Genomic and gene expression profiling defines indolent forms of mantle cell lymphoma

Recent advances and future directions in mantle cell lymphoma research: report of the 2018 mantle cell lymphoma consortium workshop

Mantle cell lymphoma (MCL) is an aggressive B-cell non-Hodgkin lymphoma characterized by the t(11;14) chromosomal translocation. This translocation most often results in overexpression of cyclin D1. MCL is clinically heterogeneous, outcomes are generally poor, and no standard treatment has been established. The recent approvals of ibrutinib and acalabrutinib have provided an additional therapeutic option; however, resistance has emerged as a significant issue and presents the need for more detailed studies of resistance mechanisms. Recent clinical trials have provided new perspectives on the relative efficacy and safety of various approaches for both transplant-eligible and transplant-ineligible patients. Multiple novel strategies are being evaluated in the treatment of MCL, including both targeted agents and cellular immunotherapies. At the Lymphoma Research Foundation's 13th MCL Workshop, researchers gathered to discuss research findings, clinical trial results, and future directions related to MCL, its biology, and its treatment. This report, which includes a summary of each presentation, aims to review recent findings in MCL research and highlight potential areas for future study.

Immunophenotypic Characterization of Canine Splenic Follicular-Derived B-Cell Lymphoma

Marginal zone lymphoma (MZL) and mantle cell lymphoma (MCL) belong to a subgroup of indolent B-cell lymphomas most commonly reported in the canine spleen. The goal of this study was to characterize the immunophenotype of splenic MZL and MCL in comparison to their human counterparts. Ten MCLs and 28 MZLs were selected based on morphology. A tissue microarray was generated, and expression of CD3, CD5, CD10, CD45, CD20, CD79a, Pax-5, Bcl-2, Bcl-6, cyclin D1, cyclin D3, MCL-1, MUM-1, and Sox-11 was evaluated. Neoplastic cells in all MCLs and MZLs were positive for CD5, CD20, CD45, CD79a, and BCL2 and negative for CD3, CD10, Bcl-6, cyclin D1, and cyclin D3. Positive labeling for Pax-5 was detected in 8 of 10 MCLs and 26 of 28 MZLs. Positive labeling for MUM-1 was detected in 3 of 10 MCLs, and 27 of 28 MZLs were positive for MUM-1. No MCLs but 8 of 24 MZLs were positive for MCL-1. Canine splenic MZL and MCL have a similar immunophenotype as their human counterparts. However, human splenic MCL overexpresses cyclin D1 due to a translocation. A similar genetic alteration has not been reported in dogs. In addition, in contrast to human MZL, canine splenic MZL generally expresses CD5. Following identification of B vs T cells with CD20 and CD3, a panel composed of BCL-2, Bcl-6, MUM-1, and MCL-1 combined with the histomorphological pattern can be used to accurately diagnose MZL and MCL in dogs. Expression of Bcl-2 and lack of MCL-1 expression in MCL may suggest a therapeutic benefit of BCL-2 inhibitors in canine MCL.

Simplified MIPI-B prognostic stratification method can predict the outcome well-retrospective analysis of clinical characteristics and management of newly-diagnosed mantle cell lymphoma patients from China

Mantle cell lymphoma (MCL) is an invasive B-cell lymphoma with significant individual differences. Currently, MCL international prognostic index (MIPI) score and tumor cell proliferation index Ki-67 have been proved to be the most important prognostic factors. But the prognostic effect of these factors in Asian population is uncertain. This study aimed to analyze the disease characteristics and prognostic factors of Chinese MCL patients.A total of 83 cases of newly-diagnosed MCL patients diagnosed by the Department of Pathology of our hospital between January 1, 2011, and May 31, 2016, were enrolled. The disease characteristics, treatment effects, and outcomes of the patients were collected and analyzed.According to our analysis, MCL cases accounted for 6.2% of non-Hodgkin lymphoma (NHL) cases and mainly occurred in elderly males. But the proportion of patients at stage IV by Ann Arbor staging system and high-risk group by simplified-MIPI (s-MIPI) were significantly lower than that among European patients. Immunochemotherapy containing rituximab was significantly more effective than chemotherapy (overall response rate, [ORR]: 88.5% vs 65.2%, P = .021) and significantly prolonged patient survival (progression free survival [PFS]: 45.5 m vs 16.2 m, P = .001; overall survival [OS]: 58.3 m vs 22.8 m, P = .001). The multivariate analysis showed that the B symptoms, s-MIPI and administration of immunochemotherapy were independent prognostic factors that affected PFS and OS of the patients. s-MIPI and B symptom make up s-MIPI-B stratification method, by which patients in low-risk group of s-MIPI without B symptom were classified as low-risk, patients in high-risk group of s-MIPI and patients in low-risk group of s-MIPI with B symptom as high-risk, the rest as middle-risk. 3-year PFS of the 3 groups were 74.9%, 43.4% and 16.1%, respectively (P = .001). 3-year OS were 84.4%, 62.2%, 27.6% (P <.001).Chinese MCL was male predominance. We have a minor proportion of late-stage and high-risk patients compared to European patients. Immunochemotherapy was proved to significantly improve the prognosis of MCL patients. B symptoms, s-MIPI, and administration of rituximab independently influenced the outcome. s-MIPI-B prognostic stratification method may better predict the prognosis of Asian MCL patients. Still, further confirmation in larger populations is needed.

Regulation of SOX11 expression through CCND1 and STAT3 in mantle cell lymphoma

The neural transcription factor SOX11 is usually highly expressed in typical mantle cell lymphoma (MCL), but it is absent in the more indolent form of MCL. Despite being an important diagnostic marker for this hard-to-treat malignancy, the mechanisms of aberrant SOX11 expression are largely unknown. Herein, we describe 2 modes of SOX11 regulation by the cell-cycle regulator cyclin D1 (CCND1) and the signal transducer and activator of transcription 3 (STAT3). We found that ectopic expression of CCND1 in multiple human MCL cell lines resulted in increased SOX11 transcription, which correlated with increased acetylated histones H3K9 and H3K14 (H3K9/14Ac). Increased H3K9/14Ac and SOX11 expression was also observed after histone deacetylase 1 (HDAC1) or HDAC2 was depleted by RNA interference or inhibited by the HDAC inhibitor vorinostat. Mechanistically, we showed that CCND1 interacted with and sequestered HDAC1 and HDAC2 from the SOX11 locus, leading to SOX11 upregulation. Interestingly, our data revealed a potential inverse relationship between phosphorylated Y705 STAT3 and SOX11 expression in MCL cell lines, primary tumors, and patient-derived xenografts. Functionally, inactivation of STAT3 by inhibiting the upstream Janus kinase (JAK) 1 or JAK2 or by STAT3 knockdown was found to increase SOX11 expression, whereas interleukin-21 (IL-21)-induced STAT3 activation or overexpression of the constitutively active form of STAT3 decreased SOX11 expression. In addition, targeting SOX11 directly by RNA interference or indirectly by IL-21 treatment induced toxicity in SOX11⁺ MCL cells. Collectively, we demonstrate the involvement of CCND1 and STAT3 in the regulation of SOX11 expression, providing new insights and therapeutic implications in MCL.

