Human T-cell Lymphotropic Virus Type I–Associated Adult T-cell Leukemia–Lymphoma: New Directions in Clinical Research

TIGIT expression on neoplastic cells is a poor prognostic factor for adult T-cell leukaemia/lymphoma

Adult T-cell leukaemia/lymphoma (ATLL) is an aggressive peripheral T-cell neoplasm with a poor prognosis. T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domains (TIGIT) is an immune checkpoint receptor expressed on T and natural killer cells. Although increased TIGIT expression in the tumour microenvironment is associated with poor prognosis in various neoplasms, its relevance in ATLL remains unknown. Herein, we investigated the clinicopathological impact of TIGIT expression on ATLL using immunohistochemistry. TIGIT expression was detected in 21 of 84 patients (25%). A partial association between the clinical features and immune checkpoint molecules and the expression of TIGIT was found including sIL-2R, CD86 and GITR. TIGIT-positive patients [median survival time (MST) 8.9 months, 95% confidence interval (CI) 7.7-15.6] had inferior overall survival compared with TIGIT-negative patients (MST 18.7 months, 95% CI 12.0-36.4) (p=0.0124]. TIGIT expression maintained its prognostic value for overall survival in both univariate and multivariate analyses [hazard ratio (HR) 1.909; 95% CI 1.044-3.488; p=0.0356]. Further studies are required to clarify the clinical and biological significance of TIGIT expression in patients with ATLL.

Novel computational and drug design strategies for the inhibition of human T-cell leukemia virus 1-associated lymphoma by Astilbin derivatives

Human T-cell leukemia virus 1 (HTLV-1) associated lymphoma is a devastating malignancy triggered by HTLV-1 infections. We employeda comprehensive drug design and computational strategy in this work to explore the inhibitory activitiesof Astilbin derivatives against HTLV-1-associated lymphoma. We evaluated the stability, binding affinities, and various computational analysis of Astilbin derivatives against target proteins, such as HTLV-1 main protease and HTLV-1 capsid protein. The root mean square deviation (RMSD), root mean square fluctuation, radius of gyration, hydrogen bond analysis, principal component analysis (PCA) and dynamic cross-correlation matrix (DCCM) were applied to characterize these protein-ligand interactions further. Ligand-03 and ligand-04 exhibited notable binding affinity to HTLV-1 capsid protein, while ligand-05 displayed high binding affinity to HTLV-1 protease. MD simulation analysis revealed that ligand-03, bound to HTLV-1 capsid protein, demonstrated enhanced stability with lower RMSD values and fewer conformational changes, suggesting a promising binding orientation. Ligand-04, despite stable binding, exhibited increased structural deviations, making it less suitable. Ligand-05 demonstrated stable binding to HTLV-1 protease throughout the simulation period at 100 nanoseconds. Hydrogen bond analysis indicated that ligand-05 formed persistent hydrogen bonds with significantresidues, contributing to its stability. PCA highlighted ligand-03's more remarkable conformational changes, while DCCM showed ligand-05's distinct dynamics, indicating its different behavior in the complex. Furthermore, binding free energy calculations supported the favorable interactions of ligand-03 and ligand-04 with HTLV-1 capsid protein, while ligand-05 showed weaker interactions with HTLV-1 protease. Molecular electrostatic potential and frontier molecular orbital analyses provided insights into these compounds' charge distribution and stability. In conclusion, this research found Astilbin derivatives as potential inhibitors of HTLV-1-associated lymphoma. Future attempts at drug development will benefit from the steady interaction landscape provided by Ligand-03, Ligand-04 and Ligand-05, which showed the most attractive binding profile with the target protein. These results open up new opportunities for innovative drug development, and more experimental testing should be done between Astilbin derivatives and HTLV-1-associated lymphoma.Communicated by Ramaswamy H. Sarma.

Th17/IL-17 Axis in HTLV-1-Associated Myelopathy Tropical Spastic Paraparesis and Multiple Sclerosis: Novel Insights into the Immunity During HAMTSP

Human T lymphotropic virus-associated myelopathy/tropical spastic paraparesis (HTLV/TSP), also known as HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP), and multiple sclerosis (MS) are chronic debilitating diseases of the central nervous system; although the etiology of which is different, similarities have been observed between these two demyelinating diseases, especially in clinical manifestation and immunopathogenesis. Exorbitant response of the immune system to the virus and neurons in CNS is the causative agent of HAM/TSP and MS, respectively. Helper T lymphocyte-17 cells (Th17s), a component of the immune system, which have a proven role in immunity and autoimmunity, mediate protection against bacterial/fungal infections. The role of these cells has been reviewed in several CNS diseases. A pivotal role for Th17s is presented in demyelination, even more axial than Th1s, during MS. The effect of Th17s is not well determined in HTLV-1-associated infections; however, the evidence that we have supplied in this review illustrates the attendance, also the role of Th17 cells during HAM/TSP. Furthermore, for better conception concerning the trace of these cells in HAM/TSP, a comparative characterization with MS, the resembling disease, has been applied here.

Current and emerging therapeutic strategies in adult T-cell leukemia-lymphoma

Adult T-cell leukemia-lymphoma (ATL) is classified into four clinical subtypes: acute, lymphoma, chronic, and smoldering. Chronic ATL is further divided into unfavorable and favorable chronic types according to serum lactate dehydrogenase, blood urea nitrogen, and serum albumin values. Acute, lymphoma, and unfavorable chronic types are categorized as aggressive ATL, whereas favorable chronic and smoldering types are categorized as indolent ATL. Intensive chemotherapy alone is not sufficient to prevent relapse of aggressive ATL. Allogeneic hematopoietic stem cell transplantation is a potential therapeutic option to cure aggressive ATL in younger patients. Reduced-intensity conditioning regimens have decreased transplantation-related mortality, and increased donor availability has dramatically improved transplant access. New agents, including mogamulizumab, brentuximab vedotin, tucidinostat, and valemetostat, have recently become available for patients with aggressive ATL in Japan. Here, I provide an overview of recent advances in therapeutic strategies for ATL.

Regulation of human T-cell leukemia virus type 1 antisense promoter by myocyte enhancer factor-2C in the context of adult T-cell leukemia and lymphoma

Adult T-cell leukemia and lymphoma (ATLL) is an intractable T-cell neoplasia caused by a retrovirus, namely human T-cell leukemia virus type 1 (HTLV-1). Patients suffering from ATLL present a poor prognosis and have a dearth of treatment options. In contrast to the sporadic expression of viral transactivator protein Tax present at the 5' promoter region long terminal repeats (LTR), HTLV-1 bZIP gene (HBZ) is encoded by 3'LTR (the antisense promoter) and maintains its constant expression in ATLL cells and patients. The antisense promoter is associated with selective retroviral gene expression and has been an understudied phenomenon. Herein, we delineate the activity of transcription factor MEF (myocyte enhancer factor)-2 family members, which were found to be enriched at the 3'LTR and play an important role in the pathogenesis of ATLL. Of the four MEF isoforms (A to D), MEF-2A and 2C were highly overexpressed in a wide array of ATLL cell lines and in acute ATLL patients. The activity of MEF-2 isoforms were determined by knockdown experiments that led to decreased cell proliferation and regulated cell cycle progression. High enrichment of MEF-2C was observed at the 3'LTR along with cofactors Menin and JunD resulting in binding of MEF-2C to HBZ at this region. Chemical inhibition of MEF-2 proteins resulted in the cytotoxicity of ATLL cells in vitro and reduction of proviral load in a humanized mouse model. Taken together, this study provides a novel mechanism of 3'LTR regulation and establishes MEF-2 signaling a potential target for therapeutic intervention for ATLL.

