quartiles remained a significant predictor of higher overall mortality (HR = 1.22; 95% CI: 1.07-1.39; p = 0.003).

CONCLUSIONS

Longer leukocyte RTL predicts higher overall mortality in patients with PCa.

Telomere length was similar in school-age children with bronchopulmonary dysplasia and allergic asthma

AIM

Inflammation is a major factor in the pathophysiology of bronchopulmonary dysplasia (BPD), and it contributes to accelerated telomere shortening and cellular ageing. This study aimed to determine its effect on telomere length and lung function in school-aged children born preterm with BPD.

METHODS

We examined 29 children with BPD, born preterm in Stockholm county 1998-99, along with 28 children with allergic asthma born at term matched for age and gender. At 10 years of age, we measured relative telomere length (RTL) in blood by quantitative polymerase chain reaction, lung function by spirometry and inflammation by fractional exhaled nitric oxide and blood cytokines.

RESULTS

RTL was not different in preterm born with BPD compared to term born children with asthma. The gender effect was strong in both groups; girls had significantly longer median RTL than boys (1.8 versus 1.5, p < 0.01). Short RTL was associated with low forced expiratory flow, also after adjusting for gender, but was not affected by severity of BPD or ongoing inflammation.

CONCLUSION

Telomere length was similar in 10-year-old children born preterm with a history of BPD and term born children with allergic asthma. However, impaired lung function and male gender were associated with short telomeres.

Telomere Length and Lung Cancer Mortality among Heavy Smokers

Background: Accumulating evidence suggests that short telomere length is associated with increased overall mortality, but the relationship with cancer mortality is less clear. We examined whether telomere length (global, and chromosome arm 5p- and 13q-specific) is associated with lung cancer mortality among cases from the β-Carotene and Retinol Efficacy Trial of heavy smokers.Methods: Telomere length was measured on average 6 years before diagnosis for 788 lung cancer cases. Adjusted Cox proportional hazards models of all-cause and lung cancer-specific mortality were assessed for lung cancer overall and by histotype.Results: Short telomere length was associated with increased mortality for small cell lung cancer (SCLC), particularly stage III/IV SCLC [HR and 95% confidence interval for shortest vs. longest telomere length tertile: 3.32 (1.78-6.21)]. Associations were strongest for those randomized to the active intervention and when telomere length was measured ≤5 years before diagnosis. All-cause mortality patterns were similar. Short chromosome 5p telomere length was suggestively associated with lung cancer mortality, but there was no association with chromosome 13q telomere length.Conclusions: Our large prospective study suggests that among heavy smokers who developed lung cancer, short prediagnosis telomere length is associated with increased risk of death from SCLC.Impact: This is the first study to examine telomere length and mortality in lung cancer cases by histotype. If the association between short telomere length and SCLC mortality is replicated, elucidation of mechanisms through which telomere length influences survival for this highly aggressive cancer may inform more effective use of telomere-targeted therapeutics. Cancer Epidemiol Biomarkers Prev; 27(7); 829-37. ©2018 AACR.

VHL status regulates transforming growth factor-β signaling pathways in renal cell carcinoma

To evaluate the role of pVHL in the regulation of TGF-β signaling pathways in clear cell renal cell carcinoma (ccRCC) as well as in non-ccRCC; the expression of pVHL, and the TGF-β pathway components and their association with clinicopathological parameters and patient’s survival were explored. Tissue samples from 143 ccRCC and 58 non-ccRCC patients were examined by immunoblot. ccRCC cell lines were utilized for mechanistic in-vitro studies. Expression levels of pVHL were significantly lower in ccRCC compared with non-ccRCC. Non-ccRCC and ccRCC pVHL-High expressed similar levels of pVHL. Expression of the TGF-β type I receptor (ALK5) and intra-cellular domain were significantly higher in ccRCC compared with non-ccRCC. In non-ccRCC, expressions of ALK5-FL, ALK5-ICD, pSMAD2/3, and PAI-1 had no association with clinicopathological parameters and survival. In ccRCC pVHL-Low, ALK5-FL, ALK5-ICD, pSMAD2/3, and PAI-1 were significantly related with tumor stage, size, and survival. In ccRCC pVHL-High, the expression of PAI-1 was associated with stage and survival. In-vitro studies revealed that pVHL interacted with ALK5 to downregulate its expression through K48-linked poly-ubiquitination and proteasomal degradation, thus negatively controlling TGF-β induced cancer cell invasiveness. The pVHL status controls the ALK5 and can thereby regulate the TGF-β pathway, aggressiveness of tumors, and survival of the ccRCC and non-ccRCC patients.

Telomere Length Dynamics and the Evolution of Cancer Genome Architecture

Telomeres are progressively eroded during repeated rounds of cell division due to the end replication problem but also undergo additional more substantial stochastic shortening events. In most cases, shortened telomeres induce a cell-cycle arrest or trigger apoptosis, although for those cells that bypass such signals during tumour progression, a critical length threshold is reached at which telomere dysfunction may ensue. Dysfunction of the telomere nucleoprotein complex can expose free chromosome ends to the DNA double-strand break (DSB) repair machinery, leading to telomere fusion with both telomeric and non-telomeric loci. The consequences of telomere fusions in promoting genome instability have long been appreciated through the breakage-fusion-bridge (BFB) cycle mechanism, although recent studies using high-throughput sequencing technologies have uncovered evidence of involvement in a wider spectrum of genomic rearrangements including chromothripsis. A critical step in cancer progression is the transition of a clone to immortality, through the stabilisation of the telomere repeat array. This can be achieved via the reactivation of telomerase, or the induction of the alternative lengthening of telomeres (ALT) pathway. Whilst telomere dysfunction may promote genome instability and tumour progression, by limiting the replicative potential of a cell and enforcing senescence, telomere shortening can act as a tumour suppressor mechanism. However, the burden of senescent cells has also been implicated as a driver of ageing and age-related pathology, and in the promotion of cancer through inflammatory signalling. Considering the critical role of telomere length in governing cancer biology, we review questions related to the prognostic value of studying the dynamics of telomere shortening and fusion, and discuss mechanisms and consequences of telomere-induced genome rearrangements.

