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

Targeting 'histone mark': Advanced approaches in epigenetic regulation of telomere dynamics in cancer

Telomere integrity is required for the maintenance of genome stability and prevention of oncogenic transformation of cells. Recent evidence suggests the presence of epigenetic modifications as an important regulator of mammalian telomeres. Telomeric and subtelomeric regions are rich in epigenetic marks that regulate telomere length majorly through DNA methylation and post-translational histone modifications. Specific histone modifying enzymes play an integral role in establishing telomeric histone codes necessary for the maintenance of structural integrity. Alterations of crucial histone moieties and histone modifiers cause deregulations in the telomeric chromatin leading to carcinogenic manifestations. This review delves into the significance of histone modifications and their influence on telomere dynamics concerning cancer. Additionally, it highlights the existing research gaps that hold the potential to drive the development of therapeutic interventions targeting the telomere epigenome.

Construction and validation of molecular subtype and signature of immune cell-related telomeric genes and prediction of prognosis and immunotherapy efficacy in ovarian cancer patients

BACKGROUND

Ovarian cancer (OVC) has emerged as a fatal gynecological malignancy as a result of a lack of reliable methods for early detection, limited biomarkers and few treatment options. Immune cell-related telomeric genes (ICRTGs) show promise as potential biomarkers.

METHODS

ICRTGs were discovered using weighted gene co-expression network analysis (WGCNA). ICRTGs were screened for significant prognosis using one-way Cox regression analysis. Subsequently, molecular subtypes of prognosis-relevant ICRTGs were constructed and validated for OVC, and the immune microenvironment's landscape across subtypes was compared. OVC prognostic models were built and validated using prognosis-relevant ICRTGs. Additionally, chemotherapy susceptibility drugs for OVC patients in the low- and high-risk groups of ICRTGs were screened using genomics of drug susceptibility to cancer (GDSC). Finally, the immunotherapy response in the low- and high-risk groups was detected using the data from GSE78220. We conducted an immune index correlation analysis of ICRTGs with significant prognoses. The MAP3K4 gene, for which the prognostic correlation coefficient is the highest, was validated using tissue microarrays for a prognostic-immune index correlation.

RESULTS

WGCNA analysis constructed a gene set of ICRTGs and screened 22 genes with prognostic significance. Unsupervised clustering analysis revealed the best molecular typing for two subtypes. The Gene Set Variation Analysis algorithm was used to calculate telomere scores and validate the molecular subtyping. A prognostic model was constructed using 17 ICRTGs. In the The Cancer Genome Atlas-OVC training set and the Gene Expression Omnibus validation set (GSE30161), the risk score model's predicted risk groups and the actual prognosis were shown to be significantly correlated. GDSC screened Axitinib, Bexarotene, Embelin and the GSE78220 datasets and demonstrated that ICRTGs effectively distinguished the group that responds to immunotherapy from the non-responsive group. Additionally, tissue microarray validation results revealed that MAP3K4 significantly predicted patient prognosis. Furthermore, MAP3K4 exhibited a positive association with PD-L1 and a negative relationship with the M1 macrophage markers CD86 and INOS.

CONCLUSIONS

ICRTGs may be reliable biomarkers for the molecular typing of patients with OVC, enabling the prediction of prognosis and immunotherapy efficacy.

Association of Telomere Length with Colorectal Cancer Risk and Prognosis: A Systematic Review and Meta-Analysis

(1) Background: Colorectal cancer risk and survival have previously been associated with telomere length in peripheral blood leukocytes and tumor tissue. A systematic review and meta-analysis of the literature was conducted. The PubMed, Embase, and Web of Science databases were searched through March 2022. (2) Methods: Relevant studies were identified through database searching following PRISMA guidelines. Risk estimates were extracted from identified studies; meta-analyses were conducted using random effects models. (3) Results: Fourteen studies were identified (eight on risk; six on survival) through systematic review. While no association was observed between circulating leukocyte telomere length and the risk of colorectal cancer [overall OR (95% CI) = 1.01 (0.82-1.24)], a worse survival for those with shorter telomeres in leukocytes and longer telomeres in tumor tissues was observed [Quartile1/Quartile2-4 overall HR (95% CI) = 1.41 (0.26-7.59) and 0.82 (0.69-0.98), respectively]. (4) Conclusions: Although there was no association with colorectal cancer risk, a poorer survival was observed among those with shorter leukocyte telomere length. Future larger studies evaluating a potentially non-linear relationship between telomeres and colorectal cancer are needed.