Blocking cholesterol efflux mechanism is a potential target for anti-lymphoma therapy

Cholesterol is an essential plasma membrane lipid for the maintenance of cellular homeostasis and cancer cell proliferation. Free cholesterol is harmful to cells; therefore, excessive free cholesterol must be quickly esterified by acetyl-coenzyme A:cholesterol acetyltransferase (ACAT) and exported by scavenger receptor class B member I (SR-BI) or ATP-binding cassette protein A1 (ABCA1) from specific cells such as macrophage foam cells, which contain cholesteryl ester-derived vacuoles. Many vacuoles are present in the cytoplasm of Burkitt's lymphoma cells. In this study, we observed that these "vacuoles" are often seen in high-grade lymphomas. Cell culture study using lymphoma cell lines found that esterified cholesterol is the main component of these "vacuoles." and the expression of cholesterol metabolism-related molecules was significantly upregulated in lymphoma cell lines, with SR-BI and ACAT inhibitors (BLT-1 and CI-976, respectively) impeding lymphoma cell proliferation. Cytoplasmic free cholesterol was increased by ACAT and SR-BI inhibitors, and the accumulation of free cholesterol induced lymphoma cell apoptosis via inducing endoplasmic reticulum stress. Furthermore, synergistic effects of SR-BI and ACAT inhibitors were observed in a preclinical study. SR-BI inhibitor administration suppressed lymphoma progression in a tumor-bearing mouse model, whereas ACAT inhibitor did not. Therefore, SR-BI inhibitors are potential new antilymphoma therapeutics that target cholesterol metabolism.

Transcription Independent Stimulation of Telomerase Enzymatic Activity by HTLV-I Tax Through Stimulation of IKK

The persistence and spreading of HTLV-I infected cells relies upon their clonal expansion through cellular replication. The development of adult T cell leukemia (ATLL) occurs decades following primary infection by HTLV-I. Moreover, identical provirus integration sites have been found in samples recovered several years apart from infected individuals. These observations suggest that infected cells persist in the host for an extended period of time. To endure long term proliferation, HTLV-I pre-leukemic cells must acquire critical oncogenic events, two of which are the bypassing of apoptosis and replicative senescence. In the early stages of disease, interleukin-2 (IL-2)/IL-2R signaling likely plays a major role in combination with activation of anti-apoptotic pathways. Avoidance of replicative senescence in HTLV-I infected cells is achieved through reactivation of human telomerase (hTERT). We have previously shown that HTLV-I viral Tax transcriptionally activates the hTERT promoter. In this study we demonstrate that Tax can stimulate hTERT enzymatic activity independently of its transcriptional effects. We further show that this occurs through Tax-mediated NF-KB activating functions. Our results suggest that in ATLL cells acquire Tax-transcriptional and post-transcriptional events to elevate telomerase activity.

Tissue Pathogens and Cancers: A Review of Commonly Seen Manifestations in Histo- and Cytopathology

Tissue pathogens are commonly encountered in histopathology and cytology practice, where they can present as either benign mimickers of malignancy or true malignancies. The aim of this review is to provide a timely synthesis of our understanding of these tissue pathogens, with an emphasis on pertinent diagnostic conundrums associated with the benign mimickers of malignancy that can be seen with viral infections and those which manifest as granulomas. The oncogenic pathogens, including viruses, bacteria, and parasites, are then discussed with relationship to their associated malignancies. Although not exhaustive, the epidemiology, clinical manifestations, pathogenesis, and histological findings are included, along with a short review of emerging therapies.

Epidemiology of adult T-cell leukemia-lymphoma in Japan: An updated analysis, 2012-2013

Adult T‐cell leukemia‐lymphoma (ATL) is a T‐cell malignancy that is endemic to Japan. In this latest nationwide study of ATL, we collected the data from 4 nationwide registries of patients diagnosed in 2012‐2013; the Hematology Blood Disease, the Skin Cancer Society, the Hospital‐Based Cancer Registries, and information from the hospitals that participated in the Japanese nationwide survey of ATL in 2010‐2011. In the present study, 2614 patients with ATL were diagnosed based on the registries, and 117 departments registered 1042 patients. Among these patients, 984 were eligible for analysis. The median age at diagnosis was 69 y. A larger proportion of patients with ATL older than 70 y was diagnosed with the lymphoma subtype, and more than half of the patients with ATL in the metropolitan areas were born in the human T‐cell leukemia virus type I (HTLV‐1)‐endemic areas of Kyushu/Okinawa, which are almost identical to the findings in our 2010‐2011 study. Additionally, we identified that patients with ATL migrated from the endemic areas for HTLV‐1 to the non‐endemic metropolitan areas. The present study was able to reduce the burden of searching each hospital and to update the clinico‐epidemiological characteristics of a large number of patients with ATL in Japan, suggesting the usefulness and feasibility of the novel data collection method. The establishment of a more sophisticated database management system for ATL is necessary for future continuous surveys.

Tumorigenesis and diagnostic practice applied in two oncogenic viruses: Epstein Barr virus and T-cell lymphotropic virus-1-Mini review

To date, seven viruses have been reliably connected to various forms of human cancer: Epstein Barr Virus (EBV), Kaposi's sarcoma-associated herpesvirus (KSHV), high-risk Human papillomavirus (HPV), Merkel Cell Polyomavirus (MCPV), Hepatitis B virus (HBV), hepatitis C virus (HCV), and Human T-cell leukemia virus type 1 (HTLV1). This mini-review summarizes two of these viruses, EPV and HTLV-1, in terms of their general pathway of infection, the key mechanism of cancer induction, and the prominent technologies used to detect the infections. EBV is the first discovered human oncovirus and HTLV - I is the first human retrovirus and both were discovered from patient with distinct lymphoma clinical condition. Both the viruses can immortalize lymphocytes invitro and lymphomas are common manifestation of majority oncogenic viruses. Lymphomagenesis are discovered in associated with EBV, HTLV-I, Human Immunodeficiency virus (HIV), Kaposi sarcoma - associated herpes virus and hepatitis c virus. Later the undefined mechanism behind the induction of cancer by these viruses was unveiled gradually along with the responsible cofactors and mimicry mechanism. These two viruses contrast in their genetic structure, location of the infection, and latency, yet clinically, they generate similar cancer disorders. The major focus of this study is to brief the mechanism of these two unrelated viral cancer promoting agents on how they simulate a condition similar to lymphoma which may or may not undergo mimicry and cofactor utilization process, handpicked and vital genes behind the transformation mechanism are given accordingly.

