Improved detection of low-frequency within-host variants from deep sequencing: A case study with human papillomavirus

High-coverage sequencing allows the study of variants occurring at low frequencies within samples, but is susceptible to false-positives caused by sequencing error. Ion Torrent has a very low single nucleotide variant (SNV) error rate and has been employed for the majority of human papillomavirus (HPV) whole genome sequences. However, benchmarking of intrahost SNVs (iSNVs) has been challenging, partly due to limitations imposed by the HPV life cycle. We address this problem by deep sequencing three replicates for each of 31 samples of HPV type 18 (HPV18). Errors, defined as iSNVs observed in only one of three replicates, are dominated by C→T (G→A) changes, independently of trinucleotide context. True iSNVs, defined as those observed in all three replicates, instead show a more diverse SNV type distribution, with particularly elevated C→T rates in CCG context (CCG→CTG; CGG→CAG) and C→A rates in ACG context (ACG→AAG; CGT→CTT). Characterization of true iSNVs allowed us to develop two methods for detecting true variants: (1) VCFgenie, a dynamic binomial filtering tool which uses each variant's allele count and coverage instead of fixed frequency cut-offs; and (2) a machine learning binary classifier which trains eXtreme Gradient Boosting models on variant features such as quality and trinucleotide context. Each approach outperforms fixed-cut-off filtering of iSNVs, and performance is enhanced when both are used together. Our results provide improved methods for identifying true iSNVs in within-host applications across sequencing platforms, specifically using HPV18 as a case study.

Genome-wide association study of lung adenocarcinoma in East Asia and comparison with a European population

Lung adenocarcinoma is the most common type of lung cancer. Known risk variants explain only a small fraction of lung adenocarcinoma heritability. Here, we conducted a two-stage genome-wide association study of lung adenocarcinoma of East Asian ancestry (21,658 cases and 150,676 controls; 54.5% never-smokers) and identified 12 novel susceptibility variants, bringing the total number to 28 at 25 independent loci. Transcriptome-wide association analyses together with colocalization studies using a Taiwanese lung expression quantitative trait loci dataset (n = 115) identified novel candidate genes, including FADS1 at 11q12 and ELF5 at 11p13. In a multi-ancestry meta-analysis of East Asian and European studies, four loci were identified at 2p11, 4q32, 16q23, and 18q12. At the same time, most of our findings in East Asian populations showed no evidence of association in European populations. In our studies drawn from East Asian populations, a polygenic risk score based on the 25 loci had a stronger association in never-smokers vs. individuals with a history of smoking (Pinteraction = 0.0058). These findings provide new insights into the etiology of lung adenocarcinoma in individuals from East Asian populations, which could be important in developing translational applications.

Targeted long-read sequencing of the Ewing sarcoma 6p25.1 susceptibility locus identifies germline-somatic interactions with EWSR1-FLI1 binding

Ewing sarcoma (EwS) is a rare bone and soft tissue malignancy driven by chromosomal translocations encoding chimeric transcription factors, such as EWSR1-FLI1, that bind GGAA motifs forming novel enhancers that alter nearby expression. We propose that germline microsatellite variation at the 6p25.1 EwS susceptibility locus could impact downstream gene expression and EwS biology. We performed targeted long-read sequencing of EwS blood DNA to characterize variation and genomic features important for EWSR1-FLI1 binding. We identified 50 microsatellite alleles at 6p25.1 and observed that EwS-affected individuals had longer alleles (>135 bp) with more GGAA repeats. The 6p25.1 GGAA microsatellite showed chromatin features of an EWSR1-FLI1 enhancer and regulated expression of RREB1, a transcription factor associated with RAS/MAPK signaling. RREB1 knockdown reduced proliferation and clonogenic potential and reduced expression of cell cycle and DNA replication genes. Our integrative analysis at 6p25.1 details increased binding of longer GGAA microsatellite alleles with acquired EWSR-FLI1 to promote Ewing sarcomagenesis by RREB1-mediated proliferation.

Distinct germline genetic susceptibility profiles identified for common non-Hodgkin lymphoma subtypes

Lymphoma risk is elevated for relatives with common non-Hodgkin lymphoma (NHL) subtypes, suggesting shared genetic susceptibility across subtypes. To evaluate the extent of mutual heritability among NHL subtypes and discover novel loci shared among subtypes, we analyzed data from eight genome-wide association studies within the InterLymph Consortium, including 10,629 cases and 9505 controls. We utilized Association analysis based on SubSETs (ASSET) to discover loci for subsets of NHL subtypes and evaluated shared heritability across the genome using Genome-wide Complex Trait Analysis (GCTA) and polygenic risk scores. We discovered 17 genome-wide significant loci (P < 5 × 10-8) for subsets of NHL subtypes, including a novel locus at 10q23.33 (HHEX) (P = 3.27 × 10-9). Most subset associations were driven primarily by only one subtype. Genome-wide genetic correlations between pairs of subtypes varied broadly from 0.20 to 0.86, suggesting substantial heterogeneity in the extent of shared heritability among subtypes. Polygenic risk score analyses of established loci for different lymphoid malignancies identified strong associations with some NHL subtypes (P < 5 × 10-8), but weak or null associations with others. Although our analyses suggest partially shared heritability and biological pathways, they reveal substantial heterogeneity among NHL subtypes with each having its own distinct germline genetic architecture.

Phylogenomic Analysis of Human Papillomavirus Type 31 and Cervical Carcinogenesis: A Study of 2093 Viral Genomes

Human papillomavirus (HPV) type 31 (HPV31) is closely related to the most carcinogenic type, HPV16, but only accounts for 4% of cervical cancer cases worldwide. Viral genetic and epigenetic variations have been associated with carcinogenesis for other high-risk HPV types, but little is known about HPV31. We sequenced 2093 HPV31 viral whole genomes from two large studies, one from the U.S. and one international. In addition, we investigated CpG methylation in a subset of 175 samples. We evaluated the association of HPV31 lineages/sublineages, single nucleotide polymorphisms (SNPs) and viral methylation with cervical carcinogenesis. HPV31 A/B clade was >1.8-fold more associated with cervical intraepithelial neoplasia grade 3 and cancer (CIN3+) compared to the most common C lineage. Lineage/sublineage distribution varied by race/ethnicity and geographic region. A viral genome-wide association analysis identified SNPs within the A/B clade associated with CIN3+, including H23Y (C626T) (odds ratio = 1.60, confidence intervals = 1.17-2.19) located in the pRb CR2 binding-site within the E7 oncogene. Viral CpG methylation was higher in lineage B, compared to the other lineages, and was most elevated in CIN3+. In conclusion, these data support the increased oncogenicity of the A/B lineages and suggest variation of E7 as a contributing risk factor.

Association of HPV35 with cervical carcinogenesis among women of African ancestry: Evidence of viral-host interaction with implications for disease intervention

HPV35 has been found in only ∼2% of invasive cervical cancers (ICC) worldwide but up to 10% in Sub-Saharan Africa, warranting further investigation and consideration of impact on preventive strategies. We studied HPV35 and ethnicity, in relation to the known steps in cervical carcinogenesis, using multiple large epidemiologic studies in the U.S. and internationally. Combining five U.S. studies, we measured HPV35 positivity and, in Northern California, observed HPV35 type-specific population prevalence and estimated 5-year risk of developing precancer when HPV35-positive. HPV35 genetic variation was examined for differences in carcinogenicity in 1053 HPV35+ cervical specimens from a U.S. cohort and an international collection. African-American women had more HPV35 (12.1% vs 5.1%, P < .001) and more HPV35-associated precancers (7.4% vs 2.1%, P < .001) compared to other ethnicities. Precancer risks after HPV35 infection did not vary by ethnicity (global P = .52). The HPV35 A2 sublineage showed an increased association with precancer/cancer in African-Americans (OR = 5.6 vs A1, 95% CI = 1.3-24.8) and A2 was more prevalent among ICC in Africa than other world regions (41.9% vs 10.4%, P < .01). Our analyses support a strong link between HPV35 and cervical carcinogenesis in women of African ancestry. Current HPV vaccines cover the majority of cervical precancer/cancer across all ethnic groups; additional analyses are required to determine whether the addition of HPV35 to the already highly effective nine-valent HPV vaccine would provide better protection for women in Africa or of African ancestry.

Low-frequency variation near common germline susceptibility loci are associated with risk of Ewing sarcoma

BACKGROUND

Ewing sarcoma (EwS) is a rare, aggressive solid tumor of childhood, adolescence and young adulthood associated with pathognomonic EWSR1-ETS fusion oncoproteins altering transcriptional regulation. Genome-wide association studies (GWAS) have identified 6 common germline susceptibility loci but have not investigated low-frequency inherited variants with minor allele frequencies below 5% due to limited genotyped cases of this rare tumor.

METHODS

We investigated the contribution of rare and low-frequency variation to EwS susceptibility in the largest EwS genome-wide association study to date (733 EwS cases and 1,346 unaffected controls of European ancestry).

RESULTS

We identified two low-frequency variants, rs112837127 and rs2296730, on chromosome 20 that were associated with EwS risk (OR = 0.186 and 2.038, respectively; P-value < 5×10-8) and located near previously reported common susceptibility loci. After adjusting for the most associated common variant at the locus, only rs112837127 remained a statistically significant independent signal (OR = 0.200, P-value = 5.84×10-8).

CONCLUSIONS

These findings suggest rare variation residing on common haplotypes are important contributors to EwS risk.

IMPACT

Motivate future targeted sequencing studies for a comprehensive evaluation of low-frequency and rare variation around common EwS susceptibility loci.

