Blastoid Variants of Mantle Cell Lymphoma: Frequent bcl-1 Rearrangements at the Major Translocation Cluster Region and Tetraploid Chromosome Clones

Outcomes of patients with blastoid and pleomorphic variant mantle cell lymphoma

Mantle cell lymphoma (MCL) is a B-cell non-Hodgkin lymphoma; data indicate that blastoid and pleomorphic variants have a poor prognosis. We report characteristics and outcomes of patients with blastoid/pleomorphic variants of MCL. We retrospectively studied adults with newly diagnosed MCL treated from 2000 to 2015. Primary objectives were to describe progression-free survival (PFS) and overall survival (OS). Secondary objectives included characterization of patient characteristics and treatments. Of the 1029 patients with MCL studied, a total of 207 neoplasms were blastoid or pleomorphic variants. Median follow-up period was 82 months (range, 0.1-174 months); median PFS was 38 months (95% confidence interval [CI], 28-66) and OS was 68 months (95% CI, 45-96). Factors associated with PFS were receipt of consolidative autologous hematopoietic transplantation (auto-HCT; hazard ratio [HR], 0.52; 95% CI, 0.31-0.80; P < .05), MCL International Prognostic Index (MIPI) intermediate (HR, 2.3; 95% CI, 1.2-4.3; P < .02) and high (HR, 3.8; 95% CI, 2.0-7.4; P < .01) scores, and complete response to induction (HR, 0.29 (95% CI, 0.17-0.51). Receipt of auto-HCT was not associated with OS (HR, 0.69; 95% CI, 0.41-1.16; P = .16) but was associated with MIPI intermediate (HR, 5.7; 95% CI, 2.5-13.2; P < .01) and high (HR, 10.8; 95% CI, 4.7-24.9; P < .01) scores. We report outcomes in a large cohort of patients with blastoid/pleomorphic variant MCL. For eligible patients, receipt of auto-HCT after induction was associated with improved PFS but not OS. Higher MIPI score and auto-HCT ineligibility were associated with worse survival.

Zanubrutinib in Mantle Cell Lymphoma Management: A Comprehensive Review

Purpose

The pharmacology, pharmacokinetics, pharmacodynamics, clinical efficacy, and safety of zanbrutinib are described.

Summary

Mantle cell lymphoma (MCL) is a mature B-cell lymphoma that is typically associated with unfavorable outcomes, and virtually all patients with MCL have refractory or relapsed disease despite aggressive treatment. The treatment paradigm for MCL has transformed dramatically over the past decade owing to rapid advancements in immunotherapy and molecular-targeted therapies. Zanubrutinib, a second-generation Bruton's tyrosine kinase inhibitor (BTKI) designated for mature B-cell non-Hodgkin's lymphoma (NHL), has drastically improved the survival outcomes in relapsed/refractory (R/R) MCL patients. This selective BTKI is a small molecule that functions by forming a covalent bond in the active site of BTK. The inhibition of BTK activity is essential for the signaling of B-cell antigen receptor (BCR) and cytokine receptor pathways. In a preclinical study, zanubrutinib inhibited malignant B-cell proliferation and reduced tumor growth. Zanubrutinib was granted FDA-accelerated approval based on the results of Phase I and II trials. The investigator-assessed overall response rate was 83.7%, of which 78% of patients achieved complete response. The median duration of response was 19.5 months, and the median progression-free survival was 22.1 months. The most common (≥20%) all-grade adverse events were low neutrophil count (46.5%), upper respiratory tract infection (38.4%), rash (36.0%), low white blood cell count (33.7%), and low platelet count (32.6%).

Conclusion

Zanubrutinib is a selective, next-generation, orally active, irreversible BTK inhibitor. The selectivity of zanubrutinib and its superior efficacy, with a well-tolerated safety profile, have proven to be attractive options for other malignancies.

Comprehensive FISH testing using FFPE tissue microarray of primary lymph node tissue identifies secondary cytogenetic abnormalities in Mantle Cell Lymphoma

INTRODUCTION

Mantle Cell Lymphoma (MCL), is characterised by the reciprocal translocation t(11;14) resulting in CCND1-IGH gene fusion and subsequent upregulation of the CCND1 gene. Rearrangements of MYC and losses of CDKN2A and TP53 have been identified as biomarkers informing prognostic and potentially therapeutic information however these are not routinely assessed in MCL investigation. We aimed to identify additional cytogenetic changes using fluorescence in situ hybridisation (FISH) on formalin fixed paraffin embedded (FFPE) primary lymph node tissue microarrays in a cohort of 28 patients diagnosed with MCL between 2004 and 2019. FISH results were compared with corresponding immunohistochemistry (IHC) biomarkers to determine if IHC was a reliable screening tool to direct FISH testing.

