Blastoid Mantle Cell Lymphoma Research Articles

Clinical and pathological characteristics of blastoid mantle cell lymphoma: a single institution experience

Background Blastoid mantle cell lymphoma (B-MCL) is a rare aggressive lymphoma. It is characterized by blastoid morphology with high proliferation and inconsistent immunohistochemistry (IHC), making it a diagnostic challenge for the pathologist. Methods This is a retrospective analytical cohort study. We reviewed biopsy confirmed cases of B-MCL diagnosed over a period of 10 years (January 2012 to December 2022). The clinical presentation, histopathological and IHC findings, treatment received, and survival outcomes were studied. Randomly selected cases of classic MCL (n=12), diagnosed during the same period served as controls. Results A total of 12 cases were studied. Four cases were transformed from previously diagnosed MCL; 8 cases arose de novo. Mean age was 61.17 years and the male: female ratio was 5:1. Half of the cases showed extra nodal extension and 81.8% had bone marrow involvement. Gastrointestinal tract was the most common site of extra nodal involvement. Histopathological examination showed diffuse involvement of the lymph node with medium sized cells. On immunohistochemistry, one of the cases showed loss of CD5 expression while the other had aberrant CD10 expression. Mean Ki-67 index was 58.09% in the cases and 16.33% in controls and was statistically significant (p=0.005). The median overall survival (OS) for cases was 2 years vs 8 years in controls. The p53 over expression (>30% nuclear positivity) was seen in 66.6% cases (4/6). Conclusion There are several factors that contribute to the aggressiveness of B-MCL, and new treatment approaches might be required to improve patient outcomes.

Comparative Transcriptome Analyses in Mantle Cell Lymphoma (MCL): Evidence of E2F1 As a Major Target in Aggressive Blastoid MCL Model

Background Mantle cell lymphoma (MCL) is a highly aggressive B-cell lymphoma characterized by the translocation t(11;14)(q13;q32) which triggers the dysregulation of the cyclin D1 by placing its coding gene CC1ND1 under the control of an immunoglobulin promoter. One of the major consequences of this molecular event is the disturbance of the cyclin D/Rb pathway leading to Rb inactivation and activation the elongation factor E2F1 mainly implicated in cell cycle progression. The mainstay of MCL therapies remains the chemo-immunotherapy followed by autologous transplantation but recently several novel therapies have been developed such as BTK inhibitors, Venetoclax, CDK4/6 inhibitors and more recently CAR-T therapies. However, patients with aggressive forms of MCL exhibit low response rates, requiring the identification of novel therapeutic targets. Materials and Methods We have previously generated an MCL cell line (UPN-1) from a patient with a blastoid variant of MCL presenting unique morphological and cytogenetics characteristics (M'kacher et al, Oncogene 2003). This cell line has been shown to harbor a TP53 mutation and a highly increased sensitivity to radiation despite the absence of functional p53. The molecular basis of this phenomenon has not been explored. In this work, we further characterized UPN-1 cell line using the Clarium S human microarray which has been compared to the gene expression profile of other existing MCL cell lines (GRANTA-519, JEKO-1, JVM-2, MAVEK-1, MINO, REC-1, SP-49, SP-53, Z-138). After mathematical correction, a supervised analysis was performed between triplicate samples of UPN-1 and a group constituted with all other MCL cell lines. We have then set up in vitro assays to determine the effect of a direct E2F1 inhibitor on the proliferative potential of UPN-1. Results The comparative transcriptome analyses revealed a list of 47 genes specifically upregulated in UPN-1. Unsupervised classification allowed to discriminate UPN-1 samples from other MCL cell lines based on the expression of these 47 genes. These data suggested a specific expression profile of UPN-1 as compared to other cell lines. Among the upregulated genes, E2F1 elongation factor was found to be highly upregulated in UPN-1 as compared to other MCL cell lines along with positive enrichment of E2F targets which are mainly implicated in cell cycle progression (Figure 1). Interestingly, UPN-1 has a low level of BCL-2 as compared to other MCL lines that could explain its radio sensitivity. However, other signaling pathways involved in the inhibition of apoptosis were found to be present in UPN-1 by geneset enrichment analysis. The expression of CDKN1A (p21), major cell cycle regulator and known as a marker of aggressive MCL, was found to be low in UPN-1. A repression of immune response pathway such as NFKB with low expression of NFKBIA was identified. Finally, the expression of PIK3CD which encodes for a therapeutic target in MCL (such as PI3KDelta inhibitor Idelalisib) was also significantly repressed in UPN-1 as compared to nine other MCL cell lines. To evaluate the effect of the direct inhibition of E2F1, we treated UPN-1 cells with a targeted E2F1 inhibitor 5‘-Deoxy-5‘-(methylthio)adenosine (MTA) which is a protein methylation inhibitor. MTT assays revealed a 50% reduction of proliferation at + 4 hours in comparison to the vehicle-treated conditions (P<0.0001).Annexin assays showed an increase in early apoptosis (36.6 %) at + 8 hours with subsequent rise in late apoptotic cells (64.5 %) observed after 24 hours of treatment. Interestingly, qRT-PCR analyses of MTA-treated cells exhibited a decrease in the expression of downstream factors associated with E2F1, such as RAD51, BRCA1, CDK2, CCNB2, RANBP1. Conclusions We report here for the first time the comparative transcriptome analysis of the unique aggressive blastoid MCL line UPN-1 as compared to other MCL lines described. This cell line exhibited a major upregulation of E2F1 expression and a down regulation of the cell cycle inhibitor CDKN1A(p21). The potential effects of the direct inhibition of E2F1 using the targeted inhibitor MTA demonstrated a reduction in cell proliferation and induction of apoptosis, suggesting the possibility of associating clinically acceptable E2F1 inhibition strategies to other current therapies.

