Relapsed diffuse large B-cell lymphoma present different genomic patterns of alterations between early and late relapses

Despite major advances in first-line treatment, a significant proportion of patients with diffuse large B-cell lymphoma (DLBCL) will experience treatment failure. Time of relapse is a major prognostic parameter in this context, with a particularly poor prognosis for early relapse. Our purpose was to determine genomic alterations associated with early-relapsed (ER) and late-relapsed (LR) DLBCLs, using high resolution array-based comparative genomic hybridization and integrating structural abnormalities and gene expression of 39 samples from the Collaborative Trial in Relapsed Aggressive Lymphoma (CORAL) study. ER and LR DLBCLs present a similar landscape of large copy number variations (CNVs), with an average 14.89 and 16.11 CNVs per sample, respectively (p=0.81). Deletions of CDKN2A/B (28%) and IBTK (23%) were frequent events in relapsed DLBCLs. We identified 56 protein-coding genes and 25 long non-coding RNAs with significantly differential CNVs distribution between ER and LR DLBCLs with a false discovery rate < 0.05. In ER DLBCLs, genetic abnormalities were related to regulation of transcription, cell cycle and apoptosis, with duplications of histone H1T (31%), deletions of DIABLO (26%), PTMS (21%) and CK2B (15%). In LR DLBCLs, genetic aberrations were related to immune response, with alterations of IgHV (40%), IgKV (15%), and deletions of B2M (20%) and CD58 (10%), regulation of cell proliferation, with duplications of HES1 and DVL3 (25% and 20%, respectively) and regulation of transcription, with MTERF4 deletions (20%). This study provides new insights into the genetic abnormalities in relapsed DLBCLs. Dysregulation of cell cycle, apoptosis and gene transcription may indicate targeted therapy. Comparative study of CNVs in 19 early- and 20 late-relapsed DLBCLs