Differences In Copy Number Variation Research Articles

Identification of a novel eighteen-gene signature of recurrent metastasis neuroblastoma.

Neuroblastoma is the most common malignant tumor in childhood, and metastases occur in more than 30% patients. Recurrent metastasis is the main cause of poor prognosis and high mortality in neuroblastoma. In this regard, there is still a lack of sufficient biomarkers and effective therapies. Therefore, we performed a multi-omics analysis of neuroblastoma patients from Therapeutically Applicable Research To Generate Effective Treatments (TARGET). With clinical relapse site information, tumor samples derived from the primary site were divided into recurrent metastasis and primary tumor groups. The initial gene signature was obtained by comparing RNA-Seq and copy number variation differences. Survival data was used to further filter prognosis-related genes. This 18-gene signature consists of three clusters: tumor suppression, cell proliferation, and immunity. A super enhancer is involved in the enhanced expression of NCAPG in cluster2 together with IRF3. Based on the gene signature expression in primary neuroblastoma, it is possible to predict tumor metastasis before it occurs. According to the anticancer drug dataset of Genomics of Drug Sensitivity in Cancer (GDSC), vinorelbine and docetaxel were predicted to have high sensitivity against recurrent metastatic neuroblastoma. In conclusion, our study offers a novel metastasis biomarker and helps understand the mechanisms of tumor recurrent metastasis. KEY MESSAGES: We identified a novel eighteen-gene signature of recurrent metastasis neuroblastoma and build risk and classification models. We dissected the regulatory role of NCAPG in signatures. We found immune exhaustion and immunosuppression in recurrent metastasis neuroblastoma. Vinorelbine and docetaxel were predicted to have high sensitivity against recurrent metastatic neuroblastoma.

Identification and Validation of an Endoplasmic Reticulum Stress-Related lncRNA Signature for Colon Adenocarcinoma Patients.

PurposeEndoplasmic reticulum (ER) stress has a significant effect on cancer cells. Increasing numbers of studies indicate that long non-coding RNAs (lncRNAs) promote the development of colon adenocarcinoma (COAD), but the relationship between ER stress-related lncRNAs and the prognosis of COAD remains unclear. The aim of the current study was to construct and validate an ER stress-related lncRNA prognostic signature to predict COAD prognoses.MethodsGene expression data and clinical information from the Cancer Genome Atlas and the Gene Expression Omnibus with COAD were downloaded and analyzed. Cox regression and least absolute shrinkage and selection operator regression were then used to develop an ER stress-related lncRNA signature. COAD patients were then divided into high-risk and low-risk groups based on the median risk score to analyze prognoses. Tumor mutation burdens (TMBs) and the differences in copy number variations (CNVs) between the two groups were also analyzed. Lastly, gene set enrichment analysis (GSEA) was used to explore the enrichment pathways and biological processes associated with differentially expressed genes in the high-risk and low-risk groups, and lncRNA expression in the model was validated via quantitative real-time PCR in colon cancer and paracancerous tissues.ResultsA signature including 8 ER stress-related lncRNAs was constructed. COAD prognoses were significantly poorer in the high-risk group than in the low-risk group. There were few differences in TMBs and CNVs between the two groups. In GSEA analysis, in the high-risk group highly expressed genes associated with extracellular matrix pathways were significantly enriched.ConclusionThe 8-ER stress-related lncRNA derived from the present study is a potential indicator of COAD prognosis.

Rapid Production and Genetic Stability of Human Mesenchymal Progenitor Cells Derived from Human Somatic Cell Nuclear Transfer-Derived Pluripotent Stem Cells.

Pluripotent stem cell-derived mesenchymal progenitor cells (PSC-MPCs) are primarily derived through two main methods: three-dimensional (3D) embryoid body-platform (EB formation) and the 2D direct differentiation method. We recently established somatic cell nuclear transfer (SCNT)-PSC lines and showed their stemness. In the present study, we produced SCNT-PSC-MPCs using a novel direct differentiation method, and the characteristics, gene expression, and genetic stability of these MPCs were compared with those derived through EB formation. The recovery and purification of SCNT-PSC-Direct-MPCs were significantly accelerated compared to those of the SCNT-PSC-EB-MPCs, but both types of MPCs expressed typical surface markers and exhibited similar proliferation and differentiation potentials. Additionally, the analysis of gene expression patterns using microarrays showed very similar patterns. Moreover, array CGH analysis showed that both SCNT-PSC-Direct-MPCs and SCNT-PSC-EB-MPCs exhibited no significant differences in copy number variation (CNV) or single-nucleotide polymorphism (SNP) frequency. These results indicate that SCNT-PSC-Direct-MPCs exhibited high genetic stability even after rapid differentiation into MPCs, and the rate at which directly derived MPCs reached a sufficient number was higher than that of MPCs derived through the EB method. Therefore, we suggest that the direct method of differentiating MPCs from SCNT-PSCs can improve the efficacy of SCNT-PSCs applied to allogeneic transplantation.