Cutaneous Involvement as a First Sign of CD5(-) Blastoid Mantle Cell Lymphoma.

Cutaneous Involvement as a First Sign of CD5(-) Blastoid Mantle Cell Lymphoma.

Skin Involvement by Hematological Neoplasms with Blastic Morphology: Lymphoblastic Lymphoma, Blastoid Variant of Mantle Cell Lymphoma and Differential Diagnoses.

Hematological neoplasms sharing a blastic morphology may involve the skin. The skin may be either the primary site of occurrence of hematological malignancies with blastic features or cutaneous lesions are the first manifestation of an underlying systemic malignancy. The assessment of skin biopsies of hematological neoplasms with blastic features poses diagnostic problems and requires expert hematopathologists considering a wide range of differential diagnoses. The precise diagnosis of diseases sharing blastic features but with different outcomes and requiring distinct therapies is essential for patient management. The present paper mainly focuses on cutaneous involvement of the blastoid variant of mantle cell lymphoma and lymphoblastic lymphoma of B-cell or T-cell origin. The relevant literature has been reviewed and the clinical aspects, pathological features, prognosis, and therapy of both blastoid mantle cell lymphoma and lymphoblastic lymphoma involving the skin are discussed. A focus on other hematological entities with blastic features, which may involve the skin, to be taken into consideration in differential diagnosis is also given.

Role of Morphology in the Diagnosis of Acute Leukemias: Systematic Review

AbstractThe role of hematopathologists in the diagnosis of acute leukemia (AL) starts with the morphological examination of either peripheral blood smear or bone marrow. The morphological hallmark for the myeloblast includes “Auer rods” and “Phi bodies.” The addition of cytochemical stains such as myeloperoxidase, Sudan Black B, periodic acid-Schiff stain, nonspecific esterase, and Perls' stain acts as an important adjunct to the morphological classification in the resource-constrained settings. The recent World Health Organization classification still endorses the utility of morphology which requires the presence of either ≥ 20% lymphoblasts or myeloblasts/or its equivalents (monoblasts, promonocytes, or megakaryoblasts) and integrates it with the clinical features, immunophenotyping (IP), and molecular genetics for making the diagnosis of AL. Morphology can give clue to the specific diagnosis of acute myeloid leukemia (AML) with t(8:21), t(15:17), t(16:16), or inv(16) and this diagnosis can be made irrespective of blasts count if such translocations are demonstrated by molecular tests. There are some interesting findings such as blasts with “hand-mirror” morphology, nuclear cleavage, prominent cytoplasmic vacuoles, pseudo-Chediak-Higashi granules, cup-like nucleus, and other dysplastic features helping in differentiating lymphoid and myeloid leukemias. Transient abnormal myelopoiesis in Down syndrome and hypoplastic AL can be picked up on morphological examination. Bone marrow biopsy would be greatly beneficial and complementary to aspirate smears and is required for diagnosing exact cellularity, topography of cells, dyspoiesis, myelonecrosis, gelatinous marrow transformation, myelofibrosis, and IP can be performed using immunohistochemistry. Morphological examination in AL is not only helpful for diagnosis but also useful for predicting the prognosis in posttherapy cases, AML with myelodysplasia-related changes, therapy-related myeloid neoplasms, and mixed phenotype AL. Hematogones, blastoid mantle cell lymphoma, high grade B cell lymphoid with blastoid morphology, Burkitt leukemia, prolymphocytes in prolymphocytic leukemia, hairy cell leukemia variant, plasmablasts especially in plasmablastic leukemia, or plasma cell leukemia can mimic AL and IP is useful in these situations. Hence, morphology should be considered as a kind of “gold-standard” starting point for the analysis of AL cases. Morphological examination cannot be replaced and advanced tests cannot be used as surrogate for morphology.

Blastoid B-Cell Neoplasms: Diagnostic Challenges and Solutions.

Blastoid B-cell neoplasms mainly include B-lymphoblastic leukemia/lymphoma (B-ALL), blastoid mantle cell lymphoma, and high-grade B-cell lymphoma with blastoid morphologic features (blastoid HGBL). Distinguishing blastoid HGBL from B-ALL can be challenging and we previously developed six-point flow cytometry-focused and three-point immunohistochemistry-focused scoring systems to aid in differential diagnosis. However, the six-point scoring system was derived from bone marrow cases and occasional cases may have a misleading score using either system. In this study, we assessed 121 cases of blastoid-HGBL (37 BM and 84 extramedullary) to validate the six-point scoring system in all tissue types and to further compare the two scoring systems. Compared with 47 B-ALL cases enriched for CD34-negative neoplasm, the 121 blastoid-HGBL cases showed distinctive pathologic features. The six-point scoring system showed a sensitivity of 100%. A comparison of the two scoring systems in blastoid HGBL (n = 64) and B-ALL (n = 37) showed a concordance score rate of 88%. Thirteen cases showed misleading scores, including five HGBL and eight B-ALL, and the diagnosis was further validated by gene transcriptome profiling. Twelve of thirteen cases had discordant scores between the two scoring systems. Simultaneous employment of both scoring systems improved the accuracy of classification of blastoid B-cell neoplasms to 99%. In conclusion, the previously defined six-point scoring system showed an excellent performance regardless of the tissue origin. Using both scoring systems together improves the accuracy of classification of blastoid B-cell neoplasms. Cases with discordant scores between the two scoring systems were extremely challenging neoplasms and classification required correlation with all available clinical and genetic features.

