Elucidating Genomic Characteristics of Lung Cancer Progression from In Situ to Invasive Adenocarcinoma

To examine the diversity of somatic alterations and clonal evolution according to aggressiveness of disease, nineteen tumor-blood pairs of 'formerly bronchiolo-alveolar carcinoma (BAC)' which had been reclassified into preinvasive lesion (adenocarcinoma in situ; AIS), focal invasive lesion (minimally invasive adenocarcinoma; MIA), and invasive lesion (lepidic predominant adenocarcinoma; LPA and non-lepidic predominant adenocarcinoma; non-LPA) according to IASLC/ATS/ERS 2011 classification were explored by whole exome sequencing. Several distinct somatic alterations were observed compare to the lung adenocarcinoma study from the Cancer Genome Atlas (TCGA). There were higher numbers of tumors with significant APOBEC mutation fold enrichment (73% vs. 58% TCGA). The frequency of KRAS mutations was lower in our study (5% vs. 32% TCGA), while a higher number of mutations of RNA-splicing genes, RBM10 and U2AF1, were found (37% vs. 11% TCGA). We found neither mutational pattern nor somatic copy number alterations that were specific to AIS/MIA. We demonstrated that clonal cell fraction was the only distinctive feature that discriminated LPA/non-LPA from AIS/MIA. The broad range of clonal frequency signified a more branched clonal evolution at the time of diagnosis. Assessment of tumor clonal cell fraction might provide critical information for individualized therapy as a prognostic factor, however this needs further study.

Identification of Circulating Tumor DNA for the Early Detection of Small-cell Lung Cancer

Circulating tumor DNA (ctDNA) is emerging as a key potential biomarker for post-diagnosis surveillance but it may also play a crucial role in the detection of pre-clinical cancer. Small-cell lung cancer (SCLC) is an excellent candidate for early detection given there are no successful therapeutic options for late-stage disease, and it displays almost universal inactivation of TP53. We assessed the presence of TP53 mutations in the cell-free DNA (cfDNA) extracted from the plasma of 51 SCLC cases and 123 non-cancer controls. We identified mutations using a pipeline specifically designed to accurately detect variants at very low fractions. We detected TP53 mutations in the cfDNA of 49% SCLC patients and 11.4% of non-cancer controls. When stratifying the 51 initial SCLC cases by stage, TP53 mutations were detected in the cfDNA of 35.7% early-stage and 54.1% late-stage SCLC patients. The results in the controls were further replicated in 10.8% of an independent series of 102 non-cancer controls. The detection of TP53 mutations in 11% of the 225 non-cancer controls suggests that somatic mutations in cfDNA among individuals without any cancer diagnosis is a common occurrence, and poses serious challenges for the development of ctDNA screening tests.

Abstract 3156: NGS-based screening for TP53 mutations in circulating cell-free DNA: A first step towards early detection of lung cancers

Background

The US National Lung Cancer Screening Trial (NLST) demonstrated in 2011 that screening with computed tomography (CT) scans could reduce lung cancer mortality by 20%, but with important financial costs and high number of false positives. The identification of novel biomarkers is a need to obtain the maximum benefit from CT screening. Given its economical and minimally invasive nature, screening for somatic mutations in circulating tumor DNA (ctDNA) using next-generation sequencing may complement existing screening tools. However, for application in early detection, variant detection must also be done agnostically, i.e. without prior knowledge from tumour tissue of the mutations expected and unfortunately, most currently available variant callers are not adapted for this task.

Methods

We performed multiplex PCR on circulating free DNA (cfDNA) extracted from the plasma of 35 lung squamous cell carcinoma (SCC) and 64 small-cell carcinoma (SCLC) patients. We additionally included 133 hospital controls to evaluate the specificity of ctDNA. We applied (>10,000X) Ion torrent targeted sequencing on the full-coding region of TP53 since this gene is known to be mutated in more than 70% and 90% of SCC and SCLC, respectively. Each amplification, library preparation, and sequencing was performed in duplicate to control for amplification and sequencing errors. Detecting mutations on ctDNA raises important statistical and bioinformatics challenges as it represents only a small fraction of cfDNA. We therefore developed and applied a method based on the idea that a data-derived model of sequencing errors has the potential to improve our ability to detect low-allelic fraction (AF) somatic variants.

Results

We detected TP53 non-synonymous coding mutations with AFs between 0.04% and 85% (median 1.7%) in 8 (23%) SCC patients, 28 (44%) SCLC patients, and 8 (6%) controls. We estimated odds ratios of 4.6 (p = 0.006) for SCC and 12.0 (p = 6.7×10-10) for SCLC. Observations in controls are surprising, but in this instance there was no information regarding a subsequent cancer diagnosis.

Conclusion

We show that it is possible to detect ctDNA in the cfDNA of lung cancer patients. Since only patients with early stage (I-IIA) SCC tumours were included, these results support the potential utility of the approach for early detection. Nevertheless, if such mutations are found prior to diagnosis has not been explored in a prospective study design with pre-diagnostic plasma samples and individuals without a cancer diagnosis through a follow-up period.

