MiR-22, a serum predictor of poor outcome and therapy response in diffuse large B-cell lymphoma patients.

Diffuse large B-cell lymphoma (DLBCL) is an aggressive, heterogeneous neoplasm where prognostication and therapeutic decision are challenging. The available prognostic tools are not able to identify all patients refractory to treatment. MicroRNAs, small RNAs frequently deregulated in cancer, stably circulate in biofluids, representing interesting candidates for non-invasive biomarkers. Here we validated serum miR-22, an evolutionarily conserved microRNA, as a prognostic/predictive biomarker in DLBCL. Moreover, we found that its expression and release from DLBCL cells are related to therapy response and adversely affect cell proliferation. These results suggest that miR-22 is a promising complementary or even independent non-invasive biomarker for DLBCL management.

Preclinical evaluation of the BET bromodomain inhibitor BAY 1238097 for the treatment of lymphoma.

The epigenome is often deregulated in cancer and treatment with inhibitors of bromodomain and extra-terminal proteins, the readers of epigenetic acetylation marks, represents a novel therapeutic approach. Here, we have characterized the anti-tumour activity of the novel bromodomain and extra-terminal (BET) inhibitor BAY 1238097 in preclinical lymphoma models. BAY 1238097 showed anti-proliferative activity in a large panel of lymphoma-derived cell lines, with a median 50% inhibitory concentration between 70 and 208 nmol/l. The compound showed strong anti-tumour efficacy in vivo as a single agent in two diffuse large B cell lymphoma models. Gene expression profiling showed BAY 1238097 targeted the NFKB/TLR/JAK/STAT signalling pathways, MYC and E2F1-regulated genes, cell cycle regulation and chromatin structure. The gene expression profiling signatures also highly overlapped with the signatures obtained with other BET Bromodomain inhibitors and partially overlapped with HDAC-inhibitors, mTOR inhibitors and demethylating agents. Notably, BAY 1238097 presented in vitro synergism with EZH2, mTOR and BTK inhibitors. In conclusion, the BET inhibitor BAY 1238097 presented promising anti-lymphoma preclinical activity in vitro and in vivo, mediated by the interference with biological processes driving the lymphoma cells. Our data also indicate the use of combination schemes targeting EZH2, mTOR and BTK alongside BET bromodomains.

Therapeutic efficacy of the bromodomain inhibitor OTX015/MK-8628 in ALK-positive anaplastic large cell lymphoma: an alternative modality to overcome resistant phenotypes.

Anaplastic large cell lymphomas (ALCL) represent a peripheral T-cell lymphoma subgroup, stratified based on the presence or absence of anaplastic lymphoma kinase (ALK) chimeras. Although ALK-positive ALCLs have a more favorable outcome than ALK-negative ALCL, refractory and/or relapsed forms are common and novel treatments are needed. Here we investigated the therapeutic potential of a novel bromodomain inhibitor, OTX015/MK-8628 in ALK-positive ALCLs.The effects of OTX015 on a panel of ALK+ ALCL cell lines was evaluated in terms of proliferation, cell cycle and downstream signaling, including gene expression profiling analyses. Synergy was tested with combination targeted therapies.Bromodomain inhibition with OTX015 led primarily to ALCL cell cycle arrest in a dose-dependent manner, along with downregulation of MYC and its downstream regulated genes. MYC overexpression did not compensate this OTX015-mediated phenotype. Transcriptomic analysis of OTX015-treated ALCL cells identified a gene signature common to various hematologic malignancies treated with bromodomain inhibitors, notably large cell lymphoma. OTX015-modulated genes included transcription factors (E2F2, NFKBIZ, FOS, JUNB, ID1, HOXA5 and HOXC6), members of multiple signaling pathways (ITK, PRKCH, and MKNK2), and histones (clusters 1-3). Combination of OTX015 with the Bruton's tyrosine kinase (BTK) inhibitor ibrutinib led to cell cycle arrest then cell death, and combination with suboptimal doses of the ALK inhibitor CEP28122 caused cell cycle arrest. When OTX015 was associated with GANT61, a selective GLI1/2 inhibitor, C1156Y-resistant ALK ALCL growth was impaired.These findings support OTX015 clinical trials in refractory ALCL in combination with inhibitors of interleukin-2-inducible kinase or SHH/GLI1.

The spectrum of MALT lymphoma at different sites: biological and therapeutic relevance.

Extranodal marginal zone (MZ) B-cell lymphomas of the mucosa-associated lymphoid tissue (MALT) arise from lymphoid populations that are induced by chronic inflammation in extranodal sites. The best evidence of an etiopathogenetic link is provided by the association between Helicobacter pylori-positive gastritis and gastric MALT lymphoma. Indeed, successful eradication of this microorganism with antibiotics can be followed by gastric MALT lymphoma regression in most cases. Other microbial agents have been implicated in the pathogenesis of MZ lymphoma arising at different sites. Apart from gastric MALT lymphoma, antibiotic therapies have been adequately tested only in ocular adnexal MALT lymphomas where upfront doxycycline may be a reasonable and effective initial treatment of patients with Chlamydophila psittaci-positive lymphoma before considering more aggressive strategies. In all other instances, antibiotic treatment of nongastric lymphomas remains investigational. Indeed, there is no clear consensus for the treatment of patients with gastric MALT lymphoma requiring further treatment beyond H pylori eradication or with extensive disease. Both radiotherapy and systemic treatments with chemotherapy and anti-CD20 antibodies are efficacious and thus the experience of individual centers and each patient's preferences in terms of adverse effects are important parameters in the decision process.

Gela histological scoring system for post-treatment biopsies of patients with gastric MALT lymphoma is feasible and reliable in routine practice.

The International Extranodal Lymphoma Study Group (IELSG) promoted this study to determine the inter-observer agreement in the application of the Groupe d' Etude des Lymphomes de l' Adulte (GELA) histological scoring system for evaluating residual disease in post-treatment gastric biopsies of patients with gastric Mucosa-Associated Lymphoid Tissue (MALT) lymphoma (GML). Twenty-one patients with Helicobacter pylori -associated GML and treated with anti-H. pylori therapies were considered. A total of 154 biopsy sets from follow-up endoscopic procedures after H. pylori eradication were examined independently by seven pathologists from four European countries, following histological criteria suggested by the GELA scoring system. The overall concordance rate was 83% with a kappa value of 0·64, indicating a significant agreement among the seven observers. Most non-concordant responses clustered across the border of complete remission (CR) and probable minimal residual disease (pMRD), a distinction that does not imply critical clinical impact. Accordingly, when the analysis considered CR/pMRD as a single entity, the responses showed an overall concordance rate of 89% with kappa value of 0·83, thus indicating a high degree of inter-observer agreement. This study provides additional validation of the GELA histological grading system. This scheme can therefore be recommended in routine practice and deserves to be used in prospective clinical trials.

Nodal marginal zone B-cell lymphoma: a diagnostic and therapeutic dilemma.

In the last lymphoma classifications, three types of marginal zone lymphoma (MZL) were delineated: extranodal mucosa-associated lymphatic tissue (MALT) lymphoma, splenic MZL, and nodal MZL (NMZL). While MALT lymphoma is already well characterized and has been extensively studied, the pathogenesis of the other two types, especially that of NMZL, remains incompletely understood. The tumor is rather uncommon, although it shares morphologic and immunophenotypic similarities with the other MZLs. Few series have been published, and the description is quite heterogeneous, reflecting the lack of consensus criteria for its diagnosis; the ability to develop such criteria is impeded by the absence of specific immunological or molecular abnormalities. The disease develops from peripheral (mostly cervical) and abdominal lymph nodes, with or without bone marrow and blood involvement. How to differentiate NMZL from lymphoplasmacytic lymphoma remains a key point of debate. NMZL also represents a therapeutic dilemma, given the absence of published large or prospective series. The 5-year overall survival as well as the failure-free survival of patients appear to be lower than those of patients with extranodal MZL.The aim of this review is twofold: to summarize descriptions of the clinical presentation provided in published series in order to help clinicians recognize and treat patients, and to discuss diagnostic difficulties faced by hematopathologists when dealing with these lesions and others in the differential diagnosis that must be distinguished from one another.

MALT lymphomas: pathogenesis can drive treatment.

Marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) lymphoma is an indolent B-cell non-Hodgkin lymphoma arising from the lymphoid tissue at extranodal sites. It is genetically characterized by different, usually mutually exclusive, genetic abnormalities that lead to activation of the nuclear factor kappa B (NF-kappaB) pathway. These lymphomas can arise in any extranodal organ or tissue; however, the stomach--where MALT lymphoma development has been strongly linked to chronic Helicobacter pylori infection--is the most common site. Other microorganisms have been associated with non-gastric MALT lymphomas, but the evidence for such associations is weaker. Treatment aimed at eradicating H pylori infection results in remission of gastric MALT lymphoma in most patients and represents a model of anticancer treatment based on the eradication of the causative factor. Treatment of non-gastric MALT lymphomas is much less well established; either radiotherapy or systemic therapy (with chemotherapy and/or rituximab [Rituxan]) can be effective, while antibiotic therapies (e.g., doxycycline in ocular adnexal lymphomas) should still be considered investigational.

Cyclin-dependent kinase inhibitor seliciclib shows in vitro activity in diffuse large B-cell lymphomas.

Despite recent improvements in treatment, a significant fraction of patients with diffuse large B-cell lymphoma (DLBCL) still fail therapy. Therefore, new therapeutic modalities are needed to advance the cure rate. Seliciclib (CYC202, R-roscovitine) is a purine analog developed as an inhibitor of CDK2/cyclin E CDK7/cyclin H and CDK9/cyclin T. Seliciclib has been shown to be active in B-cell neoplasms, such as mantle cell lymphoma, chronic lymphocytic leukemia and in multiple myeloma in vitro. The aim of this study was to assess the in vitro activity of seliciclib in DLBCL. The anti-proliferative activity of seliciclib was tested in nine human DLBCL cell lines and six DLBCL primary cell cultures. The effects of seliciclib on the cell cycle and on apoptosis, as well as on transcription-related proteins were assessed. The cell viability of all DLBCL cell lines and primary cells was reduced by seliciclib treatment. The IC50 for the cell lines ranged from 13 - 36 microm. The effect of seliciclib was independent of the genetic aberrations characterizing the cell lines. After seliciclib exposure cells accumulated in G2/M or in G1 phase, with most of the cells showing signs of apoptosis. Despite the clear cytotoxic effect and induction of apoptosis, this study could not identify a unique mechanism of action. The in vitro data suggest that seliciclib is an active agent in DLBCL. Its efficacy is apparently independent of the underlying chromosomal translocations characteristic of DLBCL. The drug might represent a new therapeutic agent in this lymphoma sub-type.

State-of-the-art therapeutics: marginal-zone lymphoma.

Marginal-zone lymphomas comprise the mucosa-associated lