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

Molecular etiology of an indolent lymphoproliferative disorder determined by whole-genome sequencing

In an attempt to assess potential treatment options, whole-genome and transcriptome sequencing were performed on a patient with an unclassifiable small lymphoproliferative disorder. Variants from genome sequencing were prioritized using a combination of comparative variant distributions in a spectrum of lymphomas, and meta-analyses of gene expression profiling. In this patient, the molecular variants that we believe to be most relevant to the disease presentation most strongly resemble a diffuse large B-cell lymphoma (DLBCL), whereas the gene expression data are most consistent with a low-grade chronic lymphocytic leukemia (CLL). The variant of greatest interest was a predicted NOTCH2-truncating mutation, which has been recently reported in various lymphomas.

Genetic aberrations in small B-cell lymphomas and leukemias: molecular pathology, clinical relevance and therapeutic targets

Small B-cell lymphomas and leukemias (SBCLs) are a clinically, morphologically, immunophenotypically and genetically heterogeneous group of clonal lymphoid neoplasms, including entities such as chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), mantle cell lymphoma (MCL), follicular lymphoma (FL), lymphoplasmacytic lymphoma (LPL), marginal zone lymphoma (MZL) and hairy cell leukemia (HCL). The pathogenesis of some of these lymphoid malignancies is characterized by distinct translocations, for example t(11;14) in the majority of cases of MCL and t(14;18) in most cases of FL, whereas other entities are associated with a variety of recurrent but nonspecific numeric chromosomal abnormalities, as exemplified by del(13q14), del(11q22), and +12 in CLL, and yet others such as LPL and HCL that lack recurrent or specific cytogenetic aberrations. The recent surge in next generation sequencing (NGS) technology has shed more light on the genetic landscape of SBCLs through characterization of numerous driver mutations including SF3B1 and NOTCH1 in CLL, ATM and CCND1 in MCL, KMT2D and EPHA7 in FL, MYD88 (L265P) in LPL, KLF2 and NOTCH2 in splenic MZL (SMZL) and BRAF (V600E) in HCL. The identification of distinct genetic lesions not only provides greater insight into the molecular pathogenesis of these disorders but also identifies potential valuable biomarkers for prognostic stratification, as well as specific targets for directed therapy. This review discusses the well-established and recently identified molecular lesions underlying the pathogenesis of SBCLs, highlights their clinical relevance and summarizes novel targeted therapies.

SOXC and MiR17-92 gene expression profiling defines two subgroups with different clinical outcome in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a heterogeneous B-cell lymphoid malignancy where most patients follow an aggressive clinical course whereas others are associated with an indolent performance. SOX4, SOX11, and SOX12 belong to SOXC family of transcription factors involved in embryonic neurogenesis and tissue remodeling. Among them, SOX11 has been found aberrantly expressed in most aggressive MCL patients, being considered a reliable biomarker in the pathology. Several studies have revealed that microRNAs (miRs) from the miR-17-92 cluster are among the most deregulated miRNAs in human cancers, still little is known about this cluster in MCL. In this study we screened the transcriptional profiles of 70 MCL patients for SOXC cluster and miR17, miR18a, miR19b and miR92a, from the miR-17-92 cluster. Gene expression analysis showed higher SOX11 and SOX12 levels compared to SOX4 (P ≤ 0.0026). Moreover we found a negative correlation between the expression of SOX11 and SOX4 (P < 0.0001). miR17-92 cluster analysis showed that miR19b and miR92a exhibited higher levels than miR17 and miR18a (P < 0.0001). Unsupervised hierarchical clustering revealed two subgroups with significant differences in relation to aggressive MCL features, such as blastoid morphological variant (P = 0.0412), nodal presentation (P = 0.0492), CD5(+) (P = 0.0004) and shorter overall survival (P < 0.0001). Together, our findings show for the first time an association between the differential expression profiles of SOXC and miR17-92 clusters in MCL and also relate them to different clinical subtypes of the disease adding new biological information that may contribute to a better understanding of this pathology. © 2016 Wiley Periodicals, Inc.