Autophagy in Human T-Cell Leukemia Virus Type 1 (HTLV-1) Induced Leukemia

Viruses play an important role in the development of certain human cancers. They are estimated to contribute 16% to all human cancers. Human T-cell leukemia virus type 1 (HTLV-1) was the first human retrovirus to be discovered and is the etiological agent of adult T-cell leukemia/lymphoma (ATLL), an aggressive T-cell malignancy with poor prognosis. HTLV-1 viral proteins interact with mechanisms and proteins present in host cells for their own benefit, evading the immune system and promoting the establishment of disease. Several viruses manipulate the autophagy pathway to achieve their infective goals, and HTLV-1 is not the exception. HTLV-1 Tax viral protein engages NF-κB and autophagy pathways prone favoring viral replication and T cell transformation. In this review we focus on describing the relationship of HTLV-1 with the autophagy machinery and its implication in the development of ATLL.

Phyllanthin inhibits MOLT-4 leukemic cancer cell growth and induces apoptosis through the inhibition of AKT and JNK signaling pathway

Among cancers, leukemia is a multistep progression that involves genetic modifications of normal hematopoietic progenitor cells to cancerous cells. In recent times, leukemia cases and their mortality rate have increased rapidly. Therefore, the immense need for a therapeutic approach is crucial that can control this type of cancer. Phyllanthin is a lignan compound constituent from the Phyllanthus species and has numerous beneficial effects as a dietary component. The present study aims to determine the impact of phyllanthin on the MOLT-4 cytotoxic effect. MOLT-4 cells and MS-5 cells were cultured at different concentrations of phyllanthin (5, 10, 25, 50, 75, and 100 μM/ml), and the viability was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. The level of reactive oxygen species, the membrane potential of mitochondria, apoptosis by 2',7'-dichlorofluorescin-diacetate (DCF-DA), rhodamine, acridine orange (AO)/ethidium bromide (EB), 4',6-diamidino-2-phenylindole (DAPI)/propidium iodide (PI) staining, gene expression of signaling molecules, and protein levels were assessed by reverse-transcription polymerase chain reaction and western blot analysis. Phyllanthin did not show toxicity toward MS-5 cells and significantly decreased the cell viability of MOLT-4 cells with an IC₅₀ value of 25 µM/ml. Also, phyllanthin induced the production of reactive oxygen species and led to the loss of mitochondrial membrane potential. AO/EB and DAPI/PI staining fluorescent image confirmed the induction of apoptosis by phyllanthin treatment. The messenger RNA (mRNA) expression of cell cycle regulator cyclin D1, antiapoptotic gene Bcl-2, NF-κB, and TNF-α decreased, but the proapoptotic Bax mRNA expression was increased. The phosphorylated protein levels of p-PI3K1/2, p-ERK1/2, and p-AKT were decreased, whereas the levels of p-p38 and p-JNKT1/2 increased. Our results confirmed that phyllanthin inhibits the MOLT-4 cells, increases apoptosis, and inhibits MOLT-4 migration and cell invasion. Therefore, phyllanthin can be used as a potential target for leukemia treatment.

Effectiveness and safety of non-tumor necrosis factor inhibitor therapy for anti-human T-cell leukemia virus type 1 antibody-positive rheumatoid arthritis

OBJECTIVES

Our previous study showed that the effectiveness of tumor necrosis factor (TNF) inhibitors was attenuated in anti-human T-cell leukemia virus type 1 (HTLV-1) antibody-positive patients with rheumatoid arthritis (RA). We aimed to evaluate the effectiveness and safety of non-TNF inhibitors in anti-HTLV-1 antibody-positive patients with RA.

METHODS

We reviewed patients with RA who received abatacept or tocilizumab as the first biologic agent. We used the data of patients treated with TNF inhibitors from our previous study to compare the effectiveness between the anti-HTLV-1 antibody-positive patients treated with TNF inhibitors and non-TNF inhibitors using the inverse probability of treatment weights (IPTW) method.

RESULTS

A total of 359 patients were divided into anti-HTLV-1 antibody-negative and -positive patients of 332 and 27, respectively. No statistically significant difference was observed in the change in the clinical disease activity index between the anti-HTLV-1 antibody-positive and -negative patients. The results using the IPTW method showed a significant association between the non-TNF inhibitors treatment and a better response. None of the patients developed adult T-cell leukemia/lymphoma or HTLV-1-associated myelopathy/tropical spastic paraparesis during the 24 weeks.

CONCLUSION

Our results indicate that non-TNF inhibitors treatment is safety, and the effectiveness is not attenuated also in anti-HTLV-1 antibody-positive patients.

Non-cytotoxic 1,2,3-triazole tethered fused heterocyclic ring derivatives display Tax protein inhibition and impair HTLV-1 infected cells

Human T cell lymphotropic virus type 1 (HTLV-1) is a human retrovirus that infects approximately 10-20 million people worldwide and causes an aggressive neoplasia (adult T-cell leukemia/lymphoma - ATL). Therapeutic approaches for the treatment of ATL have variable effectiveness and poor prognosis, thus requiring strategies to identify novel compounds with activity on infected cells. In this sense, we initially screened a small series of 25 1,2,3-triazole derivatives to discover cell proliferation inhibitors and apoptosis inducers in HTLV-1-infected T-cell line (MT-2) for further assessment of their effect on viral tax activity through inducible-tax reporter cell line (Jurkat LTR-GFP). Eight promising compounds (02, 05, 06, 13, 15, 21, 22 and 25) with activity ≥70% were initially selected, based on a suitable cell-based assay using resazurin reduction method, and evaluated towards cell cycle, apoptosis and Tax/GFP expression analyses through flow cytometry. Compound 02 induced S phase cell cycle arrest and compounds 05, 06, 22 and 25 promoted apoptosis. Remarkably, compounds 22 and 25 also reduced GFP expression in an inducible-tax reporter cell, which suggests an effect on Tax viral protein. More importantly, compounds 02, 22 and 25 were not cytotoxic in human hepatoma cell line (Huh-7). Therefore, the discovery of 3 active and non-cytotoxic compounds against HTLV-1-infected cells can potentially contribute, as an initial promising strategy, to the development process of new drugs against ATL.

Human T-cell Leukemia Virus Type 1 and Strongyloides stercoralis: Partners in Pathogenesis

Infection with human T-cell leukemia/lymphoma virus type 1 (HTLV-1) has been associated with various clinical syndromes including co-infection with Strongyloides stercoralis, which is an intestinal parasitic nematode and the leading cause of strongyloidiasis in humans. Interestingly, HTLV-1 endemic areas coincide with regions citing high prevalence of S. stercoralis infection, making these communities optimal for elucidating the pathogenesis of co-infection and its clinical significance. HTLV-1 co-infection with S. stercoralis has been observed for decades in a number of published patient cases and case series; however, the implications of this co-infection remain elusive. Thus far, data suggest that S. stercoralis increases proviral load in patients co-infected with HTLV-1 compared to HTLV-1 infection alone. Furthermore, co-infection with HTLV-1 has been associated with shifting the immune response from Th2 to Th1, affecting the ability of the immune system to address the helminth infection. Thus, despite this well-known association, further research is required to fully elucidate the impact of each pathogen on disease manifestations in co-infected patients. This review provides an analytical view of studies that have evaluated the variation within HTLV-1 patients in susceptibility to S. stercoralis infection, as well as the effects of strongyloidiasis on HTLV-1 pathogenesis. Further, it provides a compilation of available clinical reports on the epidemiology and pathology of HTLV-1 with parasitic co-infection as well as data from mechanistic studies suggesting possible immunopathogenic mechanisms. Furthermore, specific areas of potential future research have been highlighted to facilitate advancing understanding of the complex interactions between these two pathogens.

