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

ABSTRACT: 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.

ORGANISM(S): Homo sapiens

PROVIDER: GSE73791 | GEO | 2016/09/26

SECONDARY ACCESSION(S): PRJNA297892

REPOSITORIES: GEO

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Project description:Objective: Chromosomal 1q21.1 deletions and duplications are genomic disorders which are usually diagnosed postnatally. However, the genotype-phenotype correlations of 1q21.1 copy number variants (CNVs) during prenatal period are still not clear. This study aimed to provide a systematical summary of prenatal phenotypes for such genomic disorders. Methods: Twenty-six prenatal amniotic fluid samples diagnosed with 1q21.1 microdeletions/microduplications were obtained from pregnant women who opted for invasive prenatal testing. Karyotypic analysis and chromosomal microarray analysis (CMA) were performed for all cases simultaneously. The pregnancy outcomes and health conditions after birth for all cases were followed up. Meanwhile, prenatal cases with 1q21.1 microdeletions or microduplications in the literature were retrospectively collected. Results: Eleven pregnancies (11/8252, 0.13%) with 1q21.1 microdeletions and fifteen (15/8252, 0.18%) with 1q21.1 microduplications were identified. Among these 1q21.1 CNVs, four cases covered thrombocytopenia-absent radius (TAR) region, sixteen cases covered 1q21.1 recurrent microdeletion/microduplication region, and six cases covered all regions mentioned above. The prenatal abnormal ultrasound findings were recorded in four participants with 1q21.1 deletions and seven participants with 1q21.1 duplications. Finally, three cases with 1q21.1 deletions and five with 1q21.1 duplications terminated their pregnancies. Conclusion: 1q21.1 microdeletions were associated with increased nuchal translucency (NT), anomalies of urinary system and cardiovascular abnormalities, and 1q21.1 microduplications were correlated with cardiovascular malformations, nasal bone dysplasia and increased NT in prenatal setting. In addition, cerebral ventriculomegaly might be correlated with 1q21.1 microduplications. Considering the variable expressivity and incomplete penetrance of 1q21.1 CNVs, long term follow up after birth should be carried out for these cases. We identified 26 fetuses carrying the 1q21.1 microdeletions and microduplications using chromosomal microarray analysis. And diverse prenatal phenotypes and the critical genes involved in the deleted/duplicated regions were described in this study.

Project description:Gene copy-number variation, which provides the raw material for the evolution of novel genes, is surprisingly widespread in natural populations. Experimental evolution studies have demonstrated an extremely high spontaneous rate of origin of gene duplications. When organisms are suboptimally adapted to their environment, gene duplication may compensate for reduced fitness by amplifying promiscuous activity of a gene, or increasing dosage of a suboptimal gene. The overarching goal of this study is to inverstigate whether CNVs constitute a common mechanism of adaptive genetic change during compensatory evolution and to further characterize the role of natural selection in dictating their evolutionary spread at a population-genomic level. Outcrossing populations of C. elegans with low fitness were evolved for >200 generations and the frequencies of CNVs in these populations were analyzed by oligonucleotide array comparative genome hybridization, quantitative PCR, and single-worm PCR. Multiple duplications and deletions were detected in intermediate to high frequencies and several lines of evidence suggest that the changes in frequency were adaptive. 1) Many copy-number changes reached high frequency, were near fixation, or were fixed in a short time. 2) Many independent duplications and deletions in high frequency harbor overlapping regions which likely include genes that are under selection for either higher or lower rates of expression. 3) The size spectrum of deuplications and deletions in the adaptive recovery populations is significantly larger than that of spontaneous copy-number variants in mutation accumulation experiments. This is expected if larger CNVs are more likely to encompass genes that are being selected for altered gene dosage. Out results validate the great potential borne by gene copy-number changes for compensatory evolution and adaptation. Experimental genome evolution of copy-number variants in 25 experimental lines compared to 5 ancestral control lines.

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

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