Difference of copy number variation in blood of patients with lung cancer.

Lung cancer is the leading cause of cancer-related deaths worldwide. Copy number variation (CNV) in several genetic regions correlate with cancer susceptibility. Hence, this study evaluated the association between CNV and non-small cell lung cancer (NSCLC) in the peripheral blood. Blood samples of 150 patients with NSCLC and 150 normal controls were obtained from a bioresource center (Seoul, Korea). Through an epigenome-wide analysis using the MethylationEPIC BeadChip method, we extracted CNVs by using an SVS8 software-supplied multivariate method. We compared CNV frequencies between the NSCLC and controls, and then performed stratification analyses according to smoking status. We acquired 979 CNVs, with 582 and 967 copy-number gains and losses, respectively. We identified five nominally significant associations (ACOT1, NAA60, GSDMD, HLA-DPA1, and SLC35B3 genes). Among the current smokers, the NSCLC group had more CNV losses and gains at the GSDMD gene in chromosome 8 (P=0.02) and at the ACOT1 gene in chromosome 14 (P=0.03) than the control group. It also had more CNV losses at the NAA60 gene in chromosome 16 (P=0.03) among non-smokers. In the NSCLC group, current smokers had more CNV gains and losses at the ACOT1 gene in chromosome 14 (P=0.003) and at HLA-DPA1 gene in chromosome 6 (P=0.02), respectively, than non-smokers. Five nominally significant associations were found between the NSCLC and CNVs. CNVs are associated with the mechanism of lung cancer development. However, the role of CNVs in lung cancer development needs further investigation.

A case-control study to identify molecular risk factors for local recurrence in young breast cancer patients

PurposeTo investigate risk factors for local recurrence (LR) after breast conserving therapy in young breast cancer patients randomized in the “Young Boost Trial”. Material & methodsIn the “Young Boost Trial” 2421 patients ≤50 years old were randomized between a 16 Gy and 26 Gy boost after breast conserving surgery and whole breast radiation (50 Gy). We performed a case-control study comparing patients who developed a LR (cases) and for each of them three control patients free of recurrence (controls). Clinicopathological factors, copy number- and gene expression profiles of primary tumors were compared between cases and controls, and between primary tumors and local recurrences. ResultsThe cumulative 5-year LR rate was 1.07% (95% CI 0.72-1.59%) and 10-year LR rate 2.56% (1.81–3.62%). Analysis of a subset of primary tumors and local recurrences showed similar histopathological characteristics (n = 15), copy number (n = 13) and gene expression profiles (n = 14). Basal subtype was strongly associated with LR in univariable and multivariable analysis. Gains of CCND1 were identified more frequently among controls, while more frequent gains of FGFR1 and IGF1R were observed among cases. Upregulation of genes involved in the p53-pathway was observed in recurring tumors compared to non-recurring tumors. We could not identify a genomic classifier for LR. ConclusionsAll investigated local recurrences were true genomic recurrences. Although differences in copy number variation and gene expression pathways were observed in recurring tumors compared to non-recurring tumors, no genomic classifier for LR could be identified.

Ependymoma relapse goes along with a relatively stable epigenome, but a severely altered tumor morphology.