Cortactin expression in non-Hodgkin B-cell lymphomas: a new marker for the differential diagnosis between chronic lymphocytic leukemia and mantle cell lymphoma

Cortactin is a cytoskeletal-remodeling adaptor protein, playing an oncogenic role in solid tumors. Little is known on cortactin expression in non-Hodgkin B-cell lymphomas (B-NHLs). The present study aimed to characterize cortactin expression in B-NHLs and to assess its role in the differential diagnosis of such entities. Cortactin protein expression was first assessed by immunohistochemistry in a series of 131 B-NHLs, including B-cell chronic lymphocytic leukemia (CLL; n = 17), mantle cell lymphoma (MCL; n = 16), follicular lymphoma (FL; n = 25), marginal zone lymphoma (MZL; n = 30), hairy cell leukemia (HCL; n = 10), splenic diffuse red pulp small B-cell lymphomas (SDRPBL; n = 3), and diffuse large B-cell lymphoma (DLBCL; n = 30) cases. Cortactin was expressed in 14 of 17 CLLs, 10 of 10 HCLs, and 22 of 30 DLBCLs. MCLs, SDRPBLs, most FLs, and MZLs were cortactin negative. The immunohistochemical results were in keeping with in silico gene expression data. In CLL, cortactin positivity did correlate with LEF1 and CD200 expression, and the combined positivity for ≥2 markers strongly predicted CLL diagnosis. Such preliminary data suggested a role for cortactin in the differential diagnosis between CLL and MCL. This hypothesis was confirmed in a large validation set of 112 CLLs (n = 55) and MCLs (n = 57), which also disclosed rare cortactin-expressing MCLs. The immunohistochemical and gene expression results were sustained by flow cytometry and Western blot analysis on CLL and MCL cell lines. In conclusion, cortactin is mainly expressed in subsets of CLL and DLBCL and in HCL. Cortactin may represent a novel marker for the differential diagnosis between CLL and MCL.

NKL homeobox gene activities in B-cell development and lymphomas

Homeobox genes encode transcription factors which regulate basic processes in development and cell differentiation. Several members of the NKL subclass are deregulated in T-cell progenitors and support leukemogenesis. We have recently described particular expression patterns of nine NKL homeobox genes in early hematopoiesis and T-cell development. Here, we screened NKL homeobox gene activities in normal B-cell development and extended the NKL-code to include this lymphoid lineage. Analysis of public expression profiling datasets revealed that HHEX and NKX6-3 were the only members differentially active in naïve B-cells, germinal center B-cells, plasma cells and memory B-cells. Subsequent examination of different types of B-cell malignancies showed both aberrant overexpression of NKL-code members and ectopic activation of subclass members physiologically silent in lymphopoiesis including BARX2, DLX1, EMX2, NKX2-1, NKX2-2 and NKX3-2. Based on these findings we performed detailed studies of the B-cell specific NKL homeobox gene NKX6-3 which showed enhanced activity in patient subsets of follicular lymphoma, mantle cell lymphoma and diffuse large B-cell lymphoma (DLBCL), and in three DLBCL cell lines to serve as in vitro models. While excluding genomic and chromosomal rearrangements at the locus of NKX6-3 (8p11) promoter studies demonstrated that B-cell factors MYB and PAX5 activated NKX6-3 transcription. Furthermore, aberrant BMP7/SMAD1-signalling and deregulated expression of chromatin complex components AUTS2 and PCGF5 promoted NKX6-3 activation. Finally, NKL homeobox genes HHEX, HLX, MSX1 and NKX6-3 were expressed in B-cell progenitors and generated a regulatory gene network in cell lines which we propose may provide physiological support for NKL-code formation in early B-cell development. Together, we identified an NKL-code in B-cell development whose violation may deregulate differentiation and promote malignant transformation.

Clinical Impact of the 2016 Update to the WHO Lymphoma Classification

OPINION STATEMENT

The 2016 revision of the WHO classification of lymphoid neoplasms includes new entities along with a clearer definition of provisional and definitive subtypes based on better understanding of the molecular drivers of lymphomas. These changes impact current treatment paradigms and provide a framework for future clinical trials. Additionally, this update recognizes several premalignant or predominantly indolent entities and underscores the importance of avoiding unnecessarily aggressive treatment in the latter subsets.

Toward a Risk-Tailored Therapeutic Policy in Mantle Cell Lymphoma

PURPOSE OF REVIEW

Mantle cell lymphoma (MCL) prognosis is strictly related to the characteristics of the disease, which can range from very indolent cases to highly aggressive and refractory ones. Here we will review the current knowledge on MCL biomarkers.

RECENT FINDINGS

Biomarker-informed diagnosis is essential for differentiating MCL from other mature B cell tumors. Diagnosis of MCL relies on the identification of the t(11;14) translocation by FISH or the consequently aberrant expression of cyclin D1 by immunohistochemistry. For the few cases staining negative for cyclin D1, SOX11 may help to define the diagnosis. Prognostic biomarkers have been proposed to stratify MCL patients, including baseline clinical aspects (leukemic non-nodal presentation, in situ presentation, Mantle cell International Prognostic Index-MIPI), pathological aspects (blastoid morphology, Ki-67 proliferation index, SOX11 expression), genetic aspects (immunoglobulin gene mutation status, TP53 deletion or mutation, CDKN2A deletion), and depth of response after treatment (PET imaging, molecular minimal residual disease). Such tools are increasingly used as a guide for therapeutic decisions. Watchful waiting approach is recommended for patients harboring favorable clinico-biological features, such as leukemic non-nodal presentation, low MIPI score, non-blastoid disease, low Ki-67 proliferation rate, mutated immunoglobulin genes, and the lack of SOX11 expression. For patients in need of frontline therapy, the decision of whether to undertake intensive regimens is based upon patient's age and comorbidities. Central nervous system prophylaxis is recommended for cases showing blastoid morphology. The duration of remission is tightly correlated to the depth of response. With the aim of achieving a longer duration of remission and survival, younger patients may pursue more intensive regimens incorporating high-dose cytarabine, followed by myeloablative consolidation chemotherapy, autologous stem cell transplantation, and rituximab maintenance. Older patients could, on the other hand, benefit from lower intensity immunochemotherapy followed or not by a maintenance therapy depending on which frontline regimen is used. Despite the identification of several potential useful biomarkers that may inform the treatment decisions and the design of clinical trials, the treatment choice remains nowadays determined by the patient age and fitness rather than by the individual patient characteristics. Tailoring therapy toward a risk-adapted strategy to accommodate the wide spectrum of disease is an urgent challenge, and clinical trials may explore the feasibility of a biomarker-defined therapeutic policy.