METHOD

FFPE lymph node tissue samples were constructed into tissue microarrays (TMA) which were stained with 7 immunohistochemical biomarkers: Cyclin D1, c-Myc, p16, ATM, p53, Bcl-6 and Bcl-2. The same TMAs were hybridised with FISH probes for the corresponding genes; CCND1-IGH, MYC, CDKN2A, ATM, TP53, BCL6 and BCL2. FISH and the corresponding IHC biomarkers were analysed to determine if secondary cytogenetic changes could be identified and if IHC could be used as a reliable, inexpensive predictor of FISH abnormalities to potentially direct FISH testing.

RESULTS

CCND1-IGH fusion was detected in 27/28 (96%) of samples. Additional cytogenetic changes were identified by FISH in 15/28 (54%) of samples. Two additional abnormalities were detected in 2/28 (7%) samples. Cyclin D1 IHC overexpression was an excellent predictor of CCND1-IGH fusion. MYC and ATM IHC were useful screening tests to direct FISH testing and identified cases with poor prognostic features including blastoid change. IHC did not show clear concordance with FISH for other biomarkers.

CONCLUSION

FISH using FFPE primary lymph node tissue can detect secondary cytogenetic abnormalities in patients with MCL which are associated with an inferior prognosis. An expanded FISH panel including MYC, CDKN2A, TP53 and ATM should be considered in cases where anomalous IHC expression or is seen for these markers or if the patient appears to have the blastoid variant of the disease.

Increased complexity of t(11;14) rearrangements in plasma cell neoplasms compared with mantle cell lymphoma

Plasma cell neoplasms (PCN) and mantle cell lymphoma (MCL) can both harbor t(11;14)(q13;q32) (CCND1/IGH), usually resulting in cyclin D1 overexpression. In some cases, particularly at low levels of disease, it can be morphologically challenging to distinguish between these entities in the bone marrow (BM) since PCN with t(11;14) are often CD20-positive with lymphoplasmacytic cytology, while MCL can rarely have plasmacytic differentiation. We compared the difference in CCND1/IGH by fluorescence in situ hybridization (FISH) in PCN and MCL to evaluate for possible differentiating characteristics. We identified 326 cases of MCL with t(11;14) and 279 cases of PCN with t(11;14) from either formalin-fixed, paraffin-embedded tissue or fresh BM specimens. The "typical," balanced CCND1/IGH FISH signal pattern was defined as three total CCND1 signals, three total IGH signals, and two total fusion signals. Any deviation from the "typical" pattern was defined as an "atypical" pattern, which was further stratified into "gain of fusion" vs "complex" patterns. There was a significantly higher proportion of cases that showed an atypical FISH pattern in PCN compared with MCL (53% vs 27%, P < .0001). There was also a significantly higher proportion of cases that showed a complex FISH pattern in PCN compared with MCL (47% vs 17%, P < .0001). We confirmed these findings using mate-pair sequencing of 25 PCN and MCL samples. PCN more often have a complex CCND1/IGH FISH pattern compared with MCL, suggesting possible differences in the genomic mechanisms underlying these rearrangements in plasma cells compared with B cells.

Blastic Mantle Cell Lymphoma of the Gastroesophageal Junction: A Unique Presentation and Literature Review

Although vast, the medical literature is deficient in reports of gastroesophageal junction (GEJ) involvement of mantle cell lymphoma (MCL). We present the unique case of a 76-year-old male who presented with worsening dysphagia, weight loss, and heartburn and who was found to have blastic variant of MCL in the GEJ. He had undergone extensive workup in the past for an ulcerative, gastric/GEJ lesion, found on four separate esophagogastroduodenoscopies (EGDs) and two esophageal ultrasounds, whose biopsies were repeatedly negative for malignancy. On admission, physical examination and labs were unremarkable, but computed tomography showed an irregular mass involving the GEJ. EGD on admission showed a large friable, ulcerated lesion with heaped-up margins involving the GEJ whose biopsies showed histological and immunohistochemical (IHC) findings consistent with blastic MCL. A bone marrow biopsy showed minimal involvement (<5%) of CD5+/CD23+ B cells and was negative for both cyclin D1 and t(11;14). The biopsy of the lesion was diffusely infiltrated by atypical lymphocytes with prominent nucleoli and IHC stains positive for CD20, cyclin D1, BCL-2, and BCL-6 as well as a Ki-67 proliferative index >90%, all consistent with blastic MCL, a rare and aggressive subtype of MCL. He was started on guideline-based chemoimmunotherapy as he was not a candidate for stem cell transplantation. Repeat imaging 1 year later showed improvement of the mass, with negative endoscopic biopsies for lymphoma. This case provides additional distinct features to the various clinical presentations associated with this rare proliferative disorder, thereby enhancing the medical literature on MCL.