The Therapeutic Synergy of Selinexor and Venetoclax in Mantle Cell Lymphoma Through Induction of DNA Damage and Perturbation of the DNA Damage Response.

Introduction: Mantle cell lymphoma (MCL) can be stratified into blastoid and classical subtypes based on morphological features, with the former subtype having a poorer prognosis. Despite recent advances in targeted approaches, including multiple bruton tyrosine kinase inhibitors which yield impressive clinical responses and improve prognoses, MCL remains an incurable disease with frequent relapses. Additional therapeutic interventions are therefore unmet medical needs for the management of patients with MCL. Methods: Cell viability and apoptosis assays were employed to analyze the therapeutic interaction of venetoclax combined with selinexor in MCL cells. Western blot was used to investigate the potential mechanism of action for the synergy of venetoclax in combination with selinexor in MCL cells. Results: In this study, we revealed that both blastoid and classical MCL cells were vulnerable to the cytotoxic effects of selinexor, a well-established XPO1 inhibitor, manifested by loss of cell viability and induction of cell apoptosis. Moreover, our data indicated that the addition of venetoclax to selinexor showed synergistically decreased cell viabilities and increased cell deaths in blastoid and classical MCL cells compared to each single drug treatment. Either selinexor or venetoclax treatment alone decreased MCL1 expressions and increased BAX levels in MCL cells, and these effects were further enhanced by their combined regimen. Mechanistically, our findings demonstrated that induction of DNA damage and inactivation of DNA damage response were involved in the synergistic interaction of the drug combination regimen. Conclusion: Collectively, this study might provide a potential attractive therapy option for the treatment of MCL. However, the conclusion needs additional experimental validation in in vivo models and clinical evaluations are mandatory.

Updates in the treatment of mantle cell lymphoma: A Canadian expert framework

Mantle cell lymphoma (MCL) is a B cell Non-Hodgkin Lymphoma that develops in the mantle zone of the lymph node. It is more common in men and is usually diagnosed at an advanced stage with involvement of lymph nodes, bone marrow, and potentially the gastrointestinal tract. MCL accounts for 5–10% of all new NHL cases per year in Canada, which is estimated at 11,400 for 2022. While most patients respond to initial treatment, relapses occur early and MCL generally shows a variable response to subsequent treatments, often with limited duration of benefit. Two main subtypes of MCL can be distinguished that arise from in situ MCL lesions. The most common subtype, classic MCL, arises from these cells with limited or no immunoglobulin heavy chain variable region (IGHV) mutations. Cells from this subtype express SOX11, are genetically unstable, and have naïve B cell-like characteristics. Classic MCL is more often nodal and extranodal and may eventually progress to aggressive blastoid or pleomorphic MCL. The other subtype, leukemic non-nodal MCL, arises from cells that have undergone IGHV somatic hypermutations, do not express SOX11, and exhibit characteristics of memory B cells. This subtype can have an indolent clinical behavior for a long time, often several years, but frequently acquires TP53 and other mutations and progresses to a more aggressive subtype. Treatment options have expanded significantly over the past decades, with improvements in both overall survival (OS) and progression-free survival (PFS) compared to earlier treatment eras. This Canadian expert framework aims to discuss the management considerations for patients with MCL, and will present both front-line treatment options as well as those for relapsed and refractory disease.

Differential Phosphoproteomics Deciphers Physiopathology of High-Risk Mantle Cell Lymphoma