Citation Format: Patrice H. Avogbe, Tiffany Delhomme, Noémie Leblay, Florence Le Calvez-Kelm, Priscilia Chopard, Valérie Gaborieau, Ghislaine Scelo, Behnoush Abedi-Ardekani, David Zaridze, Anush Mukeria, Graham Byrnes, Paul Brennan, Lynnette Fernandez-Cuesta, Matthieu Foll, James D. McKay. NGS-based screening for TP53 mutations in circulating cell-free DNA: A first step towards early detection of lung cancers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3156.

Occupational prestige, social mobility and the association with lung cancer in men

BACKGROUND

The nature of the association between occupational social prestige, social mobility, and risk of lung cancer remains uncertain. Using data from the international pooled SYNERGY case-control study, we studied the association between lung cancer and the level of time-weighted average occupational social prestige as well as its lifetime trajectory.

METHODS

We included 11,433 male cases and 14,147 male control subjects. Each job was translated into an occupational social prestige score by applying Treiman's Standard International Occupational Prestige Scale (SIOPS). SIOPS scores were categorized as low, medium, and high prestige (reference). We calculated odds ratios (OR) with 95 % confidence intervals (CI), adjusting for study center, age, smoking, ever employment in a job with known lung carcinogen exposure, and education. Trajectories in SIOPS categories from first to last and first to longest job were defined as consistent, downward, or upward. We conducted several subgroup and sensitivity analyses to assess the robustness of our results.

RESULTS

We observed increased lung cancer risk estimates for men with medium (OR = 1.23; 95 % CI 1.13-1.33) and low occupational prestige (OR = 1.44; 95 % CI 1.32-1.57). Although adjustment for smoking and education reduced the associations between occupational prestige and lung cancer, they did not explain the association entirely. Traditional occupational exposures reduced the associations only slightly. We observed small associations with downward prestige trajectories, with ORs of 1.13, 95 % CI 0.88-1.46 for high to low, and 1.24; 95 % CI 1.08-1.41 for medium to low trajectories.

CONCLUSIONS

Our results indicate that occupational prestige is independently associated with lung cancer among men.

Fine mapping of chromosome 5p15.33 based on a targeted deep sequencing and high density genotyping identifies novel lung cancer susceptibility loci

Chromosome 5p15.33 has been identified as a lung cancer susceptibility locus, however the underlying causal mechanisms were not fully elucidated. Previous fine-mapping studies of this locus have relied on imputation or investigated a small number of known, common variants. This study represents a significant advance over previous research by investigating a large number of novel, rare variants, as well as their underlying mechanisms through telomere length. Variants for this fine-mapping study were identified through a targeted deep sequencing (average depth of coverage greater than 4000×) of 576 individuals. Subsequently, 4652 SNPs, including 1108 novel SNPs, were genotyped in 5164 cases and 5716 controls of European ancestry. After adjusting for known risk loci, rs2736100 and rs401681, we identified a new, independent lung cancer susceptibility variant in LPCAT1: rs139852726 (OR = 0.46, P = 4.73×10(-9)), and three new adenocarcinoma risk variants in TERT: rs61748181 (OR = 0.53, P = 2.64×10(-6)), rs112290073 (OR = 1.85, P = 1.27×10(-5)), rs138895564 (OR = 2.16, P = 2.06×10(-5); among young cases, OR = 3.77, P = 8.41×10(-4)). In addition, we found that rs139852726 (P = 1.44×10(-3)) was associated with telomere length in a sample of 922 healthy individuals. 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. In this largest fine-mapping study to investigate a large number of rare and novel variants within 5p15.33, we identified novel lung and adenocarcinoma susceptibility loci with large effects and provided support for the role of telomere length as the potential underlying mechanism.

Abstract A1-31: Molecular characteristics and predictors of poor prognosis in sporadic clear cell renal cancer among central/eastern European and United States patients

