Biology subjects

Morin, R. D.

Publications and source records attributed to Morin, R. D..

11 recordsLinked to original sources

bioRxiv2026

Developmental origins of thymic B-cell lymphomas

The thymus provides a specialized niche for lymphocyte differentiation, yet the developmental trajectories of its rare B-cell population and their relationship to thymic B-cell lymphomagenesis remain poorly understood. Here, we integrate single-cell multiomics and spatial profiling across human tissues to delineate a B-cell differentiation program selectively represented in the human thymus. This program links CCL17 and germinal center-like B-cell states along a trajectory distinct from canonical germinal center differentiation and can be recapitulated in vitro by signals operating in the thymic medulla. Extending this framework across human B-cell lymphomas, we identify an inherent malignant cell state in PMBCL that shares transcriptional and epigenetic features with CCL17 thymic B cells. This malignant state associates with early clonal positions in reconstructed B-cell receptor phylogenies and persists within tumor microenvironments distinct from the thymic niche. Together, these findings support a model in which thymus-specific B-cell differentiation programs are redeployed during thymic B-cell lymphomagenesis.

cancer biology↗

bioRxiv2025

LCR-modules: a collection of workflows for cancer genome analysis

The surge of genomic data from advanced sequencing technologies is outpacing current analytical pipelines. We introduce LCR-modules, an open-source suite of bioinformatics tools designed for flexible and automated cancer genome data analysis. LCR-modules enables reproducible analysis of diverse cancer genomics data at scale. The suite comprises 49 Snakemake-based workflows organized into three levels, facilitating tasks from low-level quality control to complex cohort-level analyses. LCR-modules supports various sequencing types and integrates pipelines such as mutation calling, expression quantification, and cohort-level aggregation, ensuring flexibility and reproducibility. LCR-modules represents a significant advancement in genomic data analysis, reducing barriers in reproducibility and scalability and has already been applied to a combination of exomes and genomes from over 10,800 samples.

bioinformatics↗

bioRxiv2025

Regulation of NFKBIZ by precise Regnase-1 endoribonuclease cleavage and subsequent uridylation

A conserved sequence in the 3'UTR of NFKBIZ mRNA has long been recognized as a regulator of cytokine production and interferon responses. We show that the endoribonuclease Regnase-1 controls NFKBIZ expression through a precise and modular RNA degradation mechanism. The structured core element undergoes specific endonucleolytic cleavage, while flanking upstream and downstream stem-loop modules, previously implicated in Regnase-1 recognition, act cooperatively to enhance cleavage efficiency by [~]25-fold. Following cleavage, the upstream fragment is rapidly uridylated, accelerating decay of the NFKBIZ open reading frame. This pathway explains how driver mutations - found in this RNA region - responsible for diffuse large B-cell lymphoma elevate NFKBIZ expression and how a segment of the SARS-CoV-2 genome - previously linked to NFKBIZ activation - suppresses Regnase-1 cleavage via hybridization to this regulatory RNA segment. Together, these findings define a mechanistic framework for Regnase-1-mediated control of NFKBIZ, linking its cleavage activity to both lymphomagenesis and viral pathogenesis.

biochemistry↗

bioRxiv2025

Multidimensional characterization of cellular ecosystems in Hodgkin lymphoma

The tissue architecture of classic Hodgkin Lymphoma (CHL) is unique among cancers and characterized by rare malignant Hodgkin and Reed-Sternberg cells that co-evolve with a complex ecosystem of immune cells in the tumor microenvironment (TME). The lack of a comprehensive systems-level interrogation has hindered the description of disease heterogeneity and clinically relevant molecular subtypes. Here, we employed an integrative, multimodal approach to characterize CHL tumors using malignant cell sequencing, spatial transcriptomics and imaging mass cytometry. We identified four molecular subtypes (CST, CN913, STB, and CN2P), each characterized by distinct clinical features, mutational patterns, malignant cell gene expression profiles, and spatial architecture involving immune cell populations. Functional modeling of CSF2RB mutations, a characteristic feature of the CST subtype, revealed dysregulated oncogenic signaling and unique TME crosstalk. These findings highlight the significance of multi-dimensional profiling in elucidating patterns of molecular alterations that drive immune ecosystems and underlie therapeutically exploitable vulnerabilities.

cancer biology↗

bioRxiv2025

The Origin, Diagnosis, and Prognosis of Oligomannose-Type Diffuse Large B Cell Lymphoma

