The Analysis Between Functional Human Telomerase Reverse Transcriptase MNS16A Polymorphisms and the Risk of Developing Non-Small Cell Lung Cancer in the Taiwanese Population

MNS16A polymorphism of the TERT gene on cancer risk: a systematic review and meta-analysis

Some studies have suggested that MNS16A polymorphism in telomerase reverse transcriptase (TERT) gene is associated with cancer risk in various populations and types of cancer. However, the results of previous studies exploring this link have been inconclusive. To be able to accurately assess the association between TERT MNS16A polymorphism and cancer risk, we performed a meta-analysis based on 17 studies described in 12 articles, including 13,764 controls and 7,132 cases. Combined odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were estimated to assess the strength of the association in either a fixed-effects model or, if applicable, a random-effects model. Heterogeneity between articles and their publication bias were also tested. Overall, pooled results showed that no significant association between this polymorphism and cancer was found in the five gene models tested.Considering that there may be too many negative studies in the included studies, diluting the results of the total sample size, we stratified these studies according to ethnicity, source of controls and cancer type. In the stratified analysis, a statistically significant association was observed between Asians and population-based studies. We also analyzed by cancer type and found a significantly increased risk of brain cancer in five genetic models. Our results suggest that TERT MNS16A polymorphism is likely to contribute to increased cancer risk.

The functional VNTR MNS16A of the TERT gene is associated with human longevity in a population of Central Italy

BACKGROUND

Telomerase, encoded by TERT, is the ribonucleoprotein polymerase that maintains telomere ends and it plays a crucial role in cellular senescence. TERT single nucleotide polymorphisms (SNPs) have been associated both with various malignancies and telomere length (TL). The association of TERT SNPs with longevity remains uncertain and varies with ethnicity. The aim of this study was to investigate whether the functional variable number of tandem repeat (VNTR) MNS16A of TERT is associated with longevity.

METHODS

MNS16A genotypes have been determined for 1072 unrelated healthy individuals from Central Italy (18-106 years old) divided into three gender-specific age classes defined according to demographic information and accounting for the different survivals between sexes: for men (women), the first class consists of individuals <66 years old (<73 years old), the second class of individuals 66-88 years old (73-91 years old), and the third class of individuals >88 years old (>91 years old). TL was assessed using genomic DNA from whole blood of 72 selected individuals by a multiplex real-time PCR assay.

RESULTS

MNS16A appears associated to longevity, showing significant associations in Comparison 2 (Age Class 3 vs. Age Class 2) under both additive (odds ratio [O.R.] 0.749; p=0.019) and dominant (O.R. 0.579; p=0.011) models. The MNS16A*L allele is significantly underrepresented in Age Class 3 (O.R. 0.759; p=0.020) compared to Age Class 2. A significant telomere attrition is reported along the three age classes (p=0.0001), that remains significant only in L*/L* genotype carriers (p=0.002) when the analysis was conducted according to MNS16A genotype.

CONCLUSIONS

The TERT MNS16A*L allele appears negatively associated with longevity. The concomitant significant telomere cross sectional attrition rate observed for L*/L* genotype suggests that this polymorphism could influence human longevity by affecting TL.