We investigated patient/tumor characteristics/inherited variants, hypoxia inducible factor 1 and 2 alpha (HIF1A/HIF2A) protein expression, and patient survival among Central European (CE) and United States (US) clear cell renal cancer (ccRCC) patients from two case-control studies. VHL inactivation, HIF1A, and HIF2A expression have been implicated in RCC and angiogenesis. GWAS studies have identified EPAS1 variants encoding the protein HIF2A associated with RCC risk. We conducted a hospital-based case-control study in Central/Eastern Europe (CE) and a population-based study in the US (Detroit, Chicago) that included whites and blacks. We used data on: i) patient/tumor characteristics, ii) inherited tagging single nucleotide polymorphisms (SNPs) in genes involved in the VHL-HIF pathway (HIF1A, EPAS1, VHL), HIF1A and HIF2A protein expression using immunohistochemical (IHC) methods, and survival from 696 CEERCC and 328 US ccRCC cases. ccRCC patients from CE Europe were older, presented at a higher grade, stage, with larger tumors, had lower BMI, less family history and smoked less (all p<0.0001) compared to US cases. US cases demonstrated higher intensity HIF1A and HIF2A protein expression compared to CE cases (p<0.0001). Black US ccRCC cases were more likely to be hypertensive (p<0.0001) and have lower HIF2A protein expression compared to white US cases. HIF1A and HIF2A were examined for associations with patient/tumor characteristics. In the US study, younger patients had higher levels of HIF2A expression compared to older cases and high BMI was associated with HIF1A expression. In both studies, tumor grade, stage and size at diagnosis were associated with lower HIF1A and HIF2A expression. In analyses adjusted for center, race, sex, age, hypertension, BMI, smoking, tumor grade and stage, HIF1A expression was significantly associated with HIF2A expression (P-trend<0.0001). We assessed associations of variants in EPAS1 (N=16), HIF1A (N=11), and VHL (N=9) with HIF1A and HIF2A expression in ccRCC tissue using tissue microarrays. Seven HIF1A SNPs were significantly associated with HIF1A expression and one EPAS1 SNP (rs1374748) with HIF2A expression. Median survival time was longer in CE compared to USRCC cases (100.3 vs. 86.0 months, p=0.001), women than men (97.1 vs 91.0 months, p=0.02) but similar among whites and blacks in the US study (86.0 vs 87.0 months). In Cox proportional hazard models, in both studies combined, risk of death was higher for those with large tumors (>4cm, p<0.0001) and with a higher stage 1 vs 2, 3+4 (p<0.0001, both) In contrast, ccRCC-specific survival was higher among USRCC than CE patients (19.8 vs 38.0 months, p=0.04) but similar among white compared to black US ccRCC patients (37.0 vs 40.0 months, p=0.50).

Citation Format: Lee Moore, Petra Lenz, Meredith Yeager, Ruth Pfeiffer, Ghislaine Scelo, Mark Purdue, David Zaridze, Kendra Schwartz, Neonilia szeszenia-Dabrowska, Faith Davis, Joanne Colt, vladimir Janout, Marie Navritalova, Paolo Boffetta, Laurie Burdette, Sara Karami, Paul Brennan, Jon Hofmann, Michael Nickerson, Wong-Ho Chow, Margaret Tucker, Stephen Chanock, Stephen Hewitt, Jorge Toro, Nat Rothman. Molecular characteristics and predictors of poor prognosis in sporadic clear cell renal cancer among central/eastern European and United States patients. [abstract]. In: Proceedings of the AACR Special Conference on Translation of the Cancer Genome; Feb 7-9, 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 1):Abstract nr A1-31.

Identification of lung cancer histology-specific variants applying Bayesian framework variant prioritization approaches within the TRICL and ILCCO consortia

Large-scale genome-wide association studies (GWAS) have likely uncovered all common variants at the GWAS significance level. Additional variants within the suggestive range (0.0001> P > 5×10(-8)) are, however, still of interest for identifying causal associations. This analysis aimed to apply novel variant prioritization approaches to identify additional lung cancer variants that may not reach the GWAS level. Effects were combined across studies with a total of 33456 controls and 6756 adenocarcinoma (AC; 13 studies), 5061 squamous cell carcinoma (SCC; 12 studies) and 2216 small cell lung cancer cases (9 studies). Based on prior information such as variant physical properties and functional significance, we applied stratified false discovery rates, hierarchical modeling and Bayesian false discovery probabilities for variant prioritization. We conducted a fine mapping analysis as validation of our methods by examining top-ranking novel variants in six independent populations with a total of 3128 cases and 2966 controls. Three novel loci in the suggestive range were identified based on our Bayesian framework analyses: KCNIP4 at 4p15.2 (rs6448050, P = 4.6×10(-7)) and MTMR2 at 11q21 (rs10501831, P = 3.1×10(-6)) with SCC, as well as GAREM at 18q12.1 (rs11662168, P = 3.4×10(-7)) with AC. Use of our prioritization methods validated two of the top three loci associated with SCC (P = 1.05×10(-4) for KCNIP4, represented by rs9799795) and AC (P = 2.16×10(-4) for GAREM, represented by rs3786309) in the independent fine mapping populations. This study highlights the utility of using prior functional data for sequence variants in prioritization analyses to search for robust signals in the suggestive range.

Circulating Concentrations of Vitamin B6 and Kidney Cancer Prognosis: A Prospective Case-Cohort Study

Prospective cohort studies have found that prediagnostic circulating vitamin B6 is inversely associated with both risk of kidney cancer and kidney cancer prognosis. We investigated whether circulating concentrations of vitamin B6 at kidney cancer diagnosis are associated with risk of death using a case-cohort study of 630 renal cell carcinoma (RCC) patients. Blood was collected at the time of diagnosis, and vitamin B6 concentrations were quantified using LC-MS/MS. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox regression models. After adjusting for stage, age, and sex, the hazard was 3 times lower among those in the highest compared to the lowest fourth of B6 concentration (HR4vs1 0.33, 95% CI [0.18, 0.60]). This inverse association was solely driven by death from RCC (HR4vs1 0.22, 95% CI [0.11, 0.46]), and not death from other causes (HR4vs1 0.89, 95% CI [0.35, 2.28], p-interaction = 0.008). These results suggest that circulating vitamin B6 could provide additional prognostic information for kidney cancer patients beyond that afforded by tumour stage.