SOX11 is a biomarker for cyclin D1-negative mantle cell lymphoma

Cyclin D1 (CCND1) protein overexpression and/or the t(11;14)(q13;q32) translocation are the pathognomonic hallmarks of mantle cell lymphoma (MCL). However, there have been cases that lacked both t(11;14) and cyclin D1 protein but still had a gene expression profile suggesting a diagnosis of MCL. SOX11 expression was detected in most cyclin D1- negative MCL and can serve as a specific biomarker for the diagnosis of this subset of MCL. Lack of SOX11 expression in MCL was associated with an indolent subset and favorable prognosis.

Cutaneous involvement as a rare first sign of systemic mantle cell lymphoma: A case report and review of the literature

Mantle cell lymphoma (MCL) is a unique type of B-cell non-Hodgkin's lymphoma, which very rarely exhibits skin involvement. We herein describe the case of a 55-year-old woman, who initially presented with a nodular mass of the right infraorbital region. On histological analysis of the subcutaneous tissue, a diffuse neoplastic cell infiltration was identified, composed of medium-sized lymphoid cells with irregular nuclei, which was diagnosed as MCL. The tumor cells were positive for CD5, CD20, CD79a, cyclin D1 and sex-determining region Y-box 11, but negative for CD10 and CD23. Our patient received six cycles of R-CHOP chemotherapy and intrathecal methotrexate as central nervous system prophylaxis. However, the patient relapsed 1 year later and was treated with two cycles of R-DHAP and one cycle of intrathecal methotrexate. After achieving partial remission, the patient was consolidated with peripheral blood stem cell transplantation using the BEAM conditioning regime. While prior case studies suggest that skin invasion by MCL is associated with a poor prognosis, our patient remains alive almost 4 years after the initial presentation. Skin involvement as a first sign of systemic MCL is very rare and must be considered.

The role of targeted treatment in mantle cell lymphoma: is transplant dead or alive?

Based on the profound biological insights of the last years into the molecular pathogenesis of mantle cell lymphoma and the clinical introduction of new targeted drugs, with high efficacy and a good safety profile, the therapeutic scenario for this tumor has been shown to be thoroughly favourable. No longer characterized by a uniformly dismal prognosis, mantle cell lymphoma has been revealed as a spectrum of different diseases, ranging from very indolent cases to highly aggressive and refractory ones. Thus, there is an urgent need to adapt therapy to accommodate the diverse presentations of the disease. High-dose chemotherapy, followed by autologous stem cell transplantation is the current standard of care for younger patients, generally providing high responses and long survival rates, but hampered by acute and long-term toxicity. In addition, some patients may be overtreated, while others could benefit from targeted approaches, based on the new, molecular-directed compounds. Such a personalized treatment based on the specific characteristics of individual patients may be guided by validated prognostic tools, such as the Mantle Cell Lymphoma International Prognostic Index and the Ki-67 Proliferative Index, as well as by early predictors of treatment response, like minimal residual disease analysis. Moreover, mutation screening of distinctive genomic alterations may provide new, predictive biomarkers, with an additional impact on clinical practice. Only after tailoring treatment according to the clinical and biological heterogeneity of the disease the role of transplantation and modern therapeutic options will be redefined in mantle cell lymphoma.

Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is an uncommon subtype of non-Hodgkin lymphoma previously considered to have a poor prognosis. Large gains were made in the first decade of the new century when clinical trials established the importance of high-dose therapy and autologous stem-cell rescue and high-dose cytarabine in younger patients and the benefits of maintenance rituximab and bendamustine in older patients. In particular, greater depth of understanding of the molecular pathophysiology of MCL has resulted in an explosion of specifically targeted new efficacious agents. In particular, agents recently approved by the Food and Drug Administration include the proteasome inhibitor bortezomib, immunomodulator lenalidomide, and Bruton's tyrosine kinase inhibitor ibrutinib. We review recent advances in the understanding of MCL biology and outline our recommended approach to therapy, including choice of chemoimmunotherapy, the role of stem-cell transplantation, and mechanism-based targeted therapies, on the basis of a synthesis of the data from published clinical trials.

Will new drugs change the standard of care for patients with mantle cell lymphoma?

