Citations

Abstract Background: Common cancers develop through a multistep process often including inherited susceptibility. Collaboration among multiple institutions, and funding from multiple sources, has allowed the development of an inexpensive genotyping microarray, the OncoArray. The array includes a genome-wide backbone, comprising 230,000 SNPs tagging most common genetic variants, together with dense mapping of known susceptibility regions, rare variants from sequencing experiments, pharmacogenetic markers, and cancer-related traits. Methods: The OncoArray can be genotyped using a novel technology developed by Illumina to facilitate efficient genotyping. The consortium developed standard approaches for selecting SNPs for study, for quality control of markers, and for ancestry analysis. The array was genotyped at selected sites and with prespecified replicate samples to permit evaluation of genotyping accuracy among centers and by ethnic background. Results: The OncoArray consortium genotyped 447,705 samples. A total of 494,763 SNPs passed quality control steps with a sample success rate of 97% of the samples. Participating sites performed ancestry analysis using a common set of markers and a scoring algorithm based on principal components analysis. Conclusions: Results from these analyses will enable researchers to identify new susceptibility loci, perform fine-mapping of new or known loci associated with either single or multiple cancers, assess the degree of overlap in cancer causation and pleiotropic effects of loci that have been identified for disease-specific risk, and jointly model genetic, environmental, and lifestyle-related exposures. Impact: Ongoing analyses will shed light on etiology and risk assessment for many types of cancer. Cancer Epidemiol Biomarkers Prev; 26(1); 126–35. ©2016 AACR.

Abstract Known gene mutations account for approximately 50% of the hereditary risk for breast cancer. Moderate and low penetrance variants, discovered by genomic approaches, account for an as-yet-unknown proportion of the remaining heritability. A truncating mutation c.325C>T:p.Arg109* (R109X) in the ATP-dependent helicase ERCC3 was observed recurrently among exomes sequenced in BRCA wild-type, breast cancer–affected individuals of Ashkenazi Jewish ancestry. Modeling of the mutation in ERCC3-deficient or CRISPR/Cas9-edited cell lines showed a consistent pattern of reduced expression of the protein and concomitant hypomorphic functionality when challenged with UVC exposure or treatment with the DNA alkylating agent IlludinS. Overexpressing the mutant protein in ERCC3-deficient cells only partially rescued their DNA repair–deficient phenotype. Comparison of frequency of this recurrent mutation in over 6,500 chromosomes of breast cancer cases and 6,800 Ashkenazi controls showed significant association with breast cancer risk (ORBC = 1.53, ORER+ = 1.73), particularly for the estrogen receptor–positive subset (P < 0.007). Significance: A functionally significant recurrent ERCC3 mutation increased the risk for breast cancer in a genetic isolate. Mutated cell lines showed lower survival after in vitro exposure to DNA-damaging agents. Thus, similar to tumors arising in the background of homologous repair defects, mutations in nucleotide excision repair genes such as ERCC3 could constitute potential therapeutic targets in a subset of hereditary breast cancers. Cancer Discov; 6(11); 1267–75. ©2016 AACR. This article is highlighted in the In This Issue feature, p. 1197

Purpose Massively parallel sequencing allows simultaneous testing of multiple genes associated with cancer susceptibility. Guidelines are available for variant classification; however, interpretation of these guidelines by laboratories and providers may differ and lead to conflicting reporting and, potentially, to inappropriate medical management. We describe conflicting variant interpretations between Clinical Laboratory Improvement Amendments–approved commercial clinical laboratories, as reported to the Prospective Registry of Multiplex Testing (PROMPT), an online genetic registry. Methods Clinical data and genetic testing results were gathered from 1,191 individuals tested for inherited cancer susceptibility and self-enrolled in PROMPT between September 2014 and October 2015. Overall, 518 participants (603 genetic variants) had a result interpreted by more than one laboratory, including at least one submitted to ClinVar, and these were used as the final cohort for the current analysis. Results Of the 603 variants, 221 (37%) were classified as a variant of uncertain significance (VUS), 191 (32%) as pathogenic, and 34 (6%) as benign. The interpretation differed among reporting laboratories for 155 (26%). Conflicting interpretations were most frequently reported for CHEK2 and ATM, followed by RAD51C, PALB2, BARD1, NBN, and BRIP1. Among all participants, 56 of 518 (11%) had a variant with conflicting interpretations ranging from pathogenic/likely pathogenic to VUS, a discrepancy that may alter medical management. Conclusions Conflicting interpretation of genetic findings from multiplex panel testing used in clinical practice is frequent and may have implications for medical management decisions.