Circulating 25-hydroxyvitamin D3 and survival after diagnosis with kidney cancer

Prospective cohort studies have provided some evidence that circulating vitamin D is associated with risk of, and survival from, renal cell carcinoma (RCC), but it is unclear whether concentrations of vitamin D at the time of diagnosis of RCC are associated with prognosis. We conducted a case-cohort study of 630 RCC cases, including 203 deaths, from a multicenter case-control study in Eastern Europe. Vitamin D was assessed as 25-hydroxyvitamin D3 [25(OH)D3], and we used weighted Cox models to estimate hazard ratios (HR) and 95% confidence intervals (CI) by categories of season-adjusted 25(OH)D3. Higher concentrations of 25(OH)D3 were associated with lower risk of death after adjusting for stage, age, sex, and country (HR highest vs. lowest category 0.57; 95% CI, 0.34-0.97). The inverse associations of 25(OH)D3 with death were most notable among those who died from non-RCC causes and those diagnosed with early-stage disease. In summary, 25(OH)D3 concentration at diagnosis of RCC was inversely associated with all-cause mortality rates, but not specifically with RCC outcome.

Circulating MicroRNAs as Non-Invasive Biomarkers for Early Detection of Non-Small-Cell Lung Cancer

Background

Detection of lung cancer at an early stage by sensitive screening tests could be an important strategy to improving prognosis. Our objective was to identify a panel of circulating microRNAs in plasma that will contribute to early detection of lung cancer.

Material and Methods

Plasma samples from 100 early stage (I to IIIA) non–small-cell lung cancer (NSCLC) patients and 100 non-cancer controls were screened for 754 circulating microRNAs via qRT-PCR, using TaqMan MicroRNA Arrays. Logistic regression with a lasso penalty was used to select a panel of microRNAs that discriminate between cases and controls. Internal validation of model discrimination was conducted by calculating the bootstrap optimism-corrected AUC for the selected model.

Results

We identified a panel of 24 microRNAs with optimum classification performance. The combination of these 24 microRNAs alone could discriminate lung cancer cases from non-cancer controls with an AUC of 0.92 (95% CI: 0.87-0.95). This classification improved to an AUC of 0.94 (95% CI: 0.90-0.97) following addition of sex, age and smoking status to the model. Internal validation of the model suggests that the discriminatory power of the panel will be high when applied to independent samples with a corrected AUC of 0.78 for the 24-miRNA panel alone.

Conclusion

Our 24-microRNA predictor improves lung cancer prediction beyond that of known risk factors.

A rare truncating BRCA2 variant and genetic susceptibility to upper aerodigestive tract cancer

Deleterious BRCA2 genetic variants markedly increase risk of developing breast cancer. A rare truncating BRCA2 genetic variant, rs11571833 (K3326X), has been associated with a 2.5-fold risk of lung squamous cell carcinoma but only a modest 26% increase in breast cancer risk. We analyzed the association between BRCA2 SNP rs11571833 and upper aerodigestive tract (UADT) cancer risk with multivariable unconditional logistic regression adjusted by sex and combinations of study and country for 5942 UADT squamous cell carcinoma case patients and 8086 control patients from nine different studies. All statistical tests were two-sided. rs11571833 was associated with UADT cancers (odds ratio = 2.53, 95% confidence interval = 1.89 to 3.38, P = 3x10(-10)) and was present in European, Latin American, and Indian populations but extremely rare in Japanese populations. The association appeared more apparent in smokers (current or former) compared with never smokers (P het = .026). A robust association between a truncating BRCA2 variant and UADT cancer risk suggests that treatment strategies orientated towards BRCA2 mutations may warrant further investigation in UADT tumors.

A systematic investigation of the contribution of genetic variation within the MHC region to HPV seropositivity