Background: Mantle cell lymphoma (MCL) is a rare adult-onset non-Hodgkin lymphoma of which genetic hallmark is CCND1 translocation with IG genes, although CCND2, CCND3 or CCNE translocations are alternatives. The median survival of patients with MCL has lately increased due to improved therapies. However, the identification of high-risk MCLs characterized by pleomorphic or blastoid appearance, high proliferation index and TP53 deletions/mutations, remains mandatory due to their highly aggressive features and dismal clinical course even with intensified regimens. Therefore, specific therapeutic approaches are still warranted for such patients, but clinical and biological data are scarce since high-risk MCLs represent only 10-20% of all MCLs. A valuable source of rare samples for clinical/translational research is archived collections of formalin-fixed paraffin-embedded (FFPE) tissue blocks which enable retrospective studies to be performed. However, FFPE samples remain challenging for omics studies, especially phosphoproteomics. Here we implemented an original process to overcome this technical roadblock and took full advantage of FFPE samples to investigate biological processes differentially involved in high-risk and classical MCL (cMCL) to highlight rationale for innovative targeted therapies for these aggressive forms. Material and methods: We employed an unbiased differential label-free phosphoproteomic approach using archived FFPE MCL samples. Briefly, archived FFPE lymph nodes conclusive for cMCL or blastoid MCL (bMCL) diagnoses were retrieved from the Biological Resource Center of Strasbourg University Hospital from 1996 to 2016. H&E slides were reevaluated, and areas enriched in tumoral cells were selected to be punched from FFPE blocks. Our original sample preparation procedure entailed 1/ xylene-based deparaffinization, 2/ protein extraction with high content SDS-based lysis buffer, 3/ sample reduction/alkylation followed by cleanup and protein digestion on carboxylate paramagnetic beads and Lys-C/trypsin proteolytic enzyme mix, 4/ phosphopeptide enrichment on the AssayMap Bravo platform (Agilent) using IMAC Fe(III)-NTA cartridges. All samples were then analyzed on a NanoElute coupled to a TimsTOF Pro mass spectrometer (Bruker). Label-free quantification was performed using MaxQuant with the human database downloaded from SwissProt in April 2022. Further bioinformatics analyses were conducted in Perseus and Prostar. Data were functionally annotated with Reactome Pathway Database and STRING for association networks. Results: For this monocentric study we retrieved 30 FFPE blocks of lymph node biopsies conclusive for MCL diagnosis, including 15 bMCL and 15 cMCL. Although FFPE samples represented a challenge to work with for phosphoproteomics, we extracted enough protein from three 2mm-punches to proceed to the phosphopeptide enrichment according to our original sample preparation procedure. Overall, we successfully identified and quantified 7,220 class I phosphosites, i.e., sites of phosphorylation for which the probability of the phosphate group localization is greater than 0.75. No significant difference was found considering neither the archived period length of FFPE blocks nor the MCL subtypes (bMCL or cMCL). Differential analysis of bMCL and cMCL identified 180 differentially phosphorylated phosphosites (p-value < 0.05) corresponding to 103 proteins. Among these phosphosites, 139 were more phosphorylated in bMCL. Functional annotation of their corresponding proteins highlighted an over-representation of proteins involved in cell cycle, DNA repair and RNA metabolism within bMCL differential phosphoproteome (Fig.1). In addition, the kinase enrichment analysis of these differentially phosphorylated proteins predicted an increased activity of cyclin-dependent kinases in bMCL compared to cMCL. Conclusion: Here we performed for the first time phosphoproteomics from archived FFPE MCL samples. Differential analysis revealed that high-risk MCLs are characterized by an increased phosphorylation of proteins involved in cell cycle and an increased activity of cyclin-dependent kinases. Further studies are mandatory to fully understand to which extent cyclin-dependent kinases could be suitable targeted therapeutic candidates for patients with high-risk MCL. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Establishment and characterization of a new mantle cell lymphoma cell line with a NOTCH2 mutation, Arbo.

Cell lines represent an essential tool used in preclinical research. Most hematologic malignancies have a wide array of cell lines representing their respective molecular and pathologic spectra. In mantle cell lymphoma (MCL), cell lines become specifically valuable in view of the heterogeneity of this disease. Unfortunately, the number of MCL cell lines that are available for the research community remains small, with only nine cell lines available for purchase through the American Type Culture Collection (ATCC). We have established a novel blastoid MCL cell line, isolated from the malignant pleural effusion of a 69-year-old male with refractory MCL. Arbo was fully characterized with cytogenetics, immunophenotyping, whole exome sequencing and drug sensitivity assays. One of the most notable mutations identified in Arbo (but not in normal tissue) was the missense mutation NOTCH2 R2400*, which has been proposed as a clinically significant mutation in MCL seen in 5% of cases. NOTCH2 R2400* results in a truncated Notch2 protein, leading to a more stable and active protein. Using pharmacologic inhibition of Notch2, we showed a dependence of Arbo on NOTCH2 signaling, as well as a link between CD23 expression on Arbo and NOTCH2 activity. Arbo represents a NOTCH2 mutated model that is useful in MCL as well as other lymphomas with such mutation. We plan to deposit Arbo at the ATCC to be available for the research community.

Abstract CT127: Trial in progress: A phase II, open-label, multicenter study of capivasertib, a potent, oral pan-AKT inhibitor in patients with relapsed or refractory B-cell non-hodgkin lymphoma (CAPITAL)