Peripheral Blood Leukocyte Telomere Length Is Associated with Age but Not Renal Function: A Cross-Sectional Follow-Up Study

OBJECTIVES

We aimed to evaluate the relationship between baseline renal function and changes in telomere length in Han Chinese.

METHODS

The telomere restriction fragment (TRF) length of leukocytes in the peripheral blood was measured in healthy volunteers recruited in 2014. The estimated glomerular filtration rate (eGFR) was calculated based on serum creatinine (Scr) and serum cystatin C (CysC)-eGFRcys and eGFRScr-cys through the Cockcroft-Gault formula (eGFRC-G) or the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI / eGFRCKD-EPI) equation. The correlation between telomere length changes over time and renal function was analyzed.

RESULTS

Leukocyte TRF lengths were negatively correlated to age (r = -0.393, p < 0.001) and serum CysC (r = -0.180, p < 0.01), while positively associated with eGFRCKD-EPI, eGFRC-G, eGFRcys, and eGFRScr-cys (r = 0.182, 0.122, 0.290, and 0.254 respectively, p < 0.01). The 3-year change of telomere length was 46 bp/years. When adjusted for age, the associations between telomere length changes and baseline, subsequent TRF lengths, and serum CysC were no longer present. No association was observed between TRF length changes and renal function.

CONCLUSION

The rate of telomere length changes was affected by age and baseline telomere length. The telomere length changes might be important markers for aging.

Genetic Variants Related to Longer Telomere Length are Associated with Increased Risk of Renal Cell Carcinoma

BACKGROUND

Relative telomere length in peripheral blood leukocytes has been evaluated as a potential biomarker for renal cell carcinoma (RCC) risk in several studies, with conflicting findings.

OBJECTIVE

We performed an analysis of genetic variants associated with leukocyte telomere length to assess the relationship between telomere length and RCC risk using Mendelian randomization, an approach unaffected by biases from temporal variability and reverse causation that might have affected earlier investigations.

DESIGN, SETTING, AND PARTICIPANTS

Genotypes from nine telomere length-associated variants for 10 784 cases and 20 406 cancer-free controls from six genome-wide association studies (GWAS) of RCC were aggregated into a weighted genetic risk score (GRS) predictive of leukocyte telomere length.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Odds ratios (ORs) relating the GRS and RCC risk were computed in individual GWAS datasets and combined by meta-analysis.

RESULTS AND LIMITATIONS

Longer genetically inferred telomere length was associated with an increased risk of RCC (OR=2.07 per predicted kilobase increase, 95% confidence interval [CI]:=1.70-2.53, p<0.0001). As a sensitivity analysis, we excluded two telomere length variants in linkage disequilibrium (R2>0.5) with GWAS-identified RCC risk variants (rs10936599 and rs9420907) from the telomere length GRS; despite this exclusion, a statistically significant association between the GRS and RCC risk persisted (OR=1.73, 95% CI=1.36-2.21, p<0.0001). Exploratory analyses for individual histologic subtypes suggested comparable associations with the telomere length GRS for clear cell (N=5573, OR=1.93, 95% CI=1.50-2.49, p<0.0001), papillary (N=573, OR=1.96, 95% CI=1.01-3.81, p=0.046), and chromophobe RCC (N=203, OR=2.37, 95% CI=0.78-7.17, p=0.13).

CONCLUSIONS

Our investigation adds to the growing body of evidence indicating some aspect of longer telomere length is important for RCC risk.

PATIENT SUMMARY

Telomeres are segments of DNA at chromosome ends that maintain chromosomal stability. Our study investigated the relationship between genetic variants associated with telomere length and renal cell carcinoma risk. We found evidence suggesting individuals with inherited predisposition to longer telomere length are at increased risk of developing renal cell carcinoma.

Shorter telomere length increases age-related tumor risks in von Hippel-Lindau disease patients

Von Hippel-Lindau (VHL) disease is a rare autosomal dominant cancer syndrome caused by alterations of VHL gene. Patients are predisposed to develop pheochromocytomas and solid or cystic tumors of the central nervous system, kidney, pancreas, and retina. Remarkable phenotypic heterogeneity exits in organ involvement and tumor onset age between and within VHL families. However, no reliable markers have been found to predict the age-related tumor risks in VHL patients. A large Chinese cohort composed of 300 VHL patients and 92 healthy family controls was enrolled in our study. Blood relative telomere length was measured in 184 patients and all the controls available for genomic DNA samples. Age-related risks for the five major VHL-associated tumors were evaluated using Kaplan-Meier plots and Cox regression analysis. Differences in clinical phenotype were observed between Chinese cohort and the United Kingdom cohort. VHL patients showed significantly shorter telomere length than healthy family controls(P = 0.0183), and a positive correlation was found between telomere length and onset age of the five major tumors, respectively. Moreover, patients in the shorter telomere group (age-adjusted telomere length ≤ 0.44) suffered higher age-related risks for VHL-associated central nervous system hemangioblastomas (HR: 1.879, P = 0.004), renal cell carcinoma (HR: 2.126, P = 0.002) and pancreatic cyst and neuroendocrine tumors (HR: 2.093, P = 0.001). These results indicate that blood shorter telomere length is a new biomarker for age-related tumor risks in VHL patients, which will be crucial to genetic counseling and future research about the role of telomere shortening in the pathogenesis of VHL-associated tumors.

