UNASSIGNED: Mantle cell lymphoma (MCL) is an uncommon non-Hodgkin lymphoma that is generally considered incurable. Covalent BTK inhibitors (cBTKi) are the cornerstone of treatment for relapsed or refractory (R/R) MCL, but treatment options are limited and prognosis is poor after cBTKi failure. Pirtobrutinib is a non-covalent BTK inhibitor that has demonstrated excellent efficacy and safety and represents an important new treatment in the evolving treatment landscape of R/R MCL.
UNASSIGNED: This review will provide an overview of the therapeutic landscape of R/R MCL, characteristics of pirtobrutinib, and efficacy and safety data of pirtobrutinib in R/R MCL from pivotal clinical trials. PubMed and major hematology conference proceedings were searched to identify relevant studies involving pirtobrutinib.
UNASSIGNED: For patients with R/R MCL that has progressed after treatment with cBTKi, pirtobrutinib is an important and efficacious treatment that confers favorable outcomes. In the post-cBTKi setting, when chimeric antigen receptor (CAR) T-cell therapy is not available or feasible, pirtobrutinib is the preferred treatment for R/R MCL. How to sequence or combine pirtobrutinib with CAR T-cell therapy and other available or emerging therapies requires further investigation. Future studies should also explore the role of pirtobrutinib in earlier lines of therapy for MCL.

Intrasinusoidal bone marrow involvement is an infrequent histological pattern observed in a limited number of B and T cell lymphomas. Mantle cell lymphoma is a biologically and prognostically heterogeneous B cell lymphoma that frequently involves the bone marrow, with interstitial, nodular-paratrabecular, or diffuse patterns. Intrasinusoidal bone marrow involvement has been described only anecdotally in this lymphoma. Here, we describe the clinical, histopathological, and molecular features of four patients diagnosed with advanced-stage mantle cell lymphoma, showing intrasinusoidal bone marrow involvement, and other peculiar immunophenotypical features. As similar cases may represent a relevant issue in bone marrow diagnostic histopathology, we also reviewed the literature to discuss differential diagnoses of B and T cell lymphomas with intrasinusoidal bone marrow involvement.

UNASSIGNED: 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.
UNASSIGNED: 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.
UNASSIGNED: 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).
UNASSIGNED: There are several factors that contribute to the aggressiveness of B-MCL, and new treatment approaches might be required to improve patient outcomes.

BACKGROUND: While covalent Bruton\'s tyrosine kinase inhibitors (cBTKis) have become a standard of care treatment for relapsed/refractory mantle cell lymphoma (R/R MCL), response duration is limited and resistance to BTKi and/or adverse events develop in a subset of patients. However, little real-world evidence on post-cBTKi clinical and economic outcomes exists for these patients.
METHODS: This retrospective study used 2010 to 2019 U.S. Medicare claims, to identify elderly (≥ 66 years) patients with newly-diagnosed MCL who received third-line (3L) treatment and had evidence of cBTKi use in a prior line of therapy. Outcomes were assessed ≥ 12-months post 3L-treatment initiation and included treatment patterns, all-cause and MCL-related HRU and costs, and overall survival.
RESULTS: The final sample contained 230 elderly patients with R/R MCL receiving 3L treatment who had cBTKi use in a prior line of therapy (mean age 75.0, 21.7% age > 80 years; 67.4% male; 93.9% White). Common 3L treatments included chemotherapy (26.1%), lenalidomide (18.7%), and bortezomib (18.3%); 1-quarter (25.7%) of patients received a cBTKi (17.8% ibrutinib; 7.8% acalabrutinib). Overall survival was poor from 3L treatment initiation (median OS = 9.4 months; 1-years survival rate = 43.7%). Patients exhibited high rates of HRU (73.6% experienced hospitalization) and substantial costs ($145,726) in the 12-months after 3L initiation.
CONCLUSIONS: A large unmet need exists in this patient subpopulation, highlighting the importance of ongoing development of novel therapeutics.

