Comprehensive histopathological diagnostics of aggressive B-cell lymphomas based on the updated criteria of the World Health Organisation's 2017 classification.

Revision of the fourth edition of the World Health Organisation (WHO) Classification of Haematopoietic and Lymphatic Tissues, which was published in 2017, introduced important changes updating the biology, pathology, genetics, and clinical presentation of aggressive B-cell lymphomas. High grade B-cell lymphomas (HGBLs) replaced B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma, the new provisional entity Burkitt-like lymphoma with 11q aberration was identified, and some categories were upgraded, e.g. EBV-positive diffuse large B-cell lymphoma, not otherwise specified. Still the histopathological diagnostics is based on morphology and immunoprofile, but to define the HGBLs evaluation of MYC, BCL2, and BCL6 gene statuses is required. According to the presented WHO criteria, in the comprehensive histopathological diagnostics of aggressive B-cell lymphomas a highly specialised diagnostic team including a pathologist, a molecular biologist, a geneticist, a haematologist, and immunophenotyping technicians is needed.

The pathobiology of select adolescent young adult lymphomas.

Lymphoid cancers are among the most frequent cancers diagnosed in adolescents and young adults (AYA), ranging from approximately 30%-35% of cancer diagnoses in adolescent patients (age 10-19) to approximately 10% in patients aged 30-39 years. Moreover, the specific distribution of lymphoid cancer types varies by age with substantial shifts in the subtype distributions between pediatric, AYA, adult, and older adult patients. Currently, biology studies specific to AYA lymphomas are rare and therefore insight into age-related pathogenesis is incomplete. This review focuses on the paradigmatic epidemiology and pathogenesis of select lymphomas, occurring in the AYA patient population. With the example of posttransplant lymphoproliferative disorders, nodular lymphocyte-predominant Hodgkin lymphoma, follicular lymphoma (incl. pediatric-type follicular lymphoma), and mediastinal lymphomas (incl. classic Hodgkin lymphoma, primary mediastinal large B cell lymphoma and mediastinal gray zone lymphoma), we here illustrate the current state-of-the-art in lymphoma classification, recent molecular insights including genomics, and translational opportunities. To improve outcome and quality of life, international collaboration in consortia dedicated to AYA lymphoma is needed to overcome challenges related to siloed biospecimens and data collections as well as to develop studies designed specifically for this unique population.

CAR T-Cell Therapy for B-Cell non-Hodgkin Lymphoma and Chronic Lymphocytic Leukemia: Clinical Trials and Real-World Experiences.

Chimeric antigen receptor-modified (CAR) T cells targeting CD19 have revolutionized the treatment of relapsed or refractory aggressive B-cell lymphomas, and their use has increased the cure rate for these cancers from 10 to 40%. Two second-generation anti-CD19 CAR T-cell products, axicabtagene ciloleucel and tisagenlecleucel, have been approved for use in patients, and the approval of a third product, lisocabtagene maraleucel, is expected in 2020. The commercial availability of the first two products has facilitated the development of real-world experience in treating relapsed or refractory aggressive B-cell lymphomas, shed light on anti-CD19 CAR T-cell products' feasibility in trial-ineligible patients, and raised the need for strategies to mitigate the adverse effects associated with anti-CD19 CAR T-cell therapy, such as cytokine release syndrome, neurotoxicity, and cytopenia. In addition, promising clinical data supporting the use of anti-CD19 CAR T-cell therapy in patients with indolent B-cell lymphomas or chronic lymphocytic leukemia have recently become available, breaking the paradigm that these conditions are not curable. Multiple clinical CAR T-cell therapy-based trials are ongoing. These include studies comparing CAR T-cell therapy to autologous stem cell transplantation or investigating their use at earlier stages of disease, novel combinations, and novel constructs. Here we provide a thorough review on the use of the anti-CD19 CAR T-cell products axicabtagene ciloleucel, tisagenlecleucel and lisocabtagene maraleucel in patients with indolent or aggressive B-cell lymphoma or with chronic lymphocytic leukemia, and present novel CAR T cell-based approaches currently under investigation in these disease settings.

Flow Cytometry of B-Cell Neoplasms.

Flow cytometric evaluation is considered a standard ancillary study for the diagnosis of most B-cell lymphoproliferative disorders. Establishing a neoplastic B-cell population depends on identification of light chain restriction or lack of light chain expression in mature neoplasms and demonstration of aberrant antigen expression in both immature and mature neoplasms, as compared with normal counterparts. The immunophenotypes of the most common B-cell neoplasms are herein described, with an emphasis on their immunophenotypic differential diagnosis and prognostic and therapeutic implications.

