Abstract Background: Recent genome-wide association studies (GWAS) have identified 28 susceptibility loci for Lung cancer (LC), 32 loci for smoking behavior, 10 loci for chronic obstructive pulmonary disease (COPD), 63 loci for pulmonary function and related phenotypes, totaling 107 GWAS susceptibility loci (as of November 2014). Given the common variants that have been found to be associated with LC in GWAS, targeted-region exome sequencing provides a cost-effective approach for further investigation of high-priority regions of the genome and has the great potential to identify rare causal variants in GWAS loci. Patients and Methods: Using an extreme phenotype approach, we selected 48 sporadic LC patients reporting heavy smoking histories with the presence of severe COPD in whom environmental factors are considered overwhelming, and 54 familial LC cases from families with at least three first-degree relatives with LC who are likely enriched for genomic signal, to search for the disease-causing rare mutations within the target 107 GWAS loci using exome sequencing data. Results: By focusing on exome profiles of these target 107 loci, we identified two disease-causing rare mutations on 6p21.32 TNXB p. Arg504His and 10q25.1 CCDC147 p.Arg696Cys. The homozygous Arg504His mutation presented in four familial and one sporadic LC cases. Notably, the minor allele frequency (MAF) of this variant in Caucasians from 1000 Genomes is very rare (<0.001). The heterozygous CCDC147 Arg696Cys variant were identified in two familial cases and one sporadic case. The MAF for this variant in the Caucasians from 1000 Genomes is 0.004. Both deleterious changes lead to truncation of the putative proteins, which disrupts the predicted domain and alters the cellular localization. We also observed several other suggestive rare mutations on G7C, TNS1, DBH1, and CHRNA5. Conclusion: Our target exome sequencing results demonstrate novel highly disruptive LC risk-conferring TNXB and CCDC147 mutations. Since the rare variants have appreciable effects on disease risk prediction, families and patients may warrant screening for mutations in TNXB and CCDC147 (if validated) to assess their potential LC risk. Citation Format: Yanhong Liu, Farrah Kheradmand, Michael Scheurer, Caleb Davis, David Wheeler, Edwin Silverman, Shete Sanjay, Spiridon Tsavachidis, Georgina Armstrong, Elena Kupert, Marshall Anderson, Yafang Li, Claudio Pikielny, Joan E. Bailey-Wilson, Ming You, Colette Gaba, Mariza DeAndrade, Diptasri Mandal, Claire Simpson, Susan Pinney, Christopher Amos, Margaret Spitz. Target exome sequencing for disease-causing rare mutations in familial and sporadic lung cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4600. doi:10.1158/1538-7445.AM2015-4600
Abstract 2757: Evaluation of EYA4 as a candidate risk locus in familial lung cancer families linked to 6q
Abstract Recently, Wilson et al. (doi:10.1038/onc.2013.396) found that EYA4 was frequently inactivated biallelically in sporadic lung cancer, displays tumor suppressor gene-like properties and affects DNA repair, and that 5 of 17 common SNPs in this 0.3Mb region showed nominal association to familial lung cancer (FLC, p<0.05) although these associations are not genome-wide significant after correction for multiple testing.. However, this is an interesting candidate gene for FLC risk because it is located on chromosome 6q in a region where we previously showed evidence of linkage to FLC (PMID: 15272417, 20215501). Here, we sequenced 75 individuals from our 9 most strongly 6q-linked families, using Illumina technology and a custom Agilent kit to capture 37Mb of chromosome 6 from 130Mb to 167Mb. We closely examined a region around EYA4, between 133Mb and 135Mb. This region contains a number of other genes in addition to EYA4, including the Vanin cluster; ribosomal protein S12; the tumor suppressor gene TCF21 and its antisense RNA TARID which directs methylation and activation of TCF21; solute carriers SLC18B1 and SLC2A12 and the serum/glucocorticoid regulated kinase