Development and analysis of patient-derived xenograft mouse models in intravascular large B-cell lymphoma

Spheroid culture to select theoretical therapeutic drugs in intravascular large B-cell lymphoma

Intravascular large B-cell lymphoma (IVLBCL) is a rare type of extranodal large B-cell lymphoma that is characterized by the proliferation of lymphoma cells in the lumina of small vessels. Recent progress uncovering the genetic characteristics associated with MYD88/CD79B mutations has stimulated interest in the use of drugs targeting B-cell receptor signaling, including Bruton's tyrosine kinase. However, difficulties in culturing ex vivo IVLBCL cells has hampered research on the development of novel therapies. In the present study, we demonstrated the establishment of an ex vivo culture system of IVLBCL cells obtained from patient-derived xenograft (PDX) models. The spheroid culture enabled us to culture IVLBCL PDX cells for more than 10 days and to explore the efficacy of drug treatments acting on these cells. We found that carfilzomib and ibrutinib were effective for treating IVLBCL in ex vivo experiments and conducted in vivo analyses to assess the efficacy of these drugs. Although the efficacy of carfilzomib was difficult to confirm due to its toxicity in our models, ibrutinib showed comparable efficacy to a standard combination of chemotherapy drugs. Together, our data provide a new culture method for IVLBCL PDX cells and a rationale for translating ibrutinib to clinical use in IVLBCL patients.

Cutaneous Intravascular Hematolymphoid Entities: A Review

Intravascular lymphomas are rare disease conditions that exhibit neoplastic lymphoid cells that are confined mainly to the lumens of small capillaries and medium-sized vessels. The majority of the intravascular lymphomas are of B-cell origin, but they can include NK/T-cell and CD30+ immunophenotypes. In the histologic differential diagnosis are benign proliferations such as intralymphatic histiocytosis and intravascular atypical CD30+ T-cell proliferation. In this review, we discuss the clinical, histopathologic, and molecular findings of intravascular B-cell lymphoma, intravascular NK/T-cell lymphoma, intralymphatic histiocytosis, and benign atypical intravascular CD30+ T-cell proliferation.

Large B-Cell Lymphomas in the 5th Edition of the WHO-Classification of Haematolymphoid Neoplasms-Updated Classification and New Concepts

The family/class of the large B-cell lymphomas (LBCL) in the 5th edition of the World Health Organization (WHO) classification of haematolymphoid tumors (WHO-HAEM5) features only a few major changes as compared to the 4th edition. In most entities, there are only subtle changes, many of them only representing some minor modifications in diagnostic terms. Major changes have been made in the diffuse large B-cell lymphomas (DLBCL)/high-grade B-cell lymphomas (HGBL) associated with MYC and BCL2 and/or BCL6 rearrangements. This category now consists of MYC and BCL2 rearranged cases exclusively, while the MYC/BCL6 double hit lymphomas now constitute genetic subtypes of DLBCL, not otherwise specified (NOS) or of HGBL, NOS. Other major changes are the conceptual merger of lymphomas arising in immune-privileged sites and the description of LBCL arising in the setting of immune dysregulation/deficiency. In addition, novel findings concerning underlying biological mechanisms in the pathogenesis of the different entities are provided.

Intravascular Large B-Cell Lymphoma Genomic Profile Is Characterized by Alterations in Genes Regulating NF-κB and Immune Checkpoints

Intravascular large B-cell lymphoma (IVLBCL) is an uncommon lymphoma with an aggressive clinical course characterized by selective growth of tumor cells within the vessels. Its pathogenesis is still uncertain and there is little information on the underlying genomic alterations. In this study, we performed a clinicopathologic and next-generation sequencing analysis of 15 cases of IVLBCL using a custom panel for the detection of alterations in 68 recurrently mutated genes in B-cell lymphomagenesis. Six patients had evidence of hemophagocytic syndrome. Four patients presented concomitantly a solid malignancy. Tumor cells outside the vessels were observed in 7 cases, 2 with an overt diffuse large B-cell cell lymphoma. In 4 samples, tumor cells infiltrated lymphatic vessel in addition to blood capillaries. Programmed death-ligand 1 (PD-L1) was positive in tumor cells in 4 of 11 evaluable samples and in macrophages intermingled with tumor cells in 8. PD-L1 copy number gains were identified in a higher proportion of cases expressing PD-L1 than in negative tumors. The most frequently mutated gene was PIM1 (9/15, 60%), followed by MYD88L265P and CD79B (8/15, 53% each). In 6 cases, MYD88L265P and CD79B mutations were detected concomitantly. We also identified recurrent mutations in IRF4 , TMEM30A , BTG2 , and ETV6 loci (4/15, 27% each) and novel driver mutations in NOTCH2 , CCND3 , and GNA13 , and an IRF4 translocation in 1 case each. The mutational profile was similar in patients with and without evidence of hemophagocytic syndrome and in cases with or without dissemination of tumor cells outside the vessels. Our results confirm the relevance of mutations in B-cell receptor/nuclear factor-κB signaling and immune escape pathways in IVLBCL and identify novel driver alterations. The similar mutational profile in tumors with extravascular dissemination suggests that these cases may also be considered in the spectrum of IVLBCL.