Palatine Tonsils Primary Presentation of Blastoid Variant of Mantle Cell Lymphoma: Case Report

Head and neck lymphomas can present with a wide range of symptoms. Timely and accurate diagnosis is often challenging. The blastoid variant of mantle cell lymphoma (MCL) accounts for less than one-third of all MCL cases. Isolated primary presentation on the palatine tonsils is rare, and prognosis and outcome are seemingly unfavorable. An 81-year-old man presented with persistent odynophagia, dysphagia, and obstructive hypertrophic palatine tonsils with purulent exudate. The signs and symptoms were non-responsive to antibiotic therapy, and the tonsils were biopsied. The cellular morphology, immunophenotype, and genotype supported a diagnosis of the blastoid variant of MCL. After staging, the patient underwent chemotherapy with Rituximab-Bendamustine (R-Benda). The patient is in clinical remission more than two years after therapy. We report an exceedingly rare case of blastoid MCL that is prone to be misdiagnosed as tonsillitis. We review the literature and discuss treatment options of this uncommon malignancy.

Blastoid Mantle Cell Lymphoma

Blastoid and pleomorphic mantle cell lymphoma (MCL) are among the worst prognostic, aggressive histology, high-risk variants of MCL, and, in this article, they are presented as blastoid MCL. Blastoid MCL have not been systematically studied, probably due to their rarity. De novo blastoid MCLs have superior outcomes compared with transformed MCL. Compared with classic MCL, extranodal involvement (mainly skin, central nervous system), frequent relapses, and inferior responses to conventional chemoimmunotherapy, BTK inhibitors and venetoclax are frequent in blastoid MCL. KTE-X19 induces excellent response in blastoid MCL. Combinations with novel agents are actively investigated. This article presents a comprehensive review on blastoid MCL in 2020.

Mantle Cell Lymphoma: Which Patients Should We Transplant?

PURPOSE OF REVIEW

Mantle cell lymphoma is a CD5+ non-Hodgkin lymphoma associated with suboptimal outcome. Young, fit patients are generally offered intensive induction followed by autologous hematopoietic cell transplantation (AHCT) in first remission. Some patients may not benefit from this strategy.

RECENT FINDINGS

Recent studies have investigated the role of AHCT in the modern era. First, an analysis of the National Cancer Database demonstrated improved progression-free survival (PFS) for consolidative AHCT. Second, a multi-center study associated consolidative AHCT with improved PFS even after propensity-weighted analysis. Improved overall survival (OS) for certain subgroups was suggested. Third, patients with p53 mutations derive little benefit from AHCT. Finally, retrospective series suggest certain high-risk patients may be considered for allogenic HCT. AHCT consolidation in first remission is associated with improved PFS even after adjustment for disease severity. An overall survival benefit has not been definitively shown. Patients with p53 mutations should be treated with novel agents.

Proapoptotic protein BIM as a novel prognostic marker in mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive B-cell lymphoma. Numerous studies have demonstrated many genetic aberrations in MCL in addition to the characteristic t(11:14), including frequent biallelic deletions of Bim, a proapoptotic member of the BCL-2 family. In mice, Bim deletion coupled with cyclin D1 overexpression generates pathologic and molecular features of human MCL. Since the regulation of apoptosis is crucial in MCL pathogenesis, we hypothesize that BIM expression may be associated with tumor cell survival. Clinical data and tissue from 100 nodal MCL cases between 1988 and 2009 were collected from three large academic medical centers. The average patient age of our MCL cohort was 65.5 years old (range, 42-97) with a 2:1 male to female ratio. Immunohistochemistry was performed with a validated anti-BIM antibody. Patients were separated into low and high BIM-expressing categories with a cutoff of 80%. As expected for a proapoptotic tumor suppressor, patients with high BIM expression were less likely to have progressive disease and more likely to have a complete response (P = .022). In addition, high BIM-expressing MCL tumors revealed a trend toward increased overall survival with this trend persisting in sub-analysis of Ann Arbor stages III and IV. No correlation between BIM expression, Ki-67 index, and MIPI score was observed, suggesting a role for BIM as a novel independent prognostic factor. While BIM is only one member of a complex family of apoptosis-regulating proteins, these findings may yield clinically relevant information for the prognosis and therapeutic susceptibility of MCL.

Blastoid and pleomorphic mantle cell lymphoma: still a diagnostic and therapeutic challenge!