TACC3 expression as a prognostic factor in aggressive types of adult T-cell leukemia/lymphoma patients

INTRODUCTION

Adult T-cell leukemia/lymphoma (ATLL) is a malignant peripheral T-cell neoplasm associated with human T-cell leukemia virus type-1 (HTLV-1). The acute and lymphoma subtypes are regarded as aggressive ATLLs, and the overall survival (OS) of patients remains poor. Transforming acidic coiled-coil-containing protein 3 (TACC3) regulates microtubules, which are associated with cancer-related proteins overexpressed in various cancers. Such a relationship has not been reported in hematopoietic tumors, including ATLL.

METHODS

We examined tissue microarrays of histological samples from 92 cases of aggressive ATLL and assessed clinical features, including TACC3 protein expression levels.

RESULTS

Compared with TACC3-low, TACC3-high ATLL patients were significantly older (P < .001), with a tendency toward pleomorphic variant over other morphological classifications (P = .019). TACC3-high patients (median survival time [MST] 10.6 months, confidence interval [CI] [6.27-15.6]) had poorer OS compared to TACC3-low patients (MST 20 months, CI [9.43-38.5]) (P = .0168). Moreover, multivariate analysis on TACC3 expression levels suggests that TACC3-high is an independent significant prognostic factor (HR, 1.700; 95% CI, 1.037-2.753; P = .0355).

CONCLUSION

Certain drugs that inhibit TACC3-overexpressing neoplastic cells are used clinically. Further studies might highlight a key role for TACC3 in the oncogenesis and progression of ATLL.

Molecular biology of human T cell leukemia virus

Human T cell leukemia virus type 1 (HTLV-1) is a horizontally transmitted virus infection of CD4+ lymphocytes which causes adult T cell leukemia-lymphoma (ATLL) and HTLV-associated myelopathy (HAM). The viral genome encodes two oncoproteins, transactivator protein (Tax) and helix basic zipper protein (HBZ), which are considered tumor initiator and maintenance factors, respectively. Tax is the primary inducer of clonal infected T cell expansion, and genetic instability. The immune response to Tax results in the selection of cells with little or no Tax expression, which have undergone genetic and epigenetic alterations that promote T cell activation, proliferation, and resistance to apoptosis. This selection of malignant cells occurs over several decades in 5% of infected individuals. Novel insights into the molecular details of each of these events has led to targeted therapies for ATLL.

Dermatological manifestations in patients with human T-cell lymphotropic virus at a reference service in Amazon

INTRODUCTION

Individuals infected with the human T-cell lymphotropic virus type 1 (HTLV-1) commonly present skin lesions, which may be a warning sign for the diagnosis of infection. This study describes the most prevalent skin manifestations in HTLV carriers attended at the clinic of Núcleo de Medicina Tropical (NMT) of the Universidade Federal do Pará (UFPA) in Belém, Pará, Brazil.

METHODS

This is a study of a series of cases of patients infected with human T-cell lymphotropic virus types 1 and 2 (HTLV-1/2) treated at NMT UFPA between 1999 and 2016. A descriptive analysis of data was applied.

RESULTS

Among 788 surveyed medical records in the service, 15.10% (n = 119) were referred to the dermatology clinic. From the series of cases that presented with skin lesions, 66.39% were female and 33.61% were male, and the average age of this group was 48 years. There was a predominance of patients with noninfectious inflammatory manifestations (64.2%), followed by infectious ones (24.6%), and 1.58% with lymphoproliferative diseases. As for the group of lesions, 45.26% of the erythematous-squamous type were observed, followed by dyschromia (24.21%), and eczematous (14.74%). One patient with a diagnosis of adult T-cell leukemia/lymphoma, another with parapsoriasis, and four with infective dermatitis are highlighted.

CONCLUSION

Skin disorders in the HLTV positive patient are important causes of referral to the dermatologist with etiological and skin lesions groups diversity. In the series of cases studied, lymphoproliferatives diseases and infective dermatitis associated with HTLV-1 were presented as a challenge for the diagnosis and clinical management of these patients.

Clinical features at transformation in adult T-cell leukemia-lymphoma with smoldering and chronic types

Watchful waiting (WW) is among the treatment options indicated for patients with indolent adult T-cell leukemia-lymphoma (ATL). However, we previously showed that the long-term prognosis of patients with smoldering and chronic ATL is often worse than expected, with many undergoing transformation to aggressive ATL. To identify clinical features associated with transformation of smoldering/chronic ATL, we retrospectively analyzed the clinical features of 44 patients (14 smoldering and 30 chronic) who experienced transformation during WW. An elevated lactate dehydrogenase (LDH) value was most often observed (n = 30) at the time of transformation, especially in the chronic type (n = 24). Major organ involvement, lymphadenopathy, and hypercalcemia were shown to be associated with transformation in transformed patients without elevated LDH. The median overall survival time after transformation was only 7.8 months, and the prognosis was poor after transformation in those fulfilling the criteria of acute type, similar to that of de novo aggressive ATL. Laboratory data, such as LDH, and clinical signs including exacerbation of performance status, skin lesions, and lymphadenopathy should all be monitored during WW to ensure appropriate timing of chemotherapy initiation. Identification of optimal predictive markers for transformation and new therapeutic options is warranted to improve outcomes in indolent ATL.

Adult T-Cell Leukemia-Lymphoma

Adult T-cell leukemia-lymphoma (ATL) is a peripheral T-lymphocyte malignancy caused by an RNA retrovirus, human T-cell leukemia virus type 1. ATL is clinically classified into four disease subtypes. The acute, lymphoma type, and cases of the chronic type involving unfavorable prognostic factors are regarded as aggressive ATL subtypes that require immediate treatment. Dose-intensified chemotherapy, such as the VCAP-AMP-VECP regimen, is considered to be the most recommended treatment for aggressive ATL. However, ATL remains difficult to cure and has an extremely poor prognosis, even when such chemotherapy is employed. Allogeneic stem cell transplantation is the only known curative therapy and is recommended for younger patients with aggressive ATL. However, because of the increasing age at the onset of ATL, only a small fraction of patients with ATL can benefit from such transplants; therefore, there is an unmet medical need for novel drugs. Mogamulizumab, a defucosylated, humanized anti-C-C motif chemokine receptor 4 (CCR4) monoclonal antibody, was developed using a novel glycoengineering technique. Mogamulizumab monotherapy achieved clinically meaningful effects in patients with relapsed aggressive ATL and has exhibited acceptable toxicity profiles both inside and outside of Japan. In addition, lenalidomide has shown promising antitumor activity in patients with ATL. Furthermore, based on the results of translational research, several promising novel agents are currently being investigated and might contribute to improving the prognosis of ATL.