SGK1. To detect sharing of variants among affecteds in each family while allowing for phenocopies, singlepoint affected-only linkage analysis was performed on lung cancer affection status for all sequence variants using the Elston-Stewart algorithm implemented in the R package paramlink assuming penetrance of 0.01, 0.1 and 0.1 for dd/Dd/DD and a disease allele (D) frequency of 0.01, at a recombination fraction (theta) of 0. The highest total LOD score (summed over all 9 families) in the entire 37Mb targeted region was not near EYA4. In only one family was there any variant in EYA4 that appeared on the linked haplotype with close to the highest family-specific LOD score: Family 30 had a LOD of 0.6514 at several EYA4 variants (max LOD across region 0.6519). However, many variants across the region had similar LODs. In the remaining families, all EYA4 variants had LODs much lower than the maximum family-specific LOD score in the region. Thus, EYA4 variants are unlikely to explain our 6q linkage peak in these 6q-linked families. The second highest total LOD score for the entire 37Mb targeted region was found near EYA4 at 133.9Mb (LOD = 3.82), in the middle of the TARID antisense RNA gene. This variant appears to be entirely novel, as it is not present in any of the online variant databases, such as NHLBI's ESP or 1000 Genomes. In two families, the family LOD score at this locus was at or close to the highest in the region: in Family 44 the LOD score was 1.206 (max LOD across entire region 1.207) and in Family 35 the LOD score was 0.3958 (max LOD across region 0.3959). Therefore this variant in the TARID antisense RNA is a candidate in some of our families most strongly linked to chromosome 6q. Citation Format: Joan E. Bailey-Wilson, Claire L. Simpson, Susan M. Pinney, Mariza de Andrade, Colette Gaba, Ping Yang, Ming You, Elena Y. Kupert, Ann G. Schwartz, Diptasri Mandal, Christopher I. Amos, Marshall W. Anderson. Evaluation of EYA4 as a candidate risk locus in familial lung cancer families linked to 6q. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2757. doi:10.1158/1538-7445.AM2015-2757
Abstract A106: Optimal strategies for selecting samples for sequencing families with a common cancer: The Genetic Epidemiology of Lung Cancer Consortium.
Abstract In order to select samples that are optimally informative for sequence analysis, studies for the Genetic Epidemiology Consortium, we implemented three strategies for analysis, taking into account the known family histories of lung cancer. Susceptibility for lung cancer arises from a complex interplay between largely unknown genetic factors and smoking behavior. In order to optimize our ability to identify genetic factors for lung cancer we have recruited individuals with extensive family histories of lung cancer and also collected information about their smoking behaviors. For this study, we have modeled family history to identify individuals to select for sequencing using three approaches. First, we used an expert opinion approach in which multiple investigators evaluated pedigree structures with family history to reach a consensus priority in selecting individuals. Second we developed an approximation that assumes a low penetrance among noncarriers and uses known cancer status in first degree relatives. Third, we used the cancer, smoking behaviors and family information along with a likelihood that models penetrance according to genetic susceptibility and an interaction with smoking to estimate the probabilities individuals carry susceptibility factors. In this analysis we compare results among these methods. We evaluate effectiveness of these methods using simulation-based approaches. Citation Format: Christopher Amos, Joan Bailey-Wilson, Susan Pinney, Maria de Andrada, Colette Gaba, Diptasri Mandal, Ming You, Margaret Spitz, Marshall Anderson. Optimal strategies for selecting samples for sequencing families with a common cancer: The Genetic Epidemiology of Lung Cancer Consortium. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr A106.