The acquisition of N-glycosylation sites occupied by oligomannose-type glycans in the immunoglobulin complementarity-determining region (CDR) is an early clonal tumor-specific identifier of follicular lymphoma (FL). CDR-located N-glycosylation sites are also acquired in germinal-center-B-cell-like diffuse large B-cell lymphomas (GCB-DLBCL), but their significance is less defined. We used RNA-seq immunoglobulin assembly to determine the frequency and CDR location of the acquired N-glycosylation sites (AGS) in two large independent DLBCL cohorts. Composition of the glycans occupying the AGS was determined using liquid chromatography-mass spectrometry and correlated with cell-of-origin, FL signature (defined by EZB phenotype or BCL2 translocation), transcript profile, and clinical outcome. CDR-located AGS were observed in 41-46% of GCB-DLBCL but were rare in other DLBCL. Only CDR-located AGS of DLBCL with an FL signature were occupied by oligomannose-type glycans. These DLBCL were termed Mann-type DLBCL. Conversely, the AGS of the other DLBCL were either non-glycosylated or occupied by complex-type glycans. Mann-type status was an independent marker of short progression-free survival and overall survival. In contrast, the other GCB-DLBCL cases, including those with an FL signature but without AGS, had the best outcomes. Mann-type DLBCL overexpressed gene-sets of cell growth, survival, and cycling, and underexpressed proinflammatory and apoptotic pathways, irrespective of concomitant MYC translocations. Acquisition of Mann-type glycans is a highly selective environmental pressure, identifying the most aggressive GCB-DLBCL with an origin related to FL. The detection of AGS in the CDR of GCB-DLBCLs with a BCL2 translocation defines Mann-type DLBCLs, refines prognosis and marks a precise tumor interaction to block early therapeutically. Key pointsO_LIAcquisition of Mann-type glycans is a tumor-specific environmental pressure identifying the most aggressive GCB-DLBCL with an origin related to FL. C_LIO_LIMann-type DLBCL can be diagnosed by the concomitant detection of AGS in the CDR and a BCL2 translocation. C_LI

cancer biology↗

bioRxiv2024

The CCL17-CCR4 axis is critical for mutant STAT6-mediated microenvironmental remodelling and therapeutic resistance in Relapsed/Refractory Diffuse Large B Cell Lymphoma

Relapsed and refractory Diffuse Large B Cell Lymphoma (rrDLBCL) presents a significant challenge in hematology-oncology, with approximately 30-40% of DLBCL patients experiencing relapse or resistance to treatment. This underscores the urgent need to better understand the molecular mechanisms governing therapeutic resistance. Signal Transducer and Activator of Transcription 6 (STAT6) has been previously identified as a gene with recurrent D419 gain-of-function mutations in rrDLCBL. When STAT6D419 mutations are present in DLBCL tumour cells, we have demonstrated that transcription of the chemokine CCL17 (aka TARC) is increased, and tumours have increased infiltration of CD4+ T cells. However, the significance of increased T cell infiltration had not been determined. In the present study, we developed a mouse model of STAT6D419N mutant DLBCL, that recapitulates the critical features of human STAT6D419 mutant DLBCL, including increased expression of phospho-STAT6, increased CD4+ T cell invasion, and resistance to doxorubicin treatment. With this model, we found CD4+ T cells in STAT6D419N tumours have higher expression of the receptor for CCL17, CCR4. Using ex vivo functional assays we demonstrate that STAT6D419N tumour cells are directly chemoattractive to CCR4+ CD4+ T cells, and when CCR4 is inhibited using a small molecule antagonist, CD4+ T cells in STAT6D419N tumours are reduced and STAT6D419N tumours regain therapeutic sensitivity to doxorubicin. Using PhenoCycler imaging of human rrDLBCL samples, we find that STAT6D419 tumours indeed have increased expression of phospho-STAT6+ and increased cellular interactions between phospho-STAT6+ tumour cells and CD4+/ CCR4+ CD4+ T cells. Thus, our data identify CCR4 as an attractive therapeutic target in STAT6D419 mutant rrDLBCL.

cancer biology↗

bioRxiv2023

Revisiting Reddy: A DLBCL Do-over

The 2017 study by Reddy et al described the comprehensive characterization of somatic drivers of diffuse large B-cell lymphoma using whole exome sequencing.1 After additional large studies relying on exome or whole genome sequencing were published, several oddities unique to the Reddy results have emerged. Seeking to explain the discrepancies, we reanalyzed their data using established open-source pipelines. This revealed thousands of mutations that could not be independently reproduced by these pipelines and a larger set of high-quality mutations that were not reported by Reddy. This caused an artificial under-representation of the mutation prevalence in many genes including clinically relevant hot spots affecting EZH2 and CD79B. More generally, the study had an under-representation of mutations in DLBCL genes that disproportionately affected genes known to have the highest mutation rates. The missing variants and the spurious variants can be attributed to distinct problems with the analytical approaches employed in that study. Our analysis also identified strong associations between mutations and patient outcome including TP53, KMT2D and PIM1, which were not found in the Reddy study. Overall, we demonstrate that this combination of errors influenced many of the central novel findings from their study rendering their results largely non-replicable. The full results of our analyses are included as supplemental items as a resource for other researchers with an interest in the genetics of B-cell lymphomas.