Metabolic abnormalities in adult T-cell leukemia/lymphoma and induction of specific leukemic cell death using photodynamic therapy

Adult T-cell leukemia/lymphoma (ATL) is an aggressive T-cell neoplasm caused by human T-cell leukemia virus type I (HTLV-I). Therapeutic interventions have not been associated with satisfactory outcomes. We showed that the porphyrin metabolic pathway preferentially accumulates the endogenous photosensitive metabolite, protoporphyrin IX (PpIX) in ATL, after a short-term culture with 5-aminolevulinic acid (ALA). PpIX accumulated 10-100-fold more in ATL leukemic cells when compared to healthy peripheral blood mononuclear cells (PBMCs). Patient specimens showed dynamic changes in flow cytometry profiles during the onset and progression of ATL. Furthermore, 98.7% of ATL leukemic cell death in the ATL patient specimens could be induced with 10 min of visible light exposure, while 77.5% of normal PBMCs survived. Metabolomics analyses revealed that a specific stage of the metabolic pathway progressively deteriorated with HTLV-I infection and at the onset of ATL. Therefore, this method will be useful in diagnosing and identifying high-risk HTLV-I carriers with single cell resolutions. Photodynamic therapy in the circulatory system may be a potential treatment due to its highly-specific, non-invasive, safe, simultaneous, and repeatedly-treatable modalities.

Adult T-cell Leukemia/Lymphoma as a Methotrexate-associated Lymphoproliferative Disorder in a Patient with Rheumatoid Arthritis

The patient was a 74-year-old Japanese woman with rheumatoid arthritis (RA) who developed generalized lymphadenopathy with elevated levels of lactase dehydrogenase (LD), and soluble IL-2 receptor (sIL-2R). She was found to be positive for anti-human T-cell leukemia virus type 1 (HTLV-1) antibodies. Her symptoms and laboratory abnormalities spontaneously regressed after the cessation of methotrexate (MTX), suggesting that she had an MTX-associated lymphoproliferative disorder; however, her lymphadenopathy appeared again approximately 14 months later with LD and sIL-2R elevation. A histopathological analysis and Southern blotting of a lymph node biopsy specimen for HTLV-1 provirus supported the diagnosis of adult T-cell leukemia/lymphoma (ATL) (lymphoma type). These data confirmed that an HTLV-1 positive RA patient may develop ATL.

Adult T-Cell Leukemia/Lymphoma. Review of the Literature

Adult T-cell Leukemia/Lymphoma (ATLL) is an aggressive neoplasm of T lymphocytes associated with Human T-lymphotropic virus type1 (HTLV-1) infection. HTLV-1 is a public health problem because it is endemic in native groups in Latin America, and its infection leads to several chronic diseases as ATLL. We aimed to review current literature of ATLL in order to consider it as a differential diagnosis in front of patients with compatible symptoms. Prognosis is still poor in aggressive and indolent variants, with survival rates from months to few years. Treatment based on chemotherapy, antiretroviral, and allogenic stem cell transplantation are currently improving survival rates, but with limited results.

A Review of New Findings in Adult T-cell Leukemia-Lymphoma: A Focus on Current and Emerging Treatment Strategies

Adult T-cell leukemia–lymphoma (ATL), a rare and aggressive T-cell malignancy caused by human T-cell lymphotropic virus type 1 (HTLV-1), is associated with a poor prognosis. Evidence-based standard treatment options are lacking and outcomes are generally unsatisfactory, particularly for patients with relapsed or refractory disease. Continued research is contributing to changing treatment landscape as a number of existing and investigational agents are evaluated. We describe the epidemiology of HTLV-1 and ATL, discuss the biology behind the disease, review current treatment practices and guidelines, and provide an overview of emerging therapies in ATL, with a focus on those for relapsed or refractory disease.

Distribution and Clustering of Cutaneous T-Cell Lymphoma (CTCL) Cases in Canada During 1992 to 2010

BACKGROUND

Clustering of patients with cutaneous T-cell lymphoma (CTCL) was reported in several jurisdictions around the world. This rare cancer is known to affect spouses and in some cases multiple members of the same family. These combined results suggest the existence of external disease triggers/promoters. We recently conducted the first comprehensive analysis of CTCL incidence and mortality in Canada, which revealed case clustering in several regions.

OBJECTIVES

To extend our previous analysis on CTCL incidence across Canada and to provide all the collected data on CTCL patient incidence in Canada during the period of 1992 to 2010.

METHODS

Clinical parameters for patients with CTCL in Canada were analyzed using 2 independent population-based cancer registries: Canadian Cancer Registry and Le Registre Québécois du Cancer. The CTCL incidence rates were examined on different geographical levels, including provinces/territories, cities, and forward sortation areas.

RESULTS

Our findings further corroborate our earlier observations of higher CTCL incidence in Newfoundland and Labrador, maritime provinces (Nova Scotia and New Brunswick), and prairie provinces (Manitoba and Saskatchewan). Also, most cities with high CTCL incidence were located in these provinces. Extensive mapping of high-incidence postal codes supports case clustering in a number of communities that are located in the proximity of industrial centres and seaports.

CONCLUSIONS

Detailed analysis of CTCL incidence in Canada is critical to fully understand the burden of this disease in our country, to begin the search for a possible external trigger for this lymphoma, and to reform how health care resources are distributed throughout the country to better serve Canadian patients with CTCL.

Human T Cell Leukemia Virus Type 1: Persistence and Pathogenesis

Human T cell leukemia virus type 1 (HTLV-1), also known as human T lymphotropic virus type 1, was the first exogenous human retrovirus discovered. Unlike the distantly related lentivirus HIV-1, HTLV-1 causes disease in only 5-10% of infected people, depending on their ethnic origin. But whereas HIV-1 infection and the consequent diseases can be efficiently contained in most cases by antiretroviral drug treatment, there is no satisfactory treatment for the malignant or inflammatory diseases caused by HTLV-1. The purpose of the present article is to review recent advances in the understanding of the mechanisms by which the virus persists in vivo and causes disabling or fatal diseases.

Analysis of CTCL cell lines reveals important differences between mycosis fungoides/Sézary syndrome vs. HTLV-1+ leukemic cell lines

HTLV-1 is estimated to affect ~20 million people worldwide and in ~5% of carriers it produces Adult T-Cell Leukemia/Lymphoma (ATLL), which can often masquerade and present with classic erythematous pruritic patches and plaques that are typically seen in Mycosis Fungoides (MF) and Sézary Syndrome (SS), the most recognized variants of Cutaneous T-Cell Lymphomas (CTCL). For many years the role of HTLV-1 in the pathogenesis of MF/SS has been hotly debated. In this study we analyzed CTCL vs. HTLV-1⁺ leukemic cells. We performed G-banding/spectral karyotyping, extensive gene expression analysis, TP53 sequencing in the 11 patient-derived HTLV-1⁺ (MJ and Hut102) vs. HTLV-1^- (Myla, Mac2a, PB2B, HH, H9, Hut78, SZ4, Sez4 and SeAx) CTCL cell lines. We further tested drug sensitivities to commonly used CTCL therapies and studied the ability of these cells to produce subcutaneous xenograft tumors in NOD.Cg-Prkdc^scid Il2rg^tm1Wjl/SzJ mice. Our work demonstrates that unlike classic advanced MF/SS cells that acquire many ongoing balanced and unbalanced chromosomal translocations, HTLV-1⁺ CTCL leukemia cells are diploid and exhibit only a minimal number of non-specific chromosomal alterations. Our results indicate that HTLV-1 virus is likely not involved in the pathogenesis of classic MF/SS since it drives a very different pathway of lymphomagenesis based on our findings in these cells. This study also provides for the first time a comprehensive characterization of the CTCL cells with respect to gene expression profiling, TP53 mutation status, ability to produce tumors in mice and response to commonly used therapies.

