Driver Mutation in Waldenstrom's Macroglobullinemia and Their Clonal Heterogeneity during Progression and Relapse

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1092-1092 ◽  
Author(s):  
Jihye Park ◽  
Antonio Sacco ◽  
Salomon Manier ◽  
Karma Salem ◽  
Mira Mashood ◽  
...  
Keyword(s):  
New York ◽  
Disease Progression ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Copy Number ◽  
Research Funding ◽  
Targeted Sequencing ◽  
Whole Exome ◽  
Btk Inhibitor ◽  
Serial Samples

Abstract Background: Whole genome sequencing has recently shown the presence of recurrent mutations, such as MYD88, CXCR4 and ARID1A, in patients with Waldenstrom's Macroglobulinemia (WM) at diagnosis. Nevertheless, the contribution of each genomic aberration within the clonal evolution of the tumor during WM progression has not been reported. We therefore aimed to investigate whether sequential genomic events sustain WM disease progression by using whole exome sequencing (WES) and targeted sequencing of serial samples. In addition, we investigated if specific genomic alterations can change in response to treatment with samples before and after proteasome or BTK inhibitor treatments. Methods: We have sequenced 74 samples from 32 patients using WES or targeted sequencing technology. DNA was collected from bone marrow CD19-selected cells that were isolated from 6 patients with WM at different stages of disease (2-3 serial samples per patient, total 15 samples), and was subjected to library construction, followed by Agilent Sure-Select Human All Exon v2.0-based hybrid selection. Germline DNA was isolated from matched CD19-depleted peripheral blood samples. All libraries were sequenced with Illumina Hiseq 2500 instrument (New York Genome Center, Rockefeller University, New York, NY). Reads were aligned to GRCh37, and quality control, mutation calling, insertion and deletion identification, copy number variation detection, coverage calculations were accomplished via Firehose at Broad. Somatic Single Nucleotide Variations (SSNVs) were identified and annotated using MuTect and Oncotator, respectively. Insertions and deletions were detected using Strelka. In addition, the deep targeted sequencing was done with a customized bait set in 59 independent serial samples obtained from 26 patients who were treated with either proteasome inhibitor (Pi)- or BTK inhibitor (BTKi)-based therapies in 12 and 14 cases, respectively. Results: Whole exome sequencing, performed at a total average depth of 83X for germline and 85X for tumor samples, led to the identification of average of 14 non-silent mutations per sample (range 2-60). Base conversion signature showed dominant A>C/G transitions. Copy number analysis showed 6q deletion being the most prevalent one. MYD88 was the most recurrent somatic variants in WM patients (>93%), followed by several genes including IRS4, VCAN, CXCR4 and ALDH2, being detected in ~20-30% of the samples. Specifically, changes in the Cancer Cell Fraction (CCF) of these mutations, such as MYD88 and CXCR4, occurred in the serial samples depending on progression and response to therapy. The mutated genes mentioned above, including MYD88, CXCR4, LRG1 and VCAN, were also observed in targeted sequencing of 59 independent serial samples (mean target coverage 434X). CXCR4 was linked to disease progression exposed to Pi or BTK; but not detected in patients responding to therapies. MYD88 was present in patients with either progressive disease or PR/VGPRs. Specifically, different frequencies of MYD88 mutations were identified in patients with progression or PR/VGPR to BTKi-based therapies compared to Pi-based therapies. LRG1 was detected in a patient in response to Pi, while VCAN was observed in both patients showing progression or response to Pi regimens only. Conclusion: These findings reveal the occurrence of clonal variations in patients with WM during disease progression and response to therapies. MYD88 was confirmed to be the most prevalent somatic aberration, and was present in post-treatment samples of progressors and responders to Pi- or BTKi-based regimens. In contrast, mutations in CXCR4 were enriched in patients with WM progressing to either Pi or BTKi therapies. This study demonstrates that WES and targeted sequencing of serial samples of WM patients can detect clonal variations during disease progression. Disclosures Ghobrial: Celgene: Honoraria, Research Funding; Noxxon: Honoraria; Amgen: Honoraria; BMS: Honoraria, Research Funding; Novartis: Honoraria; Takeda: Honoraria. Roccaro:Takeda Pharmaceutical Company Limited: Honoraria.