Abstract Background: The PI3K/AKT/mTOR pathway is an established therapeutic target in indolent B-cell non-Hodgkin lymphoma (B-NHL). Several PI3K inhibitors are approved to treat relapsed/refractory (R/R) follicular lymphoma (FL) and, more recently, marginal zone lymphoma (MZL). Nonetheless, potential class-specific and PI3K-isoform-related toxicities may limit their clinical utility. Capivasertib is an oral, potent, selective inhibitor of the 3 AKT isoforms that demonstrated a manageable safety profile (n&amp;gt;1500) and survival benefit in combination with other agents in patients (pts) with solid tumors. Unlike PI3K inhibitors, colitis or pneumonitis have not been a concern with monotherapy. Preclinically, capivasertib was active both in vitro in a large panel of B-NHL cell lines and in vivo in PTEN-null GCB-DLBCL PDX models, where it downregulated the oncogenic factor MYC. In the JVM2 mantle cell lymphoma (MCL) cell line, capivasertib showed superior activity vs PI3Ka/d (AZD8835) and PI3Kb/d (AZD8186) inhibitors. Of note, AKT activation following dysregulation of PTEN has been frequently described in FL (where &amp;gt;85% of tFL or FL/DLBCL exhibited a GCB phenotype). Therefore, capivasertib may represent an effective treatment option for pts with R/R B-NHL. Trial Design: This modular phase II study will enroll pts in 3 cohorts according to B-NHL type. Core inclusion criteria include: age ≥18 years and ECOG PS ≤2. Module-specific criteria include: cohort 1A: R/R FL after ≥2 prior systemic lines (max 5), including an anti-CD20 monoclonal antibody (mAb) and an alkylating agent; cohort 1B: R/R MZL of splenic, nodal, and extranodal subtypes after ≥2 prior systemic lines (max 5) including ≥1 anti-CD20 mAb; cohort 1C: R/R MCL after ≥2 prior systemic lines (max 4), previously exposed to anti-CD20 mAb and a BTK inhibitor. Pts with FL grade 3B, transformed disease, blastoid or TP53 mutation MCL, active CNS disease, diabetes requiring insulin, or being &amp;lt;3 months post-CD19-directed CAR-T therapy will be excluded.Capivasertib will be administered orally at 480 mg BID with an intermittent schedule (4 days on/3 days off; 28-day cycles) until disease progression or unacceptable toxicity. The primary efficacy endpoint in AACR 2022_Capivasertib TiP Abstracteach cohort is objective response rate based on 2014 Lugano criteria per blinded independent central review. Secondary endpoints include duration of response, progression-free survival, overall survival, patient-reported outcomes, safety, and pharmacokinetics. An interim analysis of safety will occur when approximately 30 pts across all cohorts have been treated for 8 weeks. An interim analysis of efficacy will occur after 28 pts (cohorts 1A+1B) or 24 pts (cohort 1C) have been treated for 4 months. A total of 272 pts are planned across 28 sites in 7 countries globally (US, Europe, and Asia). Recruitment began in October 2021. Funding: AstraZeneca Clinical Trial Registration: NCT050080552 Citation Format: Michael Wang, Ho-Jin Shin, Alex F. Herrera, Moshe Levy, Wong Seog Kim, Tae Min Kim, Jin Seok Kim, Dok Hyun Yoon, Vincent Ribrag, Miguel Canales, John Radford, Dima El-Sharkawi, Brandy Hemmer, Richa Manwani, Veerendra Munugalavadla, Robert Chen, Andrew Mortlock, Alessandra Forcina, Franck Morschhauser. Trial in progress: A phase II, open-label, multicenter study of capivasertib, a potent, oral pan-AKT inhibitor in patients with relapsed or refractory B-cell non-hodgkin lymphoma (CAPITAL) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT127.

Abstract 3160: Establishment and characterization of a new mantle cell lymphoma cell line with a NOTCH2 mutation, ArBo

Abstract Cell lines represent a very useful tool for cancer research. In mantle cell lymphoma (MCL), the number of characterized cell lines remains small. We have recently established a novel blastoid MCL cell line, isolated from a malignant pleural effusion of a patient with MCL. A sample of the malignant pleural effusion was obtained with informed consent, and mononuclear cells were isolated. Following a few days of in-vitro culture, cells started to grow rapidly resulting in an estimated doubling time of 48h. The cells survived multiple freeze/thaw cycles and have been maintained in culture for the last 8 months. Hence the establishment of a novel blastoid MCL cell line, named Arbo. Both Arbo and the primary MCL cells obtained from the pleural effusion were negative for EBV DNA by qPCR. Flow cytometry showed kappa-restricted cells that were positive for CD5, 19, 20, 22, and 23, and negative for CD2, 3, 7, 10, and 71. FMC7 was positive in Arbo and negative in primary cells, as opposed to CD38 that was negative in Arbo and positive in the primary cells. Arbo’s karyotype was complex contrasting with the normal 46XY karyotype found in the primary MCL cells. The presence of t(11;14)(q13;q32) was confirmed by FISH, additionally overexpression of cyclin-D1 was confirmed by western blot. Whole exome sequencing (WES) was performed on DNA collected from Arbo revealing a total of 148,059 SNPs. Mutations were detected in the ATM, TP53 and NOTCH2(C19W and R2400*) genes. Mutations in NOTCH2 have not been described in other MCL cell lines, while they were identified in 5.2% of MCL patients. Immunoblotting for NOTCH2 confirms the expression of the protein by the cell line. Additionally, expression of CD23, which has been shown to be induced through NOTCH2 signaling, was confirmed by flow cytometry. To further characterize the effect of NOTCH2 on the survival of Arbo cells and CD23 expression, we cultured the cell line with increasing concentrations of the NOTCH2 transactivation inhibitor gliotoxin. We observed a dose-dependent inhibition of cell growth with an IC50 of 100 nM. Additionally, a dose dependent decrease in the expression of CD23 was observed by flow cytometry following treatment with gliotoxin. To determine the dependence of Arbo on B-cell receptor (BCR) signaling for survival, we cultured the cells with increasing concentrations of the BTK inhibitor ibrutinib for 48h. Inhibition of cell growth was observed in a dose-dependent manner resulting in an IC50 of 0.4 µM. In conclusion, Arbo is a novel blastoid MCL cell line with a NOTCH2 mutation that is fully characterized and will be made available to the research community. Supported by a grant from the Ladies Leukemia League, Inc., of the Gulf South Region. Citation Format: Ishwarya Satyavarapu, Firas M. Safa, Terri Rasmussen, Nakhle Saba. Establishment and characterization of a new mantle cell lymphoma cell line with a NOTCH2 mutation, ArBo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3160.