NHE1 has a notable role in metastasis and drug resistance of T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) represents a spectrum of hematological malignancies that affect human health. Metastasis and chemotherapeutic drug resistance are the primary causes of mortality in patients with T-ALL. Sodium-hydrogen antiporter 1 (NHE1) is established to serve a role in metastasis and drug resistance in numerous types of cancer; however, the function of NHE1 in T-ALL remains to be elucidated. Previously, the C-C-motif chemokine ligand 25 (CCL25) was identified to be involved in metastasis and drug resistance in the MOLT4 T-ALL cell line, as was the ezrin protein. The present study investigated the role of NHE1 in the metastasis of T-ALL using a Transwell assay and scanning electron microscopy, using MOLT4 cells as a model. The association between NHE1 and ezrin was assessed using laser scanning confocal microscopy. The effect of NHE1 on resistance to the chemotherapy drug doxorubicin (DOX) was also investigated using a cell viability and cytotoxicity assay. Expression of NHE1 increased following treatment with CCL25, accompanied by morphological changes in MOLT4 cells and the co-localization of NHE1 with ezrin. In addition, wild-type MOLT4 cells exhibited an increased polarization ability compared with NHE1- or ezrin-silenced cells. NHE1- or ezrin-silenced cells exhibited higher sensitivity to DOX compared with wild-type MOLT4 cells. In conclusion, the increased expression or activity of NHE1 may potentially be a poor prognostic indicator for human T-ALL.

Human T-cell lymphotropic virus type 1 and its oncogenesis

Human T-cell lymphotropic virus type 1 (HTLV-1) is the etiologic agent of adult T-cell leukemia/lymphoma (ATL), a rapidly progressing clonal malignancy of CD4+ T lymphocytes. Exploring the host-HTLV-1 interactions and the molecular mechanisms underlying HTLV-1-mediated tumorigenesis is critical for developing efficient therapies against the viral infection and associated leukemia/lymphoma. It has been demonstrated to date that several HTLV-1 proteins play key roles in the cellular transformation and immortalization of infected T lymphocytes. Of note, the HTLV-1 oncoprotein Tax inhibits the innate IFN response through interaction with MAVS, STING and RIP1, causing the suppression of TBK1-mediated phosphorylation of IRF3/IRF7. The HTLV-1 protein HBZ disrupts genomic integrity and inhibits apoptosis and autophagy of the target cells. Furthermore, it is revealed that HBZ enhances the proliferation of ATL cells and facilitates evasion of the infected cells from immunosurveillance. These studies provide insights into the molecular mechanisms by which HTLV-1 mediates the formation of cancer as well as useful strategies for the development of new therapeutic interventions against ATL. In this article, we review the recent advances in the understanding of the pathogenesis, the underlying mechanisms, clinical diagnosis and treatment of the disease caused by HTLV-1 infection. In addition, we discuss the future direction for targeting HTLV-1-associated cancers and strategies against HTLV-1.

Safety and efficacy of mogamulizumab in patients with adult T-cell leukemia-lymphoma in Japan: interim results of postmarketing all-case surveillance

We present the interim results of a postmarketing all-case surveillance study in patients with C-C chemokine receptor 4 (CCR4)-positive, relapsed or refractory adult T-cell leukemia-lymphoma (ATL) treated with the anti-CCR4 monoclonal antibody mogamulizumab since its 2012 launch in Japan. The safety and efficacy analysis populations comprised 484 and 442 patients, respectively. The ATL subtype was acute in 58.9% and lymphoma in 34.2% of patients. All patients were scheduled to receive intravenous infusions of mogamulizumab (1.0 mg/kg) once weekly for eight weeks, alone or in combination with other modalities. Adverse drug reactions (ADRs) were reported in 74.0% of patients, of which 35.7% were serious and 6.2% were fatal. The priority survey items of infusion-related reaction, skin disorder, infection, immune disorder, and tumor lysis syndrome were reported in 29.3, 34.3, 22.1, 3.5, and 2.5% of patients, respectively. Graft-versus-host disease was reported in 25/42 patients who received mogamulizumab before allogeneic hematopoietic stem cell transplantation. The best overall response rate was 57.7% overall, 57.5% in patients treated with mogamulizumab alone, and 58.2% in patients treated with combination therapy. This surveillance indicates that mogamulizumab shows acceptable tolerability in practice; however, because of the risk of serious/fatal ADRs, patients administered mogamulizumab should be carefully monitored.

Treatment advances and prognosis for patients with adult T-cell leukemia-lymphoma

A classification for adult T-cell leukemia-lymphoma (ATL) based on clinical features was proposed in 1991: acute, lymphoma, chronic, and smoldering types, and their median survival times (MSTs) were reported to be 6.2, 10.2, 24.3 months, and not reached, respectively. Several new therapies for ATL have since been developed, i.e. dose-intensity multi-agent chemotherapies, allogeneic hematopoietic stem cell transplantation (allo-HSCT), monoclonal antibodies, and anti-viral therapy. The monoclonal antibody to CCR4, mogamulizumab, clearly improved response rates in patients with treatment-naïve and relapsed aggressive ATL, and has the potential to provide a survival advantage. The outcomes of allo-HSCT have been reported since the early 2000s. High treatment-related mortality was initially the crucial issue associated with this treatment approach; however, reduced intensity conditioning regimens have decreased the risk of treatment-related mortality. The introduction of allo- HSCT has had a positive impact on the prognosis of and potential curability with treatments for ATL. A meta-analysis of a treatment with interferon-α and zidovudine (IFN/AZT) revealed a survival benefit in patients with the leukemic subtype. A phase 3 study comparing IFN/AZT with watchful waiting in patients with indolent ATL is ongoing in Japan. Several clinical trials on novel agents are currently being conducted, such as the histone deacetylase inhibitors, alemtuzumab, brentuximab vedotin, nivolumab, and an EZH1/2 dual inhibitor.

Animals Models of Human T Cell Leukemia Virus Type I Leukemogenesis

Infection with human T cell leukemia virus type I (HTLV-I) causes adult T cell leukemia (ATL) in a minority of infected individuals after long periods of viral persistence. The various stages of HTLV-I infection and leukemia development are studied by using several different animal models: (1) the rabbit (and mouse) model of persistent HTLV-I infection, (2) transgenic mice to model tumorigenesis by HTLV-I specific protein expression, (3) ATL cell transfers into immune-deficient mice, and (4) infection of humanized mice with HTLV-I. After infection, virus replicates without clinical disease in rabbits and to a lesser extent in mice. Transgenic expression of both the transactivator protein (Tax) and the HTLV-I bZIP factor (HBZ) protein have provided insight into factors important in leukemia/lymphoma development. To investigate factors relating to tumor spread and tissue invasion, a number of immune-deficient mice based on the severe combined immunodeficiency (SCID) or non-obese diabetic/SCID background have been used. Inoculation of adult T cell leukemia cell (lines) leads to lymphoma with osteolytic bone lesions and to a lesser degree to leukemia development. These mice have been used extensively for the testing of anticancer drugs and virotherapy. A recent development is the use of so-called humanized mice, which, upon transfer of CD34(+)human umbilical cord stem cells, generate human lymphocytes. Infection with HTLV-I leads to leukemia/lymphoma development, thus providing an opportunity to investigate disease development with the aid of molecularly cloned viruses. However, further improvements of this mouse model, particularly in respect to the development of adaptive immune responses, are necessary.

