DUSP22-rearranged ALK-negative anaplastic large cell lymphoma is a pathogenetically distinct disease but can have variable clinical outcome

Optical genome mapping with whole genome sequencing identifies complex chromosomal structural variations in acute leukemia

Introduction

Chromosomal structural variations (SVs) play an important role in the formation of human cancers, including leukemias. However, many complex SVs cannot be identified by conventional tools, including karyotyping, fluorescence in situ hybridization, microarrays, and multiplex ligation-dependent probe amplification (MLPA).

Methods

Optical genome mapping (OGM) and whole genome sequencing (WGS) were employed to analyze five leukemia samples with SVs detected by karyotyping, MLPA, and RNA sequencing (RNA-seq). OGM was performed using the Saphyr chip on a Bionano Saphyr system. Copy number variation and rare variant assembly analyses were performed with Bionano software v3.7. WGS was analyzed by the Manta program for SVs.

Results

The leukemia samples had an average of 477 insertions, 457 deletions, and 32 inversions, which were significantly greater than those of the normal blood samples (p = 0.016, 0.028, and 0.028, respectively). In Case 1, OGM detected a sequential translocation between chromosomes 5, 8, 12, and 21 and ETV6::RUNX1 and BCAT1::BAALC gene fusions. Case 2 had two pathogenic SVs and a BCR::ABL1 fusion. Case 3 had one pathogenic SV and an IGH::DUSP22 fusion. Case 4 had two pathogenic SVs and a CBFB::MYH11 fusion. Case 5 had an STIL::TAL1 fusion. All breakpoint sequences were defined by WGS. An IGH::DUX4 fusion previously found by RNA-seq in Case 3 was not confirmed because DUX4, which has multiple pseudogenes, was refractory to OGM and WGS analyses.

Conclusion

OGM is a fundamental tool that complements G-banding analysis in identifying complex SVs in leukemia samples, and WGS effectively closes the gaps in OGM mapping.

Hematological Oncology journal women in lymphoma special issue: Latest updates in nodal peripheral T-cell lymphoma

In the last decade, there has been increased understanding of the pathologic features and biology of peripheral T cell lymphomas (PTCLs) through development of multi omics and molecular profiling techniques. In addition, international collaborations through multi center trials as well as prospective registry studies have improved our knowledge of host and tumor genomic factors and treatment factors affecting disease outcomes. In our review today, we aim to highlight the current epidemiology, latest advances in classification, disease biology and the evolving treatment landscape for nodal PTCLs.

A practical approach to the modern diagnosis and classification of T- and NK-cell lymphomas

ABSTRACT

T- and natural killer (NK)-cell lymphomas are neoplasms derived from immature T cells (lymphoblastic lymphomas), or more commonly, from mature T and NK cells (peripheral T-cell lymphomas, PTCLs). PTCLs are rare but show marked biological and clinical diversity. They are usually aggressive and may present in lymph nodes, blood, bone marrow, or other organs. More than 30 T/NK-cell-derived neoplastic entities are recognized in the International Consensus Classification and the classification of the World Health Organization (fifth edition), both published in 2022, which integrate the most recent knowledge in hematology, immunology, pathology, and genetics. In both proposals, disease definition aims to integrate clinical features, etiology, implied cell of origin, morphology, phenotype, and genetic features into biologically and clinically relevant clinicopathologic entities. Cell derivation from innate immune cells or specific functional subsets of CD4+ T cells such as follicular helper T cells is a major determinant delineating entities. Accurate diagnosis of T/NK-cell lymphoma is essential for clinical management and mostly relies on tissue biopsies. Because the histological presentation may be heterogeneous and overlaps with that of many benign lymphoid proliferations and B-cell lymphomas, the diagnosis is often challenging. Disease location, morphology, and immunophenotyping remain the main features guiding the diagnosis, often complemented by genetic analysis including clonality and high-throughput sequencing mutational studies. This review provides a comprehensive overview of the classification and diagnosis of T-cell lymphoma in the context of current concepts and scientific knowledge.