Ordered Subset Analysis Identifies Loci Influencing Lung Cancer Risk on Chromosomes 6q and 12q
Abstract Cigarette smoking is the major cause for lung cancer, but genetic factors also affect susceptibility. We studied families that included multiple relatives affected by lung cancer. Results from linkage analysis showed strong evidence that a region of chromosome 6q affects lung cancer risk. To characterize the effects that this region of chromosome 6q region has on lung cancer risk, we identified a haplotype that segregated with lung cancer. We then performed Cox regression analysis to estimate the differential effects that smoking behaviors have on lung cancer risk according to whether each individual carried a risk-associated haplotype or could not be classified and was assigned unknown haplotypic status. We divided smoking exposures into never smokers, light smokers (<20 pack-years), moderate smokers (20 to <40 pack-years), and heavy smokers (≥40 pack-years). Comparing results according to smoking behavior stratified by carrier status, compared with never smokers, there was weakly increasing risk for increasing smoking behaviors, with the hazards ratios being 3.44, 4.91, and 5.18, respectively, for light, moderate, or heavy smokers, whereas among the individuals from families without the risk haplotype, the risks associated with smoking increased strongly with exposure, the hazards ratios being, respectively, 4.25, 9.17, and 11.89 for light, moderate, and heavy smokers. The never smoking carriers had a 4.71-fold higher risk than the never smoking individuals without known risk haplotypes. These results identify a region of chromosome 6q that increases risk for lung cancer and that confers particularly higher risks to never and light smokers. Cancer Res; 70(6); 2359–67
The Relationship Between Smoking and Replicated Sequence Variants on Chromosomes 8 and 9 With Familial Intracranial Aneurysm
Background and Purpose— The purpose of this study was to replicate the previous association of single nucleotide polymorphisms (SNPs) with risk of intracranial aneurysm (IA) and to examine the relationship of smoking with these variants and the risk of IA. Methods— White probands with an IA from families with multiple affected members were identified by 26 clinical centers located throughout North America, New Zealand, and Australia. White control subjects free of stroke and IA were selected by random digit dialing from the Greater Cincinnati population. SNPs previously associated with IA on chromosomes 2, 8, and 9 were genotyped using a TaqMan assay or were included in the Affymetrix 6.0 array that was part of a genomewide association study of 406 IA cases and 392 control subjects. Logistic regression modeling tested whether the association of replicated SNPs with IA was modulated by smoking. Results— The strongest evidence of association with IA was found with the 8q SNP rs10958409 (genotypic P =9.2×10 −5 ; allelic P =1.3×10 −5 ; OR=1.86, 95% CI: 1.40 to 2.47). We also replicated the association with both SNPs on chromosome 9p, rs1333040 and rs10757278, but were not able to replicate the previously reported association of the 2 SNPs on chromosome 2q. Statistical testing showed a multiplicative relationship between the risk alleles and smoking with regard to the risk of IA. Conclusion— Our data provide complementary evidence that the variants on chromosomes 8q and 9p are associated with IA and that the risk of IA in patients with these variants is greatly increased with cigarette smoking.
Cumulative Effect of Multiple Loci on Genetic Susceptibility to Familial Lung Cancer
Abstract Background: Genetic factors play important roles in lung cancer susceptibility. In this study, we replicated the association of 5p15.33 and 6p21.33 with familial lung cancer. Taking into account the previously identified genetic susceptibility variants on 6q23-25/RGS17 and 15q24-25.1, we further determined the cumulative association of these four genetic regions and the population attributable risk percent of familial lung cancer they account for. Methods: One hundred ninety-four case patients and 219 cancer-free control subjects from the Genetic Epidemiology of Lung Cancer Consortium were used for the association analysis. Each familial case was chosen from one high-risk lung cancer family that has three or more affected members. Single nucleotide polymorphisms (SNP) on chromosomal regions 5p15.33, 6p21.33, 6q23-25/RGS17, and 15q24-25.1 were assessed for their associations with familial lung cancer. The cumulative association of the four chromosomal regions with familial lung cancer was evaluated with the use of a linear logistic model. Population