Correlation of Short Leukocyte Telomeres and Oxidative Stress with the Presence and Severity of Lung Cancer Explored by Principal Component Analysis

Lung cancer (LC) is the second most common malignancy and leading cause of cancer death. The potential "culprit" for local and systemic telomere shortening in LC patients is oxidative stress. We investigated the correlation between the peripheral blood leukocyte (PBL) telomere length (TL) and the presence/severity of LC and oxidative stress, and its usefulness as LC diagnostic marker. PBL TL was measured in 89 LC patients and 83 healthy subjects using the modified Cawthon RTq-PCR method. The relative PBL TL, found to be a potential diagnostic marker for LC with very good accuracy (P < 0.001), was significantly shorter in patients compared to the control group (CG) (P < 0.001). Significantly shorter telomeres were found in patients with LC TNM stage IV than in patients with stages I-III (P = 0.014), in patients without therapy compared to those on therapy (P = 0.008), and in patients with partial response and stable/progressive disease compared to those with complete response (P = 0.039). The total oxidant status (TOS), advanced oxidation protein products (AOPP), prooxidant-antioxidant balance (PAB) and C-reactive protein (CRP) were significantly higher in patients compared to CG (P < 0.001) and correlated negatively with TL in both patients and CG (P < 0.001). PCA showed a relation between PAB and TL, and between the EGFR status and TL. Oxidative stress and PBL telomere shortening are probably associated with LC development and progression.

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.

Association of circulating leukocyte telomere length with survival in patients with colorectal cancer

INTRODUCTION

Telomere shortening, as seen with aging, can cause chromosomal instability and promote cancer progression. We investigated the association between circulating telomere length and overall and disease-free survival in a sub-cohort of patients with colorectal cancer.

METHODS

Baseline genomic DNA from blood leukocytes was extracted from N = 92 newly diagnosed stage I-IV patients with colorectal cancer enrolled at the ColoCare Study site in Heidelberg, Germany. Detailed information on clinicodemographic (including age) and lifestyle risk factors, and clinical outcomes (including recurrence and survival) was collected. Telomere length was measured in DNA using multiplex quantitative polymerase chain reaction. Kaplan Meier survival curves were generated comparing shorter to longer telomere lengths with log-rank testing.

RESULTS

The mean T/S ratio for study patients was 0.5 (range: 0.3-0.9). Shorter telomeres were associated with older age at baseline. Patients with shorter telomeres experienced a worse overall and disease-free survival, although this association did not reach statistical significance. Kaplan-Meier survival curves for those with circulating telomere length below vs. above the median showed poorer overall (log-rank p = 0.31) and disease-free survival (long-rank p = 0.23).

CONCLUSIONS

Our results suggest that individuals with shorter telomeres, as seen with aging, may experience a worse overall and disease-free survival after colorectal cancer diagnosis. Larger sample sizes with longer follow-up are needed to further evaluate telomere length as a prognostic biomarker in colorectal cancer progression.

T Cell Aging in Patients with Colorectal Cancer-What Do We Know So Far?

Simple Summary

This review describes the role of T cell aging in colorectal cancer development. T cells are important mediators in cancer immunity. Aging affects T cells, leading to various dysfunctions which can impede antitumor immunity. While some hallmarks of T cell aging have been observed in colorectal cancer patients, the functional role of such cells is not clear. Therefore, understanding how aged T cells influence overall patient outcome could potentially help in the pursue to develop new therapies for the elderly.