The molecular biology of ependymomas is not well understood and this is particularly true for ependymoma relapses. We aimed at finding out if and to which extent, relapses differ from their corresponding primary tumors on the morphological, chromosomal and epigenetic level. We investigated 24 matched ependymoma primary and relapsed tumor samples and, as a first step, compared cell density, necrosis, vessel proliferation, Ki67 proliferative index, trimethylation at H3K27 and expression of CXorf67. For the investigation of global methylation profiles, we used public data in order to analyze copy number variation profiles, differential methylation, methylation status and fractions of hypo‐ and hypermethylated CpGs in different epigenomic substructures. Morphologically, we found a significant increase with relapse in cell density and proliferation. H3K27 trimethylation and CXorf67 expression remained stable between primary and relapse tumor samples, and the analysis of DNA methylation profiles neither revealed significant differences in copy number variations nor differentially methylated regions. Significant differences in the methylation status were found for CpG islands, but also in N Shelves or S Shelves, depending on the molecular subgroup. The fraction of probes changing their methylation in the epigenomic substructures appeared subgroup‐specific. Most changes occur in CpG islands, for which relapsed tumors demonstrate higher methylation values than primary tumors. The morphological differences reflect increased aggressiveness upon ependymoma relapse, but, despite slight changes, this observation does not appear to be sufficiently explained by epigenetic changes.

Genome‑wide copy number analysis of circulating tumor cells in breast cancer patients with liver metastasis.

The genome-wide copy number analysis of circulating tumor cells (CTCs) provides a promising prognostic biomarker for survival in breast cancer liver metastasis (BCLM) patients. The present study aimed to confirm the prognostic value of the presence of CTCs in BCLM patients. We previously developed an assay for the genome-wide pattern differences in copy number variations (CNVs) as an adjunct test for the routine imaging and histopathologic diagnosis methods to distinguish newly diagnosed liver metastases and recurrent liver metastases. Forty-three breast cancer patients were selected for this study in which 23 newly diagnosed and 20 recurrent liver metastases were diagnosed by histopathology and 18F-FDG PET/CT imaging. CTCs were counted from all patients using the CellSearch system and were confirmed by cytomorphology and three-color immunocytochemistry. Genomic DNA of single CTCs was amplified using multiple annealing and looping based amplification cycles (MALBAC). Then, we compared the CTC numbers of newly diagnosed and recurrent BCLM patients using Illumina platforms. A high CTC frequency (>15 CTCs/7.5 ml blood) was found to be correlated with disease severity and metastatic progression, which suggests the value for CTCs in the diagnosis of BCLM in comparison with pathohistology and PET/CT imaging (P>0.05). Moreover, CTCs isolated from BCLM patients remained an independent prognostic detection factor associated with overall survival (P=0.0041). Comparison between newly diagnosed and recurrent liver metastases revealed different frequencies of CNVs (P>0.05). Notably, the CNV pattern of isolated CTCs of recurrent BCLM patients was similar to recurrent liver metastases (nearly 82% of the gain/loss regions). Functional enrichment analysis identified 25 genes as a CNV signature of BCLM. Among them, were defensin and β-defensin genes, which are significantly associated with anti-angiogenesis and immunomodulation signaling pathways. High CTC frequencies are effective in the evaluation and differentiation between newly diagnosed liver metastases from recurrent liver metastases. Future clinical studies will be necessary to fully determine the prognostic potential of CTC cluster signatures in patients with BCLM.

Genetic Heterogeneity Between Paired Primary and Brain Metastases in Lung Adenocarcinoma.

Purpose:About one-third of nonsmall cell lung cancer (NSCLC) patients develop brain metastases (BM). However, there is an unmet need for early diagnosis and treatment of BM. The precise mechanism for BM is still unknown. However, the genetic heterogeneity between primary tumor and paired BM indicates that sampling from the primary tumor may not be able to fully represent the mutational status in metastases. In this study, the genetic heterogeneity of primary lung adenocarcinoma and paired BM was analyzed.Patients and methods:A total of 11 paired samples of primary tumors and BM from lung cancer patients were included, in which 7 paired samples of patients were finally analyzed. Samples were sequenced by whole-exome sequencing (WES) to investigate the common and unique mutations in the primary tumors and BM, and the similarities and differences in copy number variation (CNV).Results:The consistency of gene mutation between primary lung adenocarcinoma and paired BM was 33% to 86%. FAM129C and ADAMTSs specifically mutated in BM, along with NKX2-1 high amplification and SAMD2/4 copy number deletion.Conclusion:The consistency of gene mutation between primary lung adenocarcinoma and corresponding BM is relatively high, while the individual differences were significant. FAM129C and ADAMTSs mutations and high amplification of NKX2-1 may be related to BM of lung cancer. The loss of copy number of SAMD2/4 may be a potential therapeutic target for BM from lung adenocarcinoma.

