Update on the classification of T-cell lymphomas, Hodgkin lymphomas, and histiocytic/dendritic cell neoplasms

MicroRNAs and long non-coding RNAs In T-cell lymphoma: Mechanisms, pathway, therapeutic opportunities

T-cell lymphomas represent non-Hodgkin lymphomas distinguished by the uncontrolled proliferation of malignant T lymphocytes. Classifying these neoplasms and the ongoing investigation of their underlying biological mechanisms remains challenging. Significant subtypes encompass peripheral T-cell lymphomas, anaplastic large-cell lymphomas, cutaneous T-cell lymphomas, and adult T-cell leukemia/lymphoma. A systematic literature survey used electronic databases, including PubMed, Springer Link, Google Scholar, and Web of Science. Search keywords included "T-cell lymphoma," "therapeutic approaches," "RNA therapeutics," "microRNA," and "signaling pathways". T-cell lymphomas are believed to arise from a complex interplay of genetic predispositions and environmental factors. Epstein-Barr virus (EBV) and Human T-cell leukemia virus-1 (HTLV-1), have been implicated as potential etiologic agents. While the exact molecular mechanisms are under investigation, T-cell lymphomas are distinguished by aberrant proliferation of T-cells resulting from dysregulated gene expression. Contemporary research has emphasized the significance of non-coding RNAs, including microRNAs and long non-coding RNAs, in the etiology and advancement of T-cell lymphomas. Certain miRNAs function as tumor suppressors (e.g., miR-451, miR-31, miR-150, miR-29a), while others can act as oncogenes (e.g., miR-223, miR-17-92, miR-155). Additionally, lcRNAs are responsible for modulating gene expression, and their influence on T-cell function suggests their potential outcome as therapeutic targets. Current therapeutic strategies for T-cell lymphomas predominantly rely on chemotherapy, with emerging modalities encompassing immunotherapy and targeted therapies. Despite these advancements, a substantial subset of T-cell lymphomas remains challenging to manage, especially those in advanced stages or refractory to conventional treatments. RNA-based therapeutics represent a promising strategy, offering many advantages such as targeted therapy, potential for personalized medicine, reduced side effects, rapid development, and synergy with other therapies while facing challenges in delivery, immune response, and specificity. Future research should focus on improving delivery systems, modulating immune responses, and optimizing production to unlock its full potential. This review comprehensively explored T-cell lymphomas, delving into their classification, pathogenesis, and existing therapeutic options. Additionally, we explore the evolving function of non-coding RNAs in the pathogenesis of T-cell lymphoma. Furthermore, we discuss the potential of RNA-based therapeutics as a promising treatment strategy.

Exploring Differentially Expressed Genes and Immune Modulation in Diffuse Large B-Cell Lymphoma through RNA Sequencing Analysis

Background

Diffuse large B-cell lymphoma (DLBCL) is globally recognized as the most prevalent and aggressive subtype of non-Hodgkin lymphoma. While conventional treatments are effective initially, the disease can become resistant or relapse over time. This study aimed to examine the differentially expressed genes at the transcriptome level and molecular pathways in DLBCL patients.

Methods

This investigation utilized RNA sequencing analysis to compare differentially expressed gene samples from five diffuse large B-cell lymphoma patients with two healthy volunteers. These participants were admitted to UKM Medical Center, Kuala Lumpur between 2019 and 2020. The differentially expressed genes were identified using the DESeq2 R package (version 1.10.1) using a negative binomial distribution model. The obtained P values were corrected with the Benjamin and Hochberg method and identified using a False Discovery Rate threshold of <0.05, with log2 fold change (FC) of ≥2 or ≤-2.

Results

Results showed 73 differentially expressed genes between the two groups, among which 70 genes were downregulated, and three genes were upregulated. The differentially expressed genes analyzed with the Reactome pathway were significantly associated with the downregulation of antimicrobial humoral response (P<0.001), neutrophil degranulation (P<0.001), chemokine receptors bind chemokines (P=0.028), defensins (P=0.028) and metabolism of angiotensinogen (P=0.040).

Conclusion

These findings suggest that the identified pathways may contribute to cancer progression and weaken the immune response in diffuse large B-cell lymphoma patients. This study offers fresh insights into previously undiscovered downstream targets and pathways modulated by diffuse large B-cell lymphoma.