A gene signature that distinguishes conventional and leukemic nonnodal mantle cell lymphoma helps predict outcome

Mantle cell lymphoma (MCL) is an aggressive B-cell malignancy, but some patients have a very indolent evolution. This heterogeneous course is related, in part, to the different biological characteristics of conventional MCL (cMCL) and the distinct subgroup of leukemic nonnodal MCL (nnMCL). Robust criteria to distinguish these MCL subtypes and additional biological parameters that influence their evolution are not well defined. We describe a novel molecular assay that reliably distinguishes cMCL and nnMCL using blood samples. We trained a 16-gene assay (L-MCL16 assay) on the NanoString platform using 19 purified leukemic samples. The locked assay was applied to an independent cohort of 70 MCL patients with leukemic presentation. The assay assigned 37% of cases to nnMCL and 56% to cMCL. nnMCL and cMCL differed in nodal presentation, lactate dehydrogenase, immunoglobulin heavy chain gene mutational status, management options, genomic complexity, and CDKN2A/ATM deletions, but the proportion with 17p/TP53 aberrations was similar in both subgroups. Sequential samples showed that assay prediction was stable over time. nnMCL had a better overall survival (OS) than cMCL (3-year OS 92% vs 69%; P = .006) from the time of diagnosis and longer time to first treatment. Genomic complexity and TP53/CDKN2A aberrations predicted for shorter OS in the entire series and cMCL, whereas only genomic complexity was associated with shorter time to first treatment and OS in nnMCL. In conclusion, the newly developed assay robustly recognizes the 2 molecular subtypes of MCL in leukemic samples. Its combination with genetic alterations improves the prognostic evaluation and may provide useful biological information for management decisions.

Deferred treatment is a safe and viable option for selected patients with mantle cell lymphoma

Prospective identification of candidates for deferred therapy is not standardized and many patients receive immediate therapy regardless of risk. We conducted a retrospective, multi-center cohort analysis of MCL patients with comprehensive clinical data to examine the use and safety of deferred therapy for newly diagnosed patients. Previously untreated patients ≥18 years-old with MCL diagnosed in 1993-2015 at five academic sites were included. Of 395 patients, 72 (18%) received deferred therapy (defined as receipt of first treatment >90 days following initial diagnosis). Patients receiving deferred therapy were more likely to have an ECOG performance status of 0 (67 versus 44% p = .001), have no B symptoms (83 versus 65% p = .003) and have normal LDH levels at diagnosis (87 versus 55% p < .001). In multivariable analysis, deferred therapy was not associated with a significant difference in OS (HR 0.64: 95% CI 0.22-1.84, p = .407).

Early-stage mantle cell lymphoma: a retrospective analysis from the International Lymphoma Radiation Oncology Group (ILROG)

Background

Mantle cell lymphoma (MCL) rarely presents as early-stage disease, but clinical observations suggest that patients who present with early-stage disease may have better outcomes than those with advanced-stage disease.

Patients and methods

In this 13-institution study, we examined outcomes among 179 patients with early-stage (stage I or II) MCL in an attempt to identify prognostic factors that influence treatment selection and outcome. Variables examined included clinical characteristics, treatment modality, response to therapy, sites of failure, and survival.

Results

Patients were predominantly male (78%) with head and neck being the most common presenting sites (75%). Most failures occurred outside the original disease site (79%). Although the administration of radiation therapy, either alone or with chemotherapy, reduced the risk of local failure, it did not translate into an improved freedom from progression or overall survival (OS). The treatment outcomes were independent of treatment modality. The 10-year OS for patients treated with chemotherapy alone, chemo-radiation therapy and radiation therapy alone were 69%, 62%, and 74% (P = 0.79), and the 10-year freedom from progression were 46%, 43%, and 31% (P = 0.64), respectively.

Conclusion

Given the excellent OS rates regardless of initial therapy in patients with early-stage MCL, de-intensified therapy to limit treatment-related toxicity is a reasonable approach.

The Role of Macrophage/B-Cell Interactions in the Pathophysiology of B-Cell Lymphomas

Macrophages (MPs) are heterogeneous, multifunctional, myeloid-derived leukocytes that are part of the innate immune system, playing wide-ranging critical roles in basic biological activities, including maintenance of tissue homeostasis involving clearance of microbial pathogens. Tumor-associated MPs (TAMs) are MPs with defined specific M2 phenotypes now known to play central roles in the pathophysiology of a wide spectrum of malignant neoplasms. Also, TAMs are often intrinsic cellular components of the essential tumor microenvironment (TME). In concert with lymphoid-lineage B and T cells at various developmental stages, TAMs can mediate enhanced tumor progression, often leading to poor clinical prognosis, at least partly through secretion of chemokines, cytokines, and various active proteases shown to stimulate tumor growth, angiogenesis, metastasis, and immunosuppression. Researchers recently showed that TAMs express certain key checkpoint-associated proteins [e.g., programmed cell death protein 1 (PD-1), programmed cell death-ligand 1 (PD-L1)] that appear to be involved in T-cell activation and that these proteins are targets of other specific checkpoint-blocking immunotherapies (anti-PD-1/PD-L1) currently part of new therapeutic paradigms for chemotherapy-resistant neoplasms. Although much is known about the wide spectrum and flexibility of MPs under many normal and neoplastic conditions, relatively little is known about the increasingly important interactions between MPs and B-lymphoid cells, particularly in the TME in patients with aggressive B-cell non-Hodgkin lymphoma (NHL-B). Normal and neoplastic lymphoid and myeloid cell/MP lineages appear to share many primitive cellular characteristics as well as transcriptional factor interactions in human and animal ontogenic studies. Such cells are capable of ectopic transcription factor-induced lineage reprogramming or transdifferentiation from early myeloid/monocytic lineages to later induce B-cell lymphomagenesis in experimental in vivo murine systems. Close cellular interactions between endogenous clonal neoplastic B cells and related aberrant myeloid precursor cells/MPs appear to be important interactive components of aggressive NHL-B that we discuss herein in the larger context of the putative role of B-cell/MP cellular lineage interactions involved in NHL-B pathophysiology during ensuing lymphoma development.