Gene expression of ASNS, LGMN and CTSB is elevated in a subgroup of childhood BCP-ALL with PAX5 deletion.

Resistance to L-asparaginase (L-asp) is a major contributor to poor treatment outcomes of several subtypes of childhood B cell precursor acute lymphoblastic leukemia (BCP-ALL). Asparagine synthetase (ASNS), legumain (LGMN) and cathepsin B (CTSB) serve a key role in L-asp resistance. The association between genetic subtypes of BCP-ALL and the expression of ASNS, LGMN and CTSB may elucidate the mechanisms of treatment failure. Bone marrow samples of 52 children newly diagnosed with BCP-ALL were screened for major genetic abnormalities and ASNS, LGMN and CTSB gene expression levels. The cohort was further divided into groups corresponding to the key genetic aberrations occurring in BCP-ALL: Breakpoint cluster region and Abelson murine leukemia viral oncogene homolog 1 fusion; hyperdiploidy, hypodiploidy, ETS variant 6 and runt-related transcription factor 1 fusion and other BCP-ALL with no primary genetic aberration identified. A subgroup analysis based on the differences in copy number variations demonstrated a significant increase of ASNS, LGMN and CTSB median expression in other BCP-ALL cases with paired box 5 (PAX5) deletion (P=0.0117; P=0.0036; P<0.0001, respectively) compared with those with wild-type PAX5. Patients with high ASNS expression exhibited longer relapse-free survival (RFS) compared with those with low ASNS levels (P=0.0315; HR, 0.19; 95% CI, 0.04-0.86); the 5-year RFS for patients in the high ASNS expression group was 90.15% (95% CI, 87.90-92.40%). Despite the impact on ASNS, LGMN and CTSB expression, PAX5 deletion did not influence RFS in the other BCP-ALL group (P=0.6839). Therefore, the results of the present study revealed high levels of ASNS, LGMN and CTSB expression in the other BCP-ALL group with concomitant PAX5 deletion and no subsequent deterioration in 5-year RFS. High ASNS expression level, as a single factor, was strongly associated with an improved outcome.

42P - Genome wide copy number analysis of circulating tumour cells in breast cancer liver metastasis

BackgroundCirculating tumor cells (CTCs) enter peripheral blood from primary breast cancer tumors and seed liver metastasis (BCLM). The genome-wide sequencing of CTCs offers noninvasive diagnostic factor for survival in BCLM patients, which but has been impeded by low single-cell genome coverage of scarce CTCs. MethodsWe conducted a prospective clinical investigation to confirm the diagnostic value of genome-wide sequencing in BCLM. We have developed the genome-wide pattern differences in copy number variations (CNVs) and to improve a CNV signature as an adjunct test for the routine histopathologic classification of BCLM. We compared the consistency and efficiency of genome-wide sequencing of CTCs with other comment detection methods. Furthermore, functional prediction of candidate gene biomarkers was confirmed in BCLM patients. ResultsCTCs were isolated from 26 patients with BCLM, 12 of which were successfully profiled for high CTCs (> 15), including matched archival primary tumor from 17 patients. Our results characteristic cancer-metastatic variations and insertions/deletions in exomes of CTCs. Comparison with primary breast tumors in metastatic niches cell revealed similar frequencies of BCLM genomic copy number aberrations. Higher CTCs frequencies (> 35) are correlated with disease severity and metastatic progress, which suggesting effective value of CTCs for variety of staging of BCLM. The CNV pattern of CTC is similar to that of hepatic metastasis, but the mutation pattern of CTC is different from that of primary lesion. Twenty- five genes were identified as a CNV signature of BCLM. Functional pathways analysis shows all these genes might play similar and critical roles in migration and progression of BCLM that could be independent risk factors for BCLM (p < 0.05). ConclusionsOur approach utilized to explore reproducibility of cancer-specific CNVs involved in progression of metastatic breast cancer. Our study contributed a new potential non-invasive biomarker for CTC-based cancer diagnostics of BCLM to monitor therapeutic efficacy of targeted therapies. Editorial acknowledgementThe authorswould like to express their appreciation to appreciate Southwest Medical Universityfor its financial support. We also wish to thank the oncology and pathology technicians of The Affiliated Hospital of Southwest Medical University for their assistance in the work reported here. We also thank the anonymous referee for his/her very helpful comments, which remarkably improved the quality of this research. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