Mantle Cell lymphoma is a heterogeneous malignancy that has different subtypes with variable levels of aggressiveness. Research on the pathobiology of this disease is helping us understand the etiology for this heterogeneity and has the potential to guide future therapeutic options. The availability of the Ki67 proliferation index and the use of the MIPI score can help determine which of the numerous therapeutic options might be utilized. Minimal Residual Disease testing can act as a guide as to the potential benefit of maintenance therapy. This article discusses the current standard of care for Mantle Cell lymphoma and our current understanding of the pathobiology of the disease leading to strategies to improve patient outcomes with some of the newer targeted agents.

Identification of miR-15b as a transformation-related factor in mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive B cell lymphoma with a poor prognosis. It is characterized by the t(11;14)(q13;q32) translocation, resulting in overexpression of CCND1. Morphologically, MCL is categorised into two types: classical MCL (cMCL) and aggressive MCL (aMCL), with a proportion of cMCL progressing to develop into aMCL. miRNAs are currently considered to be important regulators for cell behavior and are deregulated in many malignancies. Although several genetic alterations have been implicated in the transformation of cMCL to aMCL, the involvement of miRNAs in transformation is not known. In an effort to identify the miRNAs related to the transformation of MCL, miRNA microarray analyses were used for cMCL and aMCL cases. These analyses demonstrated significant differences in the expression of seven microRNAs based on a t-test (p-value <0.05); miR-15b was greatly upregulated in aMCL. Locked nucleic acid in situ hybridization showed increased staining of miR-15b in formalin-fixed paraffin-embedded sections of aMCL. These results correlated well with the microRNA microarray analysis. Although the molecular functions of miR-15b are largely unknown, it has been found to be associated with the cell cycle and apoptosis. However, the physiological significance of increased miR-15b in MCL is still unknown. Our present findings suggest that the upregulated expression of miR-15b is likely to play an important role in the transformation of cMCL to aMCL.

SNPs Array Karyotyping in Non-Hodgkin Lymphoma

The traditional methods for detection of chromosomal aberrations, which included cytogenetic or gene candidate solutions, suffered from low sensitivity or the need for previous knowledge of the target regions of the genome. With the advent of single nucleotide polymorphism (SNP) arrays, genome screening at global level in order to find chromosomal aberrations like copy number variants, DNA amplifications, deletions, and also loss of heterozygosity became feasible. In this review, we present an update of the knowledge, gained by SNPs arrays, of the genomic complexity of the most important subtypes of non-Hodgkin lymphomas.

Bortezomib in mantle cell lymphoma: comparative therapeutic outcomes

Mantle cell lymphoma (MCL) is an incurable, typically aggressive subtype of non-Hodgkin lymphoma, accounting for 4%–7% of newly diagnosed non-Hodgkin lymphoma cases. Chemoresistance commonly ensues in MCL, and patients with this heterogeneous disease invariably relapse, underscoring the unmet need for better therapies. Over the past few years, several novel agents with promising activity and unique mechanisms of action have been deemed effective in MCL. Bortezomib is a reversible proteasome inhibitor, approved as a single agent for patients with relapsed/refractory MCL who have received at least one prior line of therapy. Addition of bortezomib to chemoimmunotherapies has demonstrated good tolerability and superior efficacy, both in the upfront and salvage settings, and recently one such combination of bortezomib plus rituximab, cyclophosphamide, doxorubicin, and prednisone was approved as a frontline regimen in untreated patients with MCL. This review examines the role of bortezomib in a multitude of clinical settings and ongoing clinical trials designed to optimize its integration in the current treatment paradigms of MCL.

Mantle cell lymphoma: biology, clinical presentation, and therapeutic approaches

Mantle cell lymphoma is molecularly characterized by the chromosomal translocation t(11;14) (q13;q32) that results in a constitutional overexpression of the cell cycle regulator protein cyclin D1. Generally, the disease is characterized by rapid relapses and poor long-term outcome. However, a subset of patients with indolent disease has been identified. Randomized trials have demonstrated the superiority of dose intensified, cytarabine-containing induction with or without autologous stem cell transplantation in younger patients. In elderly patients, a rituximab-based maintenance has significantly prolonged progression-free and overall survival after treatment with rituximab, cyclophosphamide, doxorubicin hydrochloride, vincristine, and prednisone (R-CHOP). Unfortunately, the vast majority of patients will eventually relapse. Numerous molecular targeting strategies (bortezomib, lenalidomide, temsirolimus, and especially inhibitors of the B-cell receptor pathway) have achieved high response rates in phase II studies and should be strongly considered in relapsed disease.

