Multiple Ways to Detect IDH2 Mutations in Angioimmunoblastic T-Cell Lymphoma from Immunohistochemistry to Next-Generation Sequencing

3572 Background: Oncogenic structural rearrangements (SR) in ALK, RET and ROS1 are well-described in lung cancer, and confer sensitivity to targeted therapy. SR disrupting the 3’UTR of PD-L1 gene have been reported in multiple cancer types and can potentially predict response to checkpoint immunotherapy. An amplicon-based next-generation sequencing (NGS) platform technology (AmpliMARK), previously optimized for detection of single nucleotide variations (SNVs), microsatellite instability and viral DNA, was extended to the multiplex detection of SR in ALK, RET, ROS1 and PD-L1 in cell-free DNA (cfDNA) and tumor tissue DNA. Methods: A hybrid primer-extension and adapter-ligation based method allowing detection of SR in a fusion-partner agnostic manner was utilized for multiplex target capture of genomic regions of ALK, RET, ROS1 and PD-L1 SR. Analytical validation was performed using admixtures of fragmented genomic DNA from an ALK SR-positive cell line, commercial standards containing RET and ROS1 SR, and synthetic PD-L1 SR gene constructs. Clinical performance was assessed in cfDNA samples from lung cancer patients and tumor tissue DNA samples from natural killer(NK)/T-cell lymphoma patients. Results: Detection of SR could be achieved to an allele frequency detection limit of 0.5% with sensitivity of 89.5% and specificity of 100% in admixture samples mimicking cfDNA. In an unselected series of 374 lung cancer cases, actionable SR for ALK, RET and ROS1 were detected in cfDNA of 9 samples, for an overall detection rate of 2.4%, and 1.8% (3 out of 168) when restricted to treatment-naive lung cancer cases only. In 29 NK/T-cell lymphoma tumor tissue samples, 9 samples were positive for PD-L1 SR, which were orthogonally confirmed by whole-genome sequencing, targeted sequencing or Sanger sequencing for a concordance rate of 100% across all samples. For 1 NK/T-cell lymphoma tumor tissue sample where matched plasma was available, the same PD-L1 SR was also detected in cfDNA. Conclusions: We have demonstrated and validated a comprehensive amplicon-based NGS assay for ultrasensitive multiplex detection of structural rearrangements in ALK, RET, ROS1 and PD-L1 across both cfDNA and tumor tissue DNA in analytical and clinical contexts. Ongoing studies will further evaluate the performance and utility of this assay across a larger number of clinical samples for the detection of these SR as well as additional cancer-associated SR involving NTRK1/2/3, FGFR2/3 and TMPRSS2.

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Next-Generation Sequencing Suggests Complex, Heterogeneous Pathogenesis In Peripheral T-Cell Lymphoma Unspecified

Blood ◽

10.1182/blood.v122.21.843.843 ◽

2013 ◽

Vol 122 (21) ◽

pp. 843-843 ◽

Cited By ~ 1

Author(s):

Jonathan H. Schatz ◽

Steven M. Horwitz ◽

Matthew A. Lunning ◽

Igor Dolgalev ◽

Kety Huberman ◽

...

Keyword(s):

Gene Expression ◽

Next Generation Sequencing ◽

T Cell ◽

Candidate Genes ◽

Research Funding ◽

Cell Lymphoma ◽

Next Generation ◽

Peripheral T Cell Lymphoma ◽

Tumor Dna ◽

Generation Sequencing

Abstract Peripheral T-cell lymphoma (PTCL) makes up about 12 percent of non-Hodgkin lymphoma, comprising 18 diseases that are poorly understood and carry a generally worse prognosis than B-lymphomas. PTCL not otherwise specified (PTCL-NOS), a diagnosis of exclusion, is most common, making up 25-30 percent. Gene-expression studies suggest a heterogeneous origin of this diagnosis, with overlap to other PTCL types, but the genetic factors underlying its pathogenesis are undefined. Current therapy for PTCL-NOS is empiric and ultimately ineffective for most patients. Identification of specific therapeutic targets is therefore a high priority. We have sought better understanding of pathogenesis through next-generation sequencing of PTCL-NOS tumor DNA. Whole-exome sequencing revealed candidate genes but low availability of fresh-frozen samples limited our ability to draw conclusions by this method alone. We therefore sequenced the coding regions of 237 candidate genes in a collection formalin-fixed paraffin-embedded samples. We used Nimblegen Sequence Capture for PCR amplification of exons and Illumina hiSeq for raw sequence generation. Results were aligned to hg19 and compared to dbSNP and the 1,000 genomes data to exclude germline variants. Analysis, including comparison to the COSMIC database of cancer-specific mutations, revealed high-confidence mutations affecting more than 60 known cancer-related genes in 25 PTCL-NOS cases. Recurrent mutations pointed to frequent activation of three key signaling pathways: NF-kB (TNFAIP3), WNT/B-Catenin (APC, CHD8, CELSR2), and NOTCH (NOTCH1, FBXW7). Recurrent deregulation of epigenetic processes was indicated by mutations in genes affecting histone acetylation (EP300, CREBBP), histone methylation (MLL2, KDM6A), and DNA methylation (TET2, DNMT3A). In addition, components of core tumor suppressor pathways showed evidence of frequent inactivation (TP53, ATM, RB1, CUL9, PRKDC). In all, 22 of 25 cases had mutations in at least one of these 17 recurrently mutated genes. Multiple additional candidate disease mechanisms also were suggested by lower-confidence mutations but require confirmation studies, which are under way. In sum, analysis of the coding region of PTCL-NOS tumor DNA suggests a complex and heterogeneous pathogenesis, in line with gene-expression profiling. This work provides an opportunity to better sub-classify entities within the diagnosis of PTCL-NOS and identify specific therapeutic targets and their associated biomarkers. Disclosures: Horwitz: Seattle Genetics, Inc.: Consultancy, Research Funding; Millennium: Consultancy, Research Funding.

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