Abstract
BackgroundTelomere 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 MethodsRelevant 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.ResultsThere 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).ConclusionsCurrent 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.
Highlights
As a critical structure with numerous DNA sequences of TTAGGG tandem repeats located at the end of linear chromosomes in eukaryote cells, telomere has reported to plays an important role in the protection of genomic instability and DNA degradation [1, 2]
Pooled estimate indicated that long Telomere length (TL) was not significantly associated with patient Overall survival (OS) (HR 1.26, 95% confidence interval (CI), 0.76 to 2.08)
When we conducted subgroup analyses based on baseline charcteristics, we found that long TL was significantly associated with poor OS in studies conducted in Europe (n = 4, hazard ratios (HRs) 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)
Summary
As a critical structure with numerous DNA sequences of TTAGGG tandem repeats located at the end of linear chromosomes in eukaryote cells, telomere has reported to plays an important role in the protection of genomic instability and DNA degradation [1, 2]. The associations between TL and cancer risk, mortality and progression have been reported in numerous studies with controversial results [4,5,6,7,8,9,10,11,12,13,14]. Studies www.impactjournals.com/oncotarget in a number of malignancies have showed that abnormal alternation of TL in peripheral blood leukocytes is significantly correlated with the mortality and progression of cancer patients, such as breast cancer, prostate cancer, gastric cancer and non-small cell lung cancer [16,17,18,19]. Telomere length (TL) has been reported to be associated with the risk and survival of several cancers. It is unclear for the prognostic role of TL in colorectal cancer (CRC)
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