Long-term Outcomes With Ibrutinib Treatment for Patients With Relapsed/Refractory Mantle Cell Lymphoma: A Pooled Analysis of 3 Clinical Trials With Nearly 10 Years of Follow-up.

Long-term Outcomes With Ibrutinib Treatment for Patients With Relapsed/Refractory Mantle Cell Lymphoma: A Pooled Analysis of 3 Clinical Trials With Nearly 10 Years of Follow-up.

Stem cell transplant for mantle cell lymphoma in Taiwan

Mantle cell lymphoma (MCL) is a B-cell lymphoma featuring an aggressive course and a progressive relapsing pattern. International guidelines recommend early consolidative autologous stem cell transplant (auto-SCT) for eligible patients while reserving allogeneic SCT (allo-SCT) as therapy for refractory cases. Since data describing the implementation of transplants in the Asian population with MCL are limited, we aimed to analyze post-SCT outcomes of 99 MCL patients from the Taiwan Bone Marrow Transplant Registry database. The median age was 56 years, and 11% of the patients had blastoid variant MCL. Ninety-four patients received auto-SCT, while 13 patients received allo-SCT, eight of which received allo-SCT after failing auto-SCT. Before auto-SCT, 52% of the patients were in their first complete remission (CR1). Overall, 37 patients (39%) relapsed after auto-SCT. The median post-auto-SCT progression-free survival and overall survival (OS) were 43.6 months and not reached, respectively. Blastoid variant MCL, transplant not received in CR1, and disease progression within 12 months post-auto-SCT independently predicted inferior OS in multivariable analysis. The median post-allo-SCT OS was 74 months. Two patients (15%) died of MCL recurrence post-allo-SCT. Three patients with refractory diseases were salvaged with ibrutinib or venetoclax to allo-SCT. Treatment strategies incorporating novel agents warrant further optimization.

Phase 1b/2 Study of Vipor (Venetoclax, Ibrutinib, Prednisone, Obinutuzumab, and Lenalidomide) in Relapsed/Refractory and Untreated Mantle Cell Lymphoma: Safety, Efficacy, and Molecular Analysis