Mutations in the HPV16 genome induced by APOBEC3 are associated with viral clearance

HPV16 causes half of cervical cancers worldwide; for unknown reasons, most infections resolve within two years. Here, we analyze the viral genomes of 5,328 HPV16-positive case-control samples to investigate mutational signatures and the role of human APOBEC3-induced mutations in viral clearance and cervical carcinogenesis. We identify four de novo mutational signatures, one of which matches the COSMIC APOBEC-associated signature 2. The viral genomes of the precancer/cancer cases are less likely to contain within-host somatic HPV16 APOBEC3-induced mutations (Fisher's exact test, P = 6.2 x 10-14), and have a 30% lower nonsynonymous APOBEC3 mutation burden compared to controls. We replicate the low prevalence of HPV16 APOBEC3-induced mutations in 1,749 additional cases. APOBEC3 mutations also historically contribute to the evolution of HPV16 lineages. We demonstrate that cervical infections with a greater burden of somatic HPV16 APOBEC3-induced mutations are more likely to be benign or subsequently clear, suggesting they may reduce persistence, and thus progression, within the host.

Genome-wide Association Study Identifies HLA-DPB1 as a Significant Risk Factor for Severe Aplastic Anemia

Severe aplastic anemia (SAA) is a rare disorder characterized by hypoplastic bone marrow and progressive pancytopenia. The etiology of acquired SAA is not understood but is likely related to abnormal immune responses and environmental exposures. We conducted a genome-wide association study of individuals with SAA genetically matched to healthy controls in discovery (359 cases, 1,396 controls) and validation sets (175 cases, 1,059 controls). Combined analyses identified linked SNPs in distinct blocks within the major histocompatibility complex on 6p21. The top SNP encodes p.Met76Val in the P4 binding pocket of the HLA class II gene HLA-DPB1 (rs1042151A>G, odds ratio [OR] 1.75, 95% confidence interval [CI] 1.50-2.03, p = 1.94 × 10-13) and was associated with HLA-DP cell surface expression in healthy individuals (p = 2.04 × 10-6). Phylogenetic analyses indicate that Val76 is not monophyletic and likely occurs in conjunction with different HLA-DP binding groove conformations. Imputation of HLA-DPB1 alleles revealed increased risk of SAA associated with Val76-encoding alleles DPB1∗03:01, (OR 1.66, p = 1.52 × 10-7), DPB1∗10:01 (OR 2.12, p = 0.0003), and DPB1∗01:01 (OR 1.60, p = 0.0008). A second SNP near HLA-B, rs28367832G>A, reached genome-wide significance (OR 1.49, 95% CI 1.22-1.78, p = 7.27 × 10-9) in combined analyses; the association remained significant after excluding cases with clonal copy-neutral loss-of-heterozygosity affecting class I HLA genes (8.6% of cases and 0% of controls). SNPs in the HLA class II gene HLA-DPB1 and possibly class I (HLA-B) are associated with SAA. The replacement of Met76 to Val76 in certain HLA-DPB1 alleles might influence risk of SAA through mechanisms involving DP peptide binding specificity, expression, and/or other factors affecting DP function.

Sex specific associations in genome wide association analysis of renal cell carcinoma

Renal cell carcinoma (RCC) has an undisputed genetic component and a stable 2:1 male to female sex ratio in its incidence across populations, suggesting possible sexual dimorphism in its genetic susceptibility. We conducted the first sex-specific genome-wide association analysis of RCC for men (3227 cases, 4916 controls) and women (1992 cases, 3095 controls) of European ancestry from two RCC genome-wide scans and replicated the top findings using an additional series of men (2261 cases, 5852 controls) and women (1399 cases, 1575 controls) from two independent cohorts of European origin. Our study confirmed sex-specific associations for two known RCC risk loci at 14q24.2 (DPF3) and 2p21(EPAS1). We also identified two additional suggestive male-specific loci at 6q24.3 (SAMD5, male odds ratio (ORmale) = 0.83 [95% CI = 0.78-0.89], Pmale = 1.71 × 10-8 compared with female odds ratio (ORfemale) = 0.98 [95% CI = 0.90-1.07], Pfemale = 0.68) and 12q23.3 (intergenic, ORmale = 0.75 [95% CI = 0.68-0.83], Pmale = 1.59 × 10-8 compared with ORfemale = 0.93 [95% CI = 0.82-1.06], Pfemale = 0.21) that attained genome-wide significance in the joint meta-analysis. Herein, we provide evidence of sex-specific associations in RCC genetic susceptibility and advocate the necessity of larger genetic and genomic studies to unravel the endogenous causes of sex bias in sexually dimorphic traits and diseases like RCC.

Tuberculosis infection and lung adenocarcinoma: Mendelian randomization and pathway analysis of genome-wide association study data from never-smoking Asian women

We investigated whether genetic susceptibility to tuberculosis (TB) influences lung adenocarcinoma development among never-smokers using TB genome-wide association study (GWAS) results within the Female Lung Cancer Consortium in Asia. Pathway analysis with the adaptive rank truncated product method was used to assess the association between a TB-related gene-set and lung adenocarcinoma using GWAS data from 5512 lung adenocarcinoma cases and 6277 controls. The gene-set consisted of 31 genes containing known/suggestive associations with genetic variants from previous TB-GWAS. Subsequently, we followed-up with Mendelian Randomization to evaluate the association between TB and lung adenocarcinoma using three genome-wide significant variants from previous TB-GWAS in East Asians. The TB-related gene-set was associated with lung adenocarcinoma (p = 0.016). Additionally, the Mendelian Randomization showed an association between TB and lung adenocarcinoma (OR = 1.31, 95% CI: 1.03, 1.66, p = 0.027). Our findings support TB as a causal risk factor for lung cancer development among never-smoking Asian women.

Abstract A13: Genome-wide association study identifies multiple new loci associated with Ewing sarcoma susceptibility

Ewing sarcoma (EWS), a pediatric tumor predominantly occurring in children of European ancestry, is characterized by the EWSR1-FLI1 fusion oncogene. We performed a genome-wide association study (GWAS) of 749 EWS cases and 1,378 unaffected individuals of European ancestry. Our study replicated previously reported susceptibility loci at 1p36.22, 10q21.3, and 15q15.1 and identified new loci at 6p25.1, 8q24.23, 20p11.22, and 20p11.23 (P-values &lt;5x10-8). Effect estimates exhibited odds ratios (ORs) in excess of 1.7, which is high for cancer GWAS, and striking in light of the rarity of EWS cases in familial cancer syndromes. In expression quantitative trait locus (eQTL) analyses, we observed altered expression patterns for plausible candidate genes at 6p25.1 with RREB1, a RAS-responsive element, and at 20p11.23 with KIZ, a centrosomal stabilization protein. The 20p11.22 locus is also near NKX2-2, a highly overexpressed gene in EWS. Interestingly, most loci reside near GGAA repeat sequences where binding of the EWSR1-FLI1 fusion protein occurs. The seven EWS susceptibility loci discovered in only 749 cases make EWS one of the most productive GWAS studied cancers when considering a locus-to-case discovery ratio. The substantive estimated ORs suggest a distinctive underlying genetic architecture for EWS in which moderate-risk SNPs likely constitute a significant fraction and may interact with EWSR1-FLI1 binding.

Citation Format: Mitchell J. Machiela, Thomas G.P. Grünewald, Didier Surdez, Stephanie Reynaud, Olivier Mirabeau, Eric Karlins, Rebeca Alba Rubio, Sakina Zaidi, Sandrine Grossetete-Lalami, Stelly Ballet, Eve Lapouble, Valérie Laurence, Jean Michon, Gaelle Pierron, Heinrich Kovar, Nathalie Gaspar, Udo Kontny, Anna González-Neira, Piero Picci, Javier Alonso, Ana Patino-Garcia, Nadège Corradini, Neal D. Freedman, Nathaniel Rothman, Casey L. Dagnall, Laurie Burdett, Kristine Jones, Michelle Manning, Kathleen Wyatt, Weiyin Zhou, Meredith Yeager, David G. Cox, Robert N. Hoover, Javed Khan, Gregory T. Armstrong, Wendy M. Leisenring, Smita Bhatia, Leslie L. Robison, Uta Dirksen, Markus Metzler, Wolfgang Hartmann, Konstantin Strauch, Thomas Kirchner, Andreas E. Kulozik, Lindsay M. Morton, Lisa Mirabello, Margaret A. Tucker, Franck Tirode, Stephen Chanock, Olivier Delattre. Genome-wide association study identifies multiple new loci associated with Ewing sarcoma susceptibility [abstract]. In: Proceedings of the AACR Special Conference: Pediatric Cancer Research: From Basic Science to the Clinic; 2017 Dec 3-6; Atlanta, Georgia. Philadelphia (PA): AACR; Cancer Res 2018;78(19 Suppl):Abstract nr A13.

Combined somatic mutation and copy number analysis in the survival of familial CLL

Recurrent large-scale somatic copy number alterations (SCNAs), and somatic point mutations can be analysed to stratify patients with chronic lymphocytic leukaemia (CLL) into distinct prognostic groups. To investigate the relationship between SCNAs and somatic mutations, we performed whole-exome sequencing and single nucleotide polymorphism microarray analyses on 98 CLL patients from 40 families with a high burden of CLL. Overall, 69 somatic mutations in 29 CLL driver genes were detected among 45 subjects (46%), with the most frequently mutated genes being TP53 (8·2%), NOTCH1 (8·2%) and ATM (5·1%). Additionally, 142 SCNAs from 54 subjects (57%) were detected, including losses of chromosome 13q14 (28·9%), 11q (5·6%), 17p (2·1%), and gain of chromosome 12 (4·2%). We found that patients having both an adverse point mutation in a CLL driver gene and an unfavourable SCNA tended to have poorer survival (Hazard ratio [HR] = 3·17, 95% confidence interval [CI] = 0·97-10·35; P = 0·056) than patients having either a point mutation (HR = 1·34, 95%CI = 0·66-2·71; P = 0·42) or SCNAs (HR = 2·65, 95%CI = 0·77-9·13; P = 0·12). TP53 mutation carriers were associated with the poorest overall survival (HR = 4·39, 95%CI = 1·28-15·04; P = 0·018). Our study suggests that combining SCNA and mutational data could contribute to predicting outcome in familial CLL.