Abstract

Colorectal cancer (CRC) continues to be one of the most frequently diagnosed types of cancers in the world. CRC is considered to affect mostly elderly patients, and the number of diagnosed cases increases with age. Even though general screening improves outcomes, the overall survival and recurrence-free CRC rates in aged individuals are highly dependent on their history of comorbidities. Furthermore, aging is also known to alter the immune system, and especially the adaptive immune T cells. Many studies have emphasized the importance of T cell responses to CRC. Therefore, understanding how age-related changes affect the outcome in CRC patients is crucial. This review focuses on what is so far known about age-related T cell dysfunction in elderly patients with colorectal cancer and how aged T cells can mediate its development. Last, this study describes the advances in basic animal models that have potential to be used to elucidate the role of aged T cells in CRC.

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.

Leukocyte telomere length is associated with aggressive prostate cancer in localized African American prostate cancer patients

Telomeres play important roles in cancer initiation and progression. Leukocyte telomere length (LTL) has been associated with the risk and prognosis of several cancers, but its association with prostate cancer (PCa) prognosis in African Americans (AAs) has not been reported. In this study, we measured relative LTL from 317 AA PCa patients and assessed its associations with aggressive disease characteristics at diagnosis and biochemical recurrence (BCR) after radical prostatectomy and radiotherapy. LTL was shorter in patients with higher Gleason scores (GS) at diagnosis. Dichotomized into short and long LTL groups, patients with short LTL exhibited a 1.91-fold (95% confidence interval, CI, 1.14-3.20, P = 0.013) increased risk of being diagnosed with high-risk disease (GS =7 [4 + 3] and GS ≥8) than those with long LTL in multivariable logistic regression analysis. Moreover, shorter LTL was significantly associated with an increased risk of BCR (hazard ratio = 1.68, 95% CI, 1.18-11.44, P = 0.024) compared with longer LTL in localized patients receiving prostatectomy or radiotherapy in multivariable Cox analysis. Kaplan-Meier survival analysis showed patients with short LTL had significantly shorter BCR-free survival time than patients with long LTL (Log rank P = 0.011). In conclusion, our results showed for the first time that LTL was shorter in PCa patients with higher GS and short LTL was associated with worse prognosis in AA PCa patients receiving prostatectomy or radiotherapy.

Prognostic Value of Peripheral Blood Lymphocyte Telomere Length in Gynecologic Malignant Tumors

Background: Lymphocyte telomere length is strongly correlated with patient prognosis in several malignant tumor types and is thought to be related to tumor immunity. However, this correlation has not been studied in gynecological cancers. We determined the prognostic significance of peripheral blood lymphocyte telomere length in gynecologic cancers. Methods: Telomere length of lymphocytes from patients with gynecological malignant tumors (ovarian cancer (OC), N = 72; cervical cancer (CC), N = 63; endometrial cancer (EC), N = 87) was examined by quantitative reverse-transcription PCR of isolated mononuclear cells. Kaplan–Meier and Cox proportional hazard analyses were used to determine the association between lymphocyte telomere length and clinicopathological factors. Results: The overall survival (OS) and progression-free survival (PFS) of patients were based on the dichotomized lymphocyte telomere length using the median as a threshold (OC: 0.75, CC: 1.94, and EC: 1.09). A short telomere length was significantly correlated with residual tumors (≥1 cm) in OC and with advanced stage (III and IV) of CC. In OC and CC, patients with shorter relative lymphocyte telomere length (RLT) had significantly poorer OS and PFS than patients with longer RLT (p = 0.002, p = 0.003, and p = 0.001, p = 0.001, respectively). However, in EC, RLT was not significantly associated with OS or PFS (p = 0.567 and p = 0.304, log-rank test). Multivariate analysis showed that shorter RLT was a significant independent prognostic factor of PFS and OS for OC (p = 0.03 and p = 0.04, respectively) and CC (p = 0.02 and p = 0.03, respectively). Conclusions: Patients with OC and CC with shorter lymphocyte telomeres have significantly reduced survival; therefore, the peripheral blood lymphocyte telomere length is a prognostic biomarker in OC and CC.