Leukocyte telomere length and renal cell carcinoma survival in two studies

BACKGROUND

Leukocyte telomere length (LTL) is a potential biomarker of cancer prognosis; however, evidence for renal cell carcinoma (RCC) is inconsistent.

METHODS

We investigated LTL and RCC-specific survival among 684 cases from the US kidney cancer study (USKC) and 241 cases from the prostate, lung, colorectal, and ovarian cancer screening trial (PLCO). Leukocyte telomere length was measured by quantitative polymerase chain reaction, and hazard ratios (HRs) and 95% confidence intervals (CIs) computed using multivariable Cox models.

RESULTS

Short LTL was associated with poorer disease-specific survival in both USKC (lowest vs highest quartile: HR: 2.3, 95% CI: 1.2-4.4; P for trend=0.02) and PLCO (HR: 2.4, 95% CI: 1.0-5.4; P=0.04). Among USKC cases, the association was strongest for stage-I RCC (HR: 5.5, 95% CI: 1.6-19.0; P=0.006).

CONCLUSIONS

Our findings suggest that shorter LTL is an independent marker of poor RCC prognosis, particularly for stage-I disease.

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.

Long leukocyte telomere length in prostate cancer patients at diagnosis is associated with poor metastasis-free and cancer-specific survival

Previous studies have suggested that leukocyte telomere length is associated with risk of developing prostate cancer. Investigations of leukocyte telomere length as a prognostic factor in prostate cancer are, however, lacking. In this study, leukocyte telomere length was investigated both as a risk marker, comparing control subjects and patient risk groups (based on serum levels of prostate-specific antigen, tumor differentiation, and tumor stage), and as a prognostic marker for metastasis-free and cancer-specific survival. Relative telomere length was measured by a well-established quantitative polymerase chain reaction method in 415 consecutively sampled individuals. Statistical evaluation included 162 control subjects without cancer development during follow-up and 110 untreated patients with newly diagnosed localized prostate cancer at the time of blood draw. Leukocyte telomere length did not differ significantly between control subjects and patients, or between patient risk groups. Interestingly, however, and in line with our previous results in breast and kidney cancer patients, relative telomere length at diagnosis was an independent prognostic factor. Patients with long leukocyte telomeres (⩾median) had a significantly worse prostate cancer-specific and metastasis-free survival compared to patients with short telomere length. In contrast, for patients who died of other causes than prostate cancer, long relative telomere length was not coupled to shorter survival time. To our knowledge, these results are novel and give further strength to our hypothesis that leukocyte telomere length might be used as a prognostic marker in malignancy.

Telomere Length, Long-Term Black Carbon Exposure, and Cognitive Function in a Cohort of Older Men: The VA Normative Aging Study

BACKGROUND

Long-term air pollution exposure has been associated with age-related cognitive impairment, possibly because of enhanced inflammation. Leukocytes with longer telomere length (TL) are more responsive to inflammatory stimuli, yet TL has not been evaluated in relation to air pollution and cognition.

OBJECTIVES

We assessed whether TL modifies the association of 1-year exposure to black carbon (BC), a marker of traffic-related air pollution, with cognitive function in older men, and we examined whether this modification is independent of age and of C-reactive protein (CRP), a marker of inflammation.

METHODS

Between 1999 and 2007, we conducted 1-3 cognitive examinations of 428 older men in the Veterans Affairs (VA) Normative Aging Study. We used covariate-adjusted repeated-measure logistic regression to estimate associations of 1-year BC exposure with relative odds of being a low scorer (≤ 25) on the Mini-Mental State Examination (MMSE), which is a proxy of poor cognition. Confounders included age, CRP, and lifestyle and sociodemographic factors.

RESULTS

Each doubling in BC level was associated with 1.57 (95% CI: 1.20, 2.05) times higher odds of low MMSE scores. The BC-MMSE association was greater only among individuals with longer blood TL (5th quintile) (OR = 3.23; 95% CI: 1.37, 7.59; p = 0.04 for BC-by-TL-interaction). TL and CRP were associated neither with each other nor with MMSE. However, CRP modified the BC-MMSE relationship, with stronger associations only at higher CRP (5th quintile) and reference TL level (1st quintile) (OR = 2.68; 95% CI: 1.06, 6.79; p = 0.04 for BC-by-CRP-interaction).

CONCLUSIONS

TL and CRP levels may help predict the impact of BC exposure on cognitive function in older men. Citation: Colicino E, Wilson A, Frisardi MC, Prada D, Power MC, Hoxha M, Dioni L, Spiro A III, Vokonas PS, Weisskopf MG, Schwartz JD, Baccarelli AA. 2017. Telomere length, long-term black carbon exposure, and cognitive function in a cohort of older men: the VA Normative Aging Study. Environ Health Perspect 125:76-81; http://dx.doi.org/10.1289/EHP241.

Association between genetic risk score for telomere length and risk of breast cancer

PURPOSE

While leukocyte telomere length (TL) has been associated with breast cancer risk, limited information is available regarding the role of genetically-determined TL on breast cancer risk. We investigated whether aggregated TL-associated variants are associated with the risk of breast cancer in 2,865 breast cancer cases and 2,285 controls from the Shanghai Breast Cancer Genetics Study.

METHODS

Six genetic variants, identified through a genome-wide association study (GWAS) of TL in European-ancestry participants, were included in the study. A separate sample [n = 1,536, from the Shanghai Women's Health Study (SWHS), for whom information on both phenotypical leukocyte TL and genetic information was collected] was used to evaluate the association of six variants with TL in Asians. Three genetic risk scores (GRSs), based on the number of alleles associated with shorter TL that each individual carries for the six variants, were derived for the study: un-weighted, internally weighted (from the SWHS), and externally weighted (from the European-ancestry GWAS study), and evaluated for their association with breast cancer risk by applying logistic regression analysis.