High-risk mucosal types of human papillomavirus (HPV) cause anogenital and oropharyngeal cancers, whereas cutaneous types (e.g. HPV8 and 77) are suspected to be involved in non-melanoma skin cancer. The antibody response to HPVs is a key determinant of protective immunity, but not all infected individuals seroconvert. Genetic variability of the host may have large impact on seroconversion. A previous genome-wide association study (GWAS) has identified a susceptibility locus (rs41270488) for HPV8 seropositivity within the major histocompatibility complex (MHC) region. To further study this locus, we imputed alleles at classical leukocyte antigen (HLA) loci using HLA*IMP:02 with a reference panel from the HapMap Project and the 1958 Birth Cohort, and conducted an integrated analysis among 4811 central European subjects to assess the contribution of classical HLA alleles and gene copy number variation (CNV) at the hypervariable DRB locus within the MHC region to HPV seropositivity at both the individual HPV type level and the phylogenetic species level. Our study provides evidence that the association noted between rs41270488 and HPV8 seropositivity is driven by two independent variants, namely DQB1*0301 [odds ratio (OR) = 1.51, 95% confidence interval (CI) = 1.36-1.68, P = 1.0 × 10(-14)] and DRB1*1101 (OR = 1.89, 95%CI = 1.57-2.28, P = 1.5 × 10(-11)) within the HLA class II region. Additionally, we identified two correlated alleles DRB1*0701 (OR = 1.67, 95%CI = 1.41-1.98, P = 2.6 × 10(-9)) and DQA1*0201 (OR = 1.67, 95%CI = 1.38-1.93, P = 1.7 × 10(-8)), to be associated with HPV77 seropositivity. Comparable results were observed through imputation using SNP2HLA with another reference panel from the Type 1 diabetes Genetics Consortium. This study provides support for an important role of HLA class II alleles in antibody response to HPV infection.

The 12p13.33/RAD52 locus and genetic susceptibility to squamous cell cancers of upper aerodigestive tract

Genetic variants located within the 12p13.33/RAD52 locus have been associated with lung squamous cell carcinoma (LUSC). Here, within 5,947 UADT cancers and 7,789 controls from 9 different studies, we found rs10849605, a common intronic variant in RAD52, to be also associated with upper aerodigestive tract (UADT) squamous cell carcinoma cases (OR = 1.09, 95% CI: 1.04-1.15, p = 6x10(-4)). We additionally identified rs10849605 as a RAD52 cis-eQTL inUADT(p = 1x10(-3)) and LUSC (p = 9x10(-4)) tumours, with the UADT/LUSC risk allele correlated with increased RAD52 expression levels. The 12p13.33 locus, encompassing rs10849605/RAD52, was identified as a significant somatic focal copy number amplification in UADT(n = 374, q-value = 0.075) and LUSC (n = 464, q-value = 0.007) tumors and correlated with higher RAD52 tumor expression levels (p = 6x10(-48) and p = 3x10(-29) in UADT and LUSC, respectively). In combination, these results implicate increased RAD52 expression in both genetic susceptibility and tumorigenesis of UADT and LUSC tumors.

Effect of occupational exposures on lung cancer susceptibility: a study of gene-environment interaction analysis

BACKGROUND

Occupational exposures are known risk factors for lung cancer. Role of genetically determined host factors in occupational exposure-related lung cancer is unclear.

METHODS

We used genome-wide association (GWA) data from a case-control study conducted in 6 European countries from 1998 to 2002 to identify gene-occupation interactions and related pathways for lung cancer risk. GWA analysis was performed for each exposure using logistic regression and interaction term for genotypes, and exposure was included in this model. Both SNP-based and gene-based interaction P values were calculated. Pathway analysis was performed using three complementary methods, and analyses were adjusted for multiple comparisons. We analyzed 312,605 SNPs and occupational exposure to 70 agents from 1,802 lung cancer cases and 1,725 cancer-free controls.

RESULTS

Mean age of study participants was 60.1 ± 9.1 years and 75% were male. Largest number of significant associations (P ≤ 1 × 10(-5)) at SNP level was demonstrated for nickel, brick dust, concrete dust, and cement dust, and for brick dust and cement dust at the gene-level (P ≤ 1 × 10(-4)). Approximately 14 occupational exposures showed significant gene-occupation interactions with pathways related to response to environmental information processing via signal transduction (P < 0.001 and FDR < 0.05). Other pathways that showed significant enrichment were related to immune processes and xenobiotic metabolism.

CONCLUSION

Our findings suggest that pathways related to signal transduction, immune process, and xenobiotic metabolism may be involved in occupational exposure-related lung carcinogenesis.

IMPACT

Our study exemplifies an integrative approach using pathway-based analysis to demonstrate the role of genetic variants in occupational exposure-related lung cancer susceptibility. Cancer Epidemiol Biomarkers Prev; 24(3); 570-9. ©2015 AACR.

Lung cancer risk among cooks when accounting for tobacco smoking: a pooled analysis of case-control studies from Europe, Canada, New Zealand, and China

OBJECTIVES

To investigate the risk of lung cancer among cooks, while controlling for smoking habits.

METHODS

We used data from the SYNERGY project including pooled information on lifetime work histories and smoking habits from 16 case-control studies conducted in Europe, Canada, New Zealand, and China.

RESULTS

Before adjustment for smoking, we observed an increased risk of lung cancer in male cooks, but not in female cooks. After adjusting, there was no increased risk and no significant exposure-response relationship. Nevertheless, subgroup analyses highlighted some possible excess risks of squamous cell carcinoma and small cell carcinoma in female cooks.