Background: Mantle cell lymphoma (MCL) is a biologically and clinically heterogenous B-cell lymphoma that is generally incurable with standard therapies. Novel targeted agents can disrupt key survival pathways in MCL such as regulation of apoptosis (BCL2: venetoclax), B-cell receptor signaling (BTK: ibrutinib), and NF-κB survival pathways (IRF4/SPIB: lenalidomide). As monotherapy, these agents fail to induce deep responses and doublet/triplet regimens often require continuous or maintenance therapy. ViPOR has been shown to be safe and active in non-MCL NHL pts without significant tumor lysis syndrome (TLS) (Melani et al. Blood. 2020; 136(Supplement 1):44-45). We hypothesized that combining agents that target multiple survival pathways with ViPOR will leverage efficacy and time-limited, cyclic dosing will limit toxicities in MCL.Methods: Relapsed/refractory (R/R) and untreated MCL pts with adequate organ function were eligible. In R/R MCL, a phase I “3+3” design was used to determine the maximum tolerated dose (MTD) of 2 dose-levels of dose-escalated venetoclax (200mg and 400mg) PO D2-14 (starting C2) in combination with fixed-dose ibrutinib 560mg PO D1-14, prednisone 100mg PO D1-7, obinutuzumab 1000mg IV D1-2, and lenalidomide 15mg PO D1-14. A phase II expansion in untreated MCL was included at the MTD. ViPOR q21d x 6C was given without maintenance or consolidation. All pts were admitted C2 for 12d venetoclax escalation and TLS monitoring. All pts received TLS prophylaxis (ppx) with IVFs and allopurinol as well as PCP and G-CSF ppx. VTE ppx was per investigator discretion. Baseline CT, PET, BM, and tumor biopsy was performed with CT scans after cycles 1, 2, 4, and 6 and PET after cycle 6 or at time of suspected complete response (CR). Surveillance CT was performed q3m for 1y, q4m x 1y, q6m x 1y, then annually x 2y. Plasma for ctDNA was collected at baseline, prior to each treatment cycle, at each follow-up visit, and at disease progression.Results: 11 pts have been enrolled and treated; 9 (82%) R/R in dose-escalation and 2 (18%) untreated in dose-expansion. Median age was 71y (range 57-79) with 73% >65y and 64% male. Low, intermediate, and high-risk MIPI occurred in 18%, 64%, and 18% of pts, respectively. Stage IV disease was seen in 91%, with BM involvement in 73%, extranodal disease in 82%, and both in 64%. Disease bulk >5cm occurred in 45% of pts. Blastoid morphology, Ki-67 >30%, and TP53 IHC >50% occurred in 27%, 36%, and 18% of pts, respectively. Median prior therapies in R/R pts was 3 (range 1-4) with 44% receiving prior BTKi, 11% receiving prior CAR-T, and 78% refractory (i.e., <PR) to last therapy. No pts received prior venetoclax or lenalidomide.No dose-limiting toxicities (DLTs) occurred in 9 evaluable pts in the dose-escalation cohort; thus, venetoclax 400mg was used in expansion. G3-4 heme AEs (% cycles) included neutropenia (13%), anemia (11%), and thrombocytopenia (9%). No cases of febrile neutropenia occurred across 46 total cycles. G3-4 non-heme AEs (% pts) included hypokalemia in 3 (33%) pts as well as fatigue, hypomagnesemia, elevated bilirubin, atrial fibrillation, lung infection, and syncope in 1 (11%) pt each. No laboratory or clinical TLS occurred. Dose reductions and delays occurred in 5% and 15% of cycles, respectively.Of 11 pts enrolled, 10 are evaluable for response (1 pt has not yet been restaged) with an overall response rate (ORR) and CR rate of 100% (10/10) and 80% (8/10), respectively (Fig 1A). Of 8 pts who have completed therapy, all 8 (100%) have achieved CR, including all 4 post-BTKi pts, 1 post-CAR-T pt, and 6 refractory pts. With a median potential f/u of 5.2m, median TTR and DOR was 0.7m and not reached, respectively, with 9 (90%) responses ongoing ranging from 0.3m to 14.5m after first response (Fig 1B). One pt with R/R blastoid MCL relapsed in the CNS 9.9m after initial response. Median PFS and OS were both not reached with 10 (91%) pts alive and progression-free and 1 relapse and death from progression at 11.9m.Conclusion: ViPOR is safe in MCL without significant TLS or DLTs using a 12d venetoclax ramp-up on C2 and venetoclax 400mg was taken forward in expansion. Most common G3-4 AEs were hematologic with no febrile neutropenia observed when given with G-CSF ppx. High preliminary activity is noted in MCL pts with fixed-duration ViPOR x 6C, including CRs in refractory, post-BTKi, and post-CAR-T pts. Molecular and ctDNA analyses are ongoing and will be presented at the meeting. [Display omitted] DisclosuresNo relevant conflicts of interest to declare. OffLabel Disclosure:Off-label use of ViPOR in relapsed/refractory and untreated MCL.

Somatostatin Receptors and Chemokine Receptor CXCR4 in Lymphomas: A Histopathological Review of Six Lymphoma Subtypes.

BackgroundSomatostatin receptors (SSTR) and chemokine receptor CXCR4 are expressed in lymphomas, while the abundance is known to be heterogeneous in different subtypes of lymphomas. Targeting tumor cells expressing these receptors might add to therapeutic opportunities while radiolabeled ligands for both imaging and therapy have been developed. The aim of this study was to establish SSTR subtype 2, 3 and 5 and also CXCR4 status immunohistochemically in six different lymphoma subtypes: diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), mantle cell lymphoma (MCL), mucosa-associated marginal B-cell lymphoma (MALT), Hodgkin lymphoma (HL) and peripheral T-cell lymphoma (PTCL).Material and MethodsThis study included a total of 103 lymphoma patients (24 DLBCL, 22 FL, 18 HL, 9 MALT, 20 MCL and 10 PTCL) diagnosed in the Southwest hospital district of Finland during 2010-2019. SSTR 2, 3 and 5 and CXCR4 expression was analyzed immunohistochemically (IHC) in lymphoma samples obtained from local archival Biobank tissue repository. Immunopositivity of each receptor was scored on a four-point scale accounting for staining intensity and proportion of positively stained tumor cells.ResultsOf different SSTR subtypes SSTR2 immunopositivity was most common and seen predominantly at the cell membrane of the malignant cells in 46-56% of DLBCL, HL and FL. CXCR4 co-expression was frequently present in these cases. SSTR3 and SSTR5 IHC were negative in DLBCL and FL but in HL SSTR expression was more heterogenous and SSTR3 and SSTR5 positivity was found in cytoplasm in 35% and 25% of cases. 2/4 blastoid MCL variants and one pleomorphic MCL variant had positive CXCR4 IHC whilst all other MCL cases (85%) were negative for all receptors. 30% (n=3) of the PTCL patients had positive SSTR5 IHC and CXCR4. MALT lymphomas were negative for all receptors.ConclusionSSTR2 and CXCR4 are found in DLBCL, FL and HL and co-expression of these receptors is common. Although in general expression of SSTRs and CXCR4 is heterogenous and very low in some subtypes such as MCL and MALT there are also patients with abundant expression. The latter are candidates for trials studying SSTR2 and/or CXCR4 based treatments in the future.

A Case of Blastoid Mantle Cell Lymphoma Occurring in the Parotid Gland

A Case of Blastoid Mantle Cell Lymphoma Occurring in the Parotid Gland

Brexucabtagene autoleucel therapy induces complete remission in a primary refractory blastoid mantle cell lymphoma with neurolymphomatosis

Brexucabtagene autoleucel therapy induces complete remission in a primary refractory blastoid mantle cell lymphoma with neurolymphomatosis

Outcomes with KTE-X19 in patients (pts) with relapsed/refractory (R/R) mantle cell lymphoma (MCL) in ZUMA-2 who had progression of disease within 24 months of diagnosis (POD24).