Leukocyte telomere length is associated with aggressive prostate cancer in localized prostate cancer patients

BACKGROUND

Telomeres play important roles in cancer initiation and progression. The aim of this study is to investigate whether leukocyte telomere length (LTL) is associated with aggressive prostate cancer (PCa).

METHODS

We measured relative LTL in a cohort of 1,889 white PCa patients who were treated and followed up at the University of Texas MD Anderson Cancer Center and assessed its associations with aggressive disease characteristics at diagnosis and biochemical recurrence (BCR) after active treatments (radical prostatectomy and radiotherapy). We further used a Mendelian randomization (MR) approach to compute a weighted genetic risk score (GRS) predictive of LTL using 10 established LTL-associated genetic variants and determined whether this GRS is associated with aggressive PCa.

FINDINGS

LTL was significantly shorter in patients with higher Gleason scores at diagnosis. Dichotomized at the median value of LTL, patients with short LTL exhibited a 2.74-fold (95% confidence interval, 1.79-4.18, P = 3.11 × 10^-6) increased risk of presenting with GS≥8 disease than those with long LTL in multivariate logistic regression analysis. Moreover, shorter LTL was significantly associated with an increased risk of BCR (hazard ratio = 1.53, 95% confidence interval, 1.01-2.34) compared to longer LTL in localized patients receiving prostatectomy or radiotherapy with a significant dose-response association (P for trend = 0.017) in multivariate Cox proportional hazards regression analysis. In MR analysis, genetically predicted short LTL was also associated with an increased risk of BCR (HR=1.73, 95% CI, 1.08-2.78).

INTERPRETATION

Our results showed for the first time that LTL was shorter in PCa patients with high Gleason scores and that short LTL and genetically predicted short LTL are associated with worse prognosis in PCa patients receiving prostatectomy or radiotherapy.

FUNDING

Cancer Prevention and Research Institute of Texas (CPRIT) grant (RP140556), National Cancer Institute Specialized Program of Research Excellence (SPORE) grant (CA140388), and MD Anderson Cancer Center start-up fund.

Prognostic relevance of telomere length and telomerase reverse transcriptase variant (rs2242652) on the multiple myeloma patients

BACKGROUND

The search for enhancement of multiple myeloma prognostic tools is an area of current research. This study aimed to assess the clinicopathological impact of telomere length and telomerase reverse transcriptase (TERT) polymorphic variant, rs2242652, on multiple myeloma (MM) patients.

METHODS

Fifty MM patients and 50 healthy controls were included. Relative telomere length (RTL) and rs2242652 genotype polymorphic variants of TERT were analyzed using real-time polymerase chain reaction (PCR). The MM patients' group was categorized into stage I (n = 16); stage II (n = 12), and stage III (n = 22).

RESULTS

The median telomere length was significantly longer in MM patients' group (0.78) as compared to controls (0.43) (P = .001). Multivariate regression analysis revealed that MM patients with RTL < 0.5 had significant poor response for induction remission therapy with odds ratio 26.45. On the other hand, TERT genotyping analysis of rs2242652 revealed insignificant difference between cases and controls (P = .234), regarding to induction remission response. Survival analysis using Kaplan-Meier curve revealed that patients with shorter telomere length and those with TERT genotype GA had shorter overall survival.

CONCLUSION

Telomere length and TERT rs2242652 genotype polymorphism could be used for refining risk stratification of MM patients.

Prediagnostic Leukocyte Telomere Length and Pancreatic Cancer Survival

BACKGROUND

Leukocyte telomere length has been associated with risk of subsequent pancreatic cancer. Few prospective studies have evaluated the association of prediagnostic leukocyte telomere length with pancreatic cancer survival.