RESULTS

Both internally and externally weighted GRSs were significantly associated with a decreased risk of breast cancer (OR 0.83, 95 % CI 0.72-0.95 and OR 0.84, 95 % CI 0.74-0.96, respectively, for tertile 3 vs. tertile 1). Non-genetic risk factors for breast cancer (i.e., age, years of menstruation/reproduction, oral contraceptive usage, and BMI) did not modify the association between GRSs and the risk of breast cancer.

CONCLUSION

Our results suggest that short TL, determined by genetic factors, may be associated with a reduced susceptibility to breast cancer.

Alterations of telomere length and mtDNA copy number are associated with overall survival in hepatocellular carcinoma patients treated with transarterial chemoembolization

PURPOSE

Increasing evidence suggests that alterations in mitochondrial DNA (mtDNA) copy number (mtDNAcn) and relative telomere length (RTL) may be implicated in the tumorigenesis of several malignancies. Alterations of both RTL and mtDNAcn are generally accepted as independent biomarkers for predicting risk and prognosis in various cancers. The aim of this study was to evaluate the prognostic value of combining leukocyte RTL with mtDNAcn (RTL-mtDNAcn) in hepatocellular carcinoma (HCC).

METHODS

RTL and mtDNAcn in peripheral blood leukocytes (PBLs) were measured using a real-time PCR-based method in a total of 250 HCC patients treated with transcatheter arterial chemoembolization (TACE). We evaluated the associations between RTL and/or mtDNAcn and HCC overall survival using Kaplan-Meier curve analysis and Cox proportional hazards regression model.

RESULTS

We found that patients with longer leukocyte RTL or lower mtDNAcn had shorter overall survival time. The univariate analysis (HR 1.63, 95 % CI 1.23-2.17, P = 7.7 × 10(-4)) and multivariate analysis (HR 1.78, 95 % CI 1.31-2.42, P = 2.4 × 10(-4)) indicated that longer leukocyte RTL was significantly associated with poorer OS in HCC patients. Kaplan-Meier curve analysis showed that patients with longer RTL had shorter overall survival time than those with shorter RTL (log-rank P = 0.001). Patients with lower mtDNA copy number was significantly associated with poorer OS by Cox proportional hazards model using both univariate (HR 1.60, 95 % CI 1.21-2.13, P = 0.001) and multivariate analyses (HR 1.77, 95 % CI 1.30-2.41, P = 2.8 × 10(-4)). Kaplan-Meier curve analysis showed that patients with lower mtDNA content had significantly shorter overall survival time than those with higher mtDNA content (log-rank P = 0.001). Furthermore, combination of leukocyte RTL and mtDNAcn significantly improved the efficacy of predicting HCC prognosis. Patients with longer RTL and lower mtDNAcn exhibited a significantly poorer overall survival in both the univariate analysis (HR 2.21, 95 % CI 1.52-3.22, P = 3.5 × 10(-5)) and multivariate analysis (HR 2.60, 95 % CI 1.73-3.90, P = 4.3 × 10(-6)). The effect on patient prognosis was more evident in patients with longer RTL and lower mtDNAcn than in those with shorter RTL and lower mtDNA (HR 2.11, 95 % CI 1.34-3.32, P = 0.001) or in those with longer RTL and higher mtDNA (HR 2.10, 95 % CI 1.34-3.27, P = 0.001).

CONCLUSIONS

Our data suggest that combination of leukocyte RTL-mtDNAcn may be a potential efficient prognostic marker for HCC patients receiving the TACE treatment.

Association between telomere length and survival in cancer patients: a meta-analysis and review of literature

The relationship between telomere length and cancer survival has been widely studied. To gain a deeper insight, we reviewed the published studies. A total of 29 studies evaluated telomere length in the peripheral blood; 22 studies evaluated telomere length in the tumor tissue. First, in the peripheral blood studies, for solid tumor patients with shortened telomere length, the combined hazard ratios (HRs) for mortality and tumor progression were 1.21 (95%CI, 1.10-1.32) and 1.71 (95%CI, 1.37-2.13), respectively. Meanwhile, in hematology malignancy, the combined HRs for mortality and tumor progression were 2.83 (95%CI, 2.14-3.74) and 2.65 (95%CI, 2.18-3.22), respectively. Second, in the studies that use tumor tissue, for patients with shortened telomeres, the combined HRs for mortality and tumor progression were 1.26 (95%CI, 0.95-1.66) and 1.65 (95%CI, 1.26-2.15), respectively. In the studies that calculate the telomere length ratios of tumor tissue to adjacent normal mucosa, for patients with lower telomere length ratios, the combined HRs were 0.66 (95%CI, 0.53-0.83) and 0.74 (95%CI, 0.41-1.32) for mortality and tumor progression, respectively. In conclusion, shortened telomere in peripheral blood and tumor tissue might indicate poor survival for cancer patients. However, by calculating the telomere length ratios of tumor tissue to adjacent normal mucosa, the lower ratio might indicate better survival.