Abstract 1494: Interethnic germline variants in mitochondrial DNA polymerase (POLG1) induce mitochondrial dysfunction and confer tumorigenic properties

Abstract Purpose: Germline variants contribute to large fraction of the diversity observed among different ethnic groups and could give better insights in genetic predisposition and susceptibility from one population to another for certain disease including cancer. Decreased mitochondrial OXPHOS is one of the most common phenotypes of cancer cells. Mitochondrial DNA (mtDNA) depletion impairs OXPHOS and adaptive metabolic responses. In this context, DNA polymerase γ (POLG1) is known to function in human mitochondria and performs critical function of mtDNA replication and repair. POLG1 is the most frequent target of gene mutation and is involved in variety of mitochondrial diseases. POLG1 protein consists of exonuclease, linker and polymerase domain, each with distinct functions. Mutations in exonuclease domain leads to erroneous proofreading and is responsible for increased mutations in mtDNA whereas mutations in polymerase domain leads to erroneous replication and hence depletion in mtDNA. Germline variants in these domains of POLG1 may serve as important signature markers in association studies of individuals in a population study. Through our present study, we identified germline variants, examined copy number variation, expression and regulation of POLG1 gene in human cancers. We provide evidence that altered POLG1 expression as well as germline variations in POLG1 gene contribute to tumorigenesis. Methods: A comprehensive race based bioinformatics analysis of POLG1 gene in European-American and African-American was conducted and several unique germline mutations were discovered. To analyze functional contribution of these unique germline mutations in tumor progression, these unique prevalent mutations in the evolutionary conserved regions of exonuclease and polymerase domains we generated by site directed mutagenesis and functional and tumorigenic analysis was performed. Results: We observed marked differences in copy number variation of POLG1 through cBioPortal and Cosmic databases and validated the analysis in primary tumors and cancer cell lines. Our results also indicate that mtDNA copy number in cancer cell is governed by regulation of POLG1 methylation and demethylation status, suggestive of epigenetic regulation of POLG1. We identified a mitochondrial disease causing missense variation in polymerase domain of POLG1 at amino acid 1143 (E1143G) to be 25 times more prevalent in European-Americans when compared to African-Americans population. Expression of this germline variant (E1143G) increased glucose consumption, decreased ATP production and increased matrigel invasion. Discussion/ Conclusion: We demonstrate that POLG1 is epigenetically regulated and its unique germline variants contribute to disruption of mitochondrial function. Thus contributes to differences in increased predisposition to cancer in inter-ethnic population. Note: This abstract was not presented at the meeting. Citation Format: Prachi Bajpai, Bhupendra Singh, Kjerstin M. Owens, Vinodh Srinivasasainagendra, Hemant K. Tiwari, Keshav K. Singh. Interethnic germline variants in mitochondrial DNA polymerase (POLG1) induce mitochondrial dysfunction and confer tumorigenic properties [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1494. doi:10.1158/1538-7445.AM2017-1494

Genome-wide copy number variation pattern analysis and a classification signature for non-small cell lung cancer.

The accurate classification of non-small cell lung carcinoma (NSCLC) into lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) is essential for both clinical practice and lung cancer research. Although the standard WHO diagnosis of NSCLC on biopsy material is rapid and economic, more than 13% of NSCLC tumors in the USA are not further classified. The purpose of this study was to analyze the genome-wide pattern differences in copy number variations (CNVs) and to develop a CNV signature as an adjunct test for the routine histopathologic classification of NSCLCs. We investigated the genome-wide CNV differences between these two tumor types using three independent patient datasets. Approximately half of the genes examined exhibited significant differences between LUAD and LUSC tumors and the corresponding non-malignant tissues. A new classifier was developed to identify signature genes out of 20 000 genes. Thirty-three genes were identified as a CNV signature of NSCLC. Using only their CNV values, the classification model separated the LUADs from the LUSCs with an accuracy of 0.88 and 0.84, respectively, in the training and validation datasets. The same signature also classified NSCLC tumors from their corresponding non-malignant samples with an accuracy of 0.96 and 0.98, respectively. We also compared the CNV patterns of NSCLC tumors with those of histologically similar tumors arising at other sites, such as the breast, head, and neck, and four additional tumors. Of greater importance, the significant differences between these tumors may offer the possibility of identifying the origin of tumors whose origin is unknown.