METHODS

We prospectively examined the association of prediagnostic leukocyte telomere length with overall survival (OS) time among 423 participants diagnosed with pancreatic adenocarcinoma between 1984 and 2008 within the Health Professionals Follow-up Study, Nurses' Health Study, Physicians' Health Study, and Women's Health Initiative. We measured prediagnostic leukocyte telomere length in banked blood samples using quantitative PCR. Cox proportional hazards models were used to estimate HRs for OS with adjustment for potential confounders. We also evaluated 10 SNPs at the telomerase reverse transcriptase locus.

RESULTS

Shorter prediagnostic leukocyte telomere length was associated with reduced OS among patients with pancreatic cancer (P trend = 0.04). The multivariable-adjusted HR for OS comparing the lowest with highest quintiles of leukocyte telomere length was 1.39 (95% confidence interval, 1.01-1.93), corresponding to a 3-month difference in median OS time. In an analysis excluding cases with blood collected within 2 years of cancer diagnosis, the association was moderately stronger (HR, 1.55; 95% confidence interval, 1.09-2.21; comparing the lowest with highest quintiles; P trend = 0.01). No prognostic association or effect modification for the prognostic association of prediagnostic leukocyte telomere length was noted in relation to the studied SNPs.

CONCLUSIONS

Prediagnostic leukocyte telomere length was associated with pancreatic cancer survival.

IMPACT

Prediagnostic leukocyte telomere length can be a prognostic biomarker in pancreatic cancer.

Lymphocyte telomere length predicts clinical outcomes of HPV-positive oropharyngeal cancer patients after definitive radiotherapy

Because lymphocyte telomere length (LTL) plays critical roles in the maintenance of genomic stability and integrity, LTL thus may influence the etiology and prognosis of squamous cell carcinoma of the oropharynx (SCCOP). However, given the association between LTL and risk of human papillomavirus (HPV)-associated SCCOP and between LTL and tumor HPV status of SCCOP, we hypothesized that LTL is associated with SCCOP prognosis, particularly in HPV-positive patients after definitive radiotherapy. LTL and tumor HPV type 16 (HPV16) status were determined in 564 incident SCCOP patients before radiotherapy or chemoradiation. Both univariate and multivariable Cox regression analyses were performed to estimate the association between LTL and prognosis. Eighty-five percent patients had HPV16-positive tumors. Patients with shorter telomeres had significantly better overall, disease-specific and disease-free survival than did those with longer telomeres (log-rank P < 0.001). Moreover, patients with shorter telomeres had significantly lower risk of death overall [hazard ratio (HR) = 0.2; 95% confidence interval (CI) = 0.1-0.4], death due to SCCOP (HR = 0.2; 95% CI = 0.1-0.4) and SCCOP recurrence (HR = 0.3; 95% CI = 0.2-0.5) after adjusting for other important prognostic confounders. Finally, we found more pronounced effects of LTL on survival in HPV16-positive SCCOP patients after stratified analysis according to tumor HPV status. These findings indicate that LTL plays a significant role in the survival of patients with SCCOP, especially HPV16-positive patients who undergo definitive radiotherapy. Therefore, pretreatment LTL may be an independent prognostic biomarker for HPV16-positive SCCOP. Prospective studies with larger sample sizes are needed to confirm these findings.

