Our study was powered to identify strong risk loci for lung cancer in African Americans; we confirmed results previously reported in African Americans and other populations for two loci near plausible candidate genes, CHRNA5 and TERT, on 15q25.1 and 5p15.33 respectively, are associated with lung cancer.
Recently, a number of case-control studies have been carried out to investigate the relationship between the rs2736100 polymorphism in TERT and genetic susceptibility to lung cancer.
Single-nucleotide polymorphisms rs421629 on 5p15.33 and rs1948, rs660652, rs8040868 and rs2036527 on 15q25.1, previously identified as lung cancer risk or nicotine-addiction modifiers, were associated with tumor DNA methylation levels in the promoters of TERT and CHRNB4 (P<0.001), respectively, in two independent sample sets (n=82; n=150).
The combined analyses identified six well-replicated SNPs with independent effects and significant lung cancer associations (P < 5.0 × 10(-8)) located in TP63 (rs4488809 at 3q28, P = 7.2 × 10(-26)), TERT-CLPTM1L (rs465498 and rs2736100 at 5p15.33, P = 1.2 × 10(-20) and P = 1.0 × 10(-27), respectively), MIPEP-TNFRSF19 (rs753955 at 13q12.12, P = 1.5 × 10(-12)) and MTMR3-HORMAD2-LIF (rs17728461 and rs36600 at 22q12.2, P = 1.1 × 10(-11) and P = 6.2 × 10(-13), respectively).
The differences in risk level between Israeli Jews and non-Jews could not be explained by lung cancer genetic risk variants which were identified in GWAS (genes in the CHRNA5, TERT and CLPTM1L regions).
The ectopic overexpression of CPSF4 upregulated the hTERT promoter-driven report gene expression and activated the endogenous hTERT mRNA and protein expression and the telomerase activity in lung cancer cells and normal lung cells.
The gene-based SKAT-O analysis implicated TERT as the most relevant gene in the 5p15.33 region for adenocarcinoma (P = 7.84×10(-7)) and lung cancer (P = 2.37×10(-5)) risk.
The long TL genetic score was significantly associated with increased risk of lung adenocarcinoma (P = 6.3 × 10(-15)), even after exclusion of a SNP residing in a known lung cancer susceptibility region (TERT-CLPTM1L) P = 6.6 × 10(-6)).
The quantity of plasma DNA was determined using quantitative Real-Time PCR with amplification of the human telomerase reverse transcriptase (hTERT) gene in 151 patients that suffer from lung cancer and 79 healthy controls.
The results of this meta-analysis suggest that the TERTrs2853669 polymorphism is associated with a significantly increased risk of cancer, particularly lung cancer, in Asian populations.
The risk of developing lung cancer in the population with the TERTrs2736098 locus carrying the T allele was 1.614 times that with the TERTrs2736098 locus carrying the C allele after adjustment of the age factor.
The sensitivity and specificity in lung cancer diagnosis were 89.0% and 72.7% for hTERT mRNA, and 71.3% and 80.0% for EGFR mRNA, respectively. hTERT mRNA was superior to other tumor markers in lung cancer diagnosis.
These data demonstrate a potential association between the TERT-CLPTM1L variant and levels of bulky DNA adducts measured by (32)P-postlabeling and hence a basis for susceptibility to the development of lung cancer.
These results indicate that (a) the HBEC model system is a powerful new approach to assess the contribution of individual and combinations of genetic alterations to lung cancer pathogenesis; (b) a combination of four genetic alterations, including human telomerase reverse transcriptase overexpression, bypass of p16/RB and p53 pathways, and mutant K-RAS(V12) or mutant EGFR, is still not sufficient for HBECs to completely transform to cancer; and (c) EGFR tyrosine kinase inhibitors inhibit the growth of preneoplastic HBEC cells, suggesting their potential for chemoprevention.
These results indication that pure and impure diosgenin prevents telomerase activity by down regulation of the hTERT gene expression in A549 lung cancer cell line, with the difference that pure compound is more effective than another.