Telomere length in peripheral leukocytes is associated with immune cell tumor infiltration and prognosis in colorectal cancer patients

Telomeres are protective structures at the end of chromosomes, essential for chromosomal integrity. A large number of studies have investigated leukocyte telomere length as a possible risk marker for various cancers, colorectal cancer (CRC) included. In contrast, studies investigating leukocyte telomere length in relation to CRC survival are lacking. We previously reported that relative telomere length (RTL) of leukocytes collected at diagnosis predicted survival in patients with breast and kidney cancer. We suggested that these findings might reflect various immunological mechanisms, affected by the presence of a tumor. In the present study, leukocyte RTL was examined in relation to immune cell tumor infiltration and prognosis in 130 patients with CRC diagnosis. RTL was measured with a well-established qPCR method. We found that patients with the highest degree of lymphocyte tumor infiltration had shorter leukocyte RTL. Consistent with our previous findings, short RTL was a favorable prognostic marker in univariate survival analysis. In the current study, RTL did not remain as an independent predictor in multivariate survival analysis, when including metastatic status in the model. However, a non-significant trend towards a similar telomere-associated survival pattern was observed in patients with limited disease. In contrast, for patients who died of other causes than CRC, short RTL was associated with significantly shorter survival time. To our knowledge, this is the first study to investigate an association between leukocyte RTL, immune cell tumor infiltration, and cancer-specific survival in CRC patients. Larger studies are warranted to verify these findings.

Specific genomic aberrations predict survival, but low mutation rate in cancer hot spots, in clear cell renal cell carcinoma

Supplemental Digital Content is available in the text.

Detailed genetic profiling of clear cell renal cell carcinoma (ccRCC) has revealed genomic regions commonly affected by structural changes and a general genetic heterogeneity. VHL and PBRM1, both located at chromosome 3p, are 2 major genes mutated at high frequency but apart from these aberrations, the mutational landscape in ccRCC is largely undefined. Potential prognostic information given by the genomic changes appears to depend on the particular cohort studied. We analyzed a Swedish ccRCC cohort of 74 patients and found common changes (loss or gain occurring in >20% of the tumors) in 12 chromosomal regions (1p, 3p, 3q, 5q, 6q, 7p, 7q 8p, 9p, 9q, 10q, and 14q). A poor outcome was associated with gain of 7q and losses on 9p, 9q, and 14q. These aberrations were more frequent in metastasized tumors, suggesting alterations of genes important for tumor progression. Sequencing of 48 genes implicated in cancer revealed that only VHL, TP53, and PTEN were mutated at a noticeable frequency (51%, 9%, and 9%, respectively). Shorter relative telomere length (RTL) has been associated with loss of specific chromosomal regions in ccRCC tumors, but we could not verify this finding. However, a significantly lower tumor/nontumor (T/N) RTL ratio was detected for tumors with losses in 4q or 9p. In conclusion, poor outcome in ccRCC was associated with gain of 7q and loss on 9p, 9q, and 14q, whereas the mutation rate overall was low in a screen of cancer-associated genes.

DNA methylation status defines clinicopathological parameters including survival for patients with clear cell renal cell carcinoma (ccRCC)

Epigenetic alterations in the methylome have been associated with tumor development and progression in renal cell carcinoma (RCC). In this study, 45 tumor samples, 12 tumor-free kidney cortex tissues, and 24 peripheral blood samples from patients with clear cell RCC (ccRCC) were analyzed by genome-wide promoter-directed methylation arrays and related to clinicopathological parameters. Unsupervised hierarchical clustering separated the tumors into two distinct methylation groups (clusters A and B), where cluster B had higher average methylation and increased number of hypermethylated CpG sites (CpGs). Furthermore, tumors in cluster B had, compared with cluster A, a larger tumor diameter (p = 0.033), a higher morphologic grade (p < 0.001), a higher tumor-node-metastasis (TNM) stage (p < 0.001), and a worse prognosis (p = 0.005). Higher TNM stage was correlated to an increase in average methylation level (p = 0.003) and number of hypermethylated CpGs (p = 0.003), whereas a number of hypomethylated CpGs were mainly unchanged. However, the predicted age of the tumors based on methylation profile did not correlate with TNM stage, morphological grade, or methylation cluster. Differently methylated (DM) genes (n = 840) in ccRCC samples compared with tumor-free kidney cortex samples were predominantly hypermethylated and a high proportion were identified as polycomb target genes. The DM genes were overrepresented by transcription factors, ligands, and receptors, indicating functional alterations of significance for ccRCC progression. To conclude, increased number of hypermethylated genes was associated with increased TNM stage of the tumors. DNA methylation classification of ccRCC tumor samples at diagnosis can serve as a clinically applicable prognostic marker in ccRCC.

Telomere length and recurrence risk after curative resection in patients with early-stage non-small-cell lung cancer: a prospective cohort study

BACKGROUND

We hypothesized that telomere length in peripheral blood would have significant predictive value for risk of recurrence after curative resection in non-small-cell lung cancer (NSCLC).

METHODS

This prospective study included 473 patients with histologically confirmed early stage NSCLC who underwent curative therapy at MD Anderson Cancer Center between 1995 and 2008. Relative telomere length (RTL) of peripheral leukocytes was measured by real-time polymerase chain reaction. The risk of recurrence was estimated as hazard ratios (HRs) and 95% confidence intervals (CIs) using a multivariable Cox proportional hazard regression model.

RESULTS

Median duration of follow-up was 61 months, and 151 patients (32%) had developed recurrence at time of analysis. Patients who developed recurrence had significantly longer mean RTL compared with those without recurrence (1.13 versus 1.07, p = 0.046). A subgroup analysis indicates that women had longer RTL compared with men (1.12 versus 1.06, p = 0.025), and the patients with adenocarcinoma demonstrated longer RTL compared with those with other histologic types (1.11 versus 1.05, p = 0.042). To determine whether longer RTL in women and adenocarcinoma subgroup would predict risk of recurrence, multivariate Cox analysis adjusting for age, sex, stage, pack year and treatment regimens was performed. Longer telomeres were significantly associated with higher risk of developing recurrence in women (hazard ratio [HR], 2.25; 95% confidence interval [CI], 1.02-4.96, p = 0.044) and adenocarcinoma subgroups (HR, 2.19; 95% CI, 1.05-4.55, p = 0.036). The increased risk of recurrence due to long RTL was more apparent in women with adenocarcinoma (HR, 2.67; 95% CI, 1.19-6.03, p = 0.018).