HPV16 E7 Genetic Conservation Is Critical to Carcinogenesis

Although most cervical human papillomavirus type 16 (HPV16) infections become undetectable within 1-2 years, persistent HPV16 causes half of all cervical cancers. We used a novel HPV whole-genome sequencing technique to evaluate an exceptionally large collection of 5,570 HPV16-infected case-control samples to determine whether viral genetic variation influences risk of cervical precancer and cancer. We observed thousands of unique HPV16 genomes; very few women shared the identical HPV16 sequence, which should stimulate a careful re-evaluation of the clinical implications of HPV mutation rates, transmission, clearance, and persistence. In case-control analyses, HPV16 in the controls had significantly more amino acid changing variants throughout the genome. Strikingly, E7 was devoid of variants in precancers/cancers compared to higher levels in the controls; we confirmed this in cancers from around the world. Strict conservation of the 98 amino acids of E7, which disrupts Rb function, is critical for HPV16 carcinogenesis, presenting a highly specific target for etiologic and therapeutic research.

GWAS follow-up study of esophageal squamous cell carcinoma identifies potential genetic loci associated with family history of upper gastrointestinal cancer

Based on our initial genome-wide association study (GWAS) on esophageal squamous cell carcinoma (ESCC) in Han Chinese, we conducted a follow-up study to examine the single nucleotide polymorphisms (SNPs) associated with family history (FH) of upper gastrointestinal cancer (UGI) cancer in cases with ESCC. We evaluated the association between SNPs and FH of UGI cancer among ESCC cases in a stage-1 case-only analysis of the National Cancer Institute (NCI, 541 cases with FH and 1399 without FH) and Henan GWAS (493 cases with FH and 869 without FH) data (discovery phase). The top SNPs (or their surrogates) from discovery were advanced to a stage-2 evaluation in additional Henan subjects (2801 cases with FH and 3136 without FH, replication phase). A total of 19 SNPs were associated with FH of UGI cancer in ESCC cases with P < 10^-5 in the stage-1 meta-analysis of NCI and Henan GWAS data. In stage-2, the association for rs79747906 (located at 18p11.31, P = 5.79 × 10^-6 in discovery) was replicated (P = 0.006), with a pooled-OR of 1.59 (95%CI: 1.11-2.28). We identified potential genetic variants associated with FH of UGI cancer. Our findings may provide important insights into new low-penetrance susceptibility regions involved in the susceptibility of families with multiple UGI cancer cases.

Association between GWAS-identified lung adenocarcinoma susceptibility loci and EGFR mutations in never-smoking Asian women, and comparison with findings from Western populations

To evaluate associations by EGFR mutation status for lung adenocarcinoma risk among never-smoking Asian women, we conducted a meta-analysis of 11 loci previously identified in genome-wide association studies (GWAS). Genotyping in an additional 10,780 never-smoking cases and 10,938 never-smoking controls from Asia confirmed associations with eight known single nucleotide polymorphisms (SNPs). Two new signals were observed at genome-wide significance (P < 5 × 10-8), namely, rs7216064 (17q24.3, BPTF), for overall lung adenocarcinoma risk, and rs3817963 (6p21.3, BTNL2) which is specific to cases with EGFR mutations. In further sub-analyses by EGFR status, rs9387478 (ROS1/DCBLD1) and rs2179920 (HLA-DPB1) showed stronger estimated associations in EGFR-positive compared to EGFR-negative cases. Comparison of the overall associations with published results in Western populations revealed that the majority of these findings were distinct, underscoring the importance of distinct contributing factors for smoking and non-smoking lung cancer. Our results extend the catalogue of regions associated with lung adenocarcinoma in non-smoking Asian women and highlight the importance of how the germline could inform risk for specific tumour mutation patterns, which could have important translational implications.

Multiple rare variants in high-risk pancreatic cancer-related genes may increase risk for pancreatic cancer in a subset of patients with and without germline CDKN2A mutations

The risk of pancreatic cancer (PC) is increased in melanoma-prone families but the causal relationship between germline CDKN2A mutations and PC risk is uncertain, suggesting the existence of non-CDKN2A factors. One genetic possibility involves patients having mutations in multiple high-risk PC-related genes; however, no systematic examination has yet been conducted. We used next-generation sequencing data to examine 24 putative PC-related genes in 43 PC patients with and 23 PC patients without germline CDKN2A mutations and 1001 controls. For each gene and the four pathways in which they occurred, we tested whether PC patients (overall or CDKN2A+ and CDKN2A- cases separately) had an increased number of rare nonsynonymous variants. Overall, we identified 35 missense variants in PC patients, 14 in CDKN2A+ and 21 in CDKN2A- PC cases. We found nominally significant associations for mismatch repair genes (MLH1, MSH2, MSH6, PMS2) in all PC patients and for ATM, CPA1, and PMS2 in CDKN2A- PC patients. Further, nine CDKN2A+ and four CDKN2A- PC patients had rare potentially deleterious variants in multiple PC-related genes. Loss-of-function variants were only observed in CDKN2A- PC patients, with ATM having the most pathogenic variants. Also, ATM variants (n = 5) were only observed in CDKN2A- PC patients with a family history that included digestive system tumors. Our results suggest that a subset of PC patients may have increased risk because of germline mutations in multiple PC-related genes.

HPV16 Sublineage Associations With Histology-Specific Cancer Risk Using HPV Whole-Genome Sequences in 3200 Women

BACKGROUND

HPV16 is a common sexually transmitted infection although few infections lead to cervical precancer/cancer; we cannot distinguish nor mechanistically explain why only certain infections progress. HPV16 can be classified into four main evolutionary-derived variant lineages (A, B, C, D) that have been previously suggested to have varying disease risks.

METHODS

We used a high-throughput HPV16 whole-genome sequencing assay to investigate variant lineage risk among 3215 HPV16-infected women. Using sublineages A1/A2 as the reference, we assessed all variant lineage associations with infection outcome over three or more years of follow-up: 1107 control subjects (

RESULTS

A4 sublineage was associated with an increased risk of cancer, specifically adenocarcinoma (OR = 9.81, 95% CI = 2.02 to 47.69, P = 4.7x10(-03)). Lineage B had a lower risk of CIN3 (OR = 0.51, 95% CI = 0. 28 to 0.91, P = 02) while lineage C showed increased risk (OR = 2.06, 95% CI = 1.09 to 3.89, P = 03). D2/D3 sublineages were strongly associated with an increased risk of CIN3 and cancer, particularly D2 (OR for cancer = 28.48, 95% CI = 9.27 to 87.55, P = 5.0x10(-09)). D2 had the strongest increased risk of glandular lesions, AIS (OR = 29.22, 95% CI = 8.94 to 95.51, P = 2.3x10(-08)), and adenocarcinomas (OR = 137.34, 95% CI = 37.21 to 506.88, P = 1.5x10(-13)). Moreover, the risk of precancer and cancer for specific variant lineages varied by a women's race/ethnicity; those women whose race/ethnicity matched that of the infecting HPV16 variant had an increased risk of CIN3 + (P < 001).

CONCLUSIONS

Specific HPV16 variant sublineages strongly influence risk of histologic types of precancer and cancer, and viral genetic variation may help explain its unique carcinogenic properties.

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Key Words Collapse

MESH Headings

• Adenocarcinoma/ethnology
• Adenocarcinoma/virology
• Adenocarcinoma in Situ/ethnology
• Adenocarcinoma in Situ/virology
• Adult
• Aftercare
• California/epidemiology
• Carcinoma/ethnology
• Carcinoma/virology
• Carcinoma, Squamous Cell/ethnology
• Carcinoma, Squamous Cell/virology
• Female
• Genome
• High-Throughput Nucleotide Sequencing
• Human papillomavirus 16/classification
• Human papillomavirus 16/genetics
• Human papillomavirus 16/pathogenicity
• Humans
• Middle Aged
• Papillomavirus Infections/ethnology
• Papillomavirus Infections/virology
• Phylogeny
• Precancerous Conditions/ethnology
• Precancerous Conditions/virology
• Risk Factors
• Uterine Cervical Neoplasms/ethnology
• Uterine Cervical Neoplasms/virology
• Young Adult
• Uterine Cervical Dysplasia/ethnology
• Uterine Cervical Dysplasia/virology

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Affiliation(s)

Lisa Mirabello Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Meredith Yeager Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Michael Cullen Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Joseph F Boland Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Zigui Chen Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Nicolas Wentzensen Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Xijun Zhang Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Kai Yu Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Qi Yang Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Jason Mitchell Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
David Roberson Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Sara Bass Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Yanzi Xiao Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Laurie Burdett Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Tina Raine-Bennett Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Thomas Lorey Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Philip E Castle Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Robert D Burk Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)
Mark Schiffman Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD (LM, MY, MC, JFB, NW, XZ, KY, QY, JM, DR, SB, LB, YX, MS); Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD (MY, MC, JFB, XZ, QY, JM, DR, SB, LB); Department of Microbiology, The Chinese University of Hong Kong, Hong Kong (ZC); Women's Health Research Institute, Division of Research, Kaiser Permanente Northern California, Oakland CA (TRB); Regional Laboratory, Kaiser Permanente Northern California, Oakland, CA (TL); Department of Epidemiology and Population Health, at Albert Einstein College of Medicine, Bronx, NY (PEC, RDB); Departments of Pediatrics; Microbiology & Immunology; and, Obstetrics, Gynecology and Women's Health, at Albert Einstein College of Medicine, Bronx, NY (RDB)