Upregulation of mtSSB by interleukin-6 promotes cell growth through mitochondrial biogenesis-mediated telomerase activation in colorectal cancer

It is now widely accepted that mitochondrial biogenesis is inhibited in most cancer cells. Interestingly, one of the possible exceptions is colorectal cancer (CRC), in which the content of mitochondria has been found to be higher than in normal colon mucosa. However, to date, the causes and effects of this phenomenon are still unclear. In the present study, we systematically investigated the functional role of mitochondrial single-strand DNA binding protein (mtSSB), a key molecule in the regulation of mitochondrial DNA (mtDNA) replication, in the mitochondrial biogenesis and CRC cell growth. Our results demonstrated that mtSSB was frequently upregulated in CRC tissues and that upregulated mtSSB was associated with poor prognosis in CRC patients. Furthermore, overexpression of mtSSB promoted CRC cell growth in vitro by regulating cell proliferation. The in vivo assay confirmed these results, indicating that the forced expression of mtSSB significantly increases the growth capacity of xenograft tumors. Mechanistically, the survival advantage conferred by mtSSB was primarily caused by increased mitochondrial biogenesis and subsequent ROS production, which induced telomerase reverse transcriptase (TERT) expression and telomere elongation via Akt/mTOR pathway in CRC cells. In addition, FOXP1, a member of the forkhead box family, was identified as a new transcription factor for mtSSB. Moreover, our results also demonstrate that proinflammatory IL-6/STAT3 signaling facilitates mtSSB expression and CRC cell proliferation via inducing FOXP1 expression. Collectively, our findings demonstrate that mtSSB induced by inflammation plays a critical role in the regulation of mitochondrial biogenesis, telomerase activation, and subsequent CRC proliferation, providing a strong evidence for mtSSB as drug target in CRC treatment.

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 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.

Relative telomere lengths in tumor and normal mucosa are related to disease progression and chromosome instability profiles in colorectal cancer

Telomeric dysfunction is linked to colorectal cancer (CRC) initiation. However, the relationship of normal tissue and tumor telomere lengths with CRC progression, molecular features and prognosis is unclear. Here, we measured relative telomere length (RTL) by real-time quantitative PCR in 90 adenomas (aRTL), 419 stage I-IV CRCs (cRTL) and adjacent normal mucosa (nRTL). Age-adjusted RTL was analyzed against germline variants in telomere biology genes, chromosome instability (CIN), microsatellite instability (MSI), CpG island methylator phenotype (CIMP), TP53, KRAS, BRAF mutations and clinical outcomes. In 509 adenoma or CRC patients, nRTL decreased with advancing age. Female gender, proximal location and the TERT rs2736100 G allele were independently associated with longer age-adjusted nRTL. Adenomas and carcinomas exhibited telomere shortening in 79% and 67% and lengthening in 7% and 15% of cases. Age-adjusted nRTL and cRTL were independently associated with tumor stage, decreasing from adenoma to stage III and leveling out or increasing from stage III to IV, respectively. Cancer MSI, CIMP, TP53, KRAS and BRAF status were not related to nRTL or cRTL. Near-tetraploid CRCs exhibited significantly longer cRTLs than CIN- and aneuploidy CRCs, while cRTL was significantly shorter in CRCs with larger numbers of chromosome breaks. Age-adjusted nRTL, cRTL or cRTL:nRTL ratios were not associated with disease-free or overall survival in stage II/III CRC. Taken together, our data show that both normal mucosa and tumor RTL are independently associated with CRC progression, and highlight divergent associations of CRC telomere length with tumor CIN profiles.

Telomere length variation in tumor cells and cancer-associated fibroblasts: potential biomarker for hepatocellular carcinoma

The role of telomere dysfunction and aberrant telomerase activities in hepatocellular carcinoma (HCC) has been overlooked for many years. This study aimed to delineate the variation and prognostic value of telomere length in HCC. Telomere‐specific fluorescence in situ hybridization (FISH) and qPCR were used to evaluate telomere length in HCC cell lines, tumor tissues, and isolated non‐tumor cells within the tumor. Significant telomere attrition was found in tumor cells and cancer‐associated fibroblasts (CAFs) compared to their normal counterparts, but not in intratumor leukocytes or bile duct epithelial cells. Clinical relevance and prognostic value of telomere length were investigated on tissue microarrays of 257 surgically treated HCC patients. Reduced intensity of telomere signals in tumor cells or CAFs correlated with larger tumor size and the presence of vascular invasion (p < 0.05). Shortened telomeres in tumor cells or CAFs associated with reduced survival and increased recurrence, and were identified as independent prognosticators for HCC patients (p < 0.05). These findings were validated in an independent HCC cohort of 371 HCC patients from The Cancer Genome Atlas (TCGA) database, confirming telomere attrition and its prognostic value in HCC. We also showed that telomerase reverse transcriptase promoter (TERTp) mutation correlated with telomere shortening in HCC. Telomere variation in tumor cells and non‐tumor cells within the tumor microenvironment of HCC was a valuable prognostic biomarker for this fatal malignancy. © 2017 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Meta-analysis of associations between telomere length and colorectal cancer survival from observational studies