Blastoid mantle cell lymphoma is characterized by highly aggressive features and a dismal clinical course. These blastoid and pleomorphic variants are defined by cytomorphological features, but the criteria are somewhat subjective. The diagnosis may be supported by a high cell proliferation based on the Ki-67 labeling index. Recent analyses have shown that the Ki-67 index overrules the prognostic information derived from the cytology subtypes. Nevertheless, genetic analysis suggests that blastoid and pleomorphic variants are distinct from classical mantle cell lymphoma. In clinical cohorts, the frequency of these subsets varies widely but probably represents ∼10% of all cases. Chemotherapy regimens commonly used in mantle cell lymphoma, such as bendamustine, rarely achieve prolonged remissions when given at the dosage developed for classical variants of the disease. Thus, high-dose cytarabine–containing regimens with high-dose consolidation may be generally recommended based on the more aggressive clinical course in these patients. However, even with these intensified regimens, the long-term outcome seems to be impaired. Thus, especially in this patient subset, allogeneic transplantation may be discussed at an early time point in disease management. Accordingly, targeted approaches are warranted in these patients, but clinical data are scarce. Ibrutinib treatment results in high rates of responses, but the median duration of remission is <6 months. Similarly, lenalidomide and temsirolimus result in only short-term remissions. Novel approaches, such as chimeric antigenic receptor T cells, may have the potential to finally improve the dismal long-term outcome of these patients.

Near-tetraploidy is associated with Richter transformation in chronic lymphocytic leukemia patients receiving ibrutinib

Ibrutinib is a highly effective targeted therapy for chronic lymphocytic leukemia (CLL). However, ibrutinib must be discontinued in a subset of patients due to progressive CLL or transformation to aggressive lymphoma (Richter transformation). Transformation occurs early in the course of therapy and has an extremely poor prognosis. Thus, identification of prognostic markers associated with transformation is of utmost importance. Near-tetraploidy (4 copies of most chromosomes within a cell) has been reported in various lymphomas, but its incidence and significance in CLL has not been described. Using fluorescence in situ hybridization, we detected near-tetraploidy in 9 of 297 patients with CLL prior to beginning ibrutinib treatment on 1 of 4 clinical trials (3.0%; 95% confidence interval [CI], 1.4%-5.7%). Near-tetraploidy was associated with aggressive disease characteristics: Rai stage 3/4 (P = .03), deletion 17p (P = .03), and complex karyotype (P = .01). Near-tetraploidy was also associated with ibrutinib discontinuation due to Richter transformation (P < .0001), but not due to progressive CLL (P = .41). Of the 9 patients with near-tetraploidy, 6 had Richter transformation with diffuse large B-cell lymphoma. In a multivariable model, near-tetraploidy (hazard ratio [HR], 8.66; 95% CI, 3.83-19.59; P < .0001) and complex karyotype (HR, 4.77; 95% CI, 1.42-15.94; P = .01) were independent risk factors for discontinuing ibrutinib due to transformation. Our results suggest that near-tetraploidy is a potential prognostic marker for Richter transformation to assess in patients going on ibrutinib.

Is myeloablative dose intensity necessary in allogeneic hematopoietic cell transplantation for lymphomas?

The advent of novel immunotherapy and tyrosine kinase inhibitors has ushered a new era in the treatment of Hodgkin and non-Hodgkin lymphomas. Allogeneic hematopoietic cell transplantation remains, however, a vital component in the management and potential cure of lymphomas, especially in the relapsed setting. Considering the biological and clinical heterogeneity of various subtypes of lymphomas, the optimal intensity of conditioning regimens remains controversial. Reduced intensity conditioning regimens have broadened applicability of the procedure to older and frail patients. Observational studies suggest that although reduced intensity allografting is associated with higher risk of relapse, overall survival is comparable and in some cases even better, than observed with myeloablative regimens. Here, we review the available published data pertaining to allogeneic hematopoietic cell transplantation using reduced intensity or myeloablative conditioning for various lymphoma histologies. Owing to the lack of randomized prospective trials, recommendations are mainly based on registry and single-institution studies. Special emphasis must be given to implementing strategies to prevent relapse when using reduced intensity regimens. Identifying particular patients who may benefit from myeloablative regimens in lymphomas remains to be better defined.

Clinicopathologic features and management of blastoid variant of mantle cell lymphoma

The blastoid variant of mantle cell lymphoma (MCL), which accounts for less than one-third of MCL, may arise de novo or as a transformation from the classical form of MCL. Blastoid variant, which predominantly involves men in their sixth decade, has frequent extranodal involvement (40-60%), stage IV disease (up to 85%) and central nervous system (CNS) involvement. Diagnosis relies on morphological features and is challenging. Immunophenotyping may display CD23 and CD10 positivity and CD5 negativity in a subset. Genetic analysis demonstrates an increased number of complex genetic alterations. Blastoid variant responds poorly to conventional chemotherapy and has a short duration of response. Although the optimal therapy remains to be established, CNS prophylaxis and the use of aggressive immunochemotherapy followed by autologous stem cell transplant may prolong the remission rate and survival. Further studies are crucial to expand our understanding of this disease entity and improve the clinical outcome.