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Whole exome sequencing in families at high risk for Hodgkin lymphoma: identification of a predisposing mutation in the KDR gene

Hodgkin lymphoma shows strong familial aggregation but no major susceptibility genes have been identified to date. The goal of this study was to identify high-penetrance variants using whole exome sequencing in 17 Hodgkin lymphoma prone families with three or more affected cases or obligate carriers (69 individuals), followed by targeted sequencing in an additional 48 smaller HL families (80 individuals). Alignment and variant calling were performed using standard methods. Dominantly segregating, rare, coding or potentially functional variants were further prioritized based on predicted deleteriousness, conservation, and potential importance in lymphoid malignancy pathways. We selected 23 genes for targeted sequencing. Only the p.A1065T variant in KDR (kinase insert domain receptor) also known as VEGFR2 (vascular endothelial growth factor receptor 2) was replicated in two independent Hodgkin lymphoma families. KDR is a type III receptor tyrosine kinase, the main mediator of vascular endothelial growth factor induced proliferation, survival, and migration. Its activity is associated with several diseases including lymphoma. Functional experiments have shown that p.A1065T, located in the activation loop, can promote constitutive autophosphorylation on tyrosine in the absence of vascular endothelial growth factor and that the kinase activity was abrogated after exposure to kinase inhibitors. A few other promising mutations were identified but appear to be "private". In conclusion, in the largest sequenced cohort of Hodgkin lymphoma families to date, we identified a causal mutation in the KDR gene. While independent validation is needed, this mutation may increase downstream tumor cell proliferation activity and might be a candidate for targeted therapy.

Female chromosome X mosaicism is age-related and preferentially affects the inactivated X chromosome

To investigate large structural clonal mosaicism of chromosome X, we analysed the SNP microarray intensity data of 38,303 women from cancer genome-wide association studies (20,878 cases and 17,425 controls) and detected 124 mosaic X events >2 Mb in 97 (0.25%) women. Here we show rates for X-chromosome mosaicism are four times higher than mean autosomal rates; X mosaic events more often include the entire chromosome and participants with X events more likely harbour autosomal mosaic events. X mosaicism frequency increases with age (0.11% in 50-year olds; 0.45% in 75-year olds), as reported for Y and autosomes. Methylation array analyses of 33 women with X mosaicism indicate events preferentially involve the inactive X chromosome. Our results provide further evidence that the sex chromosomes undergo mosaic events more frequently than autosomes, which could have implications for understanding the underlying mechanisms of mosaic events and their possible contribution to risk for chronic diseases.

It is unclear how often genetic mosaicism of chromosome X arises. Here, the authors examine women with cancer and cancer-free controls and show that X chromosome mosaicism occurs more frequently than on autosomes, especially on the inactive X chromosome, but is not linked to non-haematologic cancer risk

Genetically predicted longer telomere length is associated with increased risk of B-cell lymphoma subtypes

Evidence from a small number of studies suggests that longer telomere length measured in peripheral leukocytes is associated with an increased risk of non-Hodgkin lymphoma (NHL). However, these studies may be biased by reverse causation, confounded by unmeasured environmental exposures and might miss time points for which prospective telomere measurement would best reveal a relationship between telomere length and NHL risk. We performed an analysis of genetically inferred telomere length and NHL risk in a study of 10 102 NHL cases of the four most common B-cell histologic types and 9562 controls using a genetic risk score (GRS) comprising nine telomere length-associated single-nucleotide polymorphisms. This approach uses existing genotype data and estimates telomere length by weighing the number of telomere length-associated variant alleles an individual carries with the published change in kb of telomere length. The analysis of the telomere length GRS resulted in an association between longer telomere length and increased NHL risk [four B-cell histologic types combined; odds ratio (OR) = 1.49, 95% CI 1.22-1.82,P-value = 8.5 × 10(-5)]. Subtype-specific analyses indicated that chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL) was the principal NHL subtype contributing to this association (OR = 2.60, 95% CI 1.93-3.51,P-value = 4.0 × 10(-10)). Significant interactions were observed across strata of sex for CLL/SLL and marginal zone lymphoma subtypes as well as age for the follicular lymphoma subtype. Our results indicate that a genetic background that favors longer telomere length may increase NHL risk, particularly risk of CLL/SLL, and are consistent with earlier studies relating longer telomere length with increased NHL risk.

Identification of a novel susceptibility locus at 13q34 and refinement of the 20p12.2 region as a multi-signal locus associated with bladder cancer risk in individuals of European ancestry

Candidate gene and genome-wide association studies (GWAS) have identified 15 independent genomic regions associated with bladder cancer risk. In search for additional susceptibility variants, we followed up on four promising single-nucleotide polymorphisms (SNPs) that had not achieved genome-wide significance in 6911 cases and 11 814 controls (rs6104690, rs4510656, rs5003154 and rs4907479, P < 1 × 10(-6)), using additional data from existing GWAS datasets and targeted genotyping for studies that did not have GWAS data. In a combined analysis, which included data on up to 15 058 cases and 286 270 controls, two SNPs achieved genome-wide statistical significance: rs6104690 in a gene desert at 20p12.2 (P = 2.19 × 10(-11)) and rs4907479 within the MCF2L gene at 13q34 (P = 3.3 × 10(-10)). Imputation and fine-mapping analyses were performed in these two regions for a subset of 5551 bladder cancer cases and 10 242 controls. Analyses at the 13q34 region suggest a single signal marked by rs4907479. In contrast, we detected two signals in the 20p12.2 region-the first signal is marked by rs6104690, and the second signal is marked by two moderately correlated SNPs (r(2) = 0.53), rs6108803 and the previously reported rs62185668. The second 20p12.2 signal is more strongly associated with the risk of muscle-invasive (T2-T4 stage) compared with non-muscle-invasive (Ta, T1 stage) bladder cancer (case-case P ≤ 0.02 for both rs62185668 and rs6108803). Functional analyses are needed to explore the biological mechanisms underlying these novel genetic associations with risk for bladder cancer.

Meta-analysis of genome-wide association studies discovers multiple loci for chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a common lymphoid malignancy with strong heritability. To further understand the genetic susceptibility for CLL and identify common loci associated with risk, we conducted a meta-analysis of four genome-wide association studies (GWAS) composed of 3,100 cases and 7,667 controls with follow-up replication in 1,958 cases and 5,530 controls. Here we report three new loci at 3p24.1 (rs9880772, EOMES, P=2.55 × 10(-11)), 6p25.2 (rs73718779, SERPINB6, P=1.97 × 10(-8)) and 3q28 (rs9815073, LPP, P=3.62 × 10(-8)), as well as a new independent SNP at the known 2q13 locus (rs9308731, BCL2L11, P=1.00 × 10(-11)) in the combined analysis. We find suggestive evidence (P<5 × 10(-7)) for two additional new loci at 4q24 (rs10028805, BANK1, P=7.19 × 10(-8)) and 3p22.2 (rs1274963, CSRNP1, P=2.12 × 10(-7)). Pathway analyses of new and known CLL loci consistently show a strong role for apoptosis, providing further evidence for the importance of this biological pathway in CLL susceptibility.

Pathway, in silico and tissue-specific expression quantitative analyses of oesophageal squamous cell carcinoma genome-wide association studies data

BACKGROUND

Oesophageal cancer is the fourth leading cause of cancer death in China where essentially all cases are histologically oesophageal squamous cell carcinoma (ESCC). Agnostic pathway-based analyses of genome-wide association study (GWAS) data combined with tissue-specific expression quantitative trait loci (eQTL) analysis and publicly available functional data can identify biological pathways and/or genes enriched with functionally-relevant disease-associated variants.

METHOD

We used the adaptive multilocus joint test to analyse 1827 pathways containing 6060 genes using GWAS data from 1942 ESCC cases and 2111 controls with Chinese ancestry. We examined the function of risk alleles using in silico and eQTL analyses in oesophageal tissues.

RESULTS

Associations with ESCC risk were observed for 36 pathways predominantly involved in apoptosis, cell cycle regulation and DNA repair and containing known GWAS-associated genes. After excluding genes with previous GWAS signals, candidate pathways (and genes) for ESCC risk included taste transduction (KEGG_hsa04742; TAS2R13, TAS2R42, TAS2R14, TAS2R46,TAS2R50), long-patch base excision repair (Reactome_pid; POLD2) and the metabolics pathway (KEGG_hsa01100; MTAP, GAPDH, DCTD, POLD2, AMDHD1). We identified and validated CASP8 rs13016963 and IDH2 rs11630814 as eQTLs, and CASP8 rs3769823 and IDH2 rs4561444 as the potential functional variants in high-linkage disequilibrium with these single nucleotide polymorphisms (SNPs), respectively. Further, IDH2 mRNA levels were down-regulated in ESCC (tumour:normal-fold change = 0.69, P =  .75E-14).

CONCLUSION

Agnostic pathway-based analyses and integration of multiple types of functional data provide new evidence for the contribution of genes in taste transduction and metabolism to ESCC susceptibility, and for the functionality of both established and new ESCC risk-related SNPs.