7547 Background: KTE-X19 is an autologous anti-CD19 CAR T-cell therapy approved in the US and EU for the treatment of R/R MCL. In the ZUMA-2 study of KTE-X19 in R/R MCL, the objective response rate (ORR) at a median 17.5-mo follow-up was 92% (67% complete responses [CR]; Wang et al. ASH 2020 #1120). Here, we report results in pts with or w/o POD24, an indicator of poor outcomes (Visco et al. Br J Haematol 2019). Methods: Eligible pts with R/R MCL underwent leukapheresis and conditioning chemotherapy followed by a single infusion of KTE-X19. Efficacy results are reported for the 60 treated pts with ≥1 y of follow-up (median 17.5 mo); safety results are presented for all 68 treated pts. Results: High-risk disease characteristics were common in pts with (n=33) and w/o POD24 (n=35), although pts with POD24 had higher tumor burden and lactate dehydrogenase (LDH) levels, and more had blastoid type MCL (Table). ORR in pts with (n=28) and w/o POD24 (n=32) was 93% and 91%, with CR rates of 61% and 72%. In pts with and w/o POD24, median progression-free survival (PFS) was 11.3 mo (range, 0.9–30.3) and 29.3 mo (range, 0–35.9). Medians for duration of response (DOR) and overall survival (OS) were not reached in either group. Most common Grade ≥3 adverse events (AEs) in pts with vs w/o POD24 were neutropenia (91% vs 80%), thrombocytopenia (61% vs 46%), and anemia (55% vs 51%); Grade ≥3 cytokine release syndrome (CRS) and neurologic events occurred in 9% vs 20% and 27% vs 34%, respectively. There were no cases of Grade 5 CRS, KTE-X19–related secondary cancers, or replication-competent retrovirus in either group. In pts with vs w/o POD24, median peak CAR T-cell levels and median area under the curve were 53.4 cells/µL (range, 0.2–2566) and 583.4 cells/µL (range, 1.8–27,743.6) vs 112.4 cells/µL (range, 0.2–2589) and 1588.3 cells/µL (range, 3.8–27,238.7); by 12 mo, B cells were detectable in 8/11 (73%) vs 7/15 pts (47%) in ongoing response. Conclusions: KTE-X19 provided a high CR rate across all pts, with median DOR and OS not reached. Pts with POD24 had more aggressive high-risk disease characteristics (tumor burden, LDH levels, and blastoid MCL) and generally lower CAR T-cell expansion and PFS vs pts w/o POD24. Earlier intervention with CD19-directed CAR T-cell therapy may benefit pts with MCL with known high-risk factors. Clinical trial information: NCT02601313. [Table: see text]

Mantle Cell Lymphoma: An Immunomorphologic Study with SOX11 from a Tertiary Care Cancer Centre in Southern India

Introduction: Mantle Cell Lymphoma (MCL) is a relatively rare Non-Hodgkin Lymphoma (NHL) of mature B cells forming 5-7% of NHL. SOX11 has emerged as a useful antibody in the diagnosis of MCL with prognostic significance. Aim: To evaluate the immunomorphologic features and significance of SOX11 expression in MCL at a tertiary care cancer institute. Materials and Methods: This was a descriptive study which was conducted at a tertiary care cancer centre in Southern India over a period of five years from January 2013 to December 2017. Seventy six cases of newly diagnosed MCL with paraffin blocks were included in the study. Immunohistochemistry (IHC) with a panel of antibodies including SOX11 was carried out on Formalin Fixed Paraffin Embedded (FFPE) sections. Morphologic, immunologic findings were analysed and correlated with clinical data and survival, using Chi-square and Independent sample t-test to compare data and Kaplan-Meir method with Log Rank test for survival analysis. Results: Mantle Cell Lymphoma (MCL) formed in 5.8% of NHL with a striking male predominance (M:F ratio, 4.4:1), with mean age of 58 years at presentation and females at a younger age. Nearly 80% of patients presented at an advanced stage. Cervical lymphadenopathy was the most common presenting feature, followed by involvement of the gastrointestinal tract. There were 59 cases of classic and 17 cases of blastoid and pleomorphic MCL, with diffuse pattern being the most common in 36 (47.4%) cases. In the present study, 64 (92.8%) cases expressed SOX11 and showed heterogeneous staining with high expression in 34 (53.1%) cases and low expression in 30 (46.9%) cases. Ki-67 proliferation of more than 30% was seen in 52 (68.4%) cases and 30% or less in 24 (31.6%) cases. None of these findings had statistically significant correlation with survival, though high Ki-67, high MCL International Prognostic Index (MIPI) and blastoid/pleomorphic cases had relatively worse Overall Survival (OS). Conclusion: MCL is a disease of the elderly and in the present study it affected females at a slightly younger age as compared to males. SOX11 expression was heterogeneous in neoplastic cells and was complementary to cyclin D1 for diagnosis of MCL however, the staining intensity had no effect on survival.