Extracellular Vesicles for Childhood Cancer Liquid Biopsy

Liquid biopsy involves the utilization of minimally invasive or noninvasive techniques to detect biomarkers in biofluids for disease diagnosis, monitoring, or guiding treatments. This approach is promising for the early diagnosis of childhood cancer, especially for brain tumors, where tissue biopsies are more challenging and cause late detection. Extracellular vesicles offer several characteristics that make them ideal resources for childhood cancer liquid biopsy. Extracellular vesicles are nanosized particles, primarily secreted by all cell types into body fluids such as blood and urine, and contain molecular cargos, i.e., lipids, proteins, and nucleic acids of original cells. Notably, the lipid bilayer-enclosed structure of extracellular vesicles protects their cargos from enzymatic degradation in the extracellular milieu. Proteins and nucleic acids of extracellular vesicles represent genetic alterations and molecular profiles of childhood cancer, thus serving as promising resources for precision medicine in cancer diagnosis, treatment monitoring, and prognosis prediction. This review evaluates the recent progress of extracellular vesicles as a liquid biopsy platform for various types of childhood cancer, discusses the mechanistic roles of molecular cargos in carcinogenesis and metastasis, and provides perspectives on extracellular vesicle-guided therapeutic intervention. Extracellular vesicle-based liquid biopsy for childhood cancer may ultimately contribute to improving patient outcomes.

Role of cytokine in malignant T-cell metabolism and subsequent alternation in T-cell tumor microenvironment

T cells are an important component of adaptive immunity and T-cell-derived lymphomas are very complex due to many functional sub-types and functional elasticity of T-cells. As with other tumors, tissues specific factors are crucial in the development of T-cell lymphomas. In addition to neoplastic cells, T- cell lymphomas consist of a tumor micro-environment composed of normal cells and stroma. Numerous studies established the qualitative and quantitative differences between the tumor microenvironment and normal cell surroundings. Interaction between the various component of the tumor microenvironment is crucial since tumor cells can change the microenvironment and vice versa. In normal T-cell development, T-cells must respond to various stimulants deferentially and during these courses of adaptation. T-cells undergo various metabolic alterations. From the stage of quiescence to attention of fully active form T-cells undergoes various stage in terms of metabolic activity. Predominantly quiescent T-cells have ATP-generating metabolism while during the proliferative stage, their metabolism tilted towards the growth-promoting pathways. In addition to this, a functionally different subset of T-cells requires to activate the different metabolic pathways, and consequently, this regulation of the metabolic pathway control activation and function of T-cells. So, it is obvious that dynamic, and well-regulated metabolic pathways are important for the normal functioning of T-cells and their interaction with the microenvironment. There are various cell signaling mechanisms of metabolism are involved in this regulation and more and more studies have suggested the involvement of additional signaling in the development of the overall metabolic phenotype of T cells. These important signaling mediators include cytokines and hormones. The impact and role of these mediators especially the cytokines on the interplay between T-cell metabolism and the interaction of T-cells with their micro-environments in the context of T-cells lymphomas are discussed in this review article.

The Role of NOTCH1, GATA3, and c-MYC in T Cell Non-Hodgkin Lymphomas

Lymphomas are heterogeneous malignant tumours of white blood cells characterised by the aberrant proliferation of mature lymphoid cells or their precursors. Lymphomas are classified into main types depending on the histopathologic evidence of biopsy taken from an enlarged lymph node, progress stages, treatment strategies, and outcomes: Hodgkin and non-Hodgkin lymphoma (NHL). Moreover, lymphomas can be further divided into subtypes depending on the cell origin, and immunophenotypic and genetic aberrations. Many factors play vital roles in the progression, pathogenicity, incidence, and mortality rate of lymphomas. Among NHLs, peripheral T cell lymphomas (PTCLs) are rare lymphoid malignancies, that have various cellular morphology and genetic mutations. The clinical presentations are usually observed at the advanced stage of the disease. Many recent studies have reported that the expressions of NOTCH1, GATA3, and c-MYC are associated with poorer prognosis in PTCL and are involved in downstream activities. However, questions have been raised about the pathological relationship between these factors in PTCLs. Therefore, in this review, we investigate the role and relationship of the NOTCH1 pathway, transcriptional factor GATA3 and proto-oncogene c-MYC in normal T cell development and malignant PTCL subtypes.