scholarly journals Whole Exome Sequencing and Targeted Sequencing Reveal the Heterogeneity of Genomic Evolution and Mutational Profile in Smoldering Multiple Myeloma

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 237-237
Author(s):  
Karma Salem ◽  
Jihye Park ◽  
Claudia Freymond ◽  
Marzia Capelletti ◽  
Daisy Huynh ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Research Funding ◽  
Plasma Cells ◽  
Targeted Sequencing ◽  
Target Coverage ◽  
Driver Genes ◽  
Whole Exome ◽  
Agilent Sureselect

Abstract Introduction: Recent data shows that multiple myeloma (MM) almost always arises from precursor states called Monoclonal Gammopathy of Undetermined Significance (MGUS) and Smoldering Multiple Myeloma (SMM), but not all patients with MGUS or SMM develop MM. Risk factors of progression for SMM patients are largely based on tumor load as represented by an M-protein ≥ 3 g/dL, a free light chain (FLC) ratio outside the range of 0.125 to 8, and ≥ 10% plasma cells in the BM. However, the genetic lesions that underlie progression, the molecular factors that cause rapid versus slow progression, and the factors that distinguish the relatively indolent MGUS from SMM are not well known. Further, the genomic landscape of SMM is not well characterized. One potential factor is MYC overexpression. Bergsagel et al. have found that MYC levels increase when comparing MGUS, SMM and overt MM. Other frequently altered pathways in MM are NF-kB, MAPK and DNA damage. In addition, limited studies of paired SMM and MM samples show that in many cases, the aggressive subclones can already be detected, in small cell fractions, before overt MM develops. However, the cause of progression to MM is unclear, in large part because sequential genomic studies of MGUS/SMM progression have yet to be undertaken. To address these questions, in this study we examine clinically-annotated samples from patients with SMM. Methods: We performed whole exome sequencing (WES) (mean target coverage 50X/100X) on 49 germline-tumor matched samples from patients with SMM (DNA from bone marrow CD138+ plasma cells matched with germline DNA from peripheral blood mononuclear cells). Libraries were constructed using Agilent SureSelect XT2 library prep kit, and hybridized to Agilent's whole exome V5+UTR capture probes and then sequenced on HiSeq 2500 (Illumina). We also performed targeted deep sequencing using a custom enrichment bait set on 25 samples of progressor (n=12) and non-progressor (n=13) SMM samples. Libraries were also constructed with Agilent SureSelect XT2 library prep kit and enriched by hybridizing to an in-house designed customized target bait, then sequenced on HiSeq 2500. Sequencing data were analyzed using previously established analytic pipelines including MuTect, RecapSeg, GISTIC, MutSig, and ABSOLUTE. Results: The number of Somatic Single Nucleotide Variants (SSNVs) seen in SMM ranged from 1 to 98 nonsilent mutations with an average of 1.14 mutations/Mb, which is slightly lower than MM (1.6 mutations/Mb) from previous studies (p-value=0.05). This large and varying range of mutational load among samples suggests that SMM is likely a heterogenous entity where some patients are closer to MGUS and others closer to MM. We identified likely drivers in SMM in about ~32% of the samples, including mutations in MM candidate driver genes such as NRAS, KRAS and PTPN11(overall 36 events were present in COSMIC). SMM also had somatic CNAs in about ~50% of SMM samples, such as hyperdiploidy, gain of chromosome 1q, deletion of 13p and 17p, which match the hallmark chromosome changes seen in MM. Comparing deep targeted sequencing of 100 genes (mean target coverage 361X) in samples from 12 SMM patients who progressed to myeloma vs. 13 SMM patients who did not, we found non-synonymous mutations exclusive to progressors, suggesting that with more samples we may find genetic alterations that predict progression in SMM. Conclusion: This study demonstrates that WES and targeted sequencing of SMM patients can detect MM candidate driver genes as well as hallmark CNAs seen in MM patients. Further, there may be potential different mutational features between progressors and non-progressors. Thus, this approach can be used to identify genetic drivers of clonal progression from MGUS/SMM to MM that may present opportunities for early therapeutic intervention and prevention of disease progression. Disclosures Roccaro: Takeda Pharmaceutical Company Limited: Honoraria. Ghobrial:Takeda: Honoraria; Noxxon: Honoraria; Amgen: Honoraria; Novartis: Honoraria; BMS: Honoraria, Research Funding; Celgene: Honoraria, Research Funding.