TCL1 expression predicts overall survival in patients with mantle cell lymphoma

OBJECTIVES

Mantle cell lymphoma (MCL) has a heterogeneous clinical course. Although most cases show a poor prognosis, a minority has an indolent course. It is difficult to identify indolent MCL cases prospectively. T-cell leukemia/lymphoma protein 1 (TCL1) is expressed by several B-cell lymphomas, including MCL. This study examined the expression of TCL1 and its prognostic relevance for MCL.

METHODS

Clinical data for 162 patients with MCL were collected. Of these, 144 cases with available tissues for tissue microarray construction and immunostaining were included in the analysis. TCL1 staining was quantified using the Nuclear Quant application with Pannoramic™ Viewer v. 1.14. High TCL1 expression was defined as moderate to strong nuclear and/or cytoplasmic staining in 40% or more of the cells.

RESULTS

High TCL1 expression was observed in 39 of 144 samples (27.1%). Patients with low TCL1 expression were more likely to present with blastoid/pleomorphic morphology (P = 0.010). Low TCL1 expression was associated with significantly shorter overall survival (OS, P = 0.006). Multivariate analysis identified low TCL1 expression (P = 0.003), high-risk MIPI (P = 0.027), and anemia (P = 0.018) as adverse prognostic factors.

CONCLUSIONS

Our study suggests that TCL1 expression profile may have a role in the prediction of overall outcome in patient with MCL and call for prospective studies.

Pathology of B-cell lymphomas: diagnosis and biomarker discovery

The diagnosis of B-cell non-Hodgkin lymphomas has changed significantly over the past few decades as new immunophenotypic markers, molecular subtype classification schemes, and novel biomarkers have emerged. Meanwhile, there has been an increasing emphasis on individualizing treatment approaches in accordance with a biologic heterogeneity that has been uncovered within many of the individual B-cell lymphoma entities. The application of high-throughput genomic sequencing to B-cell lymphomas has yielded large amounts of valuable information. The data encompass discoveries essential to an understanding of pathogenesis, clonal or tumoral evolution, and identification of biomarkers that may be useful for prognostic or therapeutic considerations. The following review discusses several of the more common, primarily tissuebased B-cell lymphomas, with a focus on pathologic classification and certain phenotypic characteristics or genetic lesions that apply to refinement of diagnosis and therapy.

Pathology consultation on intermediate-to-large B-cell lymphomas

OBJECTIVES

Intermediate-to-large B-cell lymphomas represent a heterogeneous group of aggressive lesions frequently encountered in practice. The differential diagnosis includes the most common of all lymphomas, diffuse large B-cell lymphoma (DLBCL), as well as Burkitt lymphoma (BL), B-lymphoblastic lymphoma, and the blastoid variant of mantle cell lymphoma. In recent decades, gene expression profiling studies have clarified the biologic origins and features of these diseases. Moreover, clinically relevant subtypes of DLBCL have been identified, and a new category was defined: B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL. Herein, we review the salient diagnostic features of the various entities within this differential diagnosis and provide a stepwise diagnostic approach for dealing with challenging cases.

METHODS

A case-based approach is used to highlight diagnostic dilemmas and clinical decision points within the differential diagnosis of intermediate-to-large B-cell lymphomas.

RESULTS

Based on the published literature and World Health Organization criteria, we suggest a diagnostic algorithm for appropriate classification of these lymphomas.

CONCLUSIONS

Correct classification of intermediate-to-large B-cell lymphomas is important, because prognosis and therapeutic approach vary for different tumors and tumor subclasses. Understanding both disease-specific criteria and pathologic features that influence clinical behavior within a category is imperative for evaluation of these lymphomas.

The Complex Relationship between Liver Cancer and the Cell Cycle: A Story of Multiple Regulations

The liver acts as a hub for metabolic reactions to keep a homeostatic balance during development and growth. The process of liver cancer development, although poorly understood, is related to different etiologic factors like toxins, alcohol, or viral infection. At the molecular level, liver cancer is characterized by a disruption of cell cycle regulation through many molecular mechanisms. In this review, we focus on the mechanisms underlying the lack of regulation of the cell cycle during liver cancer, focusing mainly on hepatocellular carcinoma (HCC). We also provide a brief summary of novel therapies connected to cell cycle regulation.

Management of relapsed/refractory mantle cell lymphoma: a review of current therapeutic strategies

Abstract Despite recent advances in therapeutic strategies, a large proportion of patients with mantle cell lymphoma (MCL) experience progression after first-line treatment. Several attempts have been made to assess the role of different therapies for the treatment of patients with relapsed/refractory mantle cell lymphoma; however, a consensus on the optimal therapeutic strategy for each individual patient has not been reached. Overall, clinical evidence from phase II studies shows that high-dose cytarabine containing regimens, stem cell transplant and different biological agents all have promising activity with acceptable safety profiles. Therefore, these therapies can represent suitable treatment options for patients with relapsed/refractory MCL. Among different biological agents, at present only temsirolimus has been tested in a phase III study. This review considers available evidence on the management of relapsed/refractory MCL as discussed during a consensus meeting on the current treatment strategies for MCL.