Plasma cell and terminal B-cell differentiation in mantle cell lymphoma mainly occur in the SOX11-negative subtype

Mantle cell lymphoma is a mature lymphoid neoplasm characterized by the t(11;14)(q13;q32) and cyclin D1 overexpression. SOX11 is a transcription factor commonly overexpressed in these tumors but absent in most other mature B-cell lymphomas whose function is not well understood. Experimental studies have shown that silencing of SOX11 in mantle cell lymphoma cells promotes the shift from a mature B cell into an early plasmacytic differentiation phenotype, suggesting that SOX11 may contribute to tumor development by blocking the B-cell differentiation program. The relationship between SOX11 expression and terminal B-cell differentiation in primary mantle cell lymphoma and its relationship to the plasmacytic differentiation observed in occasional cases is not known. In this study we have investigated the terminal B-cell differentiation phenotype in 60 mantle cell lymphomas, 41 SOX11-positive and 19 SOX11-negative. Monotypic plasma cells and lymphoid cells with plasmacytic differentiation expressing cyclin D1 were observed in 7 (37%) SOX11-negative but in none of 41 SOX11-positive mantle cell lymphomas (P<0.001). Intense cytoplasmic expression of a restricted immunoglobulin light chain was significantly more frequent in SOX11-negative than -positive tumors (58 vs 13%) (P=0.001). Similarly, BLIMP1 and XBP1 expression was also significantly more frequent in SOX11-negative than in -positive cases (83 vs 34% and 75 vs 11%, respectively) (P=0.001). However, no differences in the expression of IRF4/MUM1 were observed among these subtypes of mantle cell lymphoma. In conclusion, these results indicate that SOX11-negative mantle cell lymphoma may be a particular subtype of this tumor characterized by more frequent morphological and immunophenotypic terminal B-cell differentiation features that may be facilitated by the absence of SOX11 transcription factor.

Treatment options for mantle cell lymphoma

INTRODUCTION

In this article, we provide an accurate overview of both standard treatment option and novel promising therapeutics. Major impact is on novel agents now being tested in randomized clinical trials. While the initial data are promising, they may rapidly expand treatment options, change existing paradigms and further improve outcomes for mantle cell lymphoma (MCL) patients.

AREAS COVERED

MCL is a disease with indolent histology, but aggressive clinical course. However, for now, MCL remains incurable and the search for the most effective and tumor-specific treatment still represents a great challenge for oncohematologists. However, the implementation of chemotherapy together with the anti-CD20 antibody rituximab, as well as the growing use of autologous stem cell transplantation in first remission, have improved effects of treatment in MCL, including even some improvement in overall survival. Recently, treatment modalities for MCL have been expanded by strategies based on several biologically targeted agents, including m-TOR kinase or proteasome inhibitors and immunomodulatory agents, such as lenalidomide. B-cell receptor pathway inhibitors, such as ibrutinib and idelalisib, and histone deacetylase or cyclin-dependent kinase inhibitors have also shown promising activity in resistant or relapsed disease.

EXPERT OPINION

Although enormous progress was made in the treatment of MCL over the last year, the disease remains incurable. One chance for the significant life prolongation is intensive treatment with consolidative auto SCT. However, real progress may be afforded by developing the novel agents described in this article. In this way, MCL may soon become another potentially curable oncological malignancy.

Mantle cell lymphoma: 2015 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 ± autologous stem cell transplantation should be considered. For older 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.

New paradigms in mantle cell lymphoma: is it time to risk-stratify treatment based on the proliferative signature?