Intravascular Large B Cell Lymphoma with CNS Involvement Successfully Treated with High-Dose Methotrexate and High-Dose Ara-C Based CNS-Directed Chemoimmunotherapy Alternating with Anthracycline Based Chemoimmunotherapy

Intravascular large B cell lymphoma (IVL) is a rare subtype of diffuse large B cell lymphoma confined to small blood vessels with a predilection for CNS involvement. The prognosis of IVL with CNS involvement (CNS-IVL) is extremely poor. The optimal treatment for CNS-IVL is not well defined. Thus, we report three patients with CNS-IVL successfully treated with a CNS-centric approach consisting of high-dose methotrexate (HDMTX) and high-dose Ara-C (HiDAC) based CNS-directed chemoimmunotherapy (CIT) alternating with anthracycline-based CIT. Our rationale for intensifying the CNS-directed therapy is the presence of intracerebral bleeding in two of our patients which would result in extravasation of lymphoma cells into the cerebral parenchyma with the development of CNS lymphoma. All three patients have achieved excellent therapeutic outcomes. Two patients with intracerebral bleeding have been in complete remission (CR) for about 11 years and 4 years. One patient was successfully induced into CR about 10 months ago and currently is in CR. This unique therapeutic approach should be further explored for CNS-IVL.

CUTANEOUS B-CELL LYMPHOMAS: UPDATE ON DIAGNOSIS, RISK-STRATIFICATION, AND MANAGEMENT

PCBCLs are a group of Non-Hodgkin's B-cell lymphomas originating in and usually confined to the skin, representing approximately one fourth of primary cutaneous lymphomas (PCL). Their current classification system has been the result of the joint World Health Organization (WHO) - European Organization for Research and Treatment of Cancer (EORTC) consensus in 2018. To date, several types of PCBCLs have been described in the scientific literature, with different clinical presentation and prognosis. Primary cutaneous follicle-center lymphoma (PCFCL) and primary cutaneous marginal zone lymphoma (PCMZL) are the most common forms, with a typical indolent course. On the contrary, primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL, LT) is less common, yet more aggressive, with a reported 5-year overall survival of approximatively 50%. In this review, we outline the PCBCLs defining diagnostic criteria, report the features of the less common subtypes and summarize the noteworthy therapeutical options currently available in this field.

Frequent genetic alterations in immune checkpoint-related genes in intravascular large B-cell lymphoma

Intravascular large B-cell lymphoma (IVLBCL) is a unique type of extranodal lymphoma characterized by selective growth of tumor cells in small vessels without lymphadenopathy. Greater understanding of the molecular pathogenesis of IVLBCL is hampered by the paucity of lymphoma cells in biopsy specimens, creating a limitation in obtaining sufficient tumor materials. To uncover the genetic landscape of IVLBCL, we performed whole-exome sequencing (WES) of 21 patients with IVLBCL using plasma-derived cell-free DNA (cfDNA) (n = 18), patient-derived xenograft tumors (n = 4), and tumor DNA from bone marrow (BM) mononuclear cells (n = 2). The concentration of cfDNA in IVLBCL was significantly higher than that in diffuse large B-cell lymphoma (DLBCL) (P < .0001) and healthy donors (P = .0053), allowing us to perform WES; most mutations detected in BM tumor DNA were successfully captured in cfDNA and xenograft. IVLBCL showed a high frequency of genetic lesions characteristic of activated B-cell-type DLBCL, with the former showing conspicuously higher frequencies (compared with nodal DLBCL) of mutations in MYD88 (57%), CD79B (67%), SETD1B (57%), and HLA-B (57%). We also found that 8 IVLBCL (38%) harbored rearrangements of programmed cell death 1 ligand 1 and 2 (PD-L1/PD-L2) involving the 3' untranslated region; such rearrangements are implicated in immune evasion via PD-L1/PD-L2 overexpression. Our data demonstrate the utility of cfDNA and imply important roles for immune evasion in IVLBCL pathogenesis and PD-1/PD-L1/PD-L2 blockade in therapeutics for IVLBCL.