Reducing the global burden of HTLV-1 infection: An agenda for research and action

Even though an estimated 10-20 million people worldwide are infected with the oncogenic retrovirus, human T-lymphotropic virus type 1 (HTLV-1), its epidemiology is poorly understood, and little effort has been made to reduce its prevalence. In response to this situation, the Global Virus Network launched a taskforce in 2014 to develop new methods of prevention and treatment of HTLV-1 infection and promote basic research. HTLV-1 is the etiological agent of two life-threatening diseases, adult T-cell leukemia and HTLV-associated myelopathy/tropical spastic paraparesis, for which no effective therapy is currently available. Although the modes of transmission of HTLV-1 resemble those of the more familiar HIV-1, routine diagnostic methods are generally unavailable to support the prevention of new infections. In the present article, the Taskforce proposes a series of actions to expand epidemiological studies; increase research on mechanisms of HTLV-1 persistence, replication and pathogenesis; discover effective treatments; and develop prophylactic and therapeutic vaccines.

A specific mode of microsatellite instability is a crucial biomarker in adult T-cell leukaemia/lymphoma patients

Purpose

Microsatellite instability (MSI) has been a long-standing biomarker candidate for drug resistance in tumour cells. Despite numerous clinical studies, the data in the literature are not conclusive. The complexity of the MSI phenomenon in some malignancies may, at least partly, account for the discrepancy. In addition, methodological problems are also pointed out in the assay techniques. We previously established a unique fluorescent technique in which the major methodological problems in conventional assays are overcome. Application of this technique has revealed two distinct modes of microsatellite alterations, i.e. Type A and Type B. More importantly, we demonstrated that Type A MSI is the direct consequence of defective DNA mismatch repair (MMR) that causes cellular resistance against antineoplastic agents.

Method

We first applied this technique to adult T-cell leukaemia/lymphoma (ATLL).

Results

The MSI phenomenon was indeed observed in ATLLs (4/20, 20%). Intriguingly, the observed microsatellite alterations were invariably Type A, which implies that the tumours were MMR-defective. Indeed, clinical outcomes of patients with these MSI⁺ tumours were significantly worse. Furthermore, multivariate analysis revealed that Type A MSI is an independent prognostic factor.

Conclusion

These observations strongly suggest the possibility of Type A MSI as a prognostic and potentially predictive biomarker in ATLL.

PD-L1 expression on neoplastic or stromal cells is respectively a poor or good prognostic factor for adult T-cell leukemia/lymphoma

Programmed cell death ligand 1 (PD-L1) is expressed on both tumor and tumor-infiltrating nonmalignant cells in lymphoid malignancies. The programmed cell death 1 (PD-1)/PD-L1 pathway suppresses host antitumor responses, although little is known about the significance of PD-1/PD-L1 expression in the tumor microenvironment. To investigate the clinicopathological impact of PD-L1 expression in adult T-cell leukemia/lymphoma (ATLL), we performed PD-L1 immunostaining in 135 ATLL biopsy samples. We observed 2 main groups: 1 had clear PD-L1 expression in lymphoma cells (nPD-L1(+), 7.4% of patients), and the other showed minimal expression in lymphoma cells (nPD-L1(-), 92.6%). Within the nPD-L1(-) group, 2 subsets emerged: the first displayed abundant PD-L1 expression in nonmalignant stromal cells of the tumor microenvironment (miPD-L1(+), 58.5%) and the second group did not express PD-L1 in any cell (PD-L1(-), 34.1%). nPD-L1(+) ATLL (median survival time [MST] 7.5 months, 95% CI [0.4-22.3]) had inferior overall survival (OS) compared with nPD-L1(-) ATLL (MST 14.5 months, 95% CI [10.1-20.0]) (P = .0085). Among nPD-L1(-) ATLL, miPD-L1(+) ATLL (MST 18.6 months, 95% CI [11.0-38.5]) showed superior OS compared with PD-L1(-) ATLL (MST 10.2 months, 95% CI [8.0-14.7]) (P = .0029). The expression of nPD-L1 and miPD-L1 maintained prognostic value for OS in multivariate analysis (P = .0322 and P = .0014, respectively). This is the first report describing the clinicopathological features and outcomes of PD-L1 expression in ATLL. More detailed studies will disclose clinical and biological significance of PD-L1 expression in ATLL.

Investigating potential exogenous tumor initiating and promoting factors for Cutaneous T-Cell Lymphomas (CTCL), a rare skin malignancy

Most skin malignancies are caused by external and often preventable environmental agents. Multiple reports demonstrated that cutaneous T-cell lymphomas (CTCL) can occur in married couples and cluster in families. Furthermore, recent studies document geographic clustering of this malignancy in Texas as well as in other areas of the United States. Multiple infectious, occupational, and medication causes have been proposed as triggers or promoters of this malignancy including hydrochlorothiazide diuretics, Staphylococcus aureus, dermatophytes, Mycobacterium leprae, Chlamydia pneumoniae, human T-Cell lymphotropic virus type 1 (HTLV1), Epstein-Barr virus (EBV), and herpes simplex virus (HSV). In this report, we review recent evidence evaluating the involvement of these agents in cancer initiation/progression. Most importantly, recent molecular experimental evidence documented for the first time that S. aureus can activate oncogenic STAT3 signaling in malignant T cells. Specifically, S. aureus Enterotoxin type A (SEA) was recently shown to trigger non-malignant infiltrating T cells to release IL-2 and other cytokines. These signals upon binging to their cognate receptors on malignant T cells are then able to activate STAT3 and STAT5 oncogenic signaling and promote cancer progression and IL-17 secretion. In light of these findings, it might be important for patients with exacerbation of their CTCL symptoms to maintain high index of suspicion and treat these individuals for S. aureus colonization and/or sepsis with topical and systemic antibiotics.

HTLV-1-associated myelopathy in a solid organ transplant recipient

Human T-cell lymphotropic virus type-1 (HTLV-1) is endemic in Japan, the Caribbean and in South American countries such as Ecuador. This virus is the cause of HTLV-1-associated myelopathy or tropical spastic paraparesis (HAM/TSP), a myelopathy characterised by chronic progressive paraparesis, spasticity and urinary symptoms. We report the case of a 40-year-old man who received a kidney transplant from a living donor and developed HAM/TSP, 24 months after transplant. The diagnosis was confirmed by detection of HTLV-1 in blood and cerebrospinal fluid by the ELISA and Western Blot tests. For myelopathy, the patient was treated with pulse methylprednisolone, but had poor response to treatment. We recommend that all patients receiving transplants and their donors who come from endemic countries be given a mandatory screening for HTLV-1 through an ELISA test, in an effort to inform candidates for renal transplantation of the potential risk of infection and the development of this disease.