Meta-analysis of genome-wide association studies identifies multiple lung cancer susceptibility loci in never-smoking Asian women

Genome-wide association studies (GWAS) of lung cancer in Asian never-smoking women have previously identified six susceptibility loci associated with lung cancer risk. To further discover new susceptibility loci, we imputed data from four GWAS of Asian non-smoking female lung cancer (6877 cases and 6277 controls) using the 1000 Genomes Project (Phase 1 Release 3) data as the reference and genotyped additional samples (5878 cases and 7046 controls) for possible replication. In our meta-analysis, three new loci achieved genome-wide significance, marked by single nucleotide polymorphism (SNP) rs7741164 at 6p21.1 (per-allele odds ratio (OR) = 1.17; P = 5.8 × 10(-13)), rs72658409 at 9p21.3 (per-allele OR = 0.77; P = 1.41 × 10(-10)) and rs11610143 at 12q13.13 (per-allele OR = 0.89; P = 4.96 × 10(-9)). These findings identified new genetic susceptibility alleles for lung cancer in never-smoking women in Asia and merit follow-up to understand their biological underpinnings.

Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for Thirteen Cancer Types

BACKGROUND

Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites.

METHODS

Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers.

RESULTS

GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, hl (2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (ρ = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (ρ = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (ρ = 0.51, SE =0.18), and bladder and lung (ρ = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures.

CONCLUSION

Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.

Abstract 4622: Common genetic variants in epigenetic machinery genes and risk of upper gastrointestinal cancers

Background: Populations in north central China are at high risk for esophageal squamous cell carcinoma (ESCC) and gastric cancer (GC), and genetic variation in epigenetic machinery genes and pathways may contribute to this risk. Methods: We used the adaptive multilocus joint test (AdaJoint) to analyze 191 epigenetic genes involved in DNA methylation, chromatin remodeling, and microRNA biosynthesis in 1942 ESCC and 1758 GC cases [1126 cardia (GCA) and 632 non-cardia adenocarcinoma (GNCA)] and 2111 controls with Chinese ancestry. We examined the regulatory function of risk SNPs using in silico analyses and expression quantitative trait loci (eQTL) analysis in normal esophageal and gastric tissues. Results: Significant pathway-based associations were observed for the overall epigenetics (P = 3.4E-02) and chromatin remodeling (P = 3.9E-02) pathways with GCA risk, but not GC, GNCA or ESCC. SETD1B, CBX4, KAT5, ZGPAT, BTD, EED, SMARCD1, POLE3, AGO2, RING1 and MBD3L1 were associated with ESCC risk, and SUV42OH1, ASH1L, KAT5, JARID2, PRMT1, MBD3L1, SRRT, KDM5A, DROSHA and KAT6A were associated with GC risk overall (nominal P &lt; 0.05). We identified EED rs10898459 (rho = -0.22, P = 2.9E-02) as a potential esophageal eQTL; DICER1 rs7157322 (rho = -0.42, P = 1.4E-02) and PPP1CA rs1790733 (rho = -0.41, P = 2.1E-03) as potential gastric eQTLs; and ASH1L rs12724079 and rs8179271 as potential gastric subtype eQTLs. Significance: As one of the first attempts to investigate epigenetic gene and pathway-level associations, our results suggest that chromatin remodeling and epigenetic pathways warrant further evaluation in relation to GC risk in other populations.

Citation Format: Hyuna Sung, Howard H. Yang, Han Zhang, Qi Yang, Nan Hu, Ze-Zhong Tang, Hua Su, Lemin Wang, Chaoyu Wang, Ti Ding, Jin-Hu Fan, You-Lin Qiao, William Wheeler, Carol Giffen, Laurie Burdett, Zhaoming Wang, Maxwell P. Lee, Stephen J. Chanock, Sanford M. Dawsey, Neal D. Freedman, Christian C. Abnet, Alisa M. Goldstein, Kai Yu, Philip R. Taylor, Paula L. Hyland. Common genetic variants in epigenetic machinery genes and risk of upper gastrointestinal cancers. [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 4622. doi:10.1158/1538-7445.AM2015-4622

A Genome-Wide Scan Identifies Variants in NFIB Associated with Metastasis in Patients with Osteosarcoma

Metastasis is the leading cause of death in patients with osteosarcoma, the most common pediatric bone malignancy. We conducted a multistage genome-wide association study of osteosarcoma metastasis at diagnosis in 935 osteosarcoma patients to determine whether germline genetic variation contributes to risk of metastasis. We identified an SNP, rs7034162, in NFIB significantly associated with metastasis in European osteosarcoma cases, as well as in cases of African and Brazilian ancestry (meta-analysis of all cases: P = 1.2 × 10(-9); OR, 2.43; 95% confidence interval, 1.83-3.24). The risk allele was significantly associated with lowered NFIB expression, which led to increased osteosarcoma cell migration, proliferation, and colony formation. In addition, a transposon screen in mice identified a significant proportion of osteosarcomas harboring inactivating insertions in Nfib and with lowered NFIB expression. These data suggest that germline genetic variation at rs7034162 is important in osteosarcoma metastasis and that NFIB is an osteosarcoma metastasis susceptibility gene.

SIGNIFICANCE

Metastasis at diagnosis in osteosarcoma is the leading cause of death in these patients. Here we show data that are supportive for the NFIB locus as associated with metastatic potential in osteosarcoma.

Common genetic variants in epigenetic machinery genes and risk of upper gastrointestinal cancers

BACKGROUND

Populations in north central China are at high risk for oesophageal squamous cell carcinoma (ESCC) and gastric cancer (GC), and genetic variation in epigenetic machinery genes and pathways may contribute to this risk.

METHODS

We used the adaptive multilocus joint test to analyse 192 epigenetic genes involved in chromatin remodelling, DNA methylation and microRNA biosynthesis in 1942 ESCC and 1758 GC cases [1126 cardia (GCA) and 632 non-cardia adenocarcinoma (GNCA)] and 2111 controls with Chinese ancestry. We examined potential function of risk alleles using in silico and expression quantitative trait loci (eQTLs) analyses.

RESULTS

Suggestive pathway-based associations were observed for the overall epigenetic (P-value(PATH) = 0.034) and chromatin remodelling (P-value(PATH) = 0.039) pathways with risk of GCA, but not GC, GNCA or ESCC. Overall, 37 different epigenetic machinery genes were associated with risk of one or more upper gastrointestinal (UGI) cancer sites (P-value(GENE )< 0.05), including 14 chromatin remodelling genes whose products are involved in the regulation of HOX genes. We identified a gastric eQTL (rs12724079; rho = 0.37; P = 0.0006) which regulates mRNA expression of ASH1L. Several suggestive eQTLs were also found in oesophageal (rs10898459 in EED), gastric cardia (rs7157322 in DICER1; rs8179271 in ASH1L), and gastric non-cardia (rs1790733 in PPP1CA) tissues.

CONCLUSIONS

Results of our analyses provide limited but suggestive evidence for a role of epigenetic gene variation in the aetiology of UGI cancer.

Characterization of large structural genetic mosaicism in human autosomes

Analyses of genome-wide association study (GWAS) data have revealed that detectable genetic mosaicism involving large (>2 Mb) structural autosomal alterations occurs in a fraction of individuals. We present results for a set of 24,849 genotyped individuals (total GWAS set II [TGSII]) in whom 341 large autosomal abnormalities were observed in 168 (0.68%) individuals. Merging data from the new TGSII set with data from two prior reports (the Gene-Environment Association Studies and the total GWAS set I) generated a large dataset of 127,179 individuals; we then conducted a meta-analysis to investigate the patterns of detectable autosomal mosaicism (n = 1,315 events in 925 [0.73%] individuals). Restricting to events >2 Mb in size, we observed an increase in event frequency as event size decreased. The combined results underscore that the rate of detectable mosaicism increases with age (p value = 5.5 × 10(-31)) and is higher in men (p value = 0.002) but lower in participants of African ancestry (p value = 0.003). In a subset of 47 individuals from whom serial samples were collected up to 6 years apart, complex changes were noted over time and showed an overall increase in the proportion of mosaic cells as age increased. Our large combined sample allowed for a unique ability to characterize detectable genetic mosaicism involving large structural events and strengthens the emerging evidence of non-random erosion of the genome in the aging population.

A genome-wide association study of marginal zone lymphoma shows association to the HLA region

Marginal zone lymphoma (MZL) is the third most common subtype of B-cell non-Hodgkin lymphoma. Here we perform a two-stage GWAS of 1,281 MZL cases and 7,127 controls of European ancestry and identify two independent loci near BTNL2 (rs9461741, P=3.95 × 10(-15)) and HLA-B (rs2922994, P=2.43 × 10(-9)) in the HLA region significantly associated with MZL risk. This is the first evidence that genetic variation in the major histocompatibility complex influences MZL susceptibility.

Genetic variants associated with longer telomere length are associated with increased lung cancer risk among never-smoking women in Asia: a report from the female lung cancer consortium in Asia

Recent evidence from several relatively small nested case-control studies in prospective cohorts shows an association between longer telomere length measured phenotypically in peripheral white blood cell (WBC) DNA and increased lung cancer risk. We sought to further explore this relationship by examining a panel of seven telomere-length associated genetic variants in a large study of 5,457 never-smoking female Asian lung cancer cases and 4,493 never-smoking female Asian controls using data from a previously reported genome-wide association study. Using a group of 1,536 individuals with phenotypically measured telomere length in WBCs in the prospective Shanghai Women's Health study, we demonstrated the utility of a genetic risk score (GRS) of seven telomere-length associated variants to predict telomere length in an Asian population. We then found that GRSs used as instrumental variables to predict longer telomere length were associated with increased lung cancer risk (OR = 1.51 (95% CI = 1.34-1.69) for upper vs. lower quartile of the weighted GRS, p value = 4.54 × 10(-14) ) even after removing rs2736100 (p value = 4.81 × 10(-3) ), a SNP in the TERT locus robustly associated with lung cancer risk in prior association studies. Stratified analyses suggested the effect of the telomere-associated GRS is strongest among younger individuals. We found no difference in GRS effect between adenocarcinoma and squamous cell subtypes. Our results indicate that a genetic background that favors longer telomere length may increase lung cancer risk, which is consistent with earlier prospective studies relating longer telomere length with increased lung cancer risk.