Whole-exome sequencing reveals potential germline and somatic mutations in 60 malignant ovarian germ cell tumors

2021 ◽  
Author(s):  
Juan Chen ◽  
Yan Li ◽  
Jianlei Wu ◽  
Yakun Liu ◽  
Shan Kang
Keyword(s):  
Germ Cell ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Peripheral Blood ◽  
Copy Number ◽  
Somatic Mutations ◽  
Germ Cell Tumors ◽  
Germline Mutations ◽  
Deletion Region ◽  
Whole Exome

Abstract Background Malignant ovarian germ cell tumors (MOGCTs) are rare and heterogeneous ovary tumors. We aimed to identify potential germline mutations and somatic mutations in MOGCTs by whole-exome sequencing. Methods The peripheral blood and tumor samples from these patients were used to identify germline mutations and somatic mutations, respectively. For those genes corresponding to copy number alterations (CNA) deletion and duplication region, functional annotation of was performed. Immunohistochemistry was performed to evaluate the expression of mutated genes corresponding to CNA deletion region. Results In peripheral blood, copy number loss and gain were mostly found in yolk sac tumors (YST). Moreover, POU5F1 was the most significant mutated gene with mutation frequency > 10% in both CNA deletion and duplication region. In addition, strong cytoplasm staining of POU5F1 (corresponding to CNA deletion region) was found in 2 YST and nuclear staining in 2 dysgerminomas (DG) tumor samples. Genes corresponding to CNA deletion region were significantly enriched in the signaling pathway of regulating pluripotency of stem cells. In addition, genes corresponding to CNA duplication region were significantly enriched in the signaling pathways of RIG-I-like receptor, Toll-like receptor, NF-kappa B and Jak–STAT. KRT4, RPL14, PCSK6, PABPC3 and SARM1 mutations were detected in both peripheral blood and tumor samples. Conclusions Identification of potential germline mutations and somatic mutations in MOGCTs may provide a new field in understanding the genetic feature of the rare biological tumor type in the ovary.

scholarly journals RefCNV: Identification of Gene-Based Copy Number Variants Using Whole Exome Sequencing

2016 ◽  
Vol 15 ◽  
pp. CIN.S36612 ◽  
Author(s):  
Lun-Ching Chang ◽  
Biswajit Das ◽  
Chih-Jian Lih ◽  
Han Si ◽  
Corinne E. Camalier ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Copy Number ◽  
Copy Number Variants ◽  
Estimation Methods ◽  
Single Nucleotide Variants ◽  
False Positive Error ◽  
Reference Set ◽  
Genome Wide ◽  
Whole Exome

With rapid advances in DNA sequencing technologies, whole exome sequencing (WES) has become a popular approach for detecting somatic mutations in oncology studies. The initial intent of WES was to characterize single nucleotide variants, but it was observed that the number of sequencing reads that mapped to a genomic region correlated with the DNA copy number variants (CNVs). We propose a method RefCNV that uses a reference set to estimate the distribution of the coverage for each exon. The construction of the reference set includes an evaluation of the sources of variability in the coverage distribution. We observed that the processing steps had an impact on the coverage distribution. For each exon, we compared the observed coverage with the expected normal coverage. Thresholds for determining CNVs were selected to control the false-positive error rate. RefCNV prediction correlated significantly ( r = 0.96–0.86) with CNV measured by digital polymerase chain reaction for MET (7q31), EGFR (7p12), or ERBB2 (17q12) in 13 tumor cell lines. The genome-wide CNV analysis showed a good overall correlation (Spearman's coefficient = 0.82) between RefCNV estimation and publicly available CNV data in Cancer Cell Line Encyclopedia. RefCNV also showed better performance than three other CNV estimation methods in genome-wide CNV analysis.