Chronic lymphocytic leukemia and mantle cell lymphoma: crossroads of genetic and microenvironment interactions

Chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL) are 2 well-defined entities that diverge in their basic pathogenic mechanisms and clinical evolution but they share epidemiological characteristics, cells of origin, molecular alterations, and clinical features that differ from other lymphoid neoplasms. CLL and MCL are classically considered indolent and aggressive neoplasms, respectively. However, the clinical evolution of both tumors is very heterogeneous, with subsets of patients having stable disease for a long time whereas others require immediate intervention. Both CLL and MCL include 2 major molecular subtypes that seem to derive from antigen-experienced CD5⁺ B cells that retain a naive or memory-like epigenetic signature and carry a variable load of immunoglobulin heavy-chain variable region somatic mutations from truly unmutated to highly mutated, respectively. These 2 subtypes of tumors differ in their molecular pathways, genomic alterations, and clinical behavior, being more aggressive in naive-like than memory-like-derived tumors in both CLL and MCL. The pathogenesis of the 2 entities integrates the relevant influence of B-cell receptor signaling, tumor cell microenvironment interactions, genomic alterations, and epigenome modifications that configure the evolution of the tumors and offer new possibilities for therapeutic intervention. This review will focus on the similarities and differences of these 2 tumors based on recent studies that are enhancing the understanding of their pathogenesis and creating solid bases for new management strategies.

SOX11 augments BCR signaling to drive MCL-like tumor development

Mantle cell lymphoma (MCL) is characterized by increased B-cell receptor (BCR) signaling, and BTK inhibition is an effective therapeutic intervention in MCL patients. The mechanisms leading to increased BCR signaling in MCL are poorly understood, as mutations in upstream regulators of BCR signaling such as CD79A, commonly observed in other lymphomas, are rare in MCL. The transcription factor SOX11 is overexpressed in the majority (78% to 93%) of MCL patients and is considered an MCL-specific oncogene. So far, attempts to understand SOX11 function in vivo have been hampered by the lack of appropriate animal models, because germline deletion of SOX11 is embryonically lethal. We have developed a transgenic mouse model (Eμ-SOX11-EGFP) in the C57BL/6 background expressing murine SOX11 and EGFP under the control of a B-cell-specific IgH-Eμ enhancer. The overexpression of SOX11 exclusively in B cells exhibits oligoclonal B-cell hyperplasia in the spleen, bone marrow, and peripheral blood, with an immunophenotype (CD5⁺CD19⁺CD23^-) identical to human MCL. Furthermore, phosphocytometric time-of-flight analysis of the splenocytes from these mice shows hyperactivation of pBTK and other molecules in the BCR signaling pathway, and serial bone marrow transplant from transgenic donors produces lethality with decreasing latency. We report here that overexpression of SOX11 in B cells promotes BCR signaling and a disease phenotype that mimics human MCL.

SOX11 expression as a MRD molecular marker for MCL in comparison with t(11;14) and IGH rearrangement

The main cause of death in mantle cell lymphoma (MCL) patients is relapse due to undetermined minimal residual disease (MRD) and therefore monitoring MRD is crucial for making the best treatment decisions. The gold standard method for MRD analysis is the quantitative polymerase chain reaction. The most commonly used molecular markers for measuring MRD in MCL are: t(11;14)(q13;p32) translocation or CCND1 expression and IGH rearrangement. Such markers can, however, be found in other B cell non-Hodgkin lymphomas. Recent studies demonstrate that SOX11 expression is highly specific for MCL and could be used as a marker for measuring MRD. Moreover, evidence shows that SOX11 level could be predictive for overall survival (OS) and progression-free survival (PFS). We have measured MRD level in follow-up samples from 27 patients diagnosed with MCL using the molecular markers: t(11;14), IGH rearrangement and SOX11 expression. We compared all markers by their sensitivity, utility and quantitative range. We also examined the predictive value of SOX11 expression for OS and PFS. SOX11 expression was found to have better specificity, quantitative range and utility than the t(11;14). The predictive value of SOX11 expression was confirmed. At diagnosis, patients with high SOX11 expression had shorter PFS than patients with low SOX11 expression (p = 0.04*); differences between OS being statistically insignificant. To our best knowledge this is a first study comparing SOX11 with t(11;14) and IGH rearrangement as markers of MRD level. Moreover, in this study we confirmed that SOX11 is useful in cases when other molecular markers cannot be used.

The degree of overlap between the follicular dendritic cell meshwork and tumor cells in mantle cell lymphoma is associated with prognosis

This study concerning mantle cell lymphoma (MCL) investigated retrospectively an association between patient prognosis and the percentage of the total number of lymphoma cells found in the follicular dendritic cell (FDC) meshwork, that is, the degree of overlap of lymphoma cells. Two hundred and nine MCL patients were apportioned to grades I-III, in which the CD21-positive FDC meshwork covered ≤50%, 51%-89%, and ≥90% of the tumor area, respectively. Significant differences among the grades (all, P < 0.01) were found in the following: duration of disease (from onset of clinical manifestation to diagnosis); clinical staging; extranodal involvement (non-lymphoid organs); histological subtype; and Ki-67 proliferation index (PI). After removing the aggressive variants, the overall survival rates of grade I (n = 92) and II (n = 57) patients were similar. The overall survival rates of grade III (n = 46) patients differed from that of grade I + II patients (P < 0.01). The grades negatively correlated with the Ki-67 PI value (r = -0.234, P = 0.001). At each grade the OSR of patients with Ki-67 PI ≤30% was similar to that of patients with Ki-67 >30%. In the Ki-67 PI ≤30% group, the OSRs of the patients differed significantly among the grades. In the Ki-67 >30% group the OSRs of the grades were similar. The results of multivariate Cox regression analysis showed that the degree of overlap, age and Ki-67 PI was the independent prognostic factors of the OSRs of MCL patients. Our data suggests that MCL patients in whom there was a high degree of overlap between the FDC meshwork and tumor area have a better clinical prognosis. The degree of overlap correlates well with the Ki-67 PI, which can be used to predict the prognosis of patients.

