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Targeted sequencing in DLBCL, molecular subtypes, and outcomes: a Haematological Malignancy Research Network report.

Accepted version
Peer-reviewed

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Authors

Lacy, Stuart E 
Barrans, Sharon L 
Beer, Philip A 
Painter, Daniel 
Smith, Alexandra G 

Abstract

Based on the profile of genetic alterations occurring in tumor samples from selected diffuse large B-cell lymphoma (DLBCL) patients, 2 recent whole-exome sequencing studies proposed partially overlapping classification systems. Using clustering techniques applied to targeted sequencing data derived from a large unselected population-based patient cohort with full clinical follow-up (n = 928), we investigated whether molecular subtypes can be robustly identified using methods potentially applicable in routine clinical practice. DNA extracted from DLBCL tumors diagnosed in patients residing in a catchment population of ∼4 million (14 centers) were sequenced with a targeted 293-gene hematological-malignancy panel. Bernoulli mixture-model clustering was applied and the resulting subtypes analyzed in relation to their clinical characteristics and outcomes. Five molecular subtypes were resolved, termed MYD88, BCL2, SOCS1/SGK1, TET2/SGK1, and NOTCH2, along with an unclassified group. The subtypes characterized by genetic alterations of BCL2, NOTCH2, and MYD88 recapitulated recent studies showing good, intermediate, and poor prognosis, respectively. The SOCS1/SGK1 subtype showed biological overlap with primary mediastinal B-cell lymphoma and conferred excellent prognosis. Although not identified as a distinct cluster, NOTCH1 mutation was associated with poor prognosis. The impact of TP53 mutation varied with genomic subtypes, conferring no effect in the NOTCH2 subtype and poor prognosis in the MYD88 subtype. Our findings confirm the existence of molecular subtypes of DLBCL, providing evidence that genomic tests have prognostic significance in non-selected DLBCL patients. The identification of both good and poor risk subtypes in patients treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) clearly show the clinical value of the approach, confirming the need for a consensus classification.

Description

Keywords

Adolescent, Adult, Aged, Aged, 80 and over, Biomedical Research, Child, Child, Preschool, Cohort Studies, Community Networks, DNA Mutational Analysis, Female, Gene Expression Profiling, Gene Expression Regulation, Neoplastic, Hematologic Neoplasms, Humans, Infant, Lymphoma, Large B-Cell, Diffuse, Male, Medical Oncology, Middle Aged, Molecular Diagnostic Techniques, Neoplasm Staging, Prognosis, Transcriptome, United Kingdom, Exome Sequencing, Young Adult

Journal Title

Blood

Conference Name

Journal ISSN

0006-4971
1528-0020

Volume Title

135

Publisher

American Society of Hematology

Rights

All rights reserved
Sponsorship
Medical Research Council (MC_PC_12009)
Medical Research Council (MR/M008584/1)
Medical Research Council (MC_PC_17230)
Bloodwise (grant number 15037) funded the majority of this study. Genetic sequencing was funded by 14M Genomics, a start-up company that ceased trading February 2016. DJH was funded by a clinician scientist fellowship from the MRC and receives core funding from Wellcome and MRC to the Wellcome-MRC Cambridge Stem Cell Institute. Some of the analysis in this study was performed on the “Viking” high performance computing cluster at the University of York.12