Abstract Background: Known gene mutations account for approximately 50% of the risk for breast cancer. However, a considerable fraction of heritable risk remains unexplained. Fifteen percent of the risk is accounted for by BRCA1/2 and another 3% by TP53, PTEN, LKB1 and CDH1. CHEK2, ATM, PALB2, BRIP1, RAD51C, RAD51D and BARD1 account for 4%, while SNPs discovered from large multicenter genome-wide association studies explain another 14% of the heritable risk. Founder mutations in the DNA repair pathway genes such as BRCA1 and BRCA2 account for the majority of AJ breast cancer mutations. Methods: We performed exome sequencing of 49 early onset (age <35) breast cancer cases, and 85 BRCA wild type familial breast cancer cases, all of Ashkenazi Jewish (AJ) from the New York City area. A recurrent truncating mutation was then analyzed in 3131 breast cancer cases and 2716 unaffected women of Ashkenazi ancestry from New York and Israel. Using CRISPR and overexpression systems on the human mammary epithelial cell line HMLE, transcript and protein levels were assayed for the mutant and compared to wild-type. Treatment with IlludinS and UVC were performed to assess DNA damage response. Finally, clonogenic survival assay was also performed. Results: Amongst the DNA repair pathway genes, exome sequencing revealed a heterozygous recurrent truncating mutation in ERCC3 (R109X) in 2 of 49 early onset breast cancer cases of AJ ancestry and 4 familial AJ probands. Taqman genotyping in a case control setting from New York and Israel revealed 54 mutation carriers in 3131 cases and 32 in the 2716 controls. In total, there were 60 heterozygotes detected in 3209 cases and 32 in 2716 controls [OR 1.59 (95% CI 1.01-2.50)]; p = 0.02 Fisher one- tailed). Functional studies using CRISPR and overexpression systems on human mammary epithelial cells, show that the mutation results in lower transcript levels and this reduction is effected by nonsense mediated decay of the mutant transcript. Western blotting showed that the mutation resulted in a smaller protein (∼12kDa). Clonogenic assays showed similar survival rate of mutant and wildtype under UVC exposure, however the mutant cell line showed significantly smaller colony size demonstrating a growth disadvantage that was further increased upon DNA damage. Treatment with fungal sesquiterpene IlludinS, a known sensitizer to mutant ERCC3 cell lines, showed drastically reduced survival when compared to the wild type human mammary epithelial cells. Conclusions: We demonstrate that ERCC3 is a moderate risk gene for breast cancer in individuals of Ashkenazi ancestry. ERCC3 is somatically mutated in multiple cancers including breast, ovarian and pancreatic cancers, however its role as a cancer susceptibility gene requires further elucidation. Additional functional and population genetic studies to further characterize this novel ERCC3 variant are underway. Citation Format: Joseph Vijai, Sabine Topka, Kara Maxwell, Vignesh Ravichandran, Tinu Thomas, Danylo Villano, Ann Maria, Pragna Gaddam, Anne Lincoln, Steven Hart, Susan Neuhausen, Mark Robson, Jeffrey Weitzel, Mark Daly, Katherine Nathanson, Fergus Couch, Gadi Rennert, Kenneth Offit. ERCC3 R109X is a moderate risk breast cancer risk variant in Ashkenazi Jews. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 796.

Abstract Sequencing tests assaying panels of genes or whole exomes are widely available for cancer risk evaluation. However, methods for classification of variants resulting from this testing are not well studied. We evaluated the ability of American College of Medical Genetics and Genomics (ACMG) guidelines to define the rate of mutations and variants of uncertain significance (VUS) in 180 medically relevant genes, including all ACMG designated reportable cancer and non-cancer genes, in individuals who met guidelines for hereditary cancer risk evaluation. We performed whole exome sequencing in 404 individuals in 257 families and classified 1640 variants from these genes. Potentially clinically actionable (likely-pathogenic/pathogenic, LP/P) versus nonactionable (VUS/likely-benign/benign) calls were 92% and 88% concordant with locus specific databases and Clinvar, respectively. LP/P mutations were identified in 11 of 25 breast cancer susceptibility genes in 27 BRCA1/2 negative families (11%). Evaluation of 84 additional autosomal dominant cancer susceptibility genes identified LP/P mutations in only four additional families (1.7%), suggesting they do not influence risk in this cohort. However, individuals from nine of 257 families (3.5%) had incidental LP/P mutations in 32 non-cancer disease genes, and 7% of individuals were monoallelic carriers of an LP/P mutation in 39 autosomal recessive cancer syndrome genes. Furthermore, 90% of individuals had at least one VUS. In summary, these data support the clinical utility of ACMG variant classification guidelines. In addition, evaluation of extended panels of cancer genes in breast/ovarian cancer families leads to only an incremental clinical benefit but substantially increases the complexity of the results. Citation Format: Kara N. Maxwell, Steven N. Hart, Joseph Vijai, Kasmintan A. Schrader, Tinu Thomas, Bradley Wubbenhorst, Vignesh Ravichandran, Raymond M. Moore, Chunling Hu, Lucia Guidugli, Brandon Wenz, Thomas P. Slavin, Susan M. Domchek, Mark E. Robson, Csilla Szabo, Susan L. Neuhausen, Jeffrey N. Weitzel, Kenneth Offit, Fergus J. Couch, Katherine L. Nathanson. Evaluation of ACMG guideline classified variants in 180 cancer and incidental non-cancer genes in families with breast/ovarian cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5220.