The elucidation of crucial biologic pathways of cell survival and proliferation has led to the development of highly effective drugs, some of which have markedly improved mantle cell lymphoma (MCL) therapeutic opportunities in the past 10 years. Moreover, an undeniable clinical heterogeneity in treatment response and disease behavior has become apparent in this neoplasm. Thus, the need for biologic markers stratifying patients with MCL in risk classes deserving different treatment approaches has recently been fervently expressed. Among several newly discovered biomarkers, the dismal predictive value of a high proliferative signature has been broadly recognized in large studies of patients with MCL. Different techniques have been used to assess tumor cell proliferation, including mitotic index, immunostaining with Ki-67 antibody, and gene expression profiling. Ki-67 proliferative index, in particular, has been extensively investigated, and its negative impact on relapse incidence and overall survival has been validated in large prospective clinical trials. However, one important pitfall limiting its widespread use in clinical practice is the reported interobserver variability, due to the previous lack of a standardized approach for quantification among different laboratories. In the present review, we describe some of the major techniques to assess cell proliferation in MCL, focusing in particular on the Ki-67 index and its need for a standardized approach to be used in multicenter clinical trials. The value of MCL biologic prognostic scores (as MIPI-b) is discussed, along with our proposal on how to integrate these scores in the planning of future trials investigating a tailored therapeutic approach for patients with MCL. See all articles in this CCR Focus section, "Paradigm Shifts in Lymphoma."

[Mantle cell lymphoma: Towards a personalized therapeutic strategy?]

Mantle cell lymphoma (MCL) is a clinically heterogeneous non-Hodgkin lymphoma with an aggressive clinical behaviour and short survival in some cases and an indolent course in others. Advances in the biology and pathogenesis of MCL have unveiled several genes involved in deregulation of cell cycle checkpoints and the finding of subclonal populations with specific recurrent mutations (p53, ATM, NOTCH2) with an impact on disease progression and refractoriness to treatment. Prognostic stratification helps to distinguish between indolent and aggressive forms of MCL. Currently, younger fit patients benefit from more intensive front line chemotherapy regimens and consolidation with autologous transplantation, while older or frail patients are treated with less intensive regimens and rituximab maintenance. For relapsing disease, the introduction of bortezomib and lenalidomide containing regimens and B-cell receptor pathway inhibitors such as ibrutinib and idelalisib in combination with immunochemotherapy have emerged as therapeutic agents with promising clinical outcomes.

Prognostic model for mantle cell lymphoma in the rituximab era: a nationwide study in Japan

Mantle cell lymphoma (MCL) is essentially incurable with conventional chemotherapy. The MCL International Prognostic Index (MIPI) is a validated specific prognostic index, but was derived from patients with advanced-stage disease primarily in the pre-rituximab era. We analysed 501 MCL patients (median age, 67 years; range 22-90) treated with rituximab-containing chemotherapy, and evaluated the prognostic factors adjusted by the treatment. Five-year overall survival (OS) in the low, intermediate and high MIPI groups was 74%, 70% and 35%, respectively. Additional to MIPI risk factors, multivariate analysis revealed that low serum albumin and bone-marrow involvement were also significantly associated with a poor outcome. The revised-MIPI (R-MIPI) was constructed using six factors, namely age, performance status, white blood cell count, serum lactate dehydrogenase, bone-marrow involvement and serum albumin, which is divided into four prognostic groups. Five-year OS in low, low-intermediate (L-I), high-intermediate (H-I) and high R-MIPI groups was 92%, 75%, 61% and 19%, respectively. Hazard ratio for OS of L-I, H-I and high risk to low risk patients were 5·4, 8·3 and 33·0, respectively. R-MIPI, a new prognostic index with easy application to the general patient population, shows promise for identifying low- and high-risk MCL patients in the rituximab era.

DNA methylation and histone modifications regulate SOX11 expression in lymphoid and solid cancer cells

Background

The neural transcription factor SOX11 is present at specific stages during embryo development with a very restricted expression in adult tissue, indicating precise regulation of transcription. SOX11 is strongly up-regulated in some malignancies and have a functional role in tumorgenesis. With the aim to explore differences in epigenetic regulation of SOX11 expression in normal versus neoplastic cells, we investigated methylation and histone modifications related to the SOX11 promoter and the possibility to induce re-expression using histone deacetylase (HDAC) or EZH2 inhibitors.

Methods

The epigenetic regulation of SOX11 was investigated in distinct non-malignant cell populations (n = 7) and neoplastic cell-lines (n = 42) of different cellular origins. DNA methylation was assessed using bisulfite sequencing, methylation-specific melting curve analysis, MethyLight and pyrosequencing. The presence of H3K27me3 was assessed using ChIP-qPCR. The HDAC inhibitors Vorinostat and trichostatin A were used to induce SOX11 in cell lines with no endogenous expression.