Genome-wide association study identifies multiple susceptibility loci for diffuse large B cell lymphoma

Diffuse large B cell lymphoma (DLBCL) is the most common lymphoma subtype and is clinically aggressive. To identify genetic susceptibility loci for DLBCL, we conducted a meta-analysis of 3 new genome-wide association studies (GWAS) and 1 previous scan, totaling 3,857 cases and 7,666 controls of European ancestry, with additional genotyping of 9 promising SNPs in 1,359 cases and 4,557 controls. In our multi-stage analysis, five independent SNPs in four loci achieved genome-wide significance marked by rs116446171 at 6p25.3 (EXOC2; P = 2.33 × 10(-21)), rs2523607 at 6p21.33 (HLA-B; P = 2.40 × 10(-10)), rs79480871 at 2p23.3 (NCOA1; P = 4.23 × 10(-8)) and two independent SNPs, rs13255292 and rs4733601, at 8q24.21 (PVT1; P = 9.98 × 10(-13) and 3.63 × 10(-11), respectively). These data provide substantial new evidence for genetic susceptibility to this B cell malignancy and point to pathways involved in immune recognition and immune function in the pathogenesis of DLBCL.

Genome-wide association study identifies five susceptibility loci for follicular lymphoma outside the HLA region

Genome-wide association studies (GWASs) of follicular lymphoma (FL) have previously identified human leukocyte antigen (HLA) gene variants. To identify additional FL susceptibility loci, we conducted a large-scale two-stage GWAS in 4,523 case subjects and 13,344 control subjects of European ancestry. Five non-HLA loci were associated with FL risk: 11q23.3 (rs4938573, p = 5.79 × 10(-20)) near CXCR5; 11q24.3 (rs4937362, p = 6.76 × 10(-11)) near ETS1; 3q28 (rs6444305, p = 1.10 × 10(-10)) in LPP; 18q21.33 (rs17749561, p = 8.28 × 10(-10)) near BCL2; and 8q24.21 (rs13254990, p = 1.06 × 10(-8)) near PVT1. In an analysis of the HLA region, we identified four linked HLA-DRβ1 multiallelic amino acids at positions 11, 13, 28, and 30 that were associated with FL risk (pomnibus = 4.20 × 10(-67) to 2.67 × 10(-70)). Additional independent signals included rs17203612 in HLA class II (odds ratio [OR(per-allele)] = 1.44; p = 4.59 × 10(-16)) and rs3130437 in HLA class I (OR(per-allele) = 1.23; p = 8.23 × 10(-9)). Our findings further expand the number of loci associated with FL and provide evidence that multiple common variants outside the HLA region make a significant contribution to FL risk.

Abstract 2203: Pathway analysis of genome-wide association study data highlights taste transduction and metabolic pathways and esophageal squamous cell carcinoma susceptibility

Background: In China, esophageal cancer is the fourth leading cause of cancer death and essentially all cases are histologically esophageal squamous cell carcinoma (ESCC). Agnostic pathway-based analyses applied to GWAS data can identify biological pathways and/or groups of genes enriched with disease-associated variants whose individual effect sizes may be too small to be detected by standard single locus methods. Methods: We used the adaptive rank-truncated product (ARTP) method to analyze 1,827 pathways containing 69,420 genes in GWAS data from 1942 ESCC cases and 2111 controls with Chinese ancestry. Pathways were retrieved from five databases: KEGG, BioCarta, Reactome, HumanCys and NCI-Nature curated. Statistical significance was determined by permutation. Results: Associations with ESCC risk (P&lt;0.001) were observed for 60 pathways, which included overlapping pathways from different sources predominantly associated with cell cycle control and signaling, DNA repair, and apoptosis. After excluding genes with previous GWAS hits from the pathway analysis, the KEGG taste transduction pathway and the KEGG metabolic pathways were significantly associated with risk of ESCC (P&lt;0.001). The most significant genes (P&lt;0.001) in these pathways were TAS2R13, TAS2R42, TAS2R14, TAS2R46 and TAS2R50, and MTAP, GAPDH, DCTD, POLD2 and AMDHD1, respectively. Significance: This approach provides new insights into the collective role of genetic variants and ESCC risk in Han Chinese and suggests that genetic alterations associated with taste transduction and metabolic pathways may contribute to cancer susceptibility.

Citation Format: Paula L. Hyland, Han Zhang, Qi Yang, Shih-Wen Lin, Dennis Maeder, Nan Hu, Ze-Zhong Tang, Hua Su, Lemin Wang, Chaoyu Wang, Ti Ding, Jin-Hu Fan, You-Lin Qiao, William Wheeler, Carol Giffen, Laurie Burdett, Zhaoming Wang, Stephen J. Chanock, Sanford M. Dawsey, Neal D. Freedman, Christian C. Abnet, Alisa M. Goldstein, Kai Yu, Philip R. Taylor. Pathway analysis of genome-wide association study data highlights taste transduction and metabolic pathways and esophageal squamous cell carcinoma susceptibility. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2203. doi:10.1158/1538-7445.AM2014-2203

Abstract 5071: A genome-wide association study suggests evidence of variants at 6p21.32 associated with marginal zone lymphoma

Marginal zone lymphomas (MZL) are a group of indolent non-Hodgkin's B-cell lymphomas (NHL) comprising extranodal MZL of mucosa-associated lymphoid tissue (MALT) type, splenic MZL and nodal MZL. MZL comprises 7-12% of adult NHLs. The genetic etiology of MZL is poorly understood. To better understand the genetic risk factors for MZL, we conducted the first genome-wide association study (GWAS) of this lymphoid malignancy. The GWAS included 824 MZL cases and 6,220 controls of European ancestry from 22 studies of NHL. Genotyping was carried out at the Cancer Genomics Research Laboratory (CGR) of NCI using Illumina Human OmniExpress arrays. Standard genotyping quality controls were performed. Imputation of common SNPs was performed using IMPUTE2 software and 1000 Genomes Project release version 3 data. Association testing was subsequently performed using SNPTEST, assuming a log-additive genetic model adjusting for age, gender and three significant eigenvectors. We identified one locus at 6p21.32 within the HLA class II region that attained genome-wide significance (P&lt;5x10-8). When a small number of additional cases (n=58) and controls (n=66) genotyped using Taqman assays were included, rs9461741 (BTNL2) was associated with an increased risk of MZL (per-allele odds ratio = 2.38, 95% confidence interval: 1.74-3.24; P=4.32x10-8). Other SNPs at the 6p21.32 locus were also highly associated with MZL, suggesting that this is unlikely to be a chance finding. Promising signals yet to be confirmed were also observed on chromosomes 3 and 14. The BTNL2 protein has extracellular immunoglobulin domains and is expressed in multiple tissues including various immune organs and the gut and it inhibits T-cell activation. Genetic variability at BTNL2 has been associated with inflammatory and infectious phenotypes, highlighting the importance of this locus for immune diseases. In conclusion, findings from this GWAS identify the HLA class II region as an important susceptibility locus for MZL.

Citation Format: Joseph Vijai, Zhaoming Wang, Sonja I. Berndt, Susan L. Slager, James R. Cerhan, Christine Skibola, Sophia S. Wang, Angela R. Brooks-Wilson, Silvia de Sanjose, Paige M. Bracci, Mads Melbye, Bengt Glimelius, Rebecca D. Jackson, Wendy Cozen, Nikolaus Becker, Lauren R. Teras, John J. Spinelli, Jenny Turner, Qing Lan, Mark P. Purdue, Kimberly A. Bertrand, Kenneth Offit, Paolo Vineis, Brian K. Link, Graham G. Giles, Anne Zelenuich-Jacquotte, Alain Monnereau, Maria Grazia Ennas, Demetrius Albanes, Laurie Burdett, Nathaniel Rothman, Stephen J. Chanock, Alexandra Nieters, On behalf of the NHL GWAS Consortium. A genome-wide association study suggests evidence of variants at 6p21.32 associated with marginal zone lymphoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5071. doi:10.1158/1538-7445.AM2014-5071

Dubowitz syndrome is a complex comprised of multiple, genetically distinct and phenotypically overlapping disorders

Dubowitz syndrome is a rare disorder characterized by multiple congenital anomalies, cognitive delay, growth failure, an immune defect, and an increased risk of blood dyscrasia and malignancy. There is considerable phenotypic variability, suggesting genetic heterogeneity. We clinically characterized and performed exome sequencing and high-density array SNP genotyping on three individuals with Dubowitz syndrome, including a pair of previously-described siblings (Patients 1 and 2, brother and sister) and an unpublished patient (Patient 3). Given the siblings' history of bone marrow abnormalities, we also evaluated telomere length and performed radiosensitivity assays. In the siblings, exome sequencing identified compound heterozygosity for a known rare nonsense substitution in the nuclear ligase gene LIG4 (rs104894419, NM_002312.3:c.2440C>T) that predicts p.Arg814X (MAF:0.0002) and an NM_002312.3:c.613delT variant that predicts a p.Ser205Leufs*29 frameshift. The frameshift mutation has not been reported in 1000 Genomes, ESP, or ClinSeq. These LIG4 mutations were previously reported in the sibling sister; her brother had not been previously tested. Western blotting showed an absence of a ligase IV band in both siblings. In the third patient, array SNP genotyping revealed a de novo ∼3.89 Mb interstitial deletion at chromosome 17q24.2 (chr 17:62,068,463–65,963,102, hg18), which spanned the known Carney complex gene PRKAR1A. In all three patients, a median lymphocyte telomere length of ≤1^st centile was observed and radiosensitivity assays showed increased sensitivity to ionizing radiation. Our work suggests that, in addition to dyskeratosis congenita, LIG4 and 17q24.2 syndromes also feature shortened telomeres; to confirm this, telomere length testing should be considered in both disorders. Taken together, our work and other reports on Dubowitz syndrome, as currently recognized, suggest that it is not a unitary entity but instead a collection of phenotypically similar disorders. As a clinical entity, Dubowitz syndrome will need continual re-evaluation and re-definition as its constituent phenotypes are determined.