BACKGROUND

Telomere length (TL) has been reported to be associated with the risk and survival of several cancers. But it is unclear for the prognostic role of TL in colorectal cancer (CRC).

MATERIALS AND METHODS

Relevant citations were searched and identified using several major online databases through April 2017 which investigated associations between TL and CRC prognosis. We combined summary estimates using hazard ratios (HRs) with 95% confidence interval (CI), which were pooled using a random-effects model. Overall survival (OS) was set as the primary outcome of interest.

RESULTS

There are 8 cohort studies encompassing 1622 patients included in the meta-analysis. Pooled estimate indicated that long TL was not significantly associated with patient OS (HR 1.26, 95% CI, 0.76 to 2.08). When we conducted subgroup analyses based on baseline charcteristics, we found that long TL (versus short TL) was significantly associated with poor OS in studies conducted in Europe (n = 4, HR 2.73, 95% CI, 1.65 to 4.52, I² = 0), using Southern blot to measure TL (n = 3, HR 2.93, 95% CI, 1.69 to 5.10, I² = 0) and patients' age more than 60 years (n = 3, HR 2.65, 95% CI, 1.22 to 5.76, I² = 0). We found no significant associations between TL and patient disease-free, recurrence-free or progression-free survival (HR 1.19, 95% CI, 0.45 to 3.15).

CONCLUSIONS

Current evidence did not provide solid indication that long TL is significantly associated with improved or poor survival for patients with CRC. Further large sample size prospective cohort studies are warranted to determine the true relationship for specific patients.

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.

Association between telomere length and the risk of colorectal cancer: a meta-analysis of observational studies

BACKGROUND

Human chromosomes are capped and stabilized by telomeres. Telomere length regulates a 'cellular mitotic clock' that defines the number of cell divisions and hence, cellular life span. This study aimed to synthesize the evidence on the association between peripheral blood leucocytes (PBL) telomere length and the risk of colorectal cancer (CRC).

METHODS

We searched relevant studies in electronic databases. When two or more observational studies reported the same outcome measures, we performed pooled analysis. All the analyses were performed on PBL using PCR. The odds ratio (OR) and its 95% confidence interval (CI) were used to assess the strength of association.

RESULTS

Seven studies (with 8 datasets) were included in this meta-analysis; 3 prospective studies, 3 retrospective studies and 1 study with a separate prospective and retrospective designs. The pooled analysis of 4 prospective studies (summary OR 1.01, 95% CI: 0.77-1.34, I ²:30%) and 4 retrospective studies (summary OR 1.65, 95% CI: 0.96-2.83, I ²:96%) showed no relationship between PBL telomere length and the CRC risk. A subgroup analysis of 2 prospective studies exclusively on females also showed no association between PBL telomere length and the CRC risk (summary OR, 1.17, 95% CI:0.72-1.91, I ²:57%).

CONCLUSION

The current analysis is insufficient to provide evidence on the relationship between PBL telomere length and the risk of CRC. Findings suggest that there may be a complex relationship between PBL telomere length and the CRC risk or discrepancy between genetics, age of patients and clinical studies. Future well powered, large prospective studies on the relationship between telomere length and the risk of CRC, and the investigations of the biologic mechanisms are recommended.