Abstract Women who carry a pathogenic mutation in the BRCA1 or BRCA2 gene are at high risk of breast (BC) and ovarian cancer (OC). Their clinical management usually includes invasive risk-reducing interventions with substantial side effects. Improved personalized cancer risk estimates may help to identify women at particularly high risk or with high risk of disease at early ages who may benefit from early intervention as well as women at lower risk who may opt to delay surgery or chemoprevention. Genome-wide association studies have identified >100 common genetic variants that are associated with BC or OC risks. Several of these variants are also individually associated with risk of BC or OC for BRCA1 and BRCA2 mutation carriers. However, no study has evaluated the combined effects of all the known common genetic variants on BC or OC risk for BRCA1/2 mutation carriers. We constructed polygenic risk scores (PRS) based on results of genetic association studies conducted in the general population. Each PRS was formed by the sum of the number of risk alleles across the variants weighted by their log-Odds Ratio estimate from population-based studies of BC or OC. We investigated 3 PRS for BC (overall, estrogen receptor (ER) positive, and ER-negative) and one PRS for OC. We used data for 15,252 BRCA1 and 8,211 BRCA2 female carriers. The association of each PRS with BC or OC risk was evaluated using a weighted cohort analysis with time to diagnosis as the outcome and estimated the Hazard Ratios (HR) per standard deviation increase in the PRS. All PRS were significantly associated with cancer risks for BRCA1/2 carriers. The PRS for ER-negative BC displayed the strongest association with BC risk in BRCA1 carriers (HR = 1.29 [1.25-1.33], p = 8×10−64). In BRCA2 carriers, the strongest association was seen for the overall BC PRS (HR = 1.26 [1.21-1.31], p = 3×10−27). The OC PRS was strongly associated with OC risk for both BRCA1 and BRCA2 carriers. These relative risks translate to large differences in absolute risks for carriers: e.g., the OC risk was 6% by age 80 for BRCA2 carriers at the 10th percentile of the OC PRS compared with 19% risk for those at the 90th percentile of PRS. Our findings demonstrate that BC and OC PRS derived from studies in the general population are predictive of cancer risks in BRCA1 and BRCA2 carriers. Incorporation of the PRS into risk prediction models would improve risk prediction and hence inform decisions on cancer risk management. Citation Format: Karoline Kuchenbaecker, Jacques Simard, Kenneth Offit, Fergus J. Couch, Douglas F. Easton, Georgia Chenevix-Trench, Antonis C. Antoniou, Consortium of Investigators of Modifiers of BRCA1/2. Predicting breast and ovarian cancer risks for BRCA1 and BRCA2 mutation carriers using polygenic risk scores. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2598.

Abstract 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<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