Current progress and future perspectives of research on intravascular large B-cell lymphoma

Intravascular large B‐cell lymphoma is a rare disease of the large B cells characterized by selective growth in the lumina of small vessels in systemic organs. Since first reported in 1959, the difficulty of obtaining sufficient tumor cells from biopsy specimens has hampered the elucidation of its underlying biology. Recent progress using xenograft models and plasma cell‐free DNA has uncovered genetic features that are similar to those of activated B‐cell type diffuse large B‐cell lymphoma, including MYD88 and CD79B mutations and frequent alterations in immune check point‐related genes such as PD‐L1 and PD‐L2. Given the improvement in clinical outcomes and a higher risk of secondary central nervous system (CNS) involvement in the rituximab era, a phase 2 trial of R‐CHOP combined with high‐dose methotrexate and intrathecal chemotherapy as a CNS‐oriented therapy has been conducted. This trial, the PRIMEUR‐IVL study, has displayed good progression‐free survival and a low cumulative incidence of secondary CNS involvement. Long‐term follow‐up within this trial is still ongoing. Further understanding of the pathophysiology of the disease and improvements in clinical outcomes are still needed.

Exosomes secreted from cancer-associated fibroblasts elicit anti-pyrimidine drug resistance through modulation of its transporter in malignant lymphoma

The tumor microenvironment is deeply involved in the process of tumor growth and development. In this study, we focused on cancer-associated fibroblasts (CAFs) and their derived exosomes on the lymphoma microenvironment to uncover their clinical significance. CAFs were established from primary lymphoma samples, and exosomes secreted from CAFs were obtained by standard procedures. We then investigated the roles of CAFs and their derived exosomes in the survival and drug resistance of lymphoma cells. CAFs supported the survival of lymphoma cells through increased glycolysis, and the extent differed among CAFs. Exosomes were identified as a major component of the extracellular vesicles from CAFs, and they also supported the survival of lymphoma cells. The suppression of RAB27B, which is involved in the secretion of exosomes, using a specific siRNA resulted in reduced exosome secretion and decreased survival of lymphoma cells. Moreover, anti-pyrimidine drug resistance was induced in the presence of exosomes through the suppression of the pyrimidine transporter, equilibrative nucleoside transporter 2 (ENT2), and the suppression of ENT2 was significant in in vivo experiments and clinical samples. RNA sequencing analysis of miRNAs in exosomes identified miR-4717-5p as one of the most abundant miRNAs in the exosome, which suppressed the expression of ENT2 and induced anti-pyrimidine drug resistance in vitro. Our results suggest that exosomes including miR-4717-5p secreted from CAFs play a pivotal role in the lymphoma microenvironment, indicating that they are a promising therapeutic target.

Intravascular Large B-Cell Lymphoma and Renal Clear Cell Carcinoma as Collision Tumor: A Case Report and Review of the Literature

Intravascular large B-cell lymphoma (IVLBCL) is a rare type of extranodal large B-cell lymphoma characterized by the selective growth of lymphoma cells within the lumina of vessels. The patient usually presents with nonspecific symptoms and a remarkable deterioration in performance status. The occurrence of synchronous IVLBCL and renal cell carcinoma (RCC) is extremely rare. A right kidney tumor was found in a 72-year-old man with a history of low back pain. The kidney was enlarged, with a tumor mass measuring 4.5 × 4 × 4 cm. Sections exhibited a RCC (clear cell type, nuclear grade I). Also an extensive tumor affecting capillaries and small veins was present, positive for CD45, CD20, BCL-2, and MUM1/IRF-4, consistent with IVLBCL. The lymphoma was circumscribed to the RCC. The final diagnosis was IVLBCL with a RCC as collision tumor. After that, with neurological findings, central nervous system compromise by lymphoma was made. The patient started a first cycle of chemotherapy, progressive deterioration of the sensorium, and positive blood cultures for Klebsiella pneumoniae and Escherichia coli. The patient died 8 days later of acute respiratory failure. No autopsy was done. IVLBCL is an aggressive and systemic disease characterized by massive proliferation of tumor cells without a known primary site. Clinical identification and histopathologic diagnosis are relevant issues in the therapeutic management of these lymphomas. Until now, only one case of IVLBCL coexisting with RCC has been reported. In this article, we report a second case of IVLBCL with RCC simultaneous, as an unusual collision tumor.