CD200 expression in mantle cell lymphoma identifies a unique subgroup of patients with frequent IGHV mutations, absence of SOX11 expression, and an indolent clinical course

CD200, a marker currently utilized in the diagnosis of B-cell lymphoma, is uniformly positive in chronic lymphocytic leukemia/chronic lymphocytic leukemia, and is usually absent in mantle cell lymphoma. Over a 6 year-period, of 668 mantle cell lymphoma assessed by flow cytometry, CD200 expression was detected in 25 patients (~4%). All 25 patients had bone marrow involvement; however, 11 (44%) patients had no nodal or extranodal disease and belonged to non-nodal leukemic variant mantle cell lymphoma. Morphologically, bone marrow showed an unusual interstitial infiltrative pattern in 14/25 (56%) and small round cells resembling chronic lymphocytic leukemia in 9/25 (36%). CD23 was positive in 19/25 (76%) patients; and SOX11 was only positive in 5/21(24%). All 4 patients tested showed IGHV mutations. With a median follow-up of 23 months, 12/24 (50%) patients were not treated. These clinicopathological features were significantly different from 154 randomly chosen CD200-negative mantle cell lymphoma patients, in SOX11 positivity (24% versus 74%, P<0.0001), CD23 expression (76% versus 8%, P<0.0001), a non-nodal leukemic presentation (44% versus 2%, P<0.001), and therapy requirement (50% versus 92%, P<0.0001). This is the first study to show that CD200 expression in mantle cell lymphoma, though uncommon, identifies a subgroup of mantle cell lymphoma patients with characteristic pathological features, frequent non-nodal leukemic variant, and an indolent clinical course.

Mantle cell lymphoma in the era of precision medicine-diagnosis, biomarkers and therapeutic agents

Despite advances in the development of clinical agents for treating Mantle Cell Lymphoma (MCL), treatment of MCL remains a challenge due to complexity and frequent relapse associated with MCL. The incorporation of conventional and novel diagnostic approaches such as genomic sequencing have helped improve understanding of the pathogenesis of MCL, and have led to development of specific agents targeting signaling pathways that have recently been shown to be involved in MCL. In this review, we first provide a general overview of MCL and then discuss about the role of biomarkers in the pathogenesis, diagnosis, prognosis, and treatment for MCL. We attempt to discuss major biomarkers for MCL and highlight published and ongoing clinical trials in an effort to evaluate the dominant signaling pathways as drugable targets for treating MCL so as to determine the potential combination of drugs for both untreated and relapse/refractory cases. Our analysis indicates that incorporation of biomarkers is crucial for patient stratification and improve diagnosis and predictability of disease outcome thus help us in designing future precision therapies. The evidence indicates that a combination of conventional chemotherapeutic agents and novel drugs designed to target specific dysregulated signaling pathways can provide the effective therapeutic options for both untreated and relapse/refractory MCL.

Smoldering mantle cell lymphoma

Background

Mantle cell lymphoma (MCL) is an aggressive disease, with poor prognosis and a limited survival. However, some patients with indolent MCL can survive beyond 7~10 years. These patients remain largely asymptomatic and can be in observation for a long time without any treatment. The process of “wait and watch” leaves these patients with the potential risk of evolution to classic, aggressive MCL. On the other hand, early treatment for these patients may not impact overall survival but rather affects the quality of life. Therefore, it is essential to clearly identify this type of indolent MCL at the time of diagnosis.

Results

Reported findings of indolent presentation of MCL include: lack of B symptoms, normal serum lactic dehydrogenase (LDH) and β2-microglobulin levels (β2M), low MCL-International Prognostic Index (MIPI) score, maximum tumor diameter less than 3 cm, spleen size < 20 cm, positron emission tomography/computerized tomography with the Standard Uptake Value max <6, Ki-67 less than 30%, with some particular immunophenotype, such as CD5 and CD38 negative, markedly increased CD23 positive lymphocytes proportions, high expression of CD200, kappa light chain restriction, without C-myc, TP53 and NOTCH1/2 mutations, non-blastoid/pleomorphic histology, and no tumor growth on reevaluation every 2~3 months (followed for at least 6 months). Imaging evaluation may only be performed in the presence of disease-related symptoms or organ involvement. Meanwhile, if novel nodal or extranodal lesion is found, biopsy is mandatory to exclude lymphoma.

Common clinopathological forms of indolent presentations include monoclonal B lymphocytosis with t (11; 14); “indolent leukemic” presentation of MCL with involvement of peripheral blood, bone marrow involvement, splenomegaly, and minimal lymphadenopathies and in situ lymphoma (often found in lymph nodes removed for other reasons, and in gastrointestinal biopsies).

Conclusions

Considering these distinct indolent clinical presentations with particular features in cytology and gene mutational status, we propose to include these MCL clinical presentations under the umbrella of “Smoldering Mantle Cell Lymphoma”.

CD10-positive mantle cell lymphoma: clinicopathologic and prognostic study of 30 cases

Mantle cell lymphoma is usually negative for CD10 which is useful in distinguishing MCL from other CD10 + B cell lymphomas. Here we assessed the clinicopathologic features of 30 cases of CD10+ MCL, the largest series to date in the English literature, and compared them with a group of 212 typical MCL cases (CD5+, CD10-negative, CD23-negative, cyclin D1+). The 30 patients with CD10+ MCL included 17 men and 13 women with a median age of 68 years. Compared with CD10-negative MCL, patients with CD10+ MCL showed a lower male predominance (p = 0.01), more often had a diffuse growth pattern (p = 0.04) and blastoid/pleomorphic morphology (p < 0.0001), and more often showed BCL6 expression (p = 0.009). In all MCL patients, CD10 expression was not associated with overall survival (OS) (p = 0.16). However, in more aggressive subsets of MCL patients including those with high Ki67 (> 60%), blastoid/pleomorphic morphology, or high MCL International Prognostic Index (MIPI), CD10 expression was associated with a worse OS (p = 0.003, 0.04, and 0.001, respectively). High Ki67 (> 60%), blastoid/pleomorphic morphology, and high MIPI were also been identified as poor prognostic factors patients with in CD10+ MCL (p = 0.001, 0.0003, and 0.01, respectively). In summary, CD10+ MCL more often has a diffuse growth pattern, blastoid/pleomorphic morphology, and BCL6 expression. In MCL patients with a high Ki-67 (> 60%), blastoid/pleomorphic morphology, or high MIPI, CD10 expression contributes to an even worse prognosis. MCL should be included in the differential diagnosis of CD10 + B cell lymphomas.

Expression of TP53 is associated with the outcome of MCL independent of MIPI and Ki-67 in trials of the European MCL Network

Currently, prediction of time to treatment failure (TTF) and overall survival (OS) in mantle cell lymphoma (MCL) is based on the clinical factors included in the Mantle Cell Lymphoma International Prognostic Index (MIPI), and proliferation is assessed by Ki67. However, TP53 and SOX11 immunohistochemistry might improve risk stratification. We performed SOX11 and TP53 immunohistochemistry on the so far largest published cohort of lymphoma specimens (n = 365). All patients were treated in prospective trials of the European MCL Network. In multivariate analyses, including MIPI and Ki67, SOX11 expression was not associated with TTF, but patients with low SOX11 expression had shorter OS. On the contrary, high TP53 expression was a strong predictor of TTF and inferior OS compared with low TP53 expression in univariate and multivariate analyses adjusting for MIPI score and Ki-67 index (hazard ratio [HR], 2.0; P = .0054 for TTF, and HR, 2.1; P = .068 for OS). In particular, patients with high TP53 expression (>50% positive lymphoma cells) had a shorter TTF and poor OS independent of both MIPI score and Ki-67 index. Thus, TP53 immunohistochemistry is a suitable test for routine diagnostic practice to assess MCL prognosis.