Dietary iron, iron homeostatic gene polymorphisms and the risk of advanced colorectal adenoma and cancer

Dietary iron intake and variation in iron homeostasis genes may affect colorectal neoplasia risk. We conducted two nested case-control studies within the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial: one of advanced colorectal adenoma (1205 cases; 1387 controls) and one of colorectal cancer (370 cases; 401 controls). Iron intake was estimated with a food frequency questionnaire and genotyping was performed for 21 genes. Unconditional logistic regression was used to estimate odds ratio (OR) and 95% confidence intervals (95% CIs) for colorectal neoplasia risk within quartiles of intake. Several single nucleotide polymorphisms (SNPs) modified the association between iron intake and the risk of adenoma or cancer. Dietary iron was positively associated with colorectal adenoma among three SNPs of HEPHL1, including carriers of the AA genotype at rs7946162 (ORQ4-Q1 = 2.22, 95% CI 1.15-4.27, Ptrend = 0.03; Pinteraction = 0.10), the TT genotype at rs2460063 (ORQ4-Q1 = 2.39, 95% CI 1.26-4.54, Ptrend = 0.02; Pinteraction = 0.04) and the GG genotype at rs7127348 (ORQ4-Q1 = 2.40, 95% CI 1.23-4.67, Ptrend = 0.02; Pinteraction = 0.09). Heme iron was positively associated with colorectal cancer among those with GG genotypes for ACO1 rs10970985 (ORQ4-Q 1 = 2.45, 95% CI 3.40-8.06, Ptrend = 0.004; Pinteraction = 0.05). However, none of the associations were statistically significant after adjustment for multiple comparisons. Future studies should target the specific genes and SNPs for which the association was significant prior to multiple comparison correction.

Genetic variants in fas signaling pathway genes and risk of gastric cancer

Populations in north central China are at high risk for gastric cancers (GC), and altered FAS-mediated cell signaling and/or apoptosis may contribute to this risk. We examined the association of 554 single nucleotide polymorphisms (SNPs) in 53 Fas signaling-related genes using a pathway-based approach in 1758 GC cases (1126 gastric cardia adenocarcinomas (GCA) and 632 gastric noncardia adenocarcinomas (GNCA)), and 2111 controls from a genome-wide association study (GWAS) of GC in ethnic Chinese. SNP associations with risk of overall GC, GCA and GNCA were evaluated using unconditional logistic regressions controlling for age, sex and study. Gene- and pathway-based associations were tested using the adaptive rank-truncated product (ARTP) method. Statistical significance was evaluated empirically by permutation. Significant pathway-based associations were observed for Fas signaling with risk of overall GC (p = 5.5E-04) and GCA (p = 6.3E-03), but not GNCA (p= 8.1E-02). Among examined genes in the Fas signaling pathway, MAP2K4, FAF1, MAPK8, CASP10, CASP8, CFLAR, MAP2K1, CAP8AP2, PAK2 and IKBKB were associated with risk of GC (nominal p < 0.05), and FAF1 and MAPK8 were significantly associated with risk of both GCA and GNCA (nominal p< 0.05). Our examination of genetic variation in the Fas signaling pathway is consistent with an association of altered Fas signaling and/or apoptosis with risk of GC. As one of the first attempts to investigate a pathway-level association, our results suggest that these genes and the Fas signaling pathway warrant further evaluation in relation to GC risk in other populations.

A recessive founder mutation in regulator of telomere elongation helicase 1, RTEL1, underlies severe immunodeficiency and features of Hoyeraal Hreidarsson syndrome

Dyskeratosis congenita (DC) is a heterogeneous inherited bone marrow failure and cancer predisposition syndrome in which germline mutations in telomere biology genes account for approximately one-half of known families. Hoyeraal Hreidarsson syndrome (HH) is a clinically severe variant of DC in which patients also have cerebellar hypoplasia and may present with severe immunodeficiency and enteropathy. We discovered a germline autosomal recessive mutation in RTEL1, a helicase with critical telomeric functions, in two unrelated families of Ashkenazi Jewish (AJ) ancestry. The affected individuals in these families are homozygous for the same mutation, R1264H, which affects three isoforms of RTEL1. Each parent was a heterozygous carrier of one mutant allele. Patient-derived cell lines revealed evidence of telomere dysfunction, including significantly decreased telomere length, telomere length heterogeneity, and the presence of extra-chromosomal circular telomeric DNA. In addition, RTEL1 mutant cells exhibited enhanced sensitivity to the interstrand cross-linking agent mitomycin C. The molecular data and the patterns of inheritance are consistent with a hypomorphic mutation in RTEL1 as the underlying basis of the clinical and cellular phenotypes. This study further implicates RTEL1 in the etiology of DC/HH and immunodeficiency, and identifies the first known homozygous autosomal recessive disease-associated mutation in RTEL1.

Genetic variants in epidermal growth factor receptor pathway genes and risk of esophageal squamous cell carcinoma and gastric cancer in a Chinese population

The epidermal growth factor receptor (EGFR) signaling pathway regulates cell proliferation, differentiation, and survival, and is frequently dysregulated in esophageal and gastric cancers. Few studies have comprehensively examined the association between germline genetic variants in the EGFR pathway and risk of esophageal and gastric cancers. Based on a genome-wide association study in a Han Chinese population, we examined 3443 SNPs in 127 genes in the EGFR pathway for 1942 esophageal squamous cell carcinomas (ESCCs), 1758 gastric cancers (GCs), and 2111 controls. SNP-level analyses were conducted using logistic regression models. We applied the resampling-based adaptive rank truncated product approach to determine the gene- and pathway-level associations. The EGFR pathway was significantly associated with GC risk (P = 2.16×10(-3)). Gene-level analyses found 10 genes to be associated with GC, including FYN, MAPK8, MAP2K4, GNAI3, MAP2K1, TLN1, PRLR, PLCG2, RPS6KB2, and PIK3R3 (P<0.05). For ESCC, we did not observe a significant pathway-level association (P = 0.72), but gene-level analyses suggested associations between GNAI3, CHRNE, PAK4, WASL, and ITCH, and ESCC (P<0.05). Our data suggest an association between specific genes in the EGFR signaling pathway and risk of GC and ESCC. Further studies are warranted to validate these associations and to investigate underlying mechanisms.

Evolutionary dynamics of the human NADPH oxidase genes CYBB, CYBA, NCF2, and NCF4: functional implications

The phagocyte NADPH oxidase catalyzes the reduction of O2 to reactive oxygen species with microbicidal activity. It is composed of two membrane-spanning subunits, gp91-phox and p22-phox (encoded by CYBB and CYBA, respectively), and three cytoplasmic subunits, p40-phox, p47-phox, and p67-phox (encoded by NCF4, NCF1, and NCF2, respectively). Mutations in any of these genes can result in chronic granulomatous disease, a primary immunodeficiency characterized by recurrent infections. Using evolutionary mapping, we determined that episodes of adaptive natural selection have shaped the extracellular portion of gp91-phox during the evolution of mammals, which suggests that this region may have a function in host-pathogen interactions. On the basis of a resequencing analysis of approximately 35 kb of CYBB, CYBA, NCF2, and NCF4 in 102 ethnically diverse individuals (24 of African ancestry, 31 of European ancestry, 24 of Asian/Oceanians, and 23 US Hispanics), we show that the pattern of CYBA diversity is compatible with balancing natural selection, perhaps mediated by catalase-positive pathogens. NCF2 in Asian populations shows a pattern of diversity characterized by a differentiated haplotype structure. Our study provides insight into the role of pathogen-driven natural selection in an innate immune pathway and sheds light on the role of CYBA in endothelial, nonphagocytic NADPH oxidases, which are relevant in the pathogenesis of cardiovascular and other complex diseases.

Abstract 2553: Characterization of rare germline variants in somatically mutated melanoma genes in melanoma-prone families

CDKN2A and CDK4 are the two major susceptibility genes for melanoma identified so far. However, these two genes only account for melanoma susceptibility in a small proportion of melanoma-prone families, suggesting the existence of other susceptibility genes. In addition, melanoma is among the tumors with the highest mutation rate and a large number of mutated genes have been identified that affect multiple key biological pathways. The goal of this study is to examine whether rare germline sequence variants and/or copy number variations (CNVs) in these genes may influence melanoma risk in melanoma-prone families without known CDKN2A/CDK4 mutations. Methods: We conducted exome sequencing in blood-derived DNA in 75 melanoma cases from 23 American melanoma families with ≥3 affected members. We evaluated rare non-synonymous variants, defined as allele frequency less than 0.1% reported in public databases (dbSNP, 1000 Genomes, or NHLBI's Exome Variant Server), in 37 genes (including BRAF, NRAS, KIT,PTEN, CDKN2A, GRIN2A, etc.) that are frequently mutated in melanoma. We also screened CNVs in these genes using data from the Nimblegen 3x720k exon-focused CGH tiling arrays, in which blood-derived DNA from 79 melanoma cases and 25 spouses were analyzed in the same mutation-negative families. We used the Nexus Copy Number™ built-in FASST2 algorithm to identify significant CNVs (significant threshold=0.000001; minimal number of probes per segment=5; log2 ratio&gt;0.3 for gains and -0.3 for losses). Results: We identified 10 rare variants in 10 genes that showed partial/complete co-segregation with disease and were absent in our internal controls (N∼400). Four of these variants occurred in all cases within their respective families and 3 of them were novel. We did not identify any disease-related CNVs in these genes except for a deletion in exon 1β of CDKN2A/ p14ARF in 6 out of 7 melanoma cases in one big family. Our findings suggest that rare variants in somatically mutated genes may confer susceptibility to melanoma risk in a subset of families. However, these variants need to be validated, checked for functional relevance, and evaluated in a large number of cases and controls to determine their role in disease susceptibility.

