Identification Of Functional Variants On Chromosome 5p15.33 Associated With Lung Cancer In Chinese Population

Objective:We intended to identify polymorphisms on chromosome 5p15.33associated with lung cancer susceptibility in Chinese population,evaluate the relevance between genetic variations and leukocyte telomere length,and explore the functional effects of causal variants in telomere biology and tumorigenesis.Methods:Firstly,we compared the genotypic frequency in 400 non-small cell lung cancer?NSCLC?cases by targeted sequencing with the data in East Asian population from 1000 Genomes Project.Candidate variants were selected,and their associations with lung cancer were subsequently validated in 985 cases and 970 controls.We evaluated the relationships between risk variants and telomere length in 774 healthy subjects.Based on bioinformatic analyses,luciferase assays and electrophoretic mobility shift assays?EMSA?were conducted to explore potential functions and reveal carcinogenic mechanism.Results:We identified 1478 variants through targeted sequencing on chr5p15.33region and selected 17 candidates by genotypic comparison.Four polymorphisms exhibited prominent associations with lung cancer risk,including rs7726159(OR=1.34,95%CI:1.18-1.52,P=7.78×10^-6),rs10054203(OR=1.29,95%CI:1.13-1.46,P=1.37×10^-4),rs2736107(OR=1.28,95%CI:1.11-1.47,P=5.14×10^-4)and rs2853677?OR=1.23,95%CI:1.08-1.39,P=0.002?.The minor allele of rs7726159and rs10053203 were associated with long telomeres?under additive model,P=0.008 and 0.036,respectively?.In luciferase assays,the fragment containing rs7726159-A increased luciferase activity comparing with the allele C in both A549and SK-MES-1 cell lines(P_A549=2.17×10^-6;P_SK-MES-1=2.69×10^-4).EMSA and supershift assays demonstrated the specific affinity of MYC to the rs7726159 wild type allele C.Conclusion:The functional variant rs7726159,located in 3th intron of TERT,confers lung cancer susceptibility might by affecting MYC binding and inducing telomere lengthening.