The Wnt signaling pathway and mitotic regulators in the initiation and evolution of mantle cell lymphoma: Gene expression analysis

For an accurate understanding of mantle cell lymphoma (MCL), molecular behavior could be staged into two major events: lymphomagenesis with the t(11;14) translocation (initiation), and evolution into a more aggressive form (transformation). Unfortunately, it is still unknown which genes contribute to each event. In this study, we performed cDNA microarray experiments designed based on the concept that morphologically heterogeneous MCL samples would provide insights into the role of aberrant gene expression for both events. A total of 15 MCLs were collected from the files, which include a total of 237 MCL patients confirmed by histology as CCND1-positive. We posited four stepwise morphological grades for MCL: MCL in situ, MCL with classical form (cMCL), MCL with aggressive form (aMCL), and MCL with intermediate morphology between classical and aggressive forms at the same site (iMCL). To identify genes involved in initiation, we compared the tumor cells of MCL in situ (n=4) with normal mantle zone B lymphocytes (n=4), which were selected by laser microdissection (LMD). To identify genes contributing to transformation, we selected the overlapping genes differentially expressed between both cMCL (n=4) vs. aMCL (n=5) and classical vs. aggressive areas in iMCL (n=2) obtained by LMD. A significant number of genes (n=23, p=0.016) belonging to the Wnt signaling pathway were differentially expressed in initiation. This specific activation was confirmed by immuno-histochemistry, as MCL in situ had nuclear localization of phosphorylated-β-catenin with high levels of cytoplasmic Wnt3 staining. For transformation, identified 60 overlapping genes included a number of members of the p53 interaction network (CDC2, BIRC5 and FOXM1), which is known to mediate cell cycle progression during the G2/M transition. Thus, we observe that the Wnt signaling pathway may play an important role in initial lymphomagenesis in addition to t(11;14) translocations, and that specific mitotic regulators facilitate transformation into more aggressive forms.

Genomic profiling of mantle cell lymphoma

Genomic profiling of mantle cell lymphoma (MCL) cells has enabled a better understanding of the complex mechanisms underlying the pathogenesis of disease. Besides the t(11;14)(q13;q32) leading to cyclin D1 overexpression, MCL exhibits a characteristic pattern of DNA copy number aberrations that differs from those detected in other B-cell lymphomas. These genomic changes disrupt selected oncogenes and suppressor genes that are required for lymphoma development and progression, many of which are components of cell cycle, DNA damage response and repair, apoptosis, and cell-signaling pathways. Additionally, some of them may represent effective therapeutic targets. A number of genomic and molecular abnormalities have been correlated with the clinical outcome of patients with MCL and are considered prognostic factors. However, only a few genomic markers have been shown to predict the response to current or novel targeted therapies. One representative example is the high-level amplification of the BCL2 gene, which predicts a good response to pro-apoptotic BH3 mimetic drugs. In summary, genomic analyses have contributed to the substantial advances made in the comprehension of the pathogenesis of MCL, providing a solid basis for the identification of optimal therapeutic targets and for the design of new molecular therapies aiming to cure this fatal disease.

Mantle cell lymphoma of the oral cavity with multiple foci: a case report and review of the literature

Non-Hodgkin lymphomas (NHLs) are often present outside the lymph nodes. Although primary extranodal NHLs form a substantial part of all NHLs, reports on oral primary extra nodal NHLs are rare. Mantle cell lymphoma (MCL) is a rare B-cell neoplasm that has only recently been defined as a distinct entity. MCL of the oral cavity is an uncommon diagnosis. Most oral MCLs occur in an elderly male population and have a possible predilection for the palate. The microscopic diagnosis can be challenging, given its similar appearance to other small cell lymphomas, requiring a comprehensive immunohistochemical panel for the accurate diagnosis. Like MCL occurring in other sites in the body, the prognosis and outcome of oral MCL appears to be poor.

Histopathology of mantle cell lymphoma

Mantle cell lymphoma (MCL) is a relatively rare lymphoma, accounting for less than 10% only of all lymphomas. Its morphology is quite homogeneous, but it varies strikingly in about 10% of the cases, making the diagnosis of MCL challenging for histopathologists. The definition of the disease was greatly influenced by the discovery of the translocation t(11;14)(q13,q32), which juxtaposes the cyclin D1 and the immunoglobulin heavy chain genes and is present in the vast majority of MCL cases. The introduction of monoclonal antibodies for the detection of cyclin D1 expression into the diagnostic procedure substantially improved the reproducibility and reliability of the pathological diagnosis. However, new challenges for histopathologists have arisen over the last years, among which are the detection of cyclin D1-negative MCL cases and clinically relevant prognostic subgroups.