Citation Format: Xiaohong (Rose) Yang, Laura Burke, Kevin Jacobs, Michael Cullen, Joseph Boland, Laurie Burdett, Michael Malasky, Melissa Rotunno, Meredith Yeager, Stephen Chanock, Margaret Tucker, Alisa Goldstein. Characterization of rare germline variants in somatically mutated melanoma genes in melanoma-prone families. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2553. doi:10.1158/1538-7445.AM2013-2553

Common genetic polymorphisms modify the effect of smoking on absolute risk of bladder cancer

Bladder cancer results from the combined effects of environmental and genetic factors, smoking being the strongest risk factor. Evaluating absolute risks resulting from the joint effects of smoking and genetic factors is critical to assess the public health relevance of genetic information. Analyses included up to 3,942 cases and 5,680 controls of European background in seven studies. We tested for multiplicative and additive interactions between smoking and 12 susceptibility loci, individually and combined as a polygenic risk score (PRS). Thirty-year absolute risks and risk differences by levels of the PRS were estimated for U.S. males aged 50 years. Six of 12 variants showed significant additive gene-environment interactions, most notably NAT2 (P = 7 × 10(-4)) and UGT1A6 (P = 8 × 10(-4)). The 30-year absolute risk of bladder cancer in U.S. males was 6.2% for all current smokers. This risk ranged from 2.9% for current smokers in the lowest quartile of the PRS to 9.9% for current smokers in the upper quartile. Risk difference estimates indicated that 8,200 cases would be prevented if elimination of smoking occurred in 100,000 men in the upper PRS quartile compared with 2,000 cases prevented by a similar effort in the lowest PRS quartile (P(additive) = 1 × 10(-4)). Thus, the potential impact of eliminating smoking on the number of bladder cancer cases prevented is larger for individuals at higher than lower genetic risk. Our findings could have implications for targeted prevention strategies. However, other smoking-related diseases, as well as practical and ethical considerations, need to be considered before any recommendations could be made.

Genetic variants in DNA repair pathway genes and risk of esophageal squamous cell carcinoma and gastric adenocarcinoma in a Chinese population

The DNA repair pathways help to maintain genomic integrity and therefore genetic variation in the pathways could affect the propensity to develop cancer. Selected germline single nucleotide polymorphisms (SNPs) in the pathways have been associated with esophageal cancer and gastric cancer (GC) but few studies have comprehensively examined the pathway genes. We aimed to investigate associations between DNA repair pathway genes and risk of esophageal squamous cell carcinoma (ESCC) and GC, using data from a genome-wide association study in a Han Chinese population where ESCC and GC are the predominant cancers. In sum, 1942 ESCC cases, 1758 GC cases and 2111 controls from the Shanxi Upper Gastrointestinal Cancer Genetics Project (discovery set) and the Linxian Nutrition Intervention Trials (replication set) were genotyped for 1675 SNPs in 170 DNA repair-related genes. Logistic regression models were applied to evaluate SNP-level associations. Gene- and pathway-level associations were determined using the resampling-based adaptive rank-truncated product approach. The DNA repair pathways overall were significantly associated with risk of ESCC (P = 6.37 × 10(-4)), but not with GC (P = 0.20). The most significant gene in ESCC was CHEK2 (P = 2.00 × 10(-6)) and in GC was CLK2 (P = 3.02 × 10(-4)). We observed several other genes significantly associated with either ESCC (SMUG1, TDG, TP53, GTF2H3, FEN1, POLQ, HEL308, RAD54B, MPG, FANCE and BRCA1) or GC risk (MRE11A, RAD54L and POLE) (P < 0.05). We provide evidence for an association between specific genes in the DNA repair pathways and the risk of ESCC and GC. Further studies are warranted to validate these associations and to investigate underlying mechanisms.

Genetic variants in sex hormone metabolic pathway genes and risk of esophageal squamous cell carcinoma

In China, esophageal cancer is the fourth leading cause of cancer death where essentially all cases are histologically esophageal squamous cell carcinoma (ESCC), in contrast to esophageal adenocarcinoma in the West. Globally, ESCC is 2.4 times more common among men than women and recently it has been suggested that sex hormones may be associated with the risk of ESCC. We examined the association between genetic variants in sex hormone metabolic genes and ESCC risk in a population from north central China with high-incidence rates. A total of 1026 ESCC cases and 1452 controls were genotyped for 797 unique tag single-nucleotide polymorphisms (SNPs) in 51 sex hormone metabolic genes. SNP-, gene- and pathway-based associations with ESCC risk were evaluated using unconditional logistic regression adjusted for age, sex and geographical location and the adaptive rank truncated product (ARTP) method. Statistical significance was determined through use of permutation for pathway- and gene-based associations. No associations were observed for the overall sex hormone metabolic pathway (P = 0.14) or subpathways (androgen synthesis: P = 0.30, estrogen synthesis: P = 0.15 and estrogen removal: P = 0.19) with risk of ESCC. However, six individual genes (including SULT2B1, CYP1B1, CYP3A7, CYP3A5, SHBG and CYP11A1) were significantly associated with ESCC risk (P < 0.05). Our examination of genetic variation in the sex hormone metabolic pathway is consistent with a potential association with risk of ESCC. These positive findings warrant further evaluation in relation to ESCC risk and replication in other populations.

Germline mutations of regulator of telomere elongation helicase 1, RTEL1, in Dyskeratosis congenita

Dyskeratosis congenita (DC) is an inherited bone marrow failure and cancer predisposition syndrome caused by aberrant telomere biology. The classic triad of dysplastic nails, abnormal skin pigmentation, and oral leukoplakia is diagnostic of DC, but substantial clinical heterogeneity exists; the clinically severe variant Hoyeraal Hreidarsson syndrome (HH) also includes cerebellar hypoplasia, severe immunodeficiency, enteropathy, and intrauterine growth retardation. Germline mutations in telomere biology genes account for approximately one-half of known DC families. Using exome sequencing, we identified mutations in RTEL1, a helicase with critical telomeric functions, in two families with HH. In the first family, two siblings with HH and very short telomeres inherited a premature stop codon from their mother who has short telomeres. The proband from the second family has HH and inherited a premature stop codon in RTEL1 from his father and a missense mutation from his mother, who also has short telomeres. In addition, inheritance of only the missense mutation led to very short telomeres in the proband's brother. Targeted sequencing identified a different RTEL1 missense mutation in one additional DC proband who has bone marrow failure and short telomeres. Both missense mutations affect the helicase domain of RTEL1, and three in silico prediction algorithms suggest that they are likely deleterious. The nonsense mutations both cause truncation of the RTEL1 protein, resulting in loss of the PIP box; this may abrogate an important protein-protein interaction. These findings implicate a new telomere biology gene, RTEL1, in the etiology of DC.

Genome-wide association analysis identifies new lung cancer susceptibility loci in never-smoking women in Asia

To identify common genetic variants that contribute to lung cancer susceptibility, we conducted a multistage genome-wide association study of lung cancer in Asian women who never smoked. We scanned 5,510 never-smoking female lung cancer cases and 4,544 controls drawn from 14 studies from mainland China, South Korea, Japan, Singapore, Taiwan and Hong Kong. We genotyped the most promising variants (associated at P < 5 × 10(-6)) in an additional 1,099 cases and 2,913 controls. We identified three new susceptibility loci at 10q25.2 (rs7086803, P = 3.54 × 10(-18)), 6q22.2 (rs9387478, P = 4.14 × 10(-10)) and 6p21.32 (rs2395185, P = 9.51 × 10(-9)). We also confirmed associations reported for loci at 5p15.33 and 3q28 and a recently reported finding at 17q24.3. We observed no evidence of association for lung cancer at 15q25 in never-smoking women in Asia, providing strong evidence that this locus is not associated with lung cancer independent of smoking.

Evaluation of novel renal biomarkers with a cisplatin model of kidney injury: gender and dosage differences

A number of novel urinary biomarkers have been identified and partially qualified for use as markers for renal injury in rats. We use two novel multiplex assays to quantify biomarker concentration in multiple urine collections made prior to and following administration of cisplatin, a common nephrotoxicant, to rats. We investigate the correlation of the magnitude of biomarker changes with the severity of histopathological observations and explore the relationship of these to both dose and sex. The novel biomarkers evaluated are urinary albumin, alpha glutathione s-transferase (α-GST), glutathione S-transferase-yb1 (GSTYb1), lipocalin-2, kidney injury molecule-1 (KIM-1), osteopontin, and renal papillary antigen 1 (RPA-1) and plasma cystatin C, alongside the traditional biomarkers of plasma urea, creatinine, and urinary n-acetyl-beta-d-glucosaminidase (NAG), total protein, and glucose. We show for all time points, and for almost all doses, that male rats consistently had either more severely graded or a higher incidence of histologically observed lesions than females; that changes in urinary glucose, total urinary protein, NAG, and the novel urinary biomarkers albumin, osteopontin, and KIM-1 are clearly temporally associated; and that changes are related to the severity of injury. We also found that receiver operating characteristic curve analysis and area under the curve are significantly higher than urea or creatinine for all new biomarkers except aGST, GSTYb1, cystatin c, and total protein in both sexes.