Angiotensin II type 1 receptor blocker telmisartan induces apoptosis and autophagy in adult T-cell leukemia cells

Adult T‐cell leukemia/lymphoma (ATL), an aggressive T‐cell malignancy that develops after long‐term infection with human T‐cell leukemia virus (HTLV‐1), requires new treatments. Drug repositioning, reuse of a drug previously approved for the treatment of another condition to treat ATL, offers the possibility of reduced time and risk. Among clinically available angiotensin II receptor blockers, telmisartan is well known for its unique ability to activate peroxisome proliferator‐activated receptor‐γ, which plays various roles in lipid metabolism, cellular differentiation, and apoptosis. Here, telmisartan reduced cell viability and enhanced apoptotic cells via caspase activation in ex vivo peripheral blood monocytes from asymptomatic HTLV‐1 carriers (ACs) or via caspase‐independent cell death in acute‐type ATL, which has a poor prognosis. Telmisartan also induced significant growth inhibition and apoptosis in leukemia cell lines via caspase activation, whereas other angiotensin II receptor blockers did not induce cell death. Interestingly, telmisartan increased the LC3‐II‐enriched protein fraction, indicating autophagosome accumulation and autophagy. Thus, telmisartan simultaneously caused caspase activation and autophagy. A hypertension medication with antiproliferation effects on primary and leukemia cells is intriguing. Patients with an early diagnosis of ATL are generally monitored until the disease progresses; thus, suppression of progression from AC and indolent ATL to acute ATL is important. Our results suggest that telmisartan is highly effective against primary cells and leukemia cell lines in caspase‐dependent and ‐independent manners, and its clinical use may suppress acute transformation and improve prognosis of patients with this mortal disease. This is the first report demonstrating a cell growth‐inhibitory effect of telmisartan in fresh peripheral blood mononuclear cells from leukemia patients.

Mutation of epigenetic regulators TET2 and MLL3 in patients with HTLV-I-induced acute adult T-cell leukemia

Background

Epigenetic regulators play a critical role in the maintenance of specific chromatin domains in an active or repressed state. Disruption of epigenetic regulatory mechanisms is widespread in cancer cells and largely contributes to the transformation process through active repression of tumor suppressor genes. While mutations of epigenetic regulators have been reported in various lymphoid malignancies and solid cancers, mutation of these genes in HTLV-I-associated T-cell leukemia has not been investigated.

Method

Here we used whole genome next generation sequencing (NGS) of uncultured freshly isolated ATL samples and identified the presence of mutations in SUZ12, DNMT1, DNMT3A, DNMT3B, TET1, TET2, IDH1, IDH2, MLL, MLL2, MLL3 and MLL4.

Results

TET2 was the most frequently mutated gene, occurring in 32 % (10/31) of ATL samples analyzed. Interestingly, NGS revealed nonsense mutations accompanied by loss of heterozygosity (LOH) in TET2 and MLL3, which was further confirmed by cloning and direct sequencing of DNA from uncultured cells. Finally, direct sequencing of matched control and tumor samples revealed that TET2 mutation was present only in ATL tumor cells.

Conclusions

Our results suggest that inactivation of MLL3 and TET2 may play an important role in the tumorigenesis process of HTLV-I-induced ATL.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-016-0500-z) contains supplementary material, which is available to authorized users.

Epigenetic Pathways of Oncogenic Viruses: Therapeutic Promises

Cancerous transformation comprises different events that are both genetic and epigenetic. The ultimate goal for such events is to maintain cell survival and proliferation. This transformation occurs as a consequence of different features such as environmental and genetic factors, as well as some types of infection. Many viral infections are considered to be causative agents of a number of different malignancies. To convert normal cells into cancerous cells, oncogenic viruses must function at the epigenetic level to communicate with their host cells. Oncogenic viruses encode certain epigenetic factors that lead to the immortality and proliferation of infected cells. The epigenetic effectors produced by oncogenic viruses constitute appealing targets to prevent and treat malignant diseases caused by these viruses. In this review, we highlight the importance of epigenetic reprogramming for virus-induced oncogenesis, with special emphasis on viral epigenetic oncoproteins as therapeutic targets. The discovery of molecular components that target epigenetic pathways, especially viral factors, is also discussed.

Complete Remissions of Adult T-cell Leukemia with Anti-CD25 Recombinant Immunotoxin LMB-2 and Chemotherapy to Block Immunogenicity

PURPOSE

Adult T-cell leukemia (ATL) is usually CD25(+) and rapidly fatal. Anti-CD25 recombinant immunotoxin LMB-2 had phase I activity limited by immunogenicity and rapid growth. To prevent antidrug antibodies and leukemic progression between cycles, a phase II trial was performed with LMB-2 after cyclophosphamide and fludarabine.

EXPERIMENTAL DESIGN

ATL patients received cyclophosphamide and fludarabine days 1 to 3 and 2 weeks later began up to 6 cycles at 3-week intervals of cyclophosphamide and fludarabine days 1 to 3 followed by LMB-2 30-40 μg/kg i.v. days 3, 5, and 7. Three different dose levels of cyclophosphamide and fludarabine were used, 20+200 (n = 3), 25+250 (n = 12), and 30+300 mg/m(2) (n = 2).

RESULTS

Of 17 patients enrolled and treated with fludarabine and cyclophosphamide for cycle-1, 15 received subsequent cycle(s) containing LMB-2 and were therefore evaluable for response. Lack of antibody formation permitted retreatment in most patients. Of 10 evaluable leukemic patients receiving 25+250 or 30+300 mg/m(2) of fludarabine and cyclophosphamide, 6 (60%) achieved complete remission (CR) and 2 (20%) partial remission (PR), and all 5 with >25% leukemic cells achieved CR. No responses were achieved in 5 with lymphomatous ATL or lower fludarabine and cyclophosphamide doses. Median CR duration for the 6 CRs was 40 weeks. One is without detectable ATL at 47 months. Toxicity was mostly attributable to fludarabine and cyclophosphamide. Capillary leak from LMB-2 was non-dose limiting. One patient in CR died of a preexisting infection.

CONCLUSIONS

LMB-2, administered with fludarabine and cyclophosphamide to prevent antidrug antibodies and rapid intercycle progression, is highly effective in achieving CR in leukemia ATL. Fludarabine and cyclophosphamide dose/schedule is important for safety and efficacy in this high-risk population.

Emerging role of infectious etiologies in the pathogenesis of marginal zone B-cell lymphomas

Extranodal marginal zone B-cell lymphomas of the mucosa-associated lymphoid tissue (MALT) arise from lymphoid populations that are induced by chronic inflammation in extranodal sites. The most frequently affected organ is the stomach, where MALT lymphoma is incontrovertibly associated with a chronic gastritis induced by a microbial pathogen, Helicobacter pylori. Gastric MALT lymphoma therefore represents a paradigm for evaluating inflammation-associated lymphomagenesis, which may lead to a deeper understanding of a possible etiologic association between other microorganisms and nongastric marginal zone lymphomas. Besides infectious etiology, chronic inflammation caused by autoimmune diseases, such as Sjögren syndrome or Hashimoto thyroiditis, can also carry a significant risk factor for the development of marginal zone lymphoma. In addition to the continuous antigenic drive, additional oncogenic events play a relevant role in lymphoma growth and progression to the point at which the lymphoproliferative process may eventually become independent of antigenic stimulation. Recent studies on MALT lymphomas have in fact demonstrated genetic alterations affecting the NF-κB) pathway, a major signaling pathway involved in many cancers. This review aims to present marginal zone lymphoma as an example of the close pathogenetic link between chronic inflammation and tumor development, with particular attention to the role of infectious agents and the integration of these observations into everyday clinical practice. See all articles in this CCR Focus section, "Paradigm Shifts in Lymphoma."