Mantle cell lymphoma (MCL) is a rare and aggressive type of lymphoma that can affect the kidneys. The disease can lead to kidney impairment, and glomerulonephritis (GN) is a rare but serious complication of MCL. We report a case of MCL with kidney interstitial infiltration and membranoproliferative glomerulonephritis with focal and segmental glomerulosclerosis. A 75-year-old man presented recurrent acute kidney failure and worsening of nephrotic syndrome. Kidney biopsy revealed membranoproliferative glomerulonephritis presented immunoglobulin and complement deposition, focal and segmental glomerulosclerosis of not otherwise specified type, and infiltration by mantle cell lymphoma. Bone marrow biopsy and PET/CT scan confirmed the diagnosis of mantle cell lymphoma. The patient was treated with R-CHOP21 chemotherapy with cyclophosphamide dose adjustment for nephroprotection. He achieved complete remission with normalization of hematological parameters, improvement of kidney function, and reduction of proteinuria and albuminuria. This case shows the importance of considering alternative diagnoses in patients with recurrent chronic kidney disease and worsening nephrotic syndrome. Early diagnosis and treatment of mantle cell lymphoma can lead to favorable outcomes.

Cyclin D1 has been recognized as an oncogene due to its abnormal upregulation in different types of cancers. Here, we demonstrated that cyclin D1 is SUMOylated, and we identified Itch as a specific E3 ligase recognizing SUMOylated cyclin D1 and mediating SUMO-induced ubiquitination and proteasome degradation of cyclin D1. We generated cyclin D1 mutant mice with mutations in the SUMOylation site, phosphorylation site, or both sites of cyclin D1, and found that double mutant mice developed a Mantle cell lymphoma (MCL)-like phenotype. We showed that arsenic trioxide (ATO) enhances cyclin D1 SUMOylation-mediated degradation through inhibition of cyclin D1 deSUMOylation enzymes, leading to MCL cell apoptosis. Treatment of severe combined immunodeficiency (SCID) mice grafted with MCL cells with ATO resulted in a significant reduction in tumor growth. In this study, we provide novel insights into the mechanisms of MCL tumor development and cyclin D1 regulation and discover a new strategy for MCL treatment.

BACKGROUND: Membranous nephropathy (MN) is a common type of nephrotic syndrome (NS) in adults, accounting for about 20-30% of cases. Although secondary to specific factors, the coexistence of MN and mantle cell lymphoma (MCL) has been scarcely reported in clinical literature.
METHODS: A 59-year-old Chinese male was admitted to the hospital with a generalized pruritic rash with bilateral lower extremity edema, which did not improve significantly after symptomatic treatment. He had undergone renal biopsy, and the diagnosis was thought to be secondary MN (SMN), therefore, we did a lymph node biopsy on the patient and found that MN was complicated with MCL. Soon after, the patient was admitted to the hematology department for a BR chemotherapy regimen (composed of bendamustine 90 mg/m2 BSA (body surface area), rituximab 375 mg/m2 BSA and dexamethasone 5 mg), and during the post-treatment follow-up, both his symptoms and renal function improved.
CONCLUSIONS: The mechanism underlying the combination of SMN and MCL remains elusive and exceedingly rare, consequently often overlooked in clinical practice. This case serves to offer valuable clinical insights for diagnosis and treatment, while emphasizing the pivotal role of renal pathology in clinical assessment.

Composite lymphoma (CL) is a rare cancer characterized by the concurrent occurrence of more than one type of lymphoma within the same organ or tissue in an individual. Its occurrence at extranodal sites is exceptional, with only a few cases documented in the literature. A 62-year-old gentleman presented with dystonia, dysphagia, and irregular enlargement of the right tonsil for the last three months. Based on a clinical suspicion of tonsillar malignancy, tonsillectomy was done. The histopathologic examination revealed effacement of the architecture by large irregular lymphoid nodules with interfollicular expansion. The nodules showed sheets of small atypical lymphoid cells, while the interfollicular areas showed large atypical lymphoid cells with scattered typical binucleate Reed-Sternberg cells. Immunohistochemistry confirmed mantle cell lymphoma (MCL) in the nodules and classical HL (cHL) in the interfollicular areas. Based on these features, a diagnosis of composite MCL with cHL was rendered. He was treated with bendamustine and rituximab chemotherapy and remained in complete remission for five years when he presented with significant right-sided neck swelling. Percutaneous fine needle aspiration and subsequent flow cytometry confirmed a relapse of the MCL component of the CL. The index report documents an exceptional case of CL, comprising MCL and cHL, presenting at an uncommon extranodal site. In addition, it also emphasizes the importance of adequate sampling and the simultaneous use of immunochemistry and/or flow cytometry to confirm the presence of more than a single type of lymphoma, which may be easily overlooked on microscopy alone.

Mantle cell lymphoma (MCL) is a rare, incurable, and aggressive B-cell non-Hodgkin lymphoma (NHL). Early MCL diagnosis and treatment is critical and puzzling due to inter/intra-tumoral heterogeneity and limited understanding of the underlying molecular mechanisms. We developed and applied a multifaceted analysis of selected publicly available transcriptomic data of well-defined MCL stages, integrating network-based methods for pathway enrichment analysis, co-expression module alignment, drug repurposing, and prediction of effective drug combinations. We demonstrate the \"butterfly effect\" emerging from a small set of initially differentially expressed genes, rapidly expanding into numerous deregulated cellular processes, signaling pathways, and core machineries as MCL becomes aggressive. We explore pathogenicity-related signaling circuits by detecting common co-expression modules in MCL stages, pointing out, among others, the role of VEGFA and SPARC proteins in MCL progression and recommend further study of precise drug combinations. Our findings highlight the benefit that can be leveraged by such an approach for better understanding pathobiology and identifying high-priority novel diagnostic and prognostic biomarkers, drug targets, and efficacious combination therapies against MCL that should be further validated for their clinical impact.

UNASSIGNED: The purpose of this study was to analyze the mechanism by which STAT5B inhibits ferroptosis in mantle cell lymphoma (MCL) by promoting DCAF13 transcriptional regulation of p53/xCT pathway.
UNASSIGNED: The correlations between STAT5B, DCAF13 and ferroptosis in MCL were analyzed using Gene Expression Profiling Interactive Analysis (GEPIA, http://gepia.cancer-pku.cn/index.html). The expression levels and pairwise correlations of STAT5B, DCAF13, p53 and xCT in MCL patients were detected, respectively. STAT5B was silenced to confirm their criticality in MCL ferroptosis. the effects of blocking necrosis, apoptosis and ferroptosis on the anti-MCL effects of STAT5B were examined. Cells with STAT5B overexpression and/or DCAF13 silencing were constructed to confirm the involvement of DCAF13 in the STAT5B-regulated p53/xCT pathway. The regulation of p53 ubiquitination was confirmed by DCAF13 overexpression and MG132. The effects of silencing DCAF13 and MG132 on STAT5B overexpression on MCL was clarified by a tumor-bearing nude mouse model.
UNASSIGNED: DCAF13 was overexpressed in MCL and positively correlated with STAT5B, negatively correlated with p53, and positively correlated with xCT. Inhibition of ferroptosis alleviated the inhibitory effects of siSTAT5B on MCL, while inhibition of necrosis and apoptosis had few effects. Silencing of DCAF13 led to the blocking of STAT5B regulation of p53/xCT and ferroptosis. The changes in DCAF13 and the addition of MG132 did not have statistically significant effects on p53 mRNA. Elevation of DCAF13 resulted in downregulation of p53 protein levels, and this inhibition was reversed by MG132. In animal models, the promotion of MCL and the inhibition of ferroptosis by STAT5B. Silencing of DCAF13 blocked STAT5B inhibition of p53 and induction of xCT, GPX4, and GSH.
UNASSIGNED: STAT5B suppresses ferroptosis by promoting DCAF13 transcription to regulate p53/xCT pathway to promote MCL progression.