Development and Significance of Mouse Models in Lymphoma Research

PURPOSE OF REVIEW

Animal models have played an indispensable role in interpreting cancer gene functions, pathogenesis of disease, and in the development of innovative therapeutic approaches targeting aberrant biological pathways in human cancers.

RECENT FINDINGS

These models have guided the therapeutic targeting of cancer-causing mutations and paved the way for assessing anti-cancer drug responses and the preclinical development of immunotherapies. The mammalian models of cancer utilize genetically edited or transplanted mice that develop fairly accurate disease histopathology. The mouse model also allows us to study the effect of tumor microenvironment in the development of lymphoma. The emergence of patient-derived xenografts provides a better opportunity for recapitulating primary lymphoma characteristics and researching personalized drug therapy. In conclusion, the refinement and advancement of available mouse models in lymphoma significantly minimize the therapeutic translational failures in patients.

Timely Diagnosis and Successful Treatment of Intravascular Large B-Cell Lymphoma in an Elderly Patient with Poor Performance Status

BACKGROUND Intravascular large B-cell lymphoma (IVLBCL) is a rare type of extranodal large B-cell lymphoma characterized by involvement of lymphoma cells in the lumina of small blood vessels in various organs. Although many studies have claimed that timely diagnosis and early initiation of chemotherapy are important, the literature on the successful treatment of IVLBCL in elderly patients over the age of 80 years is scarce. CASE REPORT An 82-year-old man presented with abnormal elevation of lactate dehydrogenase at 1605 IU/L and altered mental status, which manifested as forgetfulness, abnormal behavior, and worsening performance status for 2 days. There was no evidence of lymphadenopathy or skin lesions, but a computed tomography scan of the chest showed bilateral diffuse ground-glass opacities. With a primary consideration of IVLBCL, random skin biopsy and transbronchial lung biopsy were performed. Immediately after the pathologic findings on hematoxylin-eosin staining alone revealed abnormal large cells in the small vessels, chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) at half the usual dose was started; later on, immunostaining revealed CD20 expression in the abnormal lymphoid cells. Immediately after CHOP administration, his mental and physical symptoms rapidly resolved. After 8 cycles of dose-reduced CHOP with rituximab, he remained free from disease progression 2 years after the diagnosis. CONCLUSIONS We presented a case of successful early chemotherapy for IVLBCL in an elderly patient with poor performance status. Early chemotherapy with CHOP, even before obtaining a definitive diagnosis based on immunostaining, may contribute to good outcomes.

Anaplastic variant of diffuse large B-cell lymphoma with hallmark cell appearance: Two cases highlighting a broad diversity in the diagnostics

The anaplastic variant of diffuse large B-cell lymphoma (A-DLBCL) is morphologically defined but remains an enigmatic disease in its clinicopathologic distinctiveness. Here, we report two cases involving Japanese women aged 59 years, both with A-DLBCL with the hallmark cell appearance and both indistinguishable from common and giant cell-rich patterns, respectively, of anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma. Case 1 was immunohistochemically positive for CD20, CD79a and OCT-2 but not for the other pan-B-cell markers, CD30 and ALK. Case 2 showed CD20 and CD30 positivity for 50% and 20% of tumor cells in addition to strong expression of p53 and MYC. Both were positive for fascin without Epstein-Barr virus association. Our cases provide additional support for the earlier reports that A-DLBCL exhibits clinicopathologic features distinct from ordinal diffuse large B-cell lymphoma (DLBCL), and documented its broader morphologic diversity than previously recognized. They also shed light on the unique feature of absent expression of pan-B-cell markers except for CD20 and CD79a, suggesting that A-DLBCL may biologically mimic a gray zone or intermediate lymphoma between DLBCL and classic Hodgkin lymphoma.