Population genomics reveals that within-fungus polymorphism is common and maintained in populations of the mycorrhizal fungus Rhizophagus irregularis.

Arbuscular mycorrhizal (AM) fungi are symbionts of most plants, increasing plant growth and diversity. The model AM fungus Rhizophagus irregularis (isolate DAOM 197198) exhibits low within-fungus polymorphism. In contrast, another study reported high within-fungus variability. Experiments with other R. irregularis isolates suggest that within-fungus genetic variation can affect the fungal phenotype and plant growth, highlighting the biological importance of such variation. We investigated whether there is evidence of differing levels of within-fungus polymorphism in an R. irregularis population. We genotyped 20 isolates using restriction site-associated DNA sequencing and developed novel approaches for characterizing polymorphism among haploid nuclei. All isolates exhibited higher within-isolate poly-allelic single-nucleotide polymorphism (SNP) densities than DAOM 197198 in repeated and non-repeated sites mapped to the reference genome. Poly-allelic SNPs were independently confirmed. Allele frequencies within isolates deviated from diploids or tetraploids, or that expected for a strict dikaryote. Phylogeny based on poly-allelic sites was robust and mirrored the standard phylogeny. This indicates that within-fungus genetic variation is maintained in AM fungal populations. Our results predict a heterokaryotic state in the population, considerable differences in copy number variation among isolates and divergence among the copies, or aneuploidy in some isolates. The variation may be a combination of all of these hypotheses. Within-isolate genetic variation in R. irregularis leads to large differences in plant growth. Therefore, characterizing genomic variation within AM fungal populations is of major ecological importance.

Genome wide DNA copy number analysis in cholangiocarcinoma using high resolution molecular inversion probe single nucleotide polymorphism assay

In order to study molecular similarities and differences of intrahepatic (IH-CCA) and extrahepatic (EH-CCA) cholangiocarcinoma, 24 FFPE tumor samples (13 IH-CCA, 11 EH-CCA) were analyzed for whole genome copy number variations (CNVs) using a new high-density Molecular Inversion Probe Single Nucleotide Polymorphism (MIP SNP) assay.Common in both tumor subtypes the most frequent losses were detected on chromosome 1p, 3p, 6q and 9 while gains were mostly seen in 1q, 8q as well as complete chromosome 17 and 20. Applying the statistical GISTIC (Genomic Identification of Significant Targets in Cancer) tool we identified potential novel candidate tumor suppressor- (DBC1, FHIT, PPP2R2A) and oncogenes (LYN, FGF19, GRB7, PTPN1) within these regions of chromosomal instability.Next to common aberrations in IH-CCA and EH-CCA, we additionally found significant differences in copy number variations on chromosome 3 and 14. Moreover, due to the fact that mutations in the Isocitrate dehydrogenase (IDH-1 and IDH-2) genes are more frequent in our IH-CCA than in our EH-CCA samples, we suggest that the tumor subtypes have a different molecular profile.In conclusion, new possible target genes within regions of high significant copy number aberrations were detected using a high-density Molecular Inversion Probe Single Nucleotide Polymorphism (MIP SNP) assay, which opens a future perspective of fast routine copy number and marker gene identification for gene targeted therapy.

Abstract 4268: DNA copy number variation and driver mutation patterns of follicular thyroid tumors