The use of microarray technologies in mantle cell lymphoma

Mantle cell lymphoma (MCL) is characterized by adverse prognosis and the development of novel therapeutic approaches is essential to improve outcome. The introduction of gene expression profiling using DNA microarrays has significantly enhanced our understanding of the molecular pathogenesis of MCL, which is a prerequisite to the development of novel treatment strategies. Gene expression profiling can furthermore be applied to predict treatment response at diagnosis and thus can be used to assess a patient's individual risk profile. This review summarizes our current knowledge on the use of microarray technology in MCL.

Mantle cell lymphoma

MCL is a well-characterized clinically aggressive lymphoma with a poor prognosis. Recent research findings have slightly improved the outcome of this neoplasm. The addition of rituximab to conventional chemotherapy has increased overall response rates, but it does not improve overall survival with respect to chemotherapy alone. The use of intensive frontline therapies including rituximab and consolidated by ASCT ameliorates response rate and prolongs progression-free survival, but any impact on survival remains to be proven. Furthermore, the optimal timing, cytoreductive regimen and conditioning regimen, and the clinical implications of achieving a disease remission even at molecular level remain to be elucidated. The development of targeted therapies as the consequence of better dissection of pathogenetic pathways in MCL might improve the outcome of conventional chemotherapy in most patients and spare the toxicity of intense therapy in a minority of MCL patients characterized by a relatively indolent disease. Patients not eligible for intensive regimens, such as hyperC-VAD, may be considered for less demanding therapies, such as the combination of rituximab either with CHOP or with purine analogues, or bendamustine. Allogeneic SCT can be an effective option for relapsed disease in patients who are fit enough and have a compatible donor. Maintenance rituximab may be considered after response to immunochemotherapy for relapsed disease, although there are currently no data to recommend this approach as the first-line strategy. As the optimal approach to the management of MCL is still evolving, it is critical that these patients be enrolled in clinical trials to identify better treatment options.

Pathogenesis of non-Hodgkin's lymphoma

The understanding of the molecular pathogenesis of non-Hodgkin's lymphomas (NHL) has significantly improved in recent years. Advances in molecular biology and genetics lead to the identification and characterization of several oncogenic pathways involved in lymphomagenesis. This knowledge will ultimately lead to improved diagnostic and therapeutic strategies for patients with NHL. This review summarizes current concepts of the molecular pathogenesis of the most common NHL subtypes, with a special emphasis on diffuse large B-cell lymphoma, the most common lymphoma subtype.

Management of mantle cell lymphoma: key challenges and next steps

Mantle cell lymphoma (MCL) is regarded as an aggressive lymphoid malignancy that exhibits varied clinical behavior and prognoses, reflecting the biologic heterogeneity of the disease. In most cases, patients with MCL achieve a shorter median survival compared with more common B-cell lymphomas, such as follicular lymphoma, and are less likely to achieve a durable response with chemotherapy. Currently, there is no defined standard of care for patients with MCL. Rituximab-containing immunochemotherapy strategies are commonly used, but the addition of rituximab to conventional induction chemotherapy has produced suboptimal responses that are relatively short-lived and have not resulted in a survival advantage. Further intensification of the chemotherapy component, including autologous stem cell transplantation, has increased response and survival rates but has not proven to be curative while being associated with higher toxicity. Clearly, there is a need for developing novel agents and strategies that will improve clinical outcomes for patients with MCL. Targeted therapies and new cytotoxic agents are showing great promise and may have a role in maintenance and/or initial therapy. This summary highlights current challenges in the management of MCL, and outlines expert perspectives, key questions, and future directions. For the third consecutive year, a panel of global experts in MCL assembled to deliberate on topical issues in MCL including advances in pathobiology, strategies for risk-adapted therapy, front-line treatment options, consolidation approaches, and novel therapeutic strategies. The proceedings of this workshop, held December 3, 2009 in New Orleans, LA, are summarized here. It must be emphasized that this synopsis is not meant to serve as an exhaustive review of MCL biology and management, but is a distillation of the expert discussions, highlighting key questions and future directions identified.

The basis and rational use of molecular genetic testing in mature B-cell lymphomas

An increasing number of neoplasms are associated with variably specific genetic abnormalities. This is best exemplified by hematological malignancies, in which there is a growing list of entities that are defined by their genetic lesion(s); this is not (yet) the case in mature B-cell lymphomas. However, enhanced insights into the pathogenesis of this large and diverse group of lymphomas have emerged with the ongoing unraveling of a plethora of fascinating genetic abnormalities. The purpose of this review is to synthesize well-recognized data and nascent discoveries in our understanding of the genetic basis of a spectrum of mature B-cell lymphomas, and how this may be applied to contemporary clinical practice. Despite the explosion of new and exciting knowledge in this arena, with the potential for enhanced diagnostic and prognostic strategies, it is essential to remain cognizant of the limitations (and complexity) of genetic investigations, so that assays can be developed and used both judiciously and rationally.