genomics↗

bioRxiv2021

Shared and distinct genetic features in human and canine B-cell lymphomas

Animal models of human cancers are an important tool for the development and preclinical evaluation of therapeutics. Canine B-cell lymphoma (cBCL) is an appealing model for human mature B-cell neoplasms due to the high sequence similarity in cancer genes to humans and inactive telomerase in adult tissues. We performed targeted sequencing on 86 canine patients from the Canine Comparative Oncology Genomic Consortium, with 61 confirmed as B-cell lymphomas. We confirmed a high frequency of mutations in TRAF3 (45%) and FBXW7 (20%) as has been reported by our group and others. We also note a higher frequency of DDX3X (20%) and MYC (13%) mutations in our canine cohort. We compared the pattern and incidence of mutations in cBCL to human diffuse large B-cell lymphoma (hDLBCL) and human Burkitt lymphoma (hBL). Canine MYC mutations displayed a focal pattern with 80% of mutations affecting the conserved phosphodegron sequence in MYC box 1, which are known to stabilize MYC protein. We also note that MYC and FBXW7 mutations do not co-occur in our cBCL cohort, leading to the hypothesis that these mutations represent alternative approaches to stabilize MYC in canine lymphoma. We observed striking differences in the pattern of DDX3X mutations in canine lymphoma as compared to hBL and uncovered a sex-specific pattern of DDX3X mutations in hBL that is not consistent with those identified in canine lymphomas. In sum, we describe key differences between cBCL and human mature B-cell lymphomas which may indicate differences in the biology of these cancers. This should be considered in future studies of cBCL as a model of human lymphomas.

cancer biology↗

bioRxiv2021

Non-coding NFKBIZ 3' UTR mutations promote cell growth and resistance to targeted therapies in diffuse large B-cell lymphoma

Amplifications and non-coding 3' UTR mutations affecting NFKBIZ have been identified as recurrent genetic events in diffuse large B-cell lymphoma (DLBCL). We confirm the prevalence and pattern of NFKBIZ 3' UTR mutations in independent cohorts and determine they are enriched in the ABC subtype as well as the recently described novel BN2/C1/NOTCH2 classes of DLBCL. Presently, the effects of and mechanism by which non-coding mutations can act as cancer drivers has been relatively unexplored. Here, we provide a functional characterization of these non-coding NFKBIZ 3' UTR mutations. We demonstrate that the resulting elevated expression of I{kappa}B-{zeta} confers growth advantage in DLBCL cell lines and primary germinal center B-cells as well as nominate novel I{kappa}B-{zeta} target genes with potential therapeutic implications. The limited responses to targeted treatments in DLBCL, particularly those targeting the NF-{kappa}B axis, led us to investigate and confirm that NFKBIZ 3' UTR mutations affect response to therapeutics and suggest it may be a useful predictive biomarker. Statement of SignificanceThrough functional characterization we reveal that non-coding NFKBIZ 3' UTR mutations are a common driver in DLBCL, and mutation status may be a relevant biomarker to predict poor response to therapeutics targeting the NF-{kappa}B pathway.

cancer biology↗

bioRxiv2020

Robust gene expression-based classification of cancers without normalization

Binary classification using gene expression data is commonly used to stratify cancers into molecular subgroups that may have distinct prognoses and therapeutic options. A limitation of many such methods is the requirement for comparable training and testing data sets. Here, we describe and demonstrate a self-training implementation of probability ratio-based classification prediction score (PRPS-ST) that facilitates the porting of existing classification models to other gene expression data sets. We demonstrate its robustness through application to two binary classification problems in diffuse large B-cell lymphoma using a diverse variety of gene expression data types and normalization methods.

bioinformatics↗

bioRxiv2017

Genome-wide discovery of somatic coding and regulatory variants in Diffuse Large B-cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) is an aggressive cancer originating from mature B-cells. Many known driver mutations are over-represented in one of its two molecular subgroups, knowledge of which has aided in the development of therapeutics that target these features. The heterogeneity of DLBCL determined through prior genomic analysis suggests an incomplete understanding of its molecular aetiology, with a limited diversity of genetic events having thus far been attributed to the activated B-cell (ABC) subgroup. Through an integrative genomic analysis we uncovered genes and non-coding loci that are commonly mutated in DLBCL including putative regulatory sequences. We implicate recurrent mutations in the 3UTR of NFKBIZ as a novel mechanism of oncogene deregulation and found small amplifications associated with over-expression of FC-{gamma} receptor genes. These results inform on mechanisms of NF-{kappa}B pathway activation in ABC DLBCL and may reveal a high-risk population of patients that might not benefit from standard therapeutics.

genomics↗