Skin phenotypes can offer some insight about the association between telomere length and cancer susceptibility

The role of telomere biology in cancer has been studied for a wide variety of different cancers but the association with telomere length has been controversial. This is because some cancers have been found to be associated with longer telomeres in circulating white cells whilst other cancer types are more common in individuals with shorter telomeres. Hence, there has been some skepticism as to whether telomere length may be helpful in estimating cancer risk. For melanoma, however, results have been fairly consistent showing that longer telomeres are associated with an increased risk. This link was first discovered because of a link between longer telomeres and a high number of naevi. In contrast, for cutaneous squamous cell carcinomas, the relationship is reversed with higher risk in individuals with shorter telomeres. Differences in skin phenotypes with the presence of high number of naevi versus photoageing with solar elastosis and solar keratoses have already been valuable for dermatologists as the former phenotype is associated with melanoma whilst the latter is more common in patients with squamous cell carcinoma of the skin. The hypothesis is that the differences in cutaneous phenotypes already observed by dermatologists for skin cancers may, in fact, be useful as well for cancer prediction in general as it may reflect underlying telomere biology. This manuscript will address the evidence for links between telomere biology, skin phenotypes and cancer risk.

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.

High nevus counts confer a favorable prognosis in melanoma patients

A high number of nevi is the most significant phenotypic risk factor for melanoma and is in part genetically determined. The number of nevi decreases from middle age onward but this senescence can be delayed in patients with melanoma. We investigated the effects of nevus number count on sentinel node status and melanoma survival in a large cohort of melanoma cases. Out of 2,184 melanoma cases, 684 (31.3%) had a high nevus count (>50). High nevus counts were associated with favorable prognostic factors such as lower Breslow thickness, less ulceration and lower mitotic rate, despite adjustment for age. Nevus count was not predictive of sentinel node status. The crude 5- and 10-year melanoma-specific survival rate was higher in melanomas cases with a high nevus count compared to those with a low nevus count (91.2 vs. 86.4% and 87.2 vs. 79%, respectively). The difference in survival remained significant after adjusting for all known melanoma prognostic factors (hazard ratio [HR] = 0.43, confidence interval [CI] = 0.21-0.89). The favorable prognostic value of a high nevus count was also seen within the positive sentinel node subgroup of patients (HR = 0.22, CI = 0.08-0.60). High nevus count is associated with a better melanoma survival, even in the subgroup of patients with positive sentinel lymph node. This suggests a different biological behavior of melanoma tumors in patients with an excess of nevi.

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.

Independent replication of a melanoma subtype gene signature and evaluation of its prognostic value and biological correlates in a population cohort

Development and validation of robust molecular biomarkers has so far been limited in melanoma research. In this paper we used a large population-based cohort to replicate two published gene signatures for melanoma classification. We assessed the signatures prognostic value and explored their biological significance by correlating them with factors known to be associated with survival (vitamin D) or etiological routes (nevi, sun sensitivity and telomere length). Genomewide microarray gene expressions were profiled in 300 archived tumors (224 primaries, 76 secondaries). The two gene signatures classified up to 96% of our samples and showed strong correlation with melanoma specific survival (P=3 x 10(-4)), Breslow thickness (P=5 x 10(-10)), ulceration (P=9.x10-8) and mitotic rate (P=3 x 10(-7)), adding prognostic value over AJCC stage (adjusted hazard ratio 1.79, 95%CI 1.13-2.83), as previously reported. Furthermore, molecular subtypes were associated with season-adjusted serum vitamin D at diagnosis (P=0.04) and genetically predicted telomere length (P=0.03). Specifically, molecular high-grade tumors were more frequent in patients with lower vitamin D levels whereas high immune tumors came from patients with predicted shorter telomeres. Our data confirm the utility of molecular biomarkers in melanoma prognostic estimation using tiny archived specimens and shed light on biological mechanisms likely to impact on cancer initiation and progression.

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.

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.