CONCLUSIONS

This is the first prospective study to suggest that long RTL is associated with recurrence in early stage NSCLC after curative resection. Women and adenocarcinoma seem to be special subgroups in which telomere biology may play an important role.

The Association between Telomere Length and Cancer Prognosis: Evidence from a Meta-Analysis

BACKGROUND

Telomeres are essential for chromosomal integrity and stability. Shortened telomere length (TL) has been associated with risk of cancers and aging-related diseases. Several studies have explored associations between TL and cancer prognosis, but the results are conflicting.

METHODS

Prospective studies on the relationship between TL and cancer survival were identified by a search of PubMed up to May 25, 2015. There were no restrictions on the cancer type or DNA source. The quality of the included studies was assessed using the Newcastle-Ottawa Scale. Meta-analysis approaches were conducted to determine pooled relative risks and 95% confidence intervals.

RESULTS

Thirty-three articles containing forty-five independent studies were ultimately involved in our meta-analysis, of which twenty-seven were about overall cancer survival and eighteen were about cancer progression. Short TL was associated with increased cancer mortality risk (RR = 1.30, 95%CI: 1.06-1.59) and poor cancer progression (RR = 1.44, 95%CI: 1.10-1.88), both with high levels of heterogeneity (I2 = 83.5%, P = 0.012for overall survival and I2 = 75.4%, P = 0.008 for progression). TL was an independent predictor of overall cancer survival and progression in chronic lymphocytic leukemia. Besides, short telomeres were also associated with increased colorectal cancer mortality and decreased overall survival of esophageal cancer, but not in other cancers. Cancer progression was associated with TL in Asian and America populations and short TL predicted poor cancer survival in older populations. Compared with tumor tissue cells, TL in blood lymphocyte cells was better for prediction. In addition, the associations remained significant when restricted to studies with adjustments for age, with larger sample sizes, measuring TL using southern blotting or estimating risk effects by hazard ratios.

CONCLUSION

Short TL demonstrated a significant association with poor cancer survival, suggesting the potential prognostic significance of TL. Additional large well-designed studies are needed to confirm our findings.

Leukocyte telomere length: a novel biomarker to predict the prognosis of glioma patients

PURPOSE

Epidemiological studies have demonstrated that leukocyte telomere length is associated with the developing risk of various malignancies, including glioma. However, its prognostic value in glioma patients has never been investigated.

METHODS

Relative telomere length (RTL) of peripheral blood leukocytes from 301 glioma patients were examined using a real-time PCR-based method. Kaplan-Meier curves and Cox proportional hazards regression model were used to assess the association of RTL with clinical outcomes of patients. To explore the potential mechanism, the immune phenotype of peripheral blood mononuclear cells (PBMCs) and concentrations of several cytokines from another 20 glioma patients were detected by flow cytometry and enzyme-linked immunosorbent assay (ELISA), respectively. The relationship between RTL and immunological characteristics of PBMCs were further analyzed.

RESULTS

Patients with short RTL showed both poorer overall survival (OS) and progression-free survival (PFS) than those with long RTL. Multivariate Cox regression analysis demonstrated that RTL was an independent prognostic factor for both OS and PFS in glioma patients. Moreover, the effects of RTL on the prognosis of patients exhibited a dose-dependent manner. Stratified analysis showed that the prognostic value of RTL was not affected by host characteristics except for age. In addition, flow cytometry and ELISA analyses indicated that there was no significant association between RTL and frequency of different immune cell subsets or plasma cytokine concentrations.

CONCLUSIONS

Our study for the first time demonstrates that leukocyte RTL is an independent prognostic marker for glioma patients. The potential mechanism needs further investigation.

Genetic variants associated with longer telomere length are associated with increased lung cancer risk among never-smoking women in Asia: a report from the female lung cancer consortium in Asia

Recent evidence from several relatively small nested case-control studies in prospective cohorts shows an association between longer telomere length measured phenotypically in peripheral white blood cell (WBC) DNA and increased lung cancer risk. We sought to further explore this relationship by examining a panel of seven telomere-length associated genetic variants in a large study of 5,457 never-smoking female Asian lung cancer cases and 4,493 never-smoking female Asian controls using data from a previously reported genome-wide association study. Using a group of 1,536 individuals with phenotypically measured telomere length in WBCs in the prospective Shanghai Women's Health study, we demonstrated the utility of a genetic risk score (GRS) of seven telomere-length associated variants to predict telomere length in an Asian population. We then found that GRSs used as instrumental variables to predict longer telomere length were associated with increased lung cancer risk (OR = 1.51 (95% CI = 1.34-1.69) for upper vs. lower quartile of the weighted GRS, p value = 4.54 × 10(-14) ) even after removing rs2736100 (p value = 4.81 × 10(-3) ), a SNP in the TERT locus robustly associated with lung cancer risk in prior association studies. Stratified analyses suggested the effect of the telomere-associated GRS is strongest among younger individuals. We found no difference in GRS effect between adenocarcinoma and squamous cell subtypes. Our results indicate that a genetic background that favors longer telomere length may increase lung cancer risk, which is consistent with earlier prospective studies relating longer telomere length with increased lung cancer risk.