Abstract Background Our previous study using single nucleotide polymorphism (SNP) array identified significant differences in copy number variation (CNV) between tumor subtypes. This study was conducted to extend our previous findings, using both Fluorescent In-Situ Hybridization (FISH) and quantitative PCR (qPCR), and to investigate the possible relationship with major thyroid cancer driver mutations, and their association with aggressive features in follicular thyroid tumors. Methods For the validation, we obtained paraffin blocks of all cases with CNVs identified in our prior study (7 samples with Ch12 amplification, and 6 samples with Ch22 deletion), as well as 6 control samples with no CNV, for FISH analysis and qPCR. We used centromeric and distal probes to differentiate partial vs whole chromosome alterations. We then extended the study to characterize the relation between CNV and driver mutations and possible associations with aggressive features in a larger cohort of tumors, consisting of: 35 follicular adenoma (FA), 19 non-aggressive follicular variant papillary thyroid carcinoma (FVPTC), 22 aggressive FVPTC, 16 non-aggressive follicular carcinoma (FC), and 15 aggressive FC. Results Our FISH and qPCR results confirmed our earlier CNV results in this expanded sample cohort. Furthermore, FISH indicated that in each case, CNV involved the entire chromosome rather than sub-chromosomal alterations. Ch12 amplification was significantly more prevalent in FA and non-aggressive tumor than aggressive tumor subtypes (p-value &amp;lt;0.01). The HRAS mutation was predominantly detected in aggressive FCs, but the low number of events precluded reaching statistical significance. Conclusion Our study suggests that Ch12 amplification is associated with indolent tumors. Since FAs are a common source of inconclusive pre-operative cytopathology, a molecular signature such as Ch12 amplification that identifies follicular tumors with little aggressive potential could be useful. Further independent external testing is warranted. CNV and RAS pattern across follicular thyroid tumor subtypesChromosome 12 AmplificationChromosome 22 DeletionNRAS mutationHRAS mutationFA40% (14/35)17.1% (6/35)17.1% (6/35)0.3% (1/35)Non-aggressive FVPTC15.8% (3/19)15.8% (3/19)36.8% (7/19)0% (0/19)Aggressive FVPTC4.5% (1/22)22.7% (5/22)18.2% (4/22)0% (0/22)Non-aggressive FC6.3% (1/16)6.3% (1/16)50% (8/16)0% (0/16)Aggressive FC6.7% (1/15)26.7% (4/15)53.3% (8/15)26.7% (4/15) Citation Format: Hyun-seok Kim, Kathleen Wilsbach, Aurelien Marti, Alireza Najafian, Alan K. Meeker, James R. Eshleman, Justin A. Bishop, Martha Zeiger, Christopher B. Umbricht. DNA copy number variation and driver mutation patterns of follicular thyroid tumors. [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 4268. doi:10.1158/1538-7445.AM2015-4268

Androgen receptor (AR) based biomarker association with response to abiraterone acetate/prednisone (AA/P) in metastatic castrate resistant prostate cancer (mCRPC).

174 Background: AA/P is an FDA approved treatment for mCRPC. Since markers of early resistance to AA/P are unknown, we report initial findings of androgen receptor (AR) based associations with short term (12 week) progression on AA/P. Methods: mCRPC stage patients (pts) initiating pre-chemotherapy AA/P underwent metastatic site biopsies at baseline (pre AA/P) and after 12 weeks. Baseline somatic whole exome DNA, tumor gene expression for AR full length (ARFL), AR splice variant 7 (ARV7) and ARV7/ARFL ratios were compared in progessors versus non-progressors. Progression at or within 12 weeks of AA/P therapy was defined as death or disease progression by PCWG2 “composite progression (CP)” and/or “radiographic progression” endpoints. Wilcoxon rank-sum tests were used to test for differences in the two groups for comparing ARFL, ARV7 expressions and ARV7/ARFL ratios and chi square tests were used for differences in copy number variation. Results: Between 1/2013 and 6/2014, 59 pts were enrolled of which 44 have disease assessment data at the12-week time point. CP was observed in 17/44 patients. DNA seq and clinical data was available for 42/44 pts. Using radiographic progression at 12 weeks, AR Amplification/Gain was observed in 20/26 non-progressors (13 with Amplification) and in 9/16 progressors (P-value = 0.19; OR 2.5). ARFL and ARV7 gene expressions in both groups is provided in table. Conclusions: A trend towards higher ARV7/ARFL gene expression ratio in metastases was observed with early progression on AA/P. AR gain/amplification is observed less often in pts with early progression. Validation of these findings is on-going in this prospective trial. Clinical trial information: NCT# 01953640. [Table: see text]

No increase in autism-associated genetic events in children conceived by assisted reproduction

To understand the rate of genetic events in patients with autism spectrum disorder (ASD) who were exposed to assisted reproduction. Case control study using genetics data. Twelve collaborating data collection sites across North America as part of the Simons Simplex Collection. 2,760 children with ASD, for whom 1,994 had published copy number variation data and 424 had published gene mutation status available. None. Rates of autism-associated genetic events in children with ASD conceived with assisted reproduction versus those conceived naturally. No statistically significant differences in copy number variations or autism-associated gene-disrupting events were found when comparing ASD patients exposed to assisted reproduction with those not exposed to assisted reproduction. This is the first large genetic association to concurrently examine the genotype of individuals with ASD in relation to their exposure to ART versus natural conception, and it adds reassuring evidence to the argument that ART does not increase the risk of ASD.