TP53 mutations identify younger mantle cell lymphoma patients who do not benefit from intensive chemoimmunotherapy

The intensified standard-of-care regimens for younger patients with MCL do not overcome the deleterious effects of TP53 mutations. MCLs with TP53 mutations should be considered for alternative frontline treatment.

Clinical utility of recently identified diagnostic, prognostic, and predictive molecular biomarkers in mature B-cell neoplasms

Genomic profiling studies have provided new insights into the pathogenesis of mature B-cell neoplasms and have identified markers with prognostic impact. Recurrent mutations in tumor-suppressor genes (TP53, BIRC3, ATM), and common signaling pathways, such as the B-cell receptor (CD79A, CD79B, CARD11, TCF3, ID3), Toll-like receptor (MYD88), NOTCH (NOTCH1/2), nuclear factor-κB, and mitogen activated kinase signaling, have been identified in B-cell neoplasms. Chronic lymphocytic leukemia/small lymphocytic lymphoma, diffuse large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma, Burkitt lymphoma, Waldenström macroglobulinemia, hairy cell leukemia, and marginal zone lymphomas of splenic, nodal, and extranodal types represent examples of B-cell neoplasms in which novel molecular biomarkers have been discovered in recent years. In addition, ongoing retrospective correlative and prospective outcome studies have resulted in an enhanced understanding of the clinical utility of novel biomarkers. This progress is reflected in the 2016 update of the World Health Organization classification of lymphoid neoplasms, which lists as many as 41 mature B-cell neoplasms (including provisional categories). Consequently, molecular genetic studies are increasingly being applied for the clinical workup of many of these neoplasms. In this review, we focus on the diagnostic, prognostic, and/or therapeutic utility of molecular biomarkers in mature B-cell neoplasms.

The role of G protein-coupled receptors in lymphoid malignancies

B cell lymphoma consists of multiple individual diseases arising throughout the lifespan of B cell development. From pro-B cells in the bone marrow, through circulating mature memory B cells, each stage of B cell development is prone to oncogenic mutation and transformation, which can lead to a corresponding lymphoma. Therapies designed against individual types of lymphoma often target features that differ between malignant cells and the corresponding normal cells from which they arise. These genetic changes between tumor and normal cells can include oncogene activation, tumor suppressor gene repression and modified cell surface receptor expression. G protein-coupled receptors (GPCRs) are an important class of cell surface receptors that represent an ideal target for lymphoma therapeutics. GPCRs bind a wide range of ligands to relay extracellular signals through G protein-mediated signaling cascades. Each lymphoma subgroup expresses a unique pattern of GPCRs and efforts are underway to fully characterize these patterns at the genetic level. Aberrations such as overexpression, deletion and mutation of GPCRs have been characterized as having causative roles in lymphoma and such studies describing GPCRs in B cell lymphomas are summarized here.

Autologous Stem Cell Transplant: Still the Standard for Fit Patients With Mantle Cell Lymphoma

Mantle cell lymphoma is a relatively rare malignancy, comprising fewer than 10% of all non-Hodgkin lymphomas. It is a heterogeneous disease, and although most patients experience an aggressive clinical course, some have a more indolent disease and may not require immediate therapy. There are currently few reliable prognostic markers, making it difficult to accurately predict which patients require early intensive treatment. We argue that consolidative autologous stem cell transplantation in first remission remains the standard of care for the young and fit patient population, based on long-term data from phase II and III trials demonstrating that early transplantation extends both progression-free and overall survival. Novel targeted agents are currently being investigated in both the upfront and relapse settings, but to date there are few data to suggest durable treatment responses that compare favorably with results of transplantation.

Mantle cell lymphoma: 2017 update on diagnosis, risk-stratification, and clinical management

DISEASE OVERVIEW

Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma characterized by involvement of the lymph nodes, spleen, blood and bone marrow with a short remission duration to standard therapies and a median overall survival (OS) of 4-5 years.

DIAGNOSIS

Diagnosis is based on lymph node, bone marrow, or tissue morphology of centrocytic lymphocytes, small cell type, or blastoid variant cells. A chromosomal translocation t (11:14) is the molecular hallmark of MCL, resulting in the overexpression of cyclin D1. Cyclin D1 is detected by immunohistochemistry in 98% of cases. The absence of SOX-11 or a low Ki-67 may correlate with a more indolent form of MCL. The differential diagnosis of MCL includes small lymphocytic lymphoma, marginal zone lymphoma, and follicular lymphoma.

RISK STRATIFICATION

The MCL International Prognostic Index (MIPI) is the prognostic model most often used and incorporates ECOG performance status, age, leukocyte count, and lactic dehydrogenase. A modification of the MIPI also adds the Ki-67 proliferative index if available. The median OS for the low-risk group was not reached (5-year OS of 60%). The median OS for the intermediate risk group was 51 months and 29 months for the high risk group.

RISK-ADAPTED THERAPY

For selected indolent, low MIPI MCL patients, initial observation may be appropriate therapy. For younger patients with intermediate or high risk MIPI MCL, aggressive therapy with a cytotoxic Regimen followed by autologous stem cell transplantation should be considered. Rituximab maintenance after autologous stem cell transplantation has also improved the progression-free and overall survival. For older symptomatic MCL patients with intermediate or high risk MIPI, combination chemotherapy with R-CHOP, R-Bendamustine, or a clinical trial should be considered. In addition, rituximab maintenance therapy may prolong the progression-free survival. At the time of relapse, agents directed at activated pathways in MCL cells such as bortezomib (NFkB inhibitor), lenalidamide (anti-angiogenesis) and Ibruitinib (Bruton's Tyrosine Kinase [BTK] inhibitor) have demonstrated excellent clinical activity in MCL patients. Autologous or allogeneic stem cell transplantation can also be considered in young patients. Clinical trials with novel agents are always a consideration for MCL patients.

