A common genetic variant, telomerase reverse transcriptase (TERT) rs2736098, was recently reported to be associated with lung cancer risk in Caucasians.
Accumulating evidence has suggested that TERT could modulate the expression of numerous genes including interleukin 6 (IL-6), an important cytokine for the development of lung cancer.
After the 2nd stage validation (975 cases versus 1022 controls), the study clarified the association that rs2736100 of the TERT gene conferred the highest significant risk of lung cancer (P=4×10(-3) in the 1st stage association, P=4×10(-4) in the 2nd stage validation, and P=1×10(-5), odds ratio=1.24 in the combined population).
All three mapped to Chromosome 5 CLPTM1L-TERT region, previously shown to be associated with lung cancer risk in smokers and in never-smoker Asian women, and risk of other cancers including breast, ovarian, colorectal, and prostate.
As a result, 15 SNPs on or near 12 genes and one miRNA with strong evidence of association with lung cancer risk were identified, including TERT (rs2736098), CHRNA3 (rs1051730), AGPHD1 (rs8034191), CLPTM1L (rs401681 and rs402710), BAT3 (rs3117582), TRNAA (rs4324798), ERCC2 (Lys751Gln), miR-146a2 (rs2910164), CYP1B1 (Arg48Gly), GSTM1 (null/present), SOD2 (C47T), IL-10 (-592C/A and -819C/T), and TP53 (intron 6).
By chromosome conformation capture, it was identified that the segment containing these two SNPs could interact with TERT (telomerase reverse transcriptase) promoter, thus indicating that these SNPs confer lung cancer risk by regulating TERT expression instead of CLPTM1L.
Case-Control Study on Impact of the Telomerase Reverse Transcriptase Gene Polymorphism and Additional Single Nucleotide Polymorphism (SNP)- SNP Interaction on Non-Small Cell Lung Cancers Risk in Chinese Han Population.
DQA1*03 and the minor allele for a polymorphism, rs2736100, in TERT, another lung cancer susceptibility locus identified in recent GWASs on Europeans and Americans, were indicated to independently contribute to ADC risk with per allele OR of 1.43 (95% CI = 1.31-1.56, P = 7.8 x 10(-16)).
Genetic factors included six variants implicated in a previous a genome-wide association study (GWAS) of NPC and three variants residing near the CHRNA3 and TERT genes that were linked to lung cancer risk in Asian populations.
However, the joint effect of TERT and CLPTM1L variants increased the risk of lung cancer, especially squamous cell carcinoma, with an adjusted OR of 3.274.
Human telomerase reverse transcriptase (hTERT) gene amplification was detected in pleural effusions of patients with lung cancer (n = 69) and in patients with benign lung disease (n = 46) when using a quantitative polymerase chain reaction (qPCR) technique.
In conclusion, although multiple variants have been found associated with lung cancer risk in TERT-CLPTM1L region, our findings indicated that there are three independent lung cancer susceptibility signals in this region.
In summary, our results show that genetic variation in the CLPTM1L-TERT locus of chromosome 5p15.33 is directly associated with the risk of lung cancer, most notably adenocarcinoma.
In the logistic regression analysis, TERT-rs2853669, rs2736108, and CLPTM1L-rs31490 were significant associated with increased risk of lung cancer (OR = 1.46, 95% CI = 1.22-1.75; OR = 1.22, 95% CI = 1.00-1.49 and OR = 1.74, 95% CI = 1.35-2.23 under additive model, respectively).
In the subgroup analysis based on cancer type, the TERTrs2736098 with the A allele was 1.299 times more frequent than that with the G allele (OR = 1.299, 95% CI = 1.216-1.386) under the allelic genetic model in lung cancer, and 1.152 times (OR = 1.152, 95% CI = 1.032-1.286) that in bladder cancer.
Longer telomere length in peripheral white blood cells is associated with risk of lung cancer and the rs2736100 (CLPTM1L-TERT) polymorphism in a prospective cohort study among women in China.
Our data demonstrated that hTERT promoter-driven IFN-beta expression was the tumor-specific, decreased the cell viability of tumor cells but not normal cells, and induced tumor cell apoptosis via activation of caspase pathway and release of cytochrome c. AAV-mediated IFN-beta expression driven by hTERT promoter significantly suppressed the growth of colorectal cancer and lung cancer xenograft in mice and resulted in tumor cells death in vivo.
Our findings, combined with previous studies, suggest that polymorphisms in the TERT gene contribute to the risk for lung cancer in the Chinese Han population.
Our results suggest that a common functional promoter polymorphism, TERTrs2853669, may influence both telomere length and lung cancer risk in the Korean population.