(Epi)Genetic Analyses of Age-Related Macular Degeneration: Case-Control and Discordant Twin Studies

Background/Aims: Phenotypic discordance in monozygotic (MZ) twin pairs can have an epigenetic or genetic basis. Although age-related macular degeneration (AMD) has a strong genetic component, few studies have addressed its epigenetic basis. Methods: Using SNP arrays, we evaluated differences in copy number variation (CNV) and allele-specific methylation (ASM) patterns (via methyl-sensitive restriction enzyme digestion of DNA) in MZ twin pairs from the US Twin Study of AMD. Further analyses examined the relationship between ASM and CNVs with AMD by both case/control analysis of ASM at candidate regions and by analysis of ASM and CNVs in twins discordant for AMD. Results: The frequency of ASM sites differs between cases and controls in regions surrounding the AMD candidate genes CFH, C2 and CFB. While ASM patterns show a substantial dependence on local sequence polymorphisms, we observed dissimilar patterns of ASM between MZ twins. The genes closest to the sites where discordant MZ twins have dissimilar patterns of ASM are enriched for genes implicated in gliosis, a process associated with neovascular AMD. Similar twin-based analyses revealed no AMD-associated CNVs. Conclusions: Our results provide evidence of epigenetic influences beyond the known genetic susceptibility and implicate inflammatory responses and gliosis in the etiology of AMD.

Gene expression analysis of matched ovarian primary tumors and peritoneal metastasis

BackgroundOvarian cancer is the most deadly gynecological cancer due to late diagnosis at advanced stage with major peritoneal involvement. To date most research has focused on primary tumor. However the prognosis is directly related to residual disease at the end of the treatment. Therefore it is mandatory to focus and study the biology of meatastatic disease that is most frequently localized to the peritoneal caivty in ovarian cancer.MethodsWe used high-density gene expression arrays to investigate gene expression changes between matched primary and metastatic (peritoneal) lesions.ResultsHere we show that gene expression profiles in peritoneal metastasis are significantly different than their matched primary tumor and these changes are affected by underlying copy number variation differences among other causes. We show that differentially expressed genes are enriched in specific pathways including JAK/STAT pathway, cytokine signaling and other immune related pathways. We show that underlying copy number variations significantly affect gene expression. Indeed patients with important differences in copy number variation displayed greater gene expression differences between their primary and matched metastatic lesions.ConclusionsOur analysis shows a very specific targeting at both the genomic and transcriptomic level to upregulate certain pathways in the peritoneal metastasis of ovarian cancer. Moreover, while primary tumors use certain pathways we identify distinct differences with metastatic lesions. The variation between primary and metastatic lesions should be considered in personalized treatment of ovarian cancer.

Differences in Copy Number Variation between Discordant Monozygotic Twins as a Model for Exploring Chromosomal Mosaicism in Congenital Heart Defects

Studies addressing the role of somatic copy number variation (CNV) in the genesis of congenital heart defects (CHDs) are scarce, as cardiac tissue is difficult to obtain, especially in non-affected individuals. We explored the occurrence of copy number differences in monozygotic (MZ) twins discordant for the presence of a CHD, as an illustrative model for chromosomal mosaicism in CHDs. Array comparative genomic hybridization was performed on peripheral blood-derived DNA obtained from 6 discordant MZ twin pairs and on sex-matched reference samples. To identify CNV differences between both twin members as well as potential CNVs in both twins contributing to the phenotype, DNA from each twin was hybridized against its co-twin, and against a normal control. Three copy number differences in 1 out of 6 MZ twin pairs were detected, confirming the occurrence of somatic CNV events in MZ twins. Further investigation by copy number and (epi)genome sequencing analyses in MZ twins, discordant for the presence of CHDs, is required to improve our knowledge on how postzygotic genetic, environmental and stochastic factors can affect human heart development.