Mantle Cell Lymphoma With MYC Rearrangement: A Report of 17 Patients

MYC rearrangement in mantle cell lymphoma (MCL) is rare, and its clinicopathologic significance is not well defined. We report 17 cases of MCL with 8q24/MYC rearrangement, detected at the time of initial diagnosis of MCL in 10 patients and subsequently during the clinical course in 7 patients. There were 12 men and 5 women with a median age of 61 years (range, 49 to 81 y). Fourteen patients had lymphadenopathy (Ann Arbor stage III/IV), and 3 patients presented with a leukemic pattern without lymphadenopathy. Thirteen of 14 patients with available karyotyping data had a complex karyotype. In 8 cases the partner chromosome locus was an IG locus: t(8;14) (n=7) and t(8;22) (n=1). When MYC rearrangement was detected, most patients had a high-risk MCL international prognostic index, and the lymphoma cells had histologically aggressive features. Immunophenotypic analysis showed that the lymphoma cells were positive for cyclin D1 (n=16/16), Myc (9/11), and P53 (n=9/9). The Ki-67 proliferation rate was high (≥60%) in 10/11 cases. All patients received chemotherapy. The median follow-up time was 23 months. Clinical follow-up was available for 14 patients and treatment response in 13 patients. Eleven of 13 patients had refractory or relapsed disease, and 11 patients died. In conclusion, MCL with MYC rearrangement is characterized by advanced-stage disease, aggressive morphologic features, a high proliferation rate, p53 expression, a complex karyotype, and a poor prognosis. We believe these neoplasms fit within the overall concept of double-hit lymphoma, and the designation double-hit MCL may be helpful. We also believe that MYC rearrangement in MCL conveys important prognostic information that should be incorporated into the pathology report.

What is the optimal initial management of the older MCL patient?

The current first line treatment of a patient with mantle cell lymphoma (MCL) is often considered as too toxic for elderly patients. The elderly, however, comprise the majority of the patients with MCL. The results of several recent studies have shown that the outcome of this patient group is not as dismal as in the past. Indeed, if patients are not considered frail, and can tolerate rituximab and moderate intensive chemotherapy such as R-CHOP followed by rituximab maintenance or R-bendamustine, a 4-year overall survival of >80% can be achieved. In this chapter the developments of the regimens, resulting in the standard treatment options for these patients, are discussed.

Functional proteogenomics reveals biomarkers and therapeutic targets in lymphomas

Identification of biomarkers and therapeutic targets is a critical goal of precision medicine. N-glycoproteins are a particularly attractive class of proteins that constitute potential cancer biomarkers and therapeutic targets for small molecules, antibodies, and cellular therapies. Using mass spectrometry (MS), we generated a compendium of 1,091 N-glycoproteins (from 40 human primary lymphomas and cell lines). Hierarchical clustering revealed distinct subtype signatures that included several subtype-specific biomarkers. Orthogonal immunological studies in 671 primary lymphoma tissue biopsies and 32 lymphoma-derived cell lines corroborated MS data. In anaplastic lymphoma kinase-positive (ALK⁺) anaplastic large cell lymphoma (ALCL), integration of N-glycoproteomics and transcriptome sequencing revealed an ALK-regulated cytokine/receptor signaling network, including vulnerabilities corroborated by a genome-wide clustered regularly interspaced short palindromic screen. Functional targeting of IL-31 receptor β, an ALCL-enriched and ALK-regulated N-glycoprotein in this network, abrogated ALK⁺ALCL growth in vitro and in vivo. Our results highlight the utility of functional proteogenomic approaches for discovery of cancer biomarkers and therapeutic targets.

SOX11 promotes tumor protective microenvironment interactions through CXCR4 and FAK regulation in mantle cell lymphoma

SOX11 overexpression in mantle cell lymphoma (MCL) has been associated with more aggressive behavior and worse outcome. However, SOX11 oncogenic pathways driving MCL tumor progression are poorly understood. Here, we demonstrate that SOX11 binds to regulatory regions of 2 important genes for microenvironment signals in cancer: (C-X-C motif) chemokine receptor 4 (CXCR4) and PTK2 (encoding for focal adhesion kinase [FAK]). Moreover, SOX11⁺ xenograft and human primary MCL tumors overexpress cell migration and stromal stimulation gene signatures compared with their SOX11^- counterparts. We show that SOX11 directly upregulates CXCR4 and FAK expression, activating PI3K/AKT and ERK1/2 FAK-downstream pathways in MCL. Concordantly, SOX11⁺ MCL cells have higher cell migration, transmigration through endothelial cells, adhesion to stromal cells, and cell proliferation and display an increased resistance to conventional drug therapies compared with SOX11^- MCL cells. Specific FAK inhibition blocks downstream PI3K/AKT- and ERK1/2-mediated phosphorylation. Additionally, specific FAK and PI3K inhibitors reduce SOX11-enhanced MCL cell migration and stromal interactions and revert cell adhesion-mediated drug resistance (CAM-DR) to the same levels as SOX11^- MCL cells. In intravenous MCL xenograft models, SOX11⁺ MCL cells display higher cell migration, invasion, and growth compared with SOX11-knockdown cells, and specific FAK and CXCR4 inhibitors impair SOX11-enhanced MCL engraftment in bone marrow. Overall, our results suggest that SOX11 promotes MCL homing and invasion and increases CAM-DR through the direct regulation of CXCR4 and FAK expression and FAK/PI3K/AKT pathway activation, contributing to a more aggressive phenotype. Inhibition of this pathway may represent an efficient strategy to overcome stromal-mediated chemotherapy refractoriness in aggressive MCL.

Persistence of a t(11;14)-positive clone in a patient with mantle cell lymphoma for 20 years

We report here a patient with extremely indolent mantle cell lymphoma (MCL) who had progressed and required immunochemotherapy 20 years after diagnostic splenectomy. Non‐nodal, indolent MCL patients may progress after such an extraordinary long indolent phase, and we recommend lifelong follow up for such cases.

New Molecular Assay for the Proliferation Signature in Mantle Cell Lymphoma Applicable to Formalin-Fixed Paraffin-Embedded Biopsies

Purpose Mantle cell lymphoma is an aggressive B-cell neoplasm that displays heterogeneous outcomes after treatment. In 2003, the Lymphoma/Leukemia Molecular Profiling Project described a powerful biomarker-the proliferation signature-using gene expression in fresh frozen material. Herein, we describe the training and validation of a new assay that measures the proliferation signature in RNA derived from routinely available formalin-fixed paraffin-embedded (FFPE) biopsies. Methods Forty-seven FFPE biopsies were used to train an assay on the NanoString platform, using microarray gene expression data of matched fresh frozen biopsies as a gold standard. The locked assay was applied to pretreatment FFPE lymph node biopsies from an independent cohort of 110 patients uniformly treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone. Seventeen biopsies were tested across three laboratories to assess assay reproducibility. Results The MCL35 assay, which contained a 17-gene proliferation signature, yielded gene expression of sufficient quality to assign an assay score and risk group in 108 (98%) of 110 archival FFPE biopsies. The MCL35 assay assigned patients to high-risk (26%), standard-risk (29%), and low-risk (45%) groups, with different lengths of overall survival (OS): a median of 1.1, 2.6, and 8.6 years, respectively (log-rank for trend, P < .001). In multivariable analysis, these risk groups and the Mantle Cell Lymphoma International Prognostic Index were independently associated with OS ( P < .001 for both variables). Concordance of risk assignment across the three independent laboratories was 100%. Conclusion The newly developed and validated MCL35 assay for FFPE biopsies uses the proliferation signature to define groups of patients with significantly different OS independent of the Mantle Cell Lymphoma International Prognostic Index. Importantly, the analytic and clinical validity of this assay defines it as a reliable biomarker to support risk-adapted clinical trials.