CONCLUSIONS

There is evidence that lung cancer risks among cooks may be confounded by smoking. After adjustment, cooks did not experience an increased risk of lung cancer overall. The subgroup analyses showing some excess risks among female cooks require cautious interpretation.

Lung cancer risk among bricklayers in a pooled analysis of case-control studies

Bricklayers may be exposed to several lung carcinogens, including crystalline silica and asbestos. Previous studies that analyzed lung cancer risk among these workers had several study design limitations. We examined lung cancer risk among bricklayers within SYNERGY, a large international pooled analysis of case-control studies on lung cancer and the joint effects of occupational carcinogens. For men ever employed as bricklayers we estimated odds ratios (OR) and 95% confidence intervals (CI) adjusted for study center, age, lifetime smoking history and employment in occupations with exposures to known or suspected lung carcinogens. Among 15,608 cases and 18,531 controls, there were 695 cases and 469 controls who had ever worked as bricklayers (OR: 1.47; 95% CI: 1.28-1.68). In studies using population controls the OR was 1.55 (95% CI: 1.32-1.81, 540/349 cases/controls), while it was 1.24 (95% CI: 0.93-1.64, 155/120 cases/controls) in hospital-based studies. There was a clear positive trend with length of employment (p < 0.001). The relative risk was higher for squamous (OR: 1.68, 95% CI: 1.42-1.98, 309 cases) and small cell carcinomas (OR: 1.78, 95% CI: 1.44-2.20, 140 cases), than for adenocarcinoma (OR: 1.17, 95% CI: 0.95-1.43, 150 cases) (p-homogeneity: 0.0007). ORs were still elevated after additional adjustment for education and in analyses using blue collar workers as referents. This study provided robust evidence of increased lung cancer risk in bricklayers. Although non-causal explanations cannot be completely ruled out, the association is plausible in view of the potential for exposure to several carcinogens, notably crystalline silica and to a lesser extent asbestos.

Variation in genomic landscape of clear cell renal cell carcinoma across Europe

The incidence of renal cell carcinoma (RCC) is increasing worldwide, and its prevalence is particularly high in some parts of Central Europe. Here we undertake whole-genome and transcriptome sequencing of clear cell RCC (ccRCC), the most common form of the disease, in patients from four different European countries with contrasting disease incidence to explore the underlying genomic architecture of RCC. Our findings support previous reports on frequent aberrations in the epigenetic machinery and PI3K/mTOR signalling, and uncover novel pathways and genes affected by recurrent mutations and abnormal transcriptome patterns including focal adhesion, components of extracellular matrix (ECM) and genes encoding FAT cadherins. Furthermore, a large majority of patients from Romania have an unexpected high frequency of A:T>T:A transversions, consistent with exposure to aristolochic acid (AA). These results show that the processes underlying ccRCC tumorigenesis may vary in different populations and suggest that AA may be an important ccRCC carcinogen in Romania, a finding with major public health implications.

Olsson A. Is previous respiratory disease a risk factor for lung cancer?

RATIONALE

Previous respiratory diseases have been associated with increased risk of lung cancer. Respiratory conditions often co-occur and few studies have investigated multiple conditions simultaneously.

OBJECTIVES

Investigate lung cancer risk associated with chronic bronchitis, emphysema, tuberculosis, pneumonia, and asthma.

METHODS

The SYNERGY project pooled information on previous respiratory diseases from 12,739 case subjects and 14,945 control subjects from 7 case-control studies conducted in Europe and Canada. Multivariate logistic regression models were used to investigate the relationship between individual diseases adjusting for co-occurring conditions, and patterns of respiratory disease diagnoses and lung cancer. Analyses were stratified by sex, and adjusted for age, center, ever-employed in a high-risk occupation, education, smoking status, cigarette pack-years, and time since quitting smoking.

MEASUREMENTS AND MAIN RESULTS

Chronic bronchitis and emphysema were positively associated with lung cancer, after accounting for other respiratory diseases and smoking (e.g., in men: odds ratio [OR], 1.33; 95% confidence interval [CI], 1.20-1.48 and OR, 1.50; 95% CI, 1.21-1.87, respectively). A positive relationship was observed between lung cancer and pneumonia diagnosed 2 years or less before lung cancer (OR, 3.31; 95% CI, 2.33-4.70 for men), but not longer. Co-occurrence of chronic bronchitis and emphysema and/or pneumonia had a stronger positive association with lung cancer than chronic bronchitis "only." Asthma had an inverse association with lung cancer, the association being stronger with an asthma diagnosis 5 years or more before lung cancer compared with shorter.

CONCLUSIONS

Findings from this large international case-control consortium indicate that after accounting for co-occurring respiratory diseases, chronic bronchitis and emphysema continue to have a positive association with lung cancer.