RHOA takes the RHOad less traveled to cancer

RAS and RHO GTPases function as signaling nodes that regulate diverse cellular processes. Whereas RAS mutations were identified in human cancers nearly four decades ago, only recently have mutations in two RHO GTPases, RAC1 and RHOA, been identified in cancer. RAS mutations are found in a diverse spectrum of human cancer types. By contrast, RAC1 and RHOA mutations are associated with distinct and restricted cancer types. Despite a conservation of RAS and RAC1 residues that comprise mutational hotspots, RHOA mutations comprise highly divergent hotspots. Whereas RAS and RAC1 act as oncogenes, RHOA may act as both an oncogene and a tumor suppressor. Thus, while RAS and RHO each take different mutational paths, they arrive at the same biological destination as cancer drivers.

Critical Role of Flow Cytometric Immunophenotyping in the Diagnosis, Subtyping, and Staging of T-Cell/NK-Cell Non-Hodgkin's Lymphoma in Real-World Practice: A Study of 232 Cases From a Tertiary Cancer Center in India

Background

T-cell/NK-cell non-Hodgkin’s lymphoma (T/NK-NHL) is an uncommon heterogeneous group of diseases. The current classification of T/NK-NHL is mainly based on histopathology and immunohistochemistry. In practice, however, the lack of unique histopathological patterns, overlapping cytomorphology, immunophenotypic complexity, inadequate panels, and diverse clinical presentations pose a great challenge. Flow cytometric immunophenotyping (FCI) is a gold standard for the diagnosis, subtyping, and monitoring of many hematological neoplasms. However, studies emphasizing the role of FCI in the diagnosis and staging of T/NK-NHL in real-world practice are scarce.

Methods

We included T-cell non-Hodgkin’s lymphoma (T-NHL) patients evaluated for the diagnosis and/or staging of T/NK-NHL using FCI between 2014 and 2020. We studied the utility of FCI in the diagnosis and subtyping of T/NK-NHL and correlated the FCI findings with the results of histopathology/immunohistochemistry. For correlation purposes, patients were categorized under definitive diagnosis and subtyping, inadequate subtyping, inadequate diagnosis, and misdiagnosis based on the findings of each technique.

Results

A total of 232 patients were diagnosed with T/NK-NHL. FCI findings provided definitive diagnoses in 198 patients and subtyping in 187/198 (95.45%) patients. The correlation between FCI and histopathological/immunohistochemistry results (n = 150) demonstrated an agreement on the diagnosis and subtyping in 69/150 (46%) patients. Of the remaining cases, the diagnosis and subtyping were inadequate in 64/150 (42.7%), and 14/150 (9.33%) were misdiagnosed on histopathology/immunohistochemistry results. FCI provided definitive diagnosis and subtyping in 51/64 (79.7%) patients. Among these, 13 patients diagnosed with peripheral T-cell lymphoma not-otherwise-specified were reclassified (angioimmunoblastic T-cell lymphoma (AITL)-11 and prolymphocytic leukemia-2) on FCI. It corrected the diagnosis in 14 patients that were misdiagnosed (6 B-cell NHL (B-NHL), 3 Hodgkin’s lymphoma, 1 acute leukemia, and 1 subcutaneous panniculitis-like T-cell lymphoma) and misclassified (3 T-NHL) on histopathological results. AITL was the commonest T-NHL misclassified on histopathological results. FCI also confirmed the definite involvement in 7/83 (8.4%) and 27/83 (32.5%) bone marrow (BM) samples reported as suspicious and uninvolved, respectively, on histopathological evaluation.

Conclusion

AITL was the most frequently diagnosed T/NK-NHL in this study. FCI provided a distinct advantage in detecting BM involvement by T/NK-NHL, especially in patients with low-level involvement. Overall, our study concluded that FCI plays a critical role in the diagnosis, subtyping, and staging of T/NK-NHL in real-world practice.

Urinary involvement in Erdheim-Chester disease: computed tomography imaging findings

PURPOSE

To describe the urological manifestations of Erdheim-Chester disease (ECD) and their computed tomography (CT) findings.

METHODS

We retrospectively reviewed 48 patients diagnosed with ECD at Peking Union Medical College Hospital from January 2014 to January 2020. Twenty-four patients exhibited urological manifestations. Their CT findings, including appearances of the involved area (e.g., perirenal space, renal sinus, ureters, renal arteries, and adrenal glands), occurrence rate of ECD involvement in each area, signal enhancement pattern after CT contrast agent administration, disease progression, and causes of hydronephrosis were discussed.