Results

The SOX11 promoter shows a low degree of methylation and strong enrichment of H3K27me3 in non-malignant differentiated cells, independent of cellular origin. Cancers of the B-cell lineage are strongly marked by de novo methylation at the SOX11 promoter in SOX11 non-expressing cells, while solid cancer entities display a more varying degree of SOX11 promoter methylation. The silencing mark H3K27me3 was generally present at the SOX11 promoter in non-expressing cells, and an increased enrichment was observed in cancer cells with a low degree of SOX11 methylation compared to cells with dense methylation. Finally, we demonstrate that the HDAC inhibitors (vorinostat and trichostatin A) induce SOX11 expression in cancer cells with low levels of SOX11 methylation.

Conclusions

We show that SOX11 is strongly marked by repressive histone marks in non-malignant cells. In contrast, SOX11 regulation in neoplastic tissues is more complex involving both DNA methylation and histone modifications. The possibility to re-express SOX11 in non-methylated tissue is of clinical relevance, and was successfully achieved in cell lines with low levels of SOX11 methylation. In breast cancer patients, methylation of the SOX11 promoter was shown to correlate with estrogen receptor status, suggesting that SOX11 may be functionally re-expressed during treatment with HDAC inhibitors in specific patient subgroups.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1208-y) contains supplementary material, which is available to authorized users.

Clinical and prognostic significance of SOX11 in breast cancer

Recently, the transcription factor SOX11 has gained extensive attention as a diagnostic marker in a series of cancers. However, to date, the possible roles of SOX11 in breast cancer has not been investigated. In this study, immunohistochemical staining for SOX11 was performed for 116 cases of breast cancer. Nuclear SOX11 was observed in 42 (36.2%) and cytoplasmic SOX11 in 52 (44.8%) of breast cancer samples. Moreover, high expression of cytoplasmic and nuclear SOX11 was associated with clinicopathological factors, including earlier tumor grade, absence of lymph node metastasis and smaller tumor size. Kaplan-Meier survival curves demonstrated high nuclear SOX11 expression to be associated with more prolonged overall survival than those with low expression and it could be an independent predictor of survival for breast cancer patients. It is worthwhile to note that cytoplasmic SOX11 was not correlated with prognosis of breast cancer patients. These data suggest the possibility that nuclear SOX11 could be as a potential target for breast cancer therapy.

Role of allogeneic stem cell transplantation in mantle cell lymphoma

Despite a wide spectrum of treatment options, mantle cell lymphoma (MCL) remains a challenging hematologic malignancy to manage. Advances in front-line therapy, including the monoclonal antibody rituximab and increasing use of cytarabine, have improved remission rates. Autologous hematopoietic cell transplantation (HCT) can effectively consolidate remission of MCL, leading to encouraging survival beyond 5 yr. However, nearly all patients with MCL will relapse and require salvage therapy. Novel agents such as ibrutinib, bortezomib, and lenalidomide have dramatically expanded the options for treating relapsed MCL. In this review, we summarize the clinical evidence supporting the use of allogeneic donor HCT in MCL and make recommendations on indications for its use. Data suggest that allogeneic donor HCT is the only curative therapy for patients with poor prognosis or aggressive MCL. Patient selection, timing, and optimal use remain a matter of scientific debate and given the rapidly changing therapeutic landscape of MCL, the outcomes of allogeneic HCT should be interpreted in the context of novel therapeutics.

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.

Mantle cell lymphoma: observation to transplantation

Mantle cell lymphoma as a rare non-Hodgkin B-cell lymphoma can present in different clinical presentations such as an aggressive form or a more indolent picture. Treatment modality is based on multiple factors including age, presence or absence of symptoms, and comorbidities. Watchful waiting is a reasonable approach for asymptomatic patients especially in elderly. In symptomatic patients, treatment is chemo-immunotherapy followed by maintenance immunotherapy or autologous bone marrow transplant. Allogeneic bone marrow transplant has a potential benefit of cure for relapsed/refractory cases, but it has a high mortality rate. Novel treatment with agents such as ibrutinib, a Bruton tyrosine kinase inhibitor, has shown promising results in relapse/refractory cases. We extensively review the most recent data on diagnostic and therapeutic management of mantle cell lymphoma through presenting two extreme clinical scenarios.