Whole Exome Sequencing of a Patient with Atypical Congenital Pure Red Cell Aplasia Has Enabled the Identification of a Novel Key Actor of Erythropoiesis That May be Involved in CDAI Physiopathology

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 3-4
Author(s):  
Elia Colin ◽  
Genevieve Courtois ◽  
Lydie Da Costa ◽  
Carine Lefevre ◽  
Michael Dussiot ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Homologous Recombination ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Research Funding ◽  
Pure Red Cell Aplasia ◽  
Red Cell ◽  
Whole Exome

Background: The development of next generation sequencing techniques has brought important insights into the molecular mechanisms of erythropoiesis and how these processes can be perturbed in human diseases. This strategy may be valuable in some hereditary erythroid disorders where a subset of patients does not carry any mutations in the supposed causal gene and for which transgenic mouse models do not recapitulate the phenotype, suggesting that additional genetic events may be involved in pathogenesis. Here, we report the case of an adult patient presenting with atypical pure red cell aplasia associated with facial dysmorphy and chronic leg ulcers. Whole exome sequencing revealed a heterozygous missense mutation (R725W) in the CDAN1 gene, which has been previously reported in congenital dyserythropoietic anemia type I (CDAI). However, this mutation was also detected in her healthy brother, suggesting that this event alone was not sufficient to explain her phenotype. According to this hypothesis, we found an additional germline heterozygous nonsense mutation (Q732X) in the MMS22L gene, which was not shared by her unaffected relatives. MMS22L is a protein involved in homologous recombination-dependent repair of stalled or collapsed replication forks. Additionally, MMS22L is able to bind newly synthesized soluble histones H3 and H4 and exhibits a histone chaperone activity. MMS22L loading onto ssDNA during homologous recombination is promoted by the histone chaperone ASF1. Interestingly, CDAN1 acts as a negative regulator of ASF1 by mediating its sequestration in the cytoplasm, which results in the blocking of histone delivery. Aims: As MMS22L has never been reported in erythropoiesis before, we aimed to investigate the role of MMS22L in human erythropoiesis. Based on the data summarized above, the purpose of this study was also to determine the effect of combined inactivation of MMS22L and CDAN1 on in vivo erythropoiesis, while exploring the functional cooperation between both proteins. Results: To decipher the role of MMS22L in human erythropoiesis, we assessed the consequences of complete MMS22L inactivation in human cord blood CD34+ progenitors as well as in CD36+ immature erythroblasts using shRNA lentiviruses. This resulted in a severe decrease of cell proliferation and differentiation due to G1 cell cycle arrest, with a slight increase of apoptosis. Interestingly, this phenotype was not observed when MMS22L was inactivated in the granulo-monocytic lineage, in which differentiation was maintained, suggesting that erythroid cells, that are highly proliferative, are more sensitive to MMS22L inactivation. To better understand the effect of combined CDAN1 and MMS22L haploinsufficiency observed in the proband, we used zebrafish as an in vivo model. Mms22l and cdan1 expression were simultaneously or separately downregulated by about 50% using antisens morpholino oligomers. 48 hours later, zebrafish embryos were stained with o-dianisidine to detect hemoglobin-containing cells. We found that combined knock-down of mms22l and cdan1 resulted in severe anemia, while knock-down of mms22l or cdan1 alone did not lead to any erythroid disorder. This experiment provides a proof-of-concept, indicating that the phenotype of the proband is indeed caused by the combination of both MMS22L and CDAN1 mutations. Finally, in order to decipher the cooperation between MMS22L and CDAN1 we used the human erythroid UT-7 cell line. We found that CDAN1 inactivation resulted in a severe decrease in MMS22L expression within the nucleus, suggesting that CDAN1 may regulate MMS22L expression or localization. We therefore wanted to confirm these results by assessing MMS22L expression in B-EBV cell lines established from two CDAI patients with CDAN1 compound heterozygous mutations. We found a great decrease in MMS22L expression within the nucleus of the CDAI patients' cells when compared to three control B-EBV cell lines. Based on these results, we suggest that impairment of MMS22L trafficking to the nucleus could be involved in CDA1 physiopathology. Conclusion: Through comprehensive genetic analysis of a single case with atypical congenital anemia, we demonstrated for the first time that MMS22L, a cell cycle regulator, is essential for the process of erythropoiesis. The crosstalk between MMS22L and CDAN1 is currently under investigation and could bring important new insights into the physiopathology of CDAI. Disclosures Hermine: Novartis: Research Funding; Alexion: Research Funding; AB Science: Consultancy, Current equity holder in publicly-traded company, Honoraria, Patents & Royalties, Research Funding; Celgene BMS: Consultancy, Research Funding; Roche: Consultancy.