No causal association identified for human papillomavirus infections in lung cancer

Human papillomavirus (HPV) infections have been implicated in lung carcinogenesis, but causal associations remain uncertain. We evaluated a potential causal role for HPV infections in lung cancer through an analysis involving serology, tumor DNA, RNA, and p16 protein expression. Association between type-specific HPV antibodies and risk of lung cancer was examined among 3,083 cases and 4,328 controls in two case-control studies (retrospective) and one nested case-control study (prospective design). Three hundred and thirty-four available tumors were subjected to pathologic evaluation and subsequent HPV genotyping following stringent conditions to detect all high-risk and two low-risk HPV types. All HPV DNA-positive tumors were further tested for the expression of p16 protein and type-specific HPV mRNA. On the basis of the consistency of the results, although HPV11 and HPV31 E6 antibodies were associated with lung cancer risk in the retrospective study, no association was observed in the prospective design. Presence of type-specific antibodies correlated poorly with the presence of the corresponding HPV DNA in the tumor. Although nearly 10% of the lung tumors were positive for any HPV DNA (7% for HPV16 DNA), none expressed the viral oncogenes. No association was observed between HPV antibodies or DNA and lung cancer survival. In conclusion, we found no supportive evidence for the hypothesized causal association between HPV infections and lung cancer.

Rare variants of large effect in BRCA2 and CHEK2 affect risk of lung cancer

We conducted imputation to the 1000 Genomes Project of four genome-wide association studies of lung cancer in populations of European ancestry (11,348 cases and 15,861 controls) and genotyped an additional 10,246 cases and 38,295 controls for follow-up. We identified large-effect genome-wide associations for squamous lung cancer with the rare variants BRCA2 p.Lys3326X (rs11571833, odds ratio (OR) = 2.47, P = 4.74 × 10(-20)) and CHEK2 p.Ile157Thr (rs17879961, OR = 0.38, P = 1.27 × 10(-13)). We also showed an association between common variation at 3q28 (TP63, rs13314271, OR = 1.13, P = 7.22 × 10(-10)) and lung adenocarcinoma that had been previously reported only in Asians. These findings provide further evidence for inherited genetic susceptibility to lung cancer and its biological basis. Additionally, our analysis demonstrates that imputation can identify rare disease-causing variants with substantive effects on cancer risk from preexisting genome-wide association study data.

Alcohol and mortality in Russia: prospective observational study of 151,000 adults

BACKGROUND

Russian adults have extraordinarily high rates of premature death. Retrospective enquiries to the families of about 50,000 deceased Russians had found excess vodka use among those dying from external causes (accident, suicide, violence) and eight particular disease groupings. We now seek prospective evidence of these associations.

METHODS

In three Russian cities (Barnaul, Byisk, and Tomsk), we interviewed 200,000 adults during 1999-2008 (with 12,000 re-interviewed some years later) and followed them until 2010 for cause-specific mortality. In 151,000 with no previous disease and some follow-up at ages 35-74 years, Poisson regression (adjusted for age at risk, amount smoked, education, and city) was used to calculate the relative risks associating vodka consumption with mortality. We have combined these relative risks with age-specific death rates to get 20-year absolute risks.

FINDINGS

Among 57,361 male smokers with no previous disease, the estimated 20-year risks of death at ages 35-54 years were 16% (95% CI 15-17) for those who reported consuming less than a bottle of vodka per week at baseline, 20% (18-22) for those consuming 1-2·9 bottles per week, and 35% (31-39) for those consuming three or more bottles per week; trend p<0·0001. The corresponding risks of death at ages 55-74 years were 50% (48-52) for those who reported consuming less than a bottle of vodka per week at baseline, 54% (51-57) for those consuming 1-2·9 bottles per week, and 64% (59-69) for those consuming three or more bottles per week; trend p<0·0001. In both age ranges most of the excess mortality in heavier drinkers was from external causes or the eight disease groupings strongly associated with alcohol in the retrospective enquiries. Self-reported drinking fluctuated; of the men who reported drinking three or more bottles of vodka per week who were reinterviewed a few years later, about half (185 of 321) then reported drinking less than one bottle per week. Such fluctuations must have substantially attenuated the apparent hazards of heavy drinking in this study, yet self-reported vodka use at baseline still strongly predicted risk. Among male non-smokers and among females, self-reported heavy drinking was uncommon, but seemed to involve similar absolute excess risks.

INTERPRETATION

This large prospective study strongly reinforces other evidence that vodka is a major cause of the high risk of premature death in Russian adults.

FUNDING

UK Medical Research Council, British Heart Foundation, Cancer Research UK, European Union, WHO International Agency for Research on Cancer.