Clinical observations on chemotherapy curable malignancies: unique genetic events, frozen development and enduring apoptotic potential

BACKGROUND

A select number of relatively rare metastatic malignancies comprising trophoblast tumours, the rare childhood cancers, germ cells tumours, leukemias and lymphomas have been routinely curable with chemotherapy for more than 30 years. However for the more common metastatic malignancies chemotherapy treatment frequently brings clinical benefits but cure is not expected. Clinically this clear divide in outcome between the tumour types can appear at odds with the classical theories of chemotherapy sensitivity and resistance that include rates of proliferation, genetic development of drug resistance and drug efflux pumps. We have looked at the clinical characteristics of the chemotherapy curable malignancies to see if they have any common factors that could explain this extreme differential sensitivity to chemotherapy.

DISCUSSION

It has previously been noted how the onset of malignancy can leave malignant cells fixed with some key cellular functions remaining frozen at the point in development at which malignant transformation occurred. In the chemotherapy curable malignancies the onset of malignancy is in each case closely linked to one of the unique genetic events of; nuclear fusion for molar pregnancies, choriocarcinoma and placental site trophoblast tumours, gastrulation for the childhood cancers, meiosis for testicular cancer and ovarian germ cell tumours and VDJ rearrangement and somatic hypermutation for acute leukemia and lymphoma. These processes are all linked to natural periods of supra-physiological apoptotic potential and it appears that the malignant cells arising from them usually retain this heightened sensitivity to DNA damage. To investigate this hypothesis we have examined the natural history of the healthy cells during these processes and the chemotherapy sensitivity of malignancies arising before, during and after the events. To add to the debate on chemotherapy resistance and sensitivity, we would argue that malignancies can be functionally divided into 2 groups. Firstly those that arise in cells with naturally heightened apoptotic potential as a result of their proximity to the unique genetic events, where the malignancies are generally chemotherapy curable and then the more common malignancies that arise in cells of standard apoptotic potential that are not curable with classical cytotoxic drugs.

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.

Gene expression profiling in non-Hodgkin lymphomas

Although the current WHO classification (Swerdlow et al. WHO classification of tumours of haematopoietic and lymphoid tissues. International Agency for Research on Cancer, Lyon, 2008 [1]) for hematolymphoid neoplasms has delineated lymphomas based on the combined morphologic, immunophenotypic, and genotypic findings, further refinement is necessary especially in regard to therapeutics and prognostic implications. High-throughput gene expression profiling (GEP) using microarray technology (Schena et al. Science 270:467-470, 1995 [2]; Augenlicht et al. Proc Natl Acad Sci USA 88:3286-3289, 1991 [3]) was developed about 20 years ago, and further refinement of the technology and analytical approaches has enabled us to routinely evaluate practically the entire transcriptome at a time. GEP has helped to improve the classification and prognostication of non-Hodgkin lymphomas (NHL) as well as improved our understanding of their pathophysiology and response to new therapeutics. In this paper, we will briefly review how this revolutionary tool has transformed our understanding of lymphomas and given us insight into targeted therapeutics. We will also discuss the current efforts in adapting the findings to routine clinical practice, the evolution of the research technology and directions in the future.

Mantle cell lymphoma: evolving management strategies

Mantle cell lymphoma (MCL) is a rare and aggressive form of non-Hodgkin's lymphoma that generally affects older individuals and continues to have one of the worst outcomes of all the lymphomas. Over the last decade, there has been a widespread adoption of cytarabine-based therapy in younger patients, and the incorporation of rituximab into chemotherapeutic regimens has become an evidence-based standard of care. However MCL remains a largely incurable disease, and following relapse, it can be a challenge to manage. Although it is possible to define prognosis reliably, there are, as yet, no clear diagnostic or response-adjusted parameters that can help to guide therapeutic decisions. However, there are a number of highly active targeted therapies that are moving into the clinic that are set to transform the therapeutic paradigm for this disease in the very near future. This review will explore the molecular pathogenesis of MCL and the current and evolving therapeutic strategies for this disease.