Whole-Exome Sequencing Identifies a Somatic Cell Mutation Signature That Predicts Relapse Risk and Survival Probability in Multiple Myeloma

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 5-5
Author(s):  
Ehsan Malek ◽  
E. Ricky Chan ◽  
Daniel Qu ◽  
Jane Reese ◽  
Robert Fox ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Signaling Pathways ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Research Funding ◽  
Advisory Board ◽  
High Burden ◽  
Signature Genes ◽  
Whole Exome ◽  
Relapse Group

Introduction: Multiple myeloma (MM) is a plasma cell neoplasm associated with heterogeneous somatic alterations. Despite the development of novel anti-myeloma agents that have significantly prolonged patient survival, disease relapse remains a daunting problem. Our goal was to employ whole-exome sequencing (WES) to better describe the mutational landscape in MM beyond the tumor cell and identify genomic factors that might predict relapse. WES was performed using autograft samples obtained from MM patients that were then treated with high dose melphalan and autologous hematopoietic cell transplant (HCT). We identified a panel of genes that were most frequently mutated in all patients and then identified those genes mutated with greater frequency in patients that relapsed. A relapse burden signature was generated based upon the genes that were most frequently mutated genes in relapsed patients. Finally, the relapse burden signature was correlated with patient progression-free survival (PFS) and overall survival (OS) following autologous HCT. Methods. DNA was extracted from one ml of cryopreserved, mobilized hematopoietic cell product obtained from patients (N=93) that underwent HCT and was provided by the Case Comprehensive Cancer Center Hematopoietic Biorepository Core. Targeted sequencing was performed using the Tempus xE whole exome platform (Tempus, Chicago, IL). Variants were identified using a variant allele frequency (VAF) ≥0.1 for each sample. Variants were tabulated for each gene in each patient. Patients were grouped according to their relapse status; "No Relapse" (N=39) and "Relapse" (N=54) which corresponded to their post-HCT outcome. Relapse time was defined as time from transplant to event. Variants identified in each gene and patient group were counted and ranked. A relapse burden signature was defined and included twenty-two genes over-represented in the relapse group compared to the non-relapse group by > 10%. Genes in the relapse burden signature were subjected to gene set enrichment analysis (GSEA) and cross referenced against Gene Ontology (GO) categories. PFS and OS were defined as the time from transplant until the event of interest, with censoring at time of last follow up. Patients were regrouped according to their mutation burden in the relapse signature genes ("High burden" defined as >=six signature genes with variants) and their OS and PFS were analyzed with an R package (survival) to generate Kaplan-Meier curves and statistical significance based on a Chi-square test between low and high burden patients. Results: In total, 3,523 genes were identified as containing variants. Table 1 lists the top thirty genes that were identified and ranked based upon total number of mutations (mutational count) and most frequently mutated in relapsed and non-relapsed patients (sample count). We then identified those genes that were more frequently mutated by at least 10% in relapsed patients compared to non-relapsed patients (Fig. 1A). GSEA revealed that the relapse burden gene signature was associated with protein O-linked glycosylation, glycan processing, Golgi lumen and innate immune response activating cell surface receptor signaling pathways (Table 2). Interestingly, multiple mucin family members (Muc2, Muc3A, Muc12 and Muc19) were represented in the relapse burden signature. GO analysis indicated that the individual mucin genes were associated with the same signaling pathways that had been associated with the relapse burden signature by GSEA (Table 3). Importantly, a high relapse burden signature was correlated with a statistically significant reduction in both PFS and OS (Fig. 1B, C). Conclusion: Taken together, our results support the feasibility of WES to generate a relapse burden signature that predicts the risk of MM patients for relapse following HCT. Moreover, the mutational landscape associated with relapse, i.e. the specific genes mutated, has provided insights on the mechanisms of relapse. It is noteworthy that the relapse burden signature genes identified here were mutated at a much greater frequency than genes associated with clonal hematopoiesis of indeterminate potential (CHIP). The identification of patient subgroups at heightened risk of relapse can better guide treatment decisions. Future studies will be conducted to evaluate the effect of pathways identified here on myeloma cell survival and to validate actionable therapeutic targets. Disclosures Malek: Bluespark: Research Funding; Takeda: Other: Advisory board , Speakers Bureau; Medpacto: Research Funding; Janssen: Other: Advisory board, Speakers Bureau; Sanofi: Other: Advisory board; Clegene: Other: Advisory board , Speakers Bureau; Amgen: Honoraria; Cumberland: Research Funding. Caimi:Amgen: Other: Advisory Board; Bayer: Other: Advisory Board; Verastem: Other: Advisory Board; Kite pharmaceuticals: Other: Advisory Board; Celgene: Speakers Bureau; ADC therapeutics: Other: Advisory Board, Research Funding. de Lima:Celgene: Research Funding; BMS: Other: Personal Fees, advisory board; Incyte: Other: Personal Fees, advisory board; Kadmon: Other: Personal Fees, Advisory board; Pfizer: Other: Personal fees, advisory board, Research Funding.