A novel quantitative PCR of proliferation markers (Ki-67, topoisomerase IIalpha, and TPX2): an immunohistochemical correlation, testing, and optimizing for mantle cell lymphoma

A clinical course of patients with mantle cell lymphoma (MCL) is aggressive, and the disease is rarely curable. Proliferation rate is the most important prognostic factor. We developed a novel, reliable, rapid, and routinely applicable approach allowing a precise quantitative assessment of three proliferation markers, Ki-67, topoisomerase IIalpha, and TPX2. A total of 95 lymphoma specimens were measured in the study by real-time reverse transcription PCR (RQ-RT-PCR). We tested the reproducibility and accuracy of the assay and correlated the results with the immunohistochemical staining of the corresponding proteins. The results obtained indicated individual variability of the mRNA expression levels, reflecting heterogeneity of the proliferation rate in individual patients. In general, we observed the highest mRNA expression in the group of Burkitt lymphomas and the lowest in patients with reactive lymphadenopathies. We found increased proliferation rate in MCLs with high cyclin D1 mRNA, indicating a quantitative control of the cell cycle. We observed a correlation between mRNA expression level and the immunohistochemical staining of corresponding proteins, which significantly argues for the prognostic significance of the mRNA expression measuring. We confirmed the accuracy of the current assay for a precise quantitative examination of the proliferation activity. Real-time RT-PCR provides a novel approach applicable for clinical trials, and it represents a potent approach allowing to stratify MCL patients for entry into clinical trials according to the expression of the proliferation signature genes in their tumors. This approach may contribute to improved and individualized therapeutic options respecting the individual progression risk of patients with MCL.

Mantle cell lymphoma presenting with a tumor of the hard palate

We report a 71-year-old man with a disseminated disease of mantle cell lymphoma (MCL). He initially noticed instability of the maxillary denture due to swelling of the hard palate. Combined positron-emission tomography and computed tomography demonstrated a marked accumulation of fluorodeoxyglucose in the palate. A biopsy of the palatine tumor disclosed diffuse infiltrates of lymphoid cells, which were positive for CD20 and cyclin D1. The peripheral blood contained lymphoma cells with the characteristic immunophenotype, and fluorescence in situ hybridization detected fusion signals indicative of t(11;14)(q13;q32). In a literature review we identified only three cases of MCL with palatine involvement to date.

Pre-emptive treatment with rituximab of molecular relapse after autologous stem cell transplantation in mantle cell lymphoma

PURPOSE

Minimal residual disease (MRD) is predictive of clinical progression in mantle-cell lymphoma (MCL). According to the Nordic MCL-2 protocol we prospectively analyzed the efficacy of pre-emptive treatment using rituximab to MCL patients in molecular relapse after autologous stem cell transplantation (ASCT).

PATIENTS AND MATERIALS

MCL patients enrolled onto the study, who had polymerase chain reaction (PCR) detectable molecular markers and underwent ASCT, were followed with serial PCR assessments of MRD in consecutive bone marrow and peripheral blood samples after ASCT. In case of molecular relapse with increasing MRD levels, patients were offered pre-emptive treatment with rituximab 375 mg/m(2) weekly for 4 weeks.

RESULTS

Of 160 MCL patients enrolled, 145 underwent ASCT, of whom 78 had a molecular marker. Of these, 74 were in complete remission (CR) and four had progressive disease after ASCT. Of the CR patients, 36 underwent a molecular relapse up to 6 years (mean, 18.5 months) after ASCT. Ten patients did not receive pre-emptive treatment mainly due to a simultaneous molecular and clinical relapse, while 26 patients underwent pre-emptive treatment leading to reinduction of molecular remission in 92%. Median molecular and clinical relapse-free survival after pre-emptive treatment were 1.5 and 3.7 years, respectively. Of the 38 patients who remain in molecular remission for now for a median of 3.3 years (range, 0.4 to 6.6 years), 33 are still in clinical CR.

CONCLUSION

Molecular relapse may occur many years after ASCT in MCL, and PCR based pre-emptive treatment using rituximab is feasible, reinduce molecular remission, and may prevent clinical relapse.

Primary cutaneous blastoid mantle cell lymphoma-case report

Mantle cell lymphoma (MCL) commonly involves extranodal sites, usually as a manifestation of disseminated disease. In rare cases, MCLs may arise as a primary tumor in the skin. Blastoid mantle cell lymphoma (BV-MCL) is a rare variant and has a more aggressive clinical course. The phenotype of BV-MCL is characterized as CD20+, CD5+, cyclin D1+, CD23-, and CD10-. Interphase fluorescence in situ hybridization shows a characteristic t(11;14) fusion pattern. We report a case of a BV-MCL arising in skin as primary cutaneous MCL with the characteristic immunophenotype and translocation.