Flow cytometric analysis of SOX11: a new diagnostic method for distinguishing B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma from mantle cell lymphoma

The differential diagnosis between mantle cell lymphoma (MCL) and B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma (B-CLL/SLL) is essential, since MCL usually has a more aggressive clinical course. By flow cytometry both MCL and B-CLL are CD19, CD20 and usually CD5 positive. However, ambiguities in other immune phenotypic markers of these lymphoma entities sometimes complicate the flow cytometric differential diagnosis. We here demonstrate that the transcription factor SOX11, which is highly up-regulated in most MCL, can be analyzed by flow cytometry. SOX11 protein could be consistently detected in ex vivo isolated MCL but not in B-CLL/SLL. Flow cytometry also enabled protein quantification, and SOX11 protein levels correlated with mRNA expression. We suggest that implementing detection of SOX11 in diagnostic flow cytometry would be beneficial for accurate and reliable diagnosis of MCL, especially for distinguishing cases of MCL and B-CLL/SLL with aberrant immune phenotypes, and for cases of rare cyclin D1 negative MCL.

SOX11 promotes tumor angiogenesis through transcriptional regulation of PDGFA in mantle cell lymphoma

SOX11 mediates regulation of angiogenesis via the PDGFA signaling pathway in MCL. SOX11-dependent increased angiogenesis contributes to a more aggressive MCL phenotype.

Perturbations of the endocannabinoid system in mantle cell lymphoma: correlations to clinical and pathological features

The cannabinoid receptors are upregulated in many types of cancers, including mantle cell lymphoma (MCL) and have been suggested to constitute novel therapeutic targets. The expression pattern of the key members of the endocannabinoid system was analyzed in a well-characterized MCL patient cohort and correlated to biological features. 107 tumor tissues were analyzed for the mRNA levels of cannabinoid receptors 1 and 2 (CNR1 and CNR2) and the two main enzymes regulating the endocannabinoid anandamide levels in tissue: NAPEPLD and FAAH (participating in synthesis and degradation, respectively). NAPEPLD, CNR1 and CNR2 were overexpressed while FAAH expression was reduced in MCL compared to non-malignant B-cells. Both low CNR1 and high FAAH levels correlated with lymphocytosis (p=0.016 and p=0.022, respectively) and with leukocytosis (p=0.0018 and p=0.047). Weak to moderate CNR1 levels were a feature of SOX11 negative MCL (p=0.006). Both high CNR2 and high FAAH levels correlated to anemia (p=0.0006 and p=0.038, respectively). In conclusion, the relative expression of the anandamide synthesizing and metabolizing enzymes in MCL is heavily perturbed. This finding, together with high expression of cannabinoid receptors, could favor enhanced anandamide signaling and suggest that targeting the endocannabinoid system might be considered as part of lymphoma therapy.

Real world data on primary treatment for mantle cell lymphoma: a Nordic Lymphoma Group observational study

Rituximab and autologous stem cell transplantation are both independently associated with improved overall survival in mantle cell lymphoma. Male gender is an independent negative prognostic factor in mantle cell lymphoma.

Update on the molecular pathogenesis and targeted approaches of mantle cell lymphoma: summary of the 12th annual conference of the European Mantle Cell Lymphoma Network

Mantle cell lymphoma (MCL) is a distinct subtype of malignant lymphoma which is characterized by the chromosomal translocation t(11;14)(q13;q32) resulting in constitutional overexpression of cyclin D1 and cell cycle dysregulation in almost all cases. Clinically, MCL shows an aggressive clinical course with a continuous relapse pattern and a median survival of only 3-5 years. However, recently a subset of 15% long-term survivors has been identified with a rather indolent clinical course. Targeted strategies include the proteasome inhibitors, immune modulatory drugs (IMiDs), mammalian target of rapamycin (mTOR) inhibitors and especially inhibitors of the B-cell receptor pathway. Our recent annual conference focused on the molecular pathogenesis of the disease and how these underlying molecular alterations may guide the selection and integration of innovative approaches for therapy. This review of the meeting covers in particular the identification of indolent cases, and deals with the role of the B-cell receptor pathway in MCL, as well as the detection of minimal residual disease and implementation of molecular approaches in current clinical trials.