Christopher Amos and colleagues perform genome-wide association analysis for lung cancer using cohorts genotyped on the OncoArray and combing these with existing data. They identify 18 loci, 10 of which are new, finding heterogeneity across the different lung cancer subtypes, and explore candidate genes through eQTL analysis in lung tissue. Although several lung cancer susceptibility loci have been identified, much of the heritability for lung cancer remains unexplained. Here 14,803 cases and 12,262 controls of European descent were genotyped on the OncoArray and combined with existing data for an aggregated genome-wide association study (GWAS) analysis of lung cancer in 29,266 cases and 56,450 controls. We identified 18 susceptibility loci achieving genome-wide significance, including 10 new loci. The new loci highlight the striking heterogeneity in genetic susceptibility across the histological subtypes of lung cancer, with four loci associated with lung cancer overall and six loci associated with lung adenocarcinoma. Gene expression quantitative trait locus (eQTL) analysis in 1,425 normal lung tissue samples highlights RNASET2, SECISBP2L and NRG1 as candidate genes. Other loci include genes such as a cholinergic nicotinic receptor, CHRNA2, and the telomere-related genes OFBC1 and RTEL1. Further exploration of the target genes will continue to provide new insights into the etiology of lung cancer.

Lung cancer is a leading cause of cancer mortality with an inter-individual difference in susceptibility to the disease. The inheritance of low-efficiency genotypes involved in DNA repair and replication may contribute to the difference in susceptibility. We investigated 44 single nucleotide polymorphisms (SNPs) in 20 DNA repair genes including nucleotide excision repair (NER) genes XPA , ERCC1 , ERCC2/XPD , ERCC4/XPF and ERCC5/XPG; base excision repair (BER) genes APE1 / APEX , OGG1 , MPG , XRCC1 , PCNA , POLB , POLι , LIG3 and EXO1; double-strand break repair (DSB-R) genes XRCC2 , XRCC3 , XRCC9 , NBS1 and ATR; and direct damage reversal (DR) gene MGMT/AGT . The study included 343 non-small cell lung cancer (NSCLC) cases and 413 controls from Norwegian general population. Our results indicate that SNPs in the NER genes ERCC1 (Asn118Asn, 15310G>C, 8902G>T), XPA (-4G>A), ERCC2 / XPD (Lys751Gln) and ERCC5/XPD (His46His); the BER genes APE1 / APEX (Ile64Val), OGG1 (Ser326Cys), PCNA (1876A>G) and XRCC1 (Arg194Trp, Arg280His, Arg399Gln); and the DSB-R genes ATR (Thr211Met), NBS1 (Glu185Gln), XRCC2 (Arg188His) and XRCC9 (Thr297Ile) modulate NSCLC risk. The level of polycyclic aromatic hydrocarbon–DNA (PAH–DNA) adducts in normal lung tissue from 211 patients was analysed. The variant alleles of XRCC1 (Arg280His), XRCC1 (Arg399Gln), ERCC1 (G8092T), ERCC5 (His46His) and MGMT/AGT (Lys178Arg) were more frequent in patients with PAH–DNA adduct levels lower than the mean whereas the XRCC1 (Arg194Trp) variant was more frequent in cases with higher adduct levels than the mean.

Genome-wide association studies have identified three chromosomal regions at 15q25, 5p15, and 6p21 as being associated with the risk of lung cancer. To confirm these associations in independent studies and investigate heterogeneity of these associations within specific subgroups, we conducted a coordinated genotyping study within the International Lung Cancer Consortium based on independent studies that were not included in previous genome-wide association studies. Genotype data for single-nucleotide polymorphisms at chromosomes 15q25 (rs16969968, rs8034191), 5p15 (rs2736100, rs402710), and 6p21 (rs2256543, rs4324798) from 21 case–control studies for 11 645 lung cancer case patients and 14 954 control subjects, of whom 85% were white and 15% were Asian, were pooled. Associations between the variants and the risk of lung cancer were estimated by logistic regression models. All statistical tests were two-sided. Associations between 15q25 and the risk of lung cancer were replicated in white ever-smokers (rs16969968: odds ratio [OR] = 1.26, 95% confidence interval [CI] = 1.21 to 1.32, P_trend = 2 × 10⁻²⁶), and this association was stronger for those diagnosed at younger ages. There was no association in never-smokers or in Asians between either of the 15q25 variants and the risk of lung cancer. For the chromosome 5p15 region, we confirmed statistically significant associations in whites for both rs2736100 (OR = 1.15, 95% CI = 1.10 to 1.20, P_trend = 1 × 10⁻¹⁰) and rs402710 (OR = 1.14, 95% CI = 1.09 to 1.19, P_trend = 5 × 10⁻⁸) and identified similar associations in Asians (rs2736100: OR = 1.23, 95% CI = 1.12 to 1.35, P_trend = 2 × 10⁻⁵; rs402710: OR = 1.15, 95% CI = 1.04 to 1.27, P_trend = .007). The associations between the 5p15 variants and lung cancer differed by histology; odds ratios for rs2736100 were highest in adenocarcinoma and for rs402710 were highest in adenocarcinoma and squamous cell carcinomas. This pattern was observed in both ethnic groups. Neither of the two variants on chromosome 6p21 was associated with the risk of lung cancer. In this international genetic association study of lung cancer, previous associations found in white populations were replicated and new associations were identified in Asian populations. Future genetic studies of lung cancer should include detailed stratification by histology.

Studies have indicated that inflammation, in conjunction with the production of reactive oxygen species, may play a key role in lung cancer development. In this study, 250 lung cancer patients and 214 controls were genotyped for polymorphisms of the inflammation-related genes prostaglandin synthase-2/cyclooxygenase-2 (COX2/PTGS2), interleukin-6 (IL6), interleukin-8 (IL8) and peroxisome proliferator-activated receptor γ (PPARg). We found that carriers of the C allele of a polymorphism in the 3′-UTR of COX2 had a significantly increased risk of lung cancer, with odds ratios of 4.28 (95% CI, 2.44–7.49) for homozygotes and 2.12 (95% CI, 1.25–3.59) for heterozygotes. Additionally, we found that an IL8 promoter polymorphism had a protective effect for lung cancer in female subjects, whereas an IL6 promoter polymorphism was only associated with risk of squamous cell carcinoma. This is the first study implicating polymorphisms in inflammatory genes in the risk of lung cancer.

Associations between night work and breast cancer risk were investigated in a nested case-control study within a cohort of 49,402 Norwegian nurses. A total of 699 (74%) of the live cases diagnosed in 1990–2007 and 895 (65%) controls, cancer free at the time of sampling, were interviewed about work history and potential risk factors. The odds ratios for risk of breast cancer in relation to different exposure metrics were estimated by multivariate unconditional logistic regression models. No increase of risk was found after long duration of work by nurses working ≥3 night shifts per month. Small, nonsignificantly increased risks were observed for exposure to ≥30 years in hospitals or other institutions (odds ratio (OR) = 1.1), ≥12 years in schedules including night work (OR = 1.3), ≥1,007 night shifts during the lifetime (OR = 1.2), and lifetime average number of ≥4 night shifts per month (OR = 1.2). Nonsignificantly increased risks of breast cancer were observed in nurses who worked ≥5 years with ≥4 (OR = 1.4) and ≥5 (OR = 1.6) consecutive night shifts. Significantly increased risks were seen in nurses who worked ≥5 years with ≥6 consecutive night shifts (OR = 1.8, 95% confidence interval: 1.1, 2.8). The results suggest that risk may be related to number of consecutive night shifts.