Short telomere length in peripheral blood leukocyte predicts poor prognosis and indicates an immunosuppressive phenotype in gastric cancer patients

Compelling evidences indicate that relative telomere length (RTL) in peripheral blood leukocytes (PBLs) can predict the clinical outcome of several cancers. However, to date, the prognostic value of leukocyte RTL in gastric cancer (GC) patients has not been explored. In this study, relative telomere length (RTL) in peripheral blood leukocytes (PBLs) was measured using a real-time PCR-based method in a total of 693 GC patients receiving surgical resection. The prognostic value of leukocyte RTL was first explored in the training set (112 patients) using Kaplan-Meier and Cox proportional hazards regression analyses. Then an independent cohort of 581 patients was used as a validation set. To explore potential mechanism, we detected the immunophenotypes of peripheral blood mononuclear cells and plasma concentrations of several cytokines in GC patients. Patients with short RTL showed significantly worse overall survival (OS) and relapse-free survival (RFS) than those with long RTL in all patient sets. Furthermore, leukocyte RTL and TNM stage exhibited a notable joint effect in prognosis prediction. Integration of TNM stage and leukocyte RTL significantly improved the prognosis prediction efficacy for GC. In addition, we found that patients with short RTL had a higher CD4(+) T cell percentage in PBMCs, CD19(+)IL-10(+) Breg percentage in B cells and plasma IL-10 concentration, indicating an enhanced immunosuppressive status with short leukocyte RTL. In conclusion, our study for the first time demonstrates that leukocyte RTL is an independent prognostic marker complementing TNM stage and associated with an immunosuppressive phenotype in the peripheral blood lymphocytes in GC patients.

Depressive symptoms and short telomere length are associated with increased mortality in bladder cancer patients

BACKGROUND

Depression is associated with an increased risk of mortality in patients with cancer; it has been hypothesized that depression-associated alterations in cell aging mechanisms, in particular, the telomere/telomerase maintenance system, may underlie this increased risk. We evaluated the association of depressive symptoms and telomere length to mortality and recurrence/progression in 464 patients with bladder cancer.

METHODS

We used the Center for Epidemiologic Studies Depression Scale (CES-D) and Structured Clinical Interview for DSM-IV Disorder (SCID) to assess current depressive symptoms and lifetime major depressive disorder (MDD), respectively, and telomere length was assessed from peripheral blood lymphocytes. Multivariate Cox regression was used to assess the association of depression and telomere length to outcomes and the joint effect of both. Kaplan-Meier plots and log-rank tests were used to compare survival time of subgroups by depression variables and telomere length.

RESULTS

Patients with depressive symptoms (CES-D ≥ 16) had a 1.83-fold [95% confidence interval (CI), 1.08-3.08; P = 0.024] increased risk of mortality compared with patients without depressive symptoms (CES-D < 16) and shorter disease-free survival time (P = 0.004). Patients with both depressive symptoms and lifetime history of MDD were at 4.88-fold (95% CI, 1.40-16.99; P = 0.013) increased risk compared with patients with neither condition. Compared to patients without depressive symptoms and long telomere length, patients with depressive symptoms and short telomeres exhibited a 4-fold increased risk of mortality (HR, 3.96; 95% CI, 1.86-8.41; P = 0.0003) and significantly shorter disease-free survival time (P < 0.001).

CONCLUSION

Short telomere length and depressive symptoms are associated with bladder cancer mortality individually and jointly.

IMPACT

Further investigation of interventions that impact depression and telomere length may be warranted in patients with cancer.

Telomere length in white blood cell DNA and lung cancer: a pooled analysis of three prospective cohorts

We investigated the relationship between telomere length and lung cancer in a pooled analysis from three prospective cohort studies: the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, conducted among men and women in the United States, and previously published data from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Trial conducted among male smokers in Finland, and the Shanghai Women's Health Study (SWHS), which is comprised primarily of never-smokers. The pooled population included 847 cases and 847 controls matched by study, age, and sex. Leukocyte telomere length was measured by a monochrome multiplex qPCR assay. We used conditional logistic regression models to calculate ORs and their 95% confidence intervals (CI) for the association between telomere length and lung cancer risk, adjusted for age and pack-years of smoking. Longer telomere length was associated with increased lung cancer risk in the pooled analysis [OR (95% CI) by quartile: 1.00; 1.24 (0.90-1.71); 1.27 (0.91-1.78); and 1.86 (1.33-2.62); P trend = 0.000022]. Findings were consistent across the three cohorts and strongest for subjects with very long telomere length, i.e., lung cancer risks for telomere length [OR (95% CI)] in the upper half of the fourth quartile were 2.41 (1.28-4.52), 2.16 (1.11-4.23), and 3.02(1.39-6.58) for the PLCO trial, the ATBC trial, and the SWHS, respectively. In addition, the association persisted among cases diagnosed more than 6 years after blood collection and was particularly evident for female adenocarcinoma cases. Telomere length in white blood cell DNA may be a biomarker of future increased risk of lung cancer in diverse populations.

Short leukocyte telomere length predicts poor prognosis and indicates altered immune functions in colorectal cancer patients

BACKGROUND

Numerous studies indicate that the leukocyte telomere length is associated with the risk of cancers, including colorectal cancer (CRC). However, the prognostic value of leukocyte telomere length in CRC patients has not been investigated.

PATIENTS AND METHODS

Relative telomere length (RTL) of peripheral blood leukocytes (PBLs) from 571 CRC patients receiving surgical resection was measured using a polymerase chain reaction-based method. The Cox proportional hazards ratio model and the Kaplan-Meier curve were used to estimate the association between RTL and the clinical outcome of CRC patients in the training set (90 patients) and the testing set (86 patients). Finally, an independent cohort of 395 patients was used as an external validation set. The immunophenotype of PBLs and the plasma concentration of several immune-related cytokines were determined by flow cytometry and enzyme-linked immunosorbent assay, respectively.