New insights into the biology of T-cell lymphomas

ABSTRACT

Peripheral T-cell lymphomas (PTCLs) encompass a heterogeneous group of postthymic T-cell lymphomas with >30 distinct subtypes associated with varied clinicopathological features. Unfortunately, the overall survival of the major PTCL subtypes is dismal and has not improved for decades; thus, there is an urgent unmet clinical need to improve diagnosis, therapies, and clinical outcomes. The diagnosis is often challenging, requiring a combinatorial evaluation of clinical, morphologic, and immunophenotypic features. PTCL pathobiology is difficult to investigate due to enormous intertumor and intratumor heterogeneity, limited tissue availability, and the paucity of authentic T-cell lymphoma cell lines or genetically faithful animal models. The application of transcriptomic profiling and genomic sequencing has markedly accelerated the discovery of new biomarkers, molecular signatures, and genetic lesions, and some of the discoveries have been included in the revised World Health Organization or International Consensus Classification. Genome-wide investigations have revealed the mutational landscape and transcriptomic profiles of PTCL entities, defined the cell of origin as a major determinant of T-cell lymphoma biology, and allowed for the refinement of biologically and clinically meaningful entities for precision therapy. In this review, we prioritize the discussion on common nodal PTCL subtypes together with 2 virus-associated T-cell and natural killer cell lymphomas. We succinctly review normal T-cell development, differentiation, and T-cell receptor signaling as they relate to PTCL pathogenesis and biology. This review will facilitate a better biological understanding of the different PTCL entities and their stratification for additional studies and target-directed clinical trials.

Pathobiology of nodal peripheral T-cell lymphomas: current understanding and future directions

Predominantly nodal is the most common clinical presentation of peripheral T- (and NK-) cell lymphomas (PTCL), which comprise three main groups of diseases: (i) systemic anaplastic large cell lymphomas (ALCL), whether positive or negative for anaplastic lymphoma kinase (ALK); (ii) follicular helper T-cell lymphomas (TFHL); and (iii) PTCL, not otherwise specified (NOS). Recent advances in the genomic and molecular characterization of PTCL, with enhanced understanding of pathobiology, have translated into significant updates in the latest 2022 classifications of lymphomas. ALK-negative ALCL is now recognized to be genetically heterogeneous, with identification of DUSP22 rearrangements in approximately 20-30% of cases, correlated with distinctive pathological and biological features. The notion of cell-of-origin as an important determinant of the classification of nodal PTCL is best exemplified by TFHL, considered as one disease or a group of related entities, sharing oncogenic pathways with frequent recurrent epigenetic mutations as well as a relationship to clonal hematopoiesis. Data are emerging to support that a similar cell-of-origin concept might be relevant to characterize meaningful subgroups within PTCL, NOS, based on cytotoxic and/or Th1 versus Th2 signatures. The small group of primary nodal Epstein-Barr virus-positive lymphomas of T- or NK-cell derivation, formerly considered PTCL, NOS, is now classified separately, due to distinctive features, and notably an aggressive course. This review summarizes current knowledge of the pathology and biology of nodal-based PTCL entities, with an emphasis on recent findings and underlying oncogenic mechanisms.

What is new in the classification of peripheral T cell lymphomas?

In this review focus article, we highlight the main modifications introduced in the latest 2022 International Consensus Classification and World Health Organization classification (ICC and WHO-HAEM5) of mature T (and NK) cell neoplasms (PTCLs) and consequent implications for diagnostic practice. The changes result from recent advances in the genomic and molecular characterization of PTCLs and enhanced understanding of their pathobiology. Specifically, consideration is given to the following groups of diseases: Epstein-Barr virus (EBV)-associated neoplasms; follicular helper T cell lymphoma; anaplastic large cell lymphomas; primary intestinal T and NK cell lymphomas and lymphoproliferative disorders; and PTCL, not otherwise specified.

Primary cutaneous anaplastic large cell lymphoma with over-expressed Ki-67 transitioning into systemic anaplastic large cell lymphoma: A case report

BACKGROUND

Primary cutaneous anaplastic large cell lymphoma (PC-ALCL) differs from systemic anaplastic large cell lymphoma (sALCL) in cell biological behavior, clinical features, treatment, and outcome. PC-ALCL has been reported to rarely transition into sALCL, but the underlying mechanism is not clear. Here we report such a case with certain characteristics that shed light on this.

CASE SUMMARY

Herein, we report a 43-year-old male with symptoms of a skin nodule and histologically confirmed PC-ALCL with high expression of Ki-67. After three months of observation, two skin nodules re-appeared with muscle layer involvement and was histologically confirmed as sALCL. Seventeen months after receiving six cycles of CHOP regimen, the patient had pain in the chest and back, cough, shortness of breath, and night sweats. This was confirmed as relapse of sALCL by immunohistochemistry and several organs, such as the lung were involved as shown by positron emission tomography/computed tomography. After four cycles of DICE plus chidamide regimens followed by auto-hematopoietic stem cell transplantation (ASCT), complete remission (CR) duration was achieved for twelve months while the patient was on maintenance with chidamide (20 mg) pills.

CONCLUSION

This case had significantly high expression of Ki-67 when diagnosed as PC-ALCL initially and then transitioned into sALCL, which is rare. Auto-ASCT combined with demethylation drugs effectively maintained CR and prolonged progression free survival.