RESULTS

In 24 patients with evidence of ECD urological involvement, the most common manifestation was perirenal infiltration, appearing as "hairy kidney" on unenhanced CT scans and moderate signal enhancement on enhanced CT scans (17/24, 70.8%). Other manifestations included renal sinus infiltration (16/24, 66.7%), proximal ureter involvement (14, 58.3%), renal artery sheath (10, 41.7%), hydronephrosis (14, 58.3%), and adrenal glands involvement (8, 33.3%). The histiocytic infiltrate was mostly bilateral, starting from the perirenal space and spreading to the renal sinus and ureters. Hydronephrosis was usually associated with infiltration of ureters.

CONCLUSION

Kidneys are the most common visceral organs affected by ECD. CT scanning is not only advantageous in early diagnosis, but also critical for designing the treatment regime for patients with ECD.

Aggressive T-cell lymphomas: 2021 Updates on diagnosis, risk stratification and management

INTRODUCTION

Aggressive T-cell lymphomas continue to have a poor prognosis. There are over 27 different subtypes of peripheral T-cell lymphoma (PTCL), and we are now beginning to understand the differences between the various subtypes beyond histologic variations.

MOLECULAR PATHOGENESIS OF VARIOUS SUBTYPES OF PTCL

Gene expression profiling (GEP) can help in diagnosis and prognostication of various subtypes including PTCL-nos and anaplastic large cell lymphoma (ALCL). In addition, mutational analysis is now being incorporated in clinical trials of novel agents to evaluate various biomarkers of response to allow better therapeutic choices for patients.

TARGETED THERAPIES

There are many targeted agents currently in various stages of clinical trials for PTCL that take advantage of the differential expression of specific proteins or receptors in PTCL tumors. This includes the CD30 directed antibody drug conjugate brentuximab vedotin. Other notable targets are CD25, CCR4, inhibition of PI3kinase - m TOR and JAK/STAT pathways. The ALK inhibitors are promising for ALK expressing tumors.

IMMUNOTHERAPIES

Allogeneic stem cell transplant continues to be the curative therapy for most aggressive subtypes of PTCL. The use of checkpoint inhibitors in the treatment of PTCL is still controversial. The most promising results have been seen in cases of extranodal natural killer cell/T-cell (ENK/T) lymphomas and cutaneous T-cell lymphomas (CTCL). Bispecific antibody based treatments as well as CAR-T cell based therapies are in clinical trials.

Endovascular Repair for Abdominal Aortic Rupture Caused by Periaortic Mantle Cell Lymphoma

A 72-year-old man was referred to our hospital for the suspicion of ruptured abdominal aortic aneurysm. Before admission, he was suspected of having a malignant lymphoma and underwent excisional biopsy in his right groin. A contrast enhanced computed tomography scan revealed a massive retroperitoneal hematoma with an extravasation arising from the infrarenal abdominal aorta coexisting with an extensive retroperitoneal mass surrounding the aorta. An emergency endovascular aneurysm repair was performed and the postoperative course was uneventful. After the treatment, histological examination of the previous biopsy confirmed the diagnosis of mantle cell lymphoma.

Clinical Remission in a 72-Year-Old Patient with a Massive Primary Cutaneous Peripheral T-Cell Lymphoma-NOS of the Eyelid, Following Combination Chemotherapy with Etoposide Plus COP

Peripheral T-cell lymphoma not otherwise specified (PTCL-NOS) is the rarest subtype of primary cutaneous lymphoma, accounting for approximately 2% of cutaneous lymphomas. The rarity of primary cutaneous PTCL-NOS means that there is a paucity of data regarding clinical and histopathological features and its clinical course. This malignancy is an aggressive and life-threatening hematological malignancy that often presents mimicking other less severe plaque-like skin conditions. Due to the nonspecific nature of these lesions, CD4-positive cutaneous T-cell lymphoma (CTCL) is often misdiagnosed as either mycosis fungoides or Sezary syndrome. We describe a patient who presented with a large tumoral mass in the right frontal area, with involvement of the right upper eyelid and the ocular globe, causing loss of vision greatly impacting the quality of life. Biopsy revealed primary cutaneous PTCL-NOS, treated successfully with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) plus etoposide combination chemotherapy. As elderly patients are indicated to receive attenuated doses of chemotherapy, CHOP-based regimens represent viable options.