RESULTS

Patients with shorter RTL had significantly poorer overall survival and relapse-free survival than those with longer RTL in the training, testing and validation sets. Furthermore, leukocyte RTL and Tumor-Node-Metastasis (TNM) stage exhibited a significant joint effect in the prognosis prediction of combined CRC patients, indicating that patients with both short RTL and advanced stages had the worst prognosis, when compared with other subgroups. In addition, patients with short RTL showed the higher percentage of CD4(+) T cell and the lower percentage of B cell in peripheral blood mononuclear cells, as well as the lower concentration of plasma transforming growth factor-β1, suggesting a possibility that the immune functions changed with RTL alteration.

CONCLUSIONS

Our study for the first time demonstrates that leukocyte RTL is an independent prognostic marker complementing TNM stage and associated with the immune functions in CRC patients.

Review of psychotherapeutic interventions on depression in cancer patients and their impact on disease progression

Depression, ranging from mild to severe, is the most frequently found psychological symptom among individuals with cancer. Depression in cancer patients has been known to mitigate emotional distress, quality of life, adherence to medical treatment, and overall health outcomes. Specifically, depression has been associated with impaired immune response and with poorer survival in patients with cancer. Various studies have found that psychotherapeutic interventions are effective in reducing symptoms of depression, which in turn could affect disease progression and mortality. This paper provides updated information on psychotherapeutic interventions geared towards cancer patients suffering from depressive disorders, and its impact on disease progression. PubMed, Cochrane Library database, PsycINFO and PsycARTICLES databases were searched from January 1980 through August 2013 using key words: psychotherapy, treatment, oncology, cancer, psycho-oncology, psychosocial issues, psychosocial stress, depression, mood disorder, and psychoneuroimmunology.

Elevated plasma magnesium and calcium may be associated with shorter telomeres in older South Australian women

Telomeres are structures that cap the ends of chromosomes. The integrity of the telomere structure and its DNA hexamer (TTAGGG)n repeat sequence is critical for protecting the ends of chromosomes from degradation and in maintaining overall chromosomal stability. Currently, there are limited data on the influence that nutrition has on telomere length. Recent studies have suggested that micronutrients may influence telomere length. Here we examined the relationship between telomere length in lymphocytes and plasma calcium, magnesium, selenium and zinc status in a healthy cohort of younger and older adults. We report a negative association between telomere length and both plasma calcium and magnesium levels, (r=-0.47, P=0.03 and r=-0.61, P=0.001 respectively), in older females; Intriguingly Ca/Mg ratio was positively associated with telomere length (r=0.55, P=0.007). These relationships were not observed in the younger adults, nor in the older males. In conclusion, our study provides preliminary evidence suggesting that levels of plasma magnesium and calcium may impact on telomere length in lymphocytes in older women.

Telomeres and human health

Telomeres are the tips of chromosomes and consist of proteins and hexanucleotide tandem repeats of DNA. The DNA repeats are shortened at each mitotic division of normal cells, and the telomere length chronicles how many divisions the cell has undergone. Thus, telomere length is a marker of fundamental biological pathways. It has been possible to measure telomere length for more than 20 years, and it has been established that telomere length is associated with age, sex and lifestyle factors. Here, the current knowledge of telomere length as a biomarker of disease susceptibility and mortality will be reviewed. In addition, technical difficulties and the reasons why measurement of telomeres has still not been introduced into routine clinical practice will be discussed. Findings from recent studies conducted in many thousands of individuals indicate that telomere length is not-or at best only marginally-independently associated with risk of common disorders such as cardiovascular, pulmonary and neoplastic diseases. However, in sufficiently powered studies, short telomeres are repeatedly and independently found to be associated with increased risk of early death in the general population or in subsets of individuals. This indicates that measurement of telomeres could be a valuable prognostic biomarker in many clinical settings. However, whether short telomeres are a causal factor for or simply a marker of increased risk of early death must be determined. Finally, how Mendelian randomization studies could clarify this issue, and which clinical studies might be carried out to refine this very promising biomarker for routine clinical use will be considered.

Lifetime pesticide use and telomere shortening among male pesticide applicators in the Agricultural Health Study

BACKGROUND

Telomere length (TL) in surrogate tissues may be influenced by environmental exposures.

OBJECTIVE

We aimed to determine whether lifetime pesticides use is associated with buccal cell TL.

METHODS

We examined buccal cell TL in relation to lifetime use of 48 pesticides for 1,234 cancer-free white male pesticide applicators in the Agricultural Health Study (AHS), a prospective cohort study of 57,310 licensed pesticide applicators. Participants provided detailed information on lifetime use of 50 pesticides at enrollment (1993-1997). Buccal cells were collected from 1999 to 2006. Relative telomere length (RTL) was measured using quantitative real-time polymerase chain reaction. We used linear regression modeling to evaluate the associations between specific pesticides and the logarithm of RTL, adjusting for age at buccal cell collection, state of residence, applicator license type, chewing tobacco use, and total lifetime days of all pesticide use.

RESULTS

The mean RTL for participants decreased significantly in association with increased lifetime days of pesticide use for alachlor (p = 0.002), 2,4-dichlorophenoxyacetic acid (2,4-D; p = 0.004), metolachlor (p = 0.01), trifluralin (p = 0.05), permethrin (for animal application) (p = 0.02), and toxaphene (p = 0.04). A similar pattern of RTL shortening was observed with the metric lifetime intensity-weighted days of pesticide use. For dichlorodiphenyltrichloroethane (DDT), we observed significant RTL shortening for lifetime intensity-weighted days (p = 0.04), but not for lifetime days of DDT use (p = 0.08). No significant RTL lengthening was observed for any pesticide.

CONCLUSION

Seven pesticides previously associated with cancer risk in the epidemiologic literature were inversely associated with RTL in buccal cell DNA among cancer-free pesticide applicators. Replication of these findings is needed because we cannot rule out chance or fully rule out bias.