Concurrent inhibition of MYC and BCL2 is a potentially effective treatment strategy for double hit and triple hit B-cell lymphomas.

Double hit lymphoma or triple hit lymphoma (DHL/THL) is a rare form of aggressive B-Cell Lymphoma. Overexpression of MYC, BCL2 or/and BCL6 due to genomic rearrangements are the key molecular features of DHL/THL. Patients with DHL/THL show very aggressive disease course and poor survival due to the lack of effective treatment modalities. Here, we established new THL cell model and assessed its in vitro growth characteristics along with the DHL cell line in response to potent MYC inhibitors, 10058-F4 and JQ-1, and a BCL2 inhibitor, ABT-199, with or without chemotherapeutic agent vincristine or doxorubicin. We found that 10058-F4, JQ-1 or ABT-199 exposure as a single agent inhibited the growth of DHL/THL cells in a dose-dependent manner. Combined exposure of 10058-F4 or JQ-1 and ABT-199 as well as vincristine or doxorubicin markedly suppressed the growth of DHL/THL cells compared with the single treatment. As assessed by multiple approaches, apoptosis induced by ABT-199, 10058-F4 or JQ-1 was underlying cause of the observed growth suppression. These findings suggest that co-inhibition of MYC and BCL2 signaling is a promising therapeutic strategy for patients with DHL/THL lymphomas.

HIV-1 Tat induces DNMT over-expression through microRNA dysregulation in HIV-related non Hodgkin lymphomas.

BACKGROUND: A close association between HIV infection and the development of cancer exists. Although the advent of highly active antiretroviral therapy has changed the epidemiology of AIDS-associated malignancies, a better understanding on how HIV can induce malignant transformation will help the development of novel therapeutic agents. METHODS: HIV has been reported to induce the expression of DNMT1 in vitro, but still no information is available about the mechanisms regulating DNMT expression in HIV-related B-cell lymphomas. In this paper, we investigated the expression of DNMT family members (DNMT1, DNMT3a/b) in primary cases of aggressive B-cell lymphomas of HIV-positive subjects. RESULTS: Our results confirmed the activation of DNMT1 by HIV in vivo, and reported for the first time a marked up-regulation of DNMT3a and DNMT3b in HIV-positive aggressive B-cell lymphomas. DNMT up-regulation in HIV-positive tumors correlated with down-regulation of specific microRNAs, as the miR29 family, the miR148-152 cluster, known to regulate their expression. Literature reports the activation of DNMTs by the human polyomavirus BKV large T-antigen and adenovirus E1a, through the pRb/E2F pathway. We have previously demonstrated that the HIV Tat protein is able to bind to the pocket proteins and to inactivate their oncosuppressive properties, resulting in uncontrolled cell proliferation. Therefore, we focused on the role of Tat, due to its capability to be released from infected cells and to dysregulate uninfected ones, using an in vitro model in which Tat was ectopically expressed in B-cells. CONCLUSIONS: Our findings demonstrated that the ectopic expression of Tat was per se sufficient to determine DNMT up-regulation, based on microRNA down-regulation, and that this results in aberrant hypermethylation of target genes and microRNAs. These results point at a direct role for Tat in participating in uninfected B-cell lymphomagenesis, through dysregulation of the epigenetical control of gene expression.

c-MYC-miRNA circuitry: a central regulator of aggressive B-cell malignancies.

MYC (c-Myc) deregulation has been frequently associated with aggressive lymphomas and adverse clinical outcome in B-cell malignancies. MYC has been implicated in controlling the expression of miRNAs, and MYC-regulated miRNAs affect virtually all aspects of the hallmarks of MYC-driven lymphomas. Increasing evidence has indicated that there is significant cross-talk between MYC and miRNAs, with MYC regulating expression of a number of miRNAs, resulting in widespread repression of miRNA and, at the same time, MYC being subjected to regulation by miRNAs, leading to sustained MYC activity and the corresponding MYC downstream pathways. Thus, these combined effects of MYC overexpression and downregulation of miRNAs play a central regulatory role in the MYC oncogenic pathways and MYC-driven lymphomagenesis. Here, we provide biological insight on the function of MYC-regulated miRNAs, the mechanisms of MYC-induced miRNA repression, and the complicated feedback circuitry underlying lymphoma progression, as well as potential therapeutic targets in aggressive B-cell lymphomas.