Novel genetic variants in the chromosome 5p15.33 region associate with lung cancer risk

Chromosome 5p15.33 has been identified by genome-wide association studies as one of the regions that associate with lung cancer risk. A few single-nucleotide polymorphisms (SNPs) in the telomerase reverse transcriptase (TERT) and cleft lip and palate transmembrane 1-like (CLPTM1L) genes located in this region have shown consistent associations. We performed dense genotyping of SNPs in this region to refine the previously reported association signals for lung cancer risk. Two hundred and fifteen SNPs were genotyped on an Illumina iSelect panel, in a hospital-based case-control study of 1681 lung cancer cases and 1235 unaffected controls. Association was tested using unconditional logistic regression, while adjusting for age, sex and pack-years smoked. Furthermore, since many of the SNPs were in linkage disequilibrium (LD), haplotype blocks were constructed, from which tagging SNPs at an r ² threshold of ≥0.95 were included in a stepwise forward selection logistic regression model. Of the 215 SNPs, 69 were significant at P < 0.05 in univariate analysis; of these, 35 SNPs meeting the r ² threshold were included in the multiple logistic regression model. Two SNPs, rs370348 (odds ratio = 0.76, P = 1.6 × 10 ^-6) and rs4975538 (odds ratio = 1.18, P = 0.005), significantly associated with risk in the overall sample. Among ever smokers, rs4975615 (odds ratio = 0.75, P = 1.2 × 10 ^-4) and rs4975538 (odds ratio = 1.26, P = 0.002) were significant, whereas among never-smokers, rs451360 (odds ratio = 0.62, P = 7.6 × 10 ^-5) was significant. We refined the consistent association signal in this region, allowing for the considerable LD between SNPs and identified four novel SNPs that were independently and significantly associated with lung cancer risk. Results of these analyses strongly suggest effects on risk from several loci in the TERT/CLPTM1L region.