Exposure to secondhand tobacco smoke and lung cancer by histological type: a pooled analysis of the International Lung Cancer Consortium (ILCCO)

While the association between exposure to secondhand smoke and lung cancer risk is well established, few studies with sufficient power have examined the association by histological type. In this study, we evaluated the secondhand smoke-lung cancer relationship by histological type based on pooled data from 18 case-control studies in the International Lung Cancer Consortium (ILCCO), including 2,504 cases and 7,276 control who were never smokers and 10,184 cases and 7,176 controls who were ever smokers. We used multivariable logistic regression, adjusting for age, sex, race/ethnicity, smoking status, pack-years of smoking, and study. Among never smokers, the odds ratios (OR) comparing those ever exposed to secondhand smoke with those never exposed were 1.31 (95% CI: 1.17-1.45) for all histological types combined, 1.26 (95% CI: 1.10-1.44) for adenocarcinoma, 1.41 (95% CI: 0.99-1.99) for squamous cell carcinoma, 1.48 (95% CI: 0.89-2.45) for large cell lung cancer, and 3.09 (95% CI: 1.62-5.89) for small cell lung cancer. The estimated association with secondhand smoke exposure was greater for small cell lung cancer than for nonsmall cell lung cancers (OR=2.11, 95% CI: 1.11-4.04). This analysis is the largest to date investigating the relation between exposure to secondhand smoke and lung cancer. Our study provides more precise estimates of the impact of secondhand smoke on the major histological types of lung cancer, indicates the association with secondhand smoke is stronger for small cell lung cancer than for the other histological types, and suggests the importance of intervention against exposure to secondhand smoke in lung cancer prevention.

Effect modification of the association of cumulative exposure and cancer risk by intensity of exposure and time since exposure cessation: a flexible method applied to cigarette smoking and lung cancer in the SYNERGY Study

The indiscriminate use of the cumulative exposure metric (the product of intensity and duration of exposure) might bias reported associations between exposure to hazardous agents and cancer risk. To assess the independent effects of duration and intensity of exposure on cancer risk, we explored effect modification of the association of cumulative exposure and cancer risk by intensity of exposure. We applied a flexible excess odds ratio model that is linear in cumulative exposure but potentially nonlinear in intensity of exposure to 15 case-control studies of cigarette smoking and lung cancer (1985-2009). Our model accommodated modification of the excess odds ratio per pack-year of cigarette smoking by time since smoking cessation among former smokers. We observed negative effect modification of the association of pack-years of cigarette smoking and lung cancer by intensity of cigarette smoke for persons who smoked more than 20-30 cigarettes per day. Patterns of effect modification were similar across individual studies and across major lung cancer subtypes. We observed strong negative effect modification by time since smoking cessation. Application of our method in this example of cigarette smoking and lung cancer demonstrated that reducing a complex exposure history to a metric such as cumulative exposure is too restrictive.

Welding and lung cancer in a pooled analysis of case-control studies

Several epidemiologic studies have indicated an increased risk of lung cancer among welders. We used the SYNERGY project database to assess welding as a risk factor for developing lung cancer. The database includes data on 15,483 male lung cancer cases and 18,388 male controls from 16 studies in Europe, Canada, China, and New Zealand conducted between 1985 and 2010. Odds ratios and 95% confidence intervals between regular or occasional welding and lung cancer were estimated, with adjustment for smoking, age, study center, and employment in other occupations associated with lung cancer risk. Overall, 568 cases and 427 controls had ever worked as welders and had an odds ratio of developing lung cancer of 1.44 (95% confidence interval: 1.25, 1.67) with the odds ratio increasing for longer duration of welding. In never and light smokers, the odds ratio was 1.96 (95% confidence interval: 1.37, 2.79). The odds ratios were somewhat higher for squamous and small cell lung cancers than for adenocarcinoma. Another 1,994 cases and 1,930 controls had ever worked in occupations with occasional welding. Work in any of these occupations was associated with some elevation of risk, though not as much as observed in regular welders. Our findings lend further support to the hypothesis that welding is associated with an increased risk of lung cancer.

Lung cancer risk among hairdressers: a pooled analysis of case-control studies conducted between 1985 and 2010

Increased lung cancer risks among hairdressers were observed in large registry-based cohort studies from Scandinavia, but these studies could not adjust for smoking. Our objective was to evaluate the lung cancer risk among hairdressers while adjusting for smoking and other confounders in a pooled database of 16 case-control studies conducted in Europe, Canada, China, and New Zealand between 1985 and 2010 (the Pooled Analysis of Case-Control Studies on the Joint Effects of Occupational Carcinogens in the Development of Lung Cancer). Lifetime occupational and smoking information was collected through interviews with 19,369 cases of lung cancer and 23,674 matched population or hospital controls. Overall, 170 cases and 167 controls had ever worked as hairdresser or barber. The odds ratios for lung cancer in women were 1.65 (95% confidence interval (CI): 1.16, 2.35) without adjustment for smoking and 1.12 (95% CI: 0.75, 1.68) with adjustment for smoking; however, women employed before 1954 also experienced an increased lung cancer risk after adjustment for smoking (odds ratio = 2.66, 95% CI: 1.09, 6.47). The odds ratios in male hairdressers/barbers were generally not elevated, except for an increased odds ratio for adenocarcinoma in long-term barbers (odds ratio = 2.20, 95% CI: 1.02, 4.77). Our results suggest that the increased lung cancer risks among hairdressers are due to their smoking behavior; single elevated risk estimates should be interpreted with caution and need replication in other studies.