Catalog of genetic progression of human cancers: non-Hodgkin lymphoma

The recent application of next-generation sequencing technologies lead to significant improvements in our understanding of genetic underpinnings of non-Hodgkin lymphomas with identification of an unexpectedly high number of novel mutation targets across the different B-cell lymphoma entities. These recently discovered molecular lesions are expected to have a major impact on development of novel biomarkers and targeted therapies as well as patient stratification based on the underlying genetic profile. This review will cover the major discoveries in B-cell lymphomas using next-generation sequencing technologies over the last few years, highlighting alterations associated with relapse and progression of these diseases.

Splenic marginal zone lymphoma

Splenic marginal zone lymphoma (SMZL) is an indolent small B-cell lymphoma involving the spleen and bone marrow characterized by a micronodular tumoral infiltration that replaces the preexisting lymphoid follicles and shows marginal zone differentiation as a distinctive finding. SMZL cases are characterized by prominent splenomegaly and bone marrow and peripheral blood infiltration. Cells in peripheral blood show a villous cytology. Bone marrow and peripheral blood characteristic features usually allow a diagnosis of SMZL to be performed. Mutational spectrum of SMZL identifies specific findings, such as 7q loss and NOTCH2 and KLF2 mutations, both genes related with marginal zone differentiation. There is a striking clinical variability in SMZL cases, dependent of the tumoral load and performance status. Specific molecular markers such as 7q loss, p53 loss/mutation, NOTCH2 and KLF2 mutations have been found to be associated with the clinical variability. Distinction from Monoclonal B-cell lymphocytosis with marginal zone phenotype is still an open issue that requires identification of precise and specific thresholds with clinical meaning.

Diagnostic and predictive biomarkers for lymphoma diagnosis and treatment in the era of precision medicine

Lymphomas are a group of hematological malignancies derived from lymphocytes. Lymphomas are clinically and biologically heterogeneous and have overlapping diagnostic features. With the advance of new technologies and the application of efficient and feasible detection platforms, an unprecedented number of novel biomarkers have been discovered or are under investigation at the genetic, epigenetic, and protein level as well as the tumor microenvironment. These biomarkers have enabled new clinical and pathological insights into the mechanisms underlying lymphomagenesis and also have facilitated improvements in the diagnostic workup, sub-classification, outcome stratification, and personalized therapy for lymphoma patients. However, integrating these biomarkers into clinical practice effectively and precisely in daily practice is challenging. More in-depth studies are required to further validate these novel biomarkers and to assess other parameters that can affect the reproducibility of these biomarkers such as the selection of detection methods, biological reagents, interpretation of data, and cost efficiency. Despite these challenges, there are many reasons to be optimistic that novel biomarkers will facilitate better algorithms and strategies as we enter a new era of precision medicine to better refine diagnosis, prognostication, and rational treatment design for patients with lymphomas.

Leukemic non-nodal mantle cell lymphomas have a distinct phenotype and are associated with deletion of PARP1 and 13q14

Leukemic non-nodal mantle cell lymphoma (lMCL) is a particular subtype of mantle cell lymphoma (MCL), characterized by leukemic non-nodal disease and slow progression. Recognition of this entity is relevant to avoid overtreatment. Despite indolent clinical behaviour, lMCL might transform to a more aggressive disease. The purpose of this study was to compare lMCL with classical MCL (cMCL) and aggressive MCL (aMCL) using immunohistochemistry, interphase fluorescence in situ hybridization (FISH), and array-based comparative genomic hybridization, in order to identify biomarkers for lMCL diagnosis and prognosis. Seven lMCL patients were included. All had bone marrow involvement without lymphadenopathy. An lMCL phenotype was distinct from that of cMCL and aMCL: SOX11-, ATM+, PARP1+/-, and low KI67 (average 2 %). Beyond the t(11;14) translocation, fewer secondary cytogenetic alterations were found in lMCL compared to cMCL and aMCL, including deletion of PARP1 and 13q14. At last follow-up, one patient with lMCL had died of disease and another had progressive disease. These patients were respectively 13q14 deletion- and PARP1-positive. One other case of lMCL harbored a 13q14 deletion associated with PARP1 deletion. This patient had indolent disease. lMCL has a particular phenotype and fewer secondary cytogenetic alterations than cMCL and aMCL. PARP1 protein expression and 13q14 deletion are associated with a progressive clinical course of lMCL and should be included in initial diagnostic studies as predictors of unfavorable outcome. PARP1 deletion is involved in lMCL pathogenesis and might confer advantage.

Investigation of Rho-Kinase Expressions and Polymorphisms in Mantle Cell Lymphoma Patients

OBJECTIVE

Mantle cell lymphoma (MCL) is a rare but aggressive form of B-cell non-Hodgkin lymphoma characterized by excessive expression of cyclin D1. Intracellular signaling enzyme Rho-kinase (ROCK) can contribute to cellular migration, proliferation, and differentiation, as well as tumor development and metastasis. However, ROCK gene and protein expressions or polymorphisms have never been investigated in MCL patients. The purpose of this study was to investigate the role of ROCK gene and protein expressions in MCL patients. We also examined ROCK2 gene polymorphisms in this study.

MATERIALS AND METHODS

A total of 60 patients with MCL and 60 healthy controls were included in this retrospective study. Hematoxylin and eosin-stained lymph node tissue slides in the entire archive were reevaluated and used for immunohistochemistry, gene expression, and polymerase chain reaction studies.

RESULTS

In immunohistochemical studies, there were significant increases in ROCK1 (p=0.0009) and ROCK2 (p<0.0001) protein expressions in MCL patients when compared with the control group. Although a marked increase in ROCK1 gene expression (p=0.0215) was noted, no significant change was observed in ROCK2 gene expression in MCL patients. Seven ROCK2 polymorphisms were studied, but the results showed no significant differences between the groups.

CONCLUSION

This is the first study to show that ROCK1 gene and ROCK protein expressions may contribute to the development of MCL.