attributable risk percent was calculated for each SNP using risk ratio. Results: SNP rs31489 showed the strongest evidence of familial lung cancer association on 5p15.33 (P = 2 × 10−4; odds ratio, 0.57; 95% confidence interval, 0.42-0.77), whereas rs3117582 showed a weak association on 6p21.33 (P = 0.09; odds ratio, 1.47; 95% confidence interval, 0.94-2.31). Analysis of a combination of SNPs from the four regions provided a stronger cumulative association with familial lung cancer (P = 6.70 × 10−6) than any individual SNPs. The risk of lung cancer was increased to 3- to 11-fold among those subjects who had at least one copy of risk allele at each region compared with subjects without any of the risk factors. These four genetic regions contribute to a total of 34.6% of familial lung cancer in smokers. Conclusions: The SNPs in four chromosomal regions have a cumulative and significant association with familial lung cancer and account for about one-third of the population attributable risk for familial lung cancer. Cancer Epidemiol Biomarkers Prev; 19(2); 517–24
Haplotype and Cell Proliferation Analyses of Candidate Lung Cancer Susceptibility Genes on Chromosome 15q24-25.1
Abstract Recent genome-wide association studies have linked the chromosome 15q24-25.1 locus to nicotine addiction and lung cancer susceptibility. To refine the 15q24-25.1 locus, we performed a haplotype-based association analysis of 194 familial lung cases and 219 cancer-free controls from the Genetic Epidemiology of Lung Cancer Consortium (GELCC) collection, and used proliferation and apoptosis analyses to determine which gene(s) in the 15q24-25.1 locus mediates effects on lung cancer cell growth in vitro. We identified two distinct subregions, hapL (P = 3.20 × 10−6) and hapN (P = 1.51 × 10−6), which were significantly associated with familial lung cancer. hapL encompasses IREB2, LOC123688, and PSMA4, and hapN encompasses the three nicotinic acetylcholine receptor subunit genes CHRNA5, CHRNA3, and CHRNB4. Examination of the genes around hapL revealed that PSMA4 plays a role in promoting cancer cell proliferation. PSMA4 mRNA levels were increased in lung tumors compared with normal lung tissues. Down-regulation of PSMA4 expression decreased proteasome activity and induced apoptosis. Proteasome dysfunction leads to many diseases including cancer, and drugs that inhibit proteasome activity show promise as a form of cancer treatment. Genes around hapN were also investigated, but did not show any direct effect on lung cancer cell proliferation. We concluded that PSMA4 is a strong candidate mediator of lung cancer cell growth, and may directly affect lung cancer susceptibility through its modulation of cell proliferation and apoptosis. [Cancer Res 2009;69(19):7844–50]
Fine Mapping of Chromosome 6q23-25 Region in Familial Lung Cancer Families Reveals
RGS17
as a Likely Candidate Gene
Abstract Purpose: We have previously mapped a major susceptibility locus influencing familial lung cancer risk to chromosome 6q23-25. However, the causal gene at this locus remains undetermined. In this study, we further refined this locus to identify a single candidate gene, by fine mapping using microsatellite markers and association studies using high-density single nucleotide polymorphisms (SNP). Experimental Design: Six multigenerational families with five or more affected members were chosen for fine-mapping the 6q linkage region using microsatellite markers. For association mapping, we genotyped 24 6q-linked cases and 72 unrelated noncancer controls from the Genetic Epidemiology of Lung Cancer Consortium resources using the Affymetrix 500K chipset. Significant associations were validated in two independent familial lung cancer populations: 226 familial lung cases and 313 controls from the Genetic Epidemiology of Lung Cancer Consortium, and 154 familial cases and 325 controls from Mayo Clinic. Each familial case was chosen from one high-risk lung cancer family that has three or more affected members. Results: A region-wide scan across 6q23-25 found significant association between lung cancer susceptibility and three single nucleotide polymorphisms in the first intron of the RGS17 gene. This association was further confirmed in two independent familial lung cancer populations. By quantitative real-time PCR analysis of matched tumor and normal human tissues, we found that RGS17 transcript accumulation is highly and consistently increased in sporadic lung cancers. Human lung tumor cell proliferation and tumorigenesis in nude mice are inhibited upon knockdown of RGS17 levels. Conclusion: RGS17 is a major candidate for the familial lung cancer susceptibility locus on chromosome 6q23-25.