Whole Exome Sequencing to Predict Response to Hypomethylating Agents in MDS

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1698-1698 ◽  
Author(s):  
Holleh D Husseinzadeh ◽  
Edward P Evans ◽  
Kenichi Yoshida ◽  
Hideki Makishima ◽  
Andres Jerez ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Research Funding ◽  
Somatic Mutations ◽  
Prolonged Exposure ◽  
Mutational Analysis ◽  
Outcome Analysis ◽  
Individual Treatment ◽  
Hypomethylating Agents ◽  
Whole Exome

Abstract Abstract 1698 Hypomethylating agents decitabine and azacitidine are standard treatments for myelodysplastic syndromes (MDS). In their use, one hopes to rectify cytopenias and prolong survival by retarding further disease progression. However, individual treatment responses vary from complete remission (CR) to complete refractoriness. In general, at least 4 cycles of therapy are administered prior to assessing response. Thus, patients may have prolonged exposure to ineffective therapy, suffering toxicities without clinical benefit, while alternative and potentially more effective treatments are delayed. Currently, there are no reliable phenotypic or mutational markers for predicting response to hypomethylating agents. Once whole exome sequencing (WES) became available for more routine analysis, we theorized that somatic mutational patterns may help identify patients who would most benefit from these drugs, thereby maximizing response rate by rational patient selection. To pursue this hypothesis, we screened a cohort of 168 patients with MDS who received either azacitidine or decitabine for the presence of somatic mutations. Only those who received sufficient therapy, i.e., completed at least 4 cycles, were selected for outcome analysis. Targeted Sanger sequencing, including a panel of up to 19 genes frequently affected by somatic mutations was performed. For a representative subset of 26 patients (this subset is expanding) of whom there were 15 responders and 11 non-responders, mutational analysis was performed by WES to select target genes for further analysis. WES utilizes paired DNA (tumor vs. CD3+ lymphocytes) to produce raw sequence reads aligned using Burrows-Wheeler Aligner (BWA). Variants are detected using the Broad Institute's Best Practice Variant Detection GATK toolkit. Median age was 68 years (range, 55–85), 50% were female, and MDS subtypes were as follows: RA/RCUD/RARS 13%, RCMD 16%, RAEB-1/2 20%, MDS/MPN & CMML-1/2 31%, and sAML 20%. Response was assessed using IWG 2006 criteria at 4 and 7 months after therapy initiation. Overall response was 48%; rate of CR (including marrow/cytogenetic CR) was 28%, any HI 20%, SD 22%, and no response 29%. The cohort was then dichotomized into “responders” and “non-responders,” with responders