Fenton reaction-induced renal carcinogenesis in Mutyh-deficient mice exhibits less chromosomal aberrations than the rat model

Oxidative stress including iron excess has been associated with carcinogenesis. The level of 8-oxoguanine, a major oxidatively modified base in DNA, is maintained very low by three distinct enzymes, encoded by OGG1, MUTYH and MTH1. Germline biallelic inactivation of MUTYH represents a familial cancer syndrome called MUTYH-associated polyposis. Here, we used Mutyh-deficient mice to evaluate renal carcinogenesis induced by ferric nitrilotriacetate (Fe-NTA). Although the C57BL/6 background is cancer-resistant, a repeated intraperitoneal administration of Fe-NTA induced a high incidence of renal cell carcinoma (RCC; 26.7%) in Mutyh-deficient mice in comparison to wild-type mice (7.1%). Fe-NTA treatment also induced renal malignant lymphoma, which did not occur without the Fe-NTA treatment in both the genotypes. Renal tumor-free survival after Fe-NTA treatment was marginally different (P = 0.157) between the two genotypes. Array-based comparative genome hybridization analyses revealed, in RCC, the loss of heterozygosity in chromosomes 4 and 12 without p16^INKA inactivation; these results were confirmed by a methylation analysis and showed no significant difference between the genotypes. Lymphomas showed a preference for genomic amplifications. Dlk1 inactivation by promoter methylation may be involved in carcinogenesis in both tumors. Fe-NTA-induced murine RCCs revealed significantly less genomic aberrations than those in rats, demonstrating a marked species difference.

Emetine elicits apoptosis of intractable B-cell lymphoma cells with MYC rearrangement through inhibition of glycolytic metabolism

Despite improved clinical outcomes of diffuse large B-cell lymphoma, a certain proportion of patients still develop a primary refractory disease. To overcome these lymphomas that are intractable to existing treatment strategies, the tumor microenvironment has been identified as a potential therapeutic target. Here we describe our search for effective drugs for primary refractory lymphoma cells with MYC rearrangement. Through the drug screening of 3,440 known compounds, we identified a unique compound, emetine. This compound was effective against lymphoma cells with MYC rearrangement from two different patients that were co-cultured with cancer associated fibroblasts. Emetine induced the death of these cells with a half maximal inhibitory concentration of 312 nM and 506 nM, respectively. Subsequent analyses of the mechanism of action of emetine showed that the drug induced apoptosis of tumor cells via alteration of glucose metabolism through inhibition of hypoxia inducible factor-1α. Moreover, emetine inhibited the potential of cancer associated fibroblasts to support tumor cell viability in vitro and demonstrated significant inhibition of tumor growth in in vivo analyses. Emetine also induced cell death in other primary refractory lymphoma cells with MYC rearrangement. Our combined data indicate that emetine is a potential promising drug for the treatment of intractable lymphomas, which targets both the tumor and its microenvironment.

An unexpected finding of hepatic lymphoma after emergent cholecystectomy

Herein we describe a case report of a patient with elevated liver enzymes, leukocytosis, anemia and fevers after cholecystectomy surgery done for presumed acute cholecystitis. Numerous post-surgical tests showed no acute surgical complications to account for the laboratory abnormalities. Due to systemic symptoms of joint pain and the chronicity of the symptoms, a liver biopsy was recommended by the gastroenterology service to rule out infectious or auto-immune causes. After the liver biopsy, the patient was diagnosed with intravascular large B-cell lymphoma (IVLBCL), a subset of diffuse large B-cell lymphoma. After a thorough lymphoma evaluation, the IVLBCL was found to be isolated to the liver and treated successfully with chemotherapy. This is only the second case report in the literature of this entity.

Lymphoma: current status of clinical and preclinical imaging with radiolabeled antibodies

Lymphoma is a complex disease that arises from cells of the immune system with an intricate pathology. While lymphoma may be classified as Hodgkin or non-Hodgkin, each type of tumor is genetically and phenotypically different and highly invasive tissue biopsies are the only method to investigate these differences. Noninvasive imaging strategies, such as immunoPET, can provide a vital insight into disease staging, monitoring treatment response in patients, and dose planning in radioimmunotherapy. ImmunoPET imaging with radiolabeled antibody-based tracers may also assist physicians in optimizing treatment strategies and enhancing patient stratification. Currently, there are two common biomarkers for molecular imaging of lymphoma, CD20 and CD30, both of which have been considered for investigation in preclinical imaging studies. In this review, we examine the current status of both preclinical and clinical imaging of lymphoma using radiolabeled antibodies. Additionally, we briefly investigate the role of radiolabeled antibodies in lymphoma therapy. As radiolabeled antibodies play critical roles in both imaging and therapy of lymphoma, the development of novel antibodies and the discovery of new biomarkers may greatly affect lymphoma imaging and therapy in the future.