Abstract Germline mutations of BRCA1 and BRCA2 underlie joint susceptibility to breast and ovarian cancers, but do not account for all cases. Genome wide association studies show little overlap between common variants associated with breast and ovarian cancer susceptibility, whereas rare variants in genes initially identified as breast cancer susceptibility genes also confer susceptibility to ovarian cancer cases, unselected for breast cancer. Ovarian and breast tumors also are observed in Peutz-Jeghers and possibly in Lynch syndrome. To further elucidate rare germline susceptibilities for breast and ovarian cancer, we have ascertained a unique cohort of 90 BRCA1/2-negative probands with a personal history of breast cancer and ovarian/fallopian tube/peritoneal cancer, unselected for family history. Cases are from the clinical genetics services of Memorial Sloan-Kettering Cancer Center and University of Pennsylvania. Analysis is ongoing using both targeted and exome sequencing approaches. Germline DNA of 69 cases will be subjected to whole exome sequencing. A total of 21 additional cases will undergo targeted sequencing for 28 genes (8 cases) and an extended panel of 54 genes (13 cases). The majority of ovarian cancers are high-grade serous epithelial ovarian carcinoma (n=51), in combination with invasive ductal or DCIS (n=36), invasive lobular (n=4), or unspecified (n=11) breast cancers. The remaining ovarian subgroups comprise other epithelial subtypes; endometrioid (n=9), clear cell (n=3), mucinous and low-grade serous (n=3) and non-epithelial (n=4) or unclassified (n=20), in combination with invasive ductal or DCIS (n=21), invasive lobular (n=5) or unspecified (n=13) breast cancers. Preliminary analysis of the targeted set of genes in 69 cases, reveals 43 predicted pathogenic coding or splice site variants; 17 of which are within PALB2, MSH2, MSH6, BARD1, FANCE, CDKN2A, TP53, SETD2, SIRT1, BRIP1, RAD50, and RAD51D and are not seen in dbSNP138, 1000 Genomes or Exome Variant Server ESP6500 and 26 variants with reported frequencies in MUTYH, MSH6, MLH1, FAM175A, RAD50, UIMC1, JARID2, PHF3, SIRT1, MRE11A, ATM, BRCA2, TP53BP1, CDH1, RAD51D, BRCA1, BABAM1 of less than 1% allele frequency in public databases. Analysis of these variants across and within histologic subtypes is being undertaken to look for specific genotype-phenotype correlations. Analysis of novel candidate genes and pathways by co-segregation, functional analysis, as well as external replication is underway to determine whether shared rare variants, mutated genes, or altered pathways confer cancer susceptibility in this cohort. Germline susceptibility to breast and ovarian cancer is heterogenous and remains a critical research and clinical question. Improved understanding of the susceptibility genetics will allow further examination of the utility of targeted cancer prevention strategies in those who are found to be at risk. Citation Format: Kasmintan A. Schrader, Kara N. Maxwell, Joseph Vijai, Steven Hart, Tinu Thomas, Bradley Wubbenhorst, Lucia Guidugli, Robert Klein, Marina Corines, Liying Zhang, Susan Neuhausen, Jeffrey Weitzel, Namrata Gupta, Larry Norton, Clifford Hudis, Gad Getz, Mark Daly, Steven Lipkin, David Altshuler, Fergus Couch, Katherine Nathanson, Kenneth Offit. Determination of cancer susceptibility in probands with breast and ovarian cancer. [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 3282. doi:10.1158/1538-7445.AM2014-3282

Abstract Massively parallel next generation sequencing data (NGS) has proved to be useful in identification of rare Mendelian disorders. Efforts are on-going to use NGS for discovery of novel rare variants in common disease etiology. Distinguishing rare private mutations from causal variants remains a major challenge in complex disorders. With decreasing cost, investigators are generating NGS data for common cancers. However, power and other considerations suggest that a consortia approach of pooling data is more likely to succeed where individual efforts fail. Combining data within such consortia brings its own level of challenges. We enumerate these challenges and suggest recommendations based on our experience of combining and harmonizing NGS data on 358 breast cancer samples from four centers; (City of Hope n=8, Mayo Clinic n=221, MSKCC n=96 and University of Pennsylvania n=33). Major concerns were ability of individual datasets to discover known and novel variations, depth of coverage across the exome, and quality of variants. Using pre- and post-processed data, we demonstrate an increased power for detecting variants when using a joint-calling method, quality control (QC) and quality assurance pre- and post-merge, as well as the advantages of combined annotations and filtering procedures. To generate a filtered list of high confident calls, we subset the data on Depth per Allele (DP), Genotyping Quality (GQ), Allele balance, Phred likelihood score (PL) as well as using frequency filters on the alternate allele both within the data and comparing against convenience control summaries. We describe general principles and QC measures to be adopted when NGS data is used from diverse sources, specifically applicable to large consortia. Note: This abstract was not presented at the meeting. Citation Format: Joseph Vijai, Steven Hart, Tinu Thomas, Bradley Wubbenhorst, Lucia Guidugli, Kasmintan Schrader, Kara Maxwell, Lauren Jacobs, Danylo Villano, Robert Klein, Steven Lipkin, Susan Neuhausen, Jeffrey Weitzel, David Altshuler, Fergus Couch, Kenneth Offit, Katherine Nathanson. Harmonization of next generation sequencing data within consortia for gene discovery in familial breast cancer. [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 2378. doi:10.1158/1538-7445.AM2014-2378