classified as those achieving CR or any HI. Baseline patient characteristics were similar between both groups, including average age at treatment initiation, disease subtypes, proportion of abnormal/complex karyotypes, and presence of common cytogenetic aberrations. Overall, the most frequently mutated genes include TET2/IDH1/IDH2, SRSF2, ASXL1, SF3B1, RUNX1, EZH2/EED/SUZ12, SETBP1, CBL, and PPIAF2. The highest rate of refractoriness was noted in mutants of TET2/IDH1/IDH2 (67%), SF3B1 (67%), U2AF1/2 (67%). We also identified several genes whose mutants were few but associated exclusively with refractory disease (100%), including KIT, ZRSR2, PRPF8, LUC7L2. We next applied a recursive partitioning algorithm to construct a decision tree for identifying the most pivotal mutations associated with response: we found mutant CBL and PPFIA2 to be strongly associated with response, whereas mutant U2AF1/2, SF3B1 and PRPF8 were strongly associated with refractoriness. Our final approach was to dichotomize the cohort by the presence/absence of each mutation/group of mutations, and response within mutant vs. wild type cases was compared. Among refractory cases, TET2/IDH1/IDH2 (26%) and SF3B1 (17%) were most frequently mutated; among responders, mutations in RUNX1 (19% vs. 4%]), CBL (14% vs. 0%), SRSF2 (23% vs. 9%), and SETBP1 (18% vs. 4%) were most frequent. When multiple genes were combined in “either-or” fashion, mutation in TET2, SF3B1, PRPF8, or LUCL71 was significantly associated with refractoriness (52%, p=.0287), whereas mutations of RUNX1, CBL, SRSF2, SETBP1, or PPFIA2 mutation was significantly associated with response (86%, p=.0001). Mutational patterns appear to predict response to standard hypomethylating agents. Identification of the most predictive genes could guide development of molecular maker-based selection of patients for hypomethylating agent therapy, but will require ongoing analysis and additional prospective testing for validation. Disclosures: Advani: Genzyme: Honoraria, Research Funding; Immunomedics: Research Funding. Maciejewski:NIH: Research Funding; Aplastic Anemia&MDS International Foundation: Research Funding.

Whole Exome Sequencing In Relapsed Pediatric T-ALL: Progression Into Relapse Is Characterized By An Increased Number Of Somatic Mutations and a Conservation Of Mutations In Leukemogenic Driver Genes

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 228-228
Author(s):  
Joachim Kunz ◽  
Tobias Rausch ◽  
Obul R Bandapalli ◽  
Martina U. Muckenthaler ◽  
Adrian M Stuetz ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Copy Number ◽  
Lymphoblastic Leukemia ◽  
Initial Diagnosis ◽  
Driver Mutations ◽  
Single Nucleotide Variants ◽  
Single Nucleotide ◽  
Whole Exome ◽  
Recurrent Mutations

Abstract Acute precursor T-lymphoblastic leukemia (T-ALL) remains a serious challenge in pediatric oncology, because relapses carry a particularly poor prognosis with high rates of induction failure and death despite generally excellent treatment responses of the initial disease. It is critical, therefore, to understand the molecular evolution of pediatric T-ALL and to elucidate the mechanisms leading to T-ALL relapse and to understand the differences in treatment response between the two phases of the disease. We have thus subjected DNA from bone marrow samples obtained at the time of initial diagnosis, remission and relapse of 14 patients to whole exome sequencing (WES). Eleven patients suffered from early relapse (duration of remission 6-19 months) and 3 patients from late relapse (duration of remission 29-46 months).The Agilent SureSelect Target Enrichment Kit was used to capture human exons for deep sequencing. The captured fragments were sequenced as 100 bp paired reads using an Illumina HiSeq2000 sequencing instrument. All sequenced DNA reads were preprocessed using Trimmomatic (Lohse et al., Nucl. Acids Res., 2012) to clip adapter contaminations and to trim reads for low quality bases. The remaining reads greater than 36bp were mapped to build hg19 of the human reference genome with Stampy (Lunter & Goodson, Genome Res. 2011), using default parameters. Following such preprocessing, the number of mapped reads was >95% for all samples. Single-nucleotide variants (SNVs) were called using SAMtools mpileup (Li et al., Bioinformatics, 2009). The number of exonic SNVs varied between 23,741 and 31,418 per sample. To facilitate a fast classification and identification of candidate driver mutations, all identified coding SNVs were comprehensively annotated using the ANNOVAR framework (Wang et al., Nat. Rev. Genet., 2010). To identify possible somatic driver mutations, candidate SNVs were filtered for non-synonymous, stopgain or stoploss SNVs, requiring an SNV quality greater or equal to 50, and requiring absence of segmental duplications. Leukemia-specific mutations were identified by filtering against the corresponding remission sample and validated by Sanger sequencing of the genomic DNA following PCR amplification. We identified on average 9.3 somatic single nucleotide variants (SNV) and 0.6 insertions and deletions (indels) per patient sample at the time of initial diagnosis and 21.7 SNVs and 0.3 indels in relapse. On average, 6.3 SNVs were detected both at the time of initial diagnosis and in relapse. These SNVs were thus defined as leukemia specific. Further to SNVs, we have also estimated the frequency of copy number variations (CNV) at low resolution. Apart from the deletions resulting from T-cell receptor rearrangement, we identified on average for each patient 0.7 copy number gains and 2.2 copy number losses at the time of initial diagnosis and 0.5 copy number gains and 2.4 copy number losses in relapse. We detected 24/27 copy number alterations both in initial diagnosis and in relapse. The most common CNV detected was the CDKN2A/B deletion on chromosome 9p. Nine genes were recurrently mutated in 2 or more patients thus indicating the functional leukemogenic potential of these SNVs in T-ALL. These recurrent mutations included known oncogenes (Notch1), tumor suppressor genes (FBXW7, PHF6, WT1) and genes conferring drug resistance (NT5C2). In several patients one gene (such as Notch 1, PHF6, WT1) carried different mutations either at the time of initial diagnosis and or in relapse, indicating that the major leukemic clone had been eradicated by primary treatment, but that a minor clone had persisted and expanded during relapse. The types of mutations did not differ significantly between mutations that were either already present at diagnosis or those that were newly acquired in relapse, indicating that the treatment did not cause specific genomic damage. We will further characterize the clonal evolution of T-ALL into relapse by targeted re-sequencing at high depth of genes with either relapse specific or initial-disease specific mutations. In conclusion, T-ALL relapse differs from primary disease by a higher number of leukemogenic SNVs without gross genomic instability resulting in large CNVs. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Copy Number Changes Identified Using Whole Exome Sequencing in Nonsyndromic Cleft Lip and Palate in a Honduran Population

2017 ◽  
Vol 109 (16) ◽  
pp. 1257-1267 ◽  
Author(s):  
Yi Cai ◽  
Karynne E. Patterson ◽  
Frederic Reinier ◽  
Sarah E. Keesecker ◽  
Elizabeth Blue ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Copy Number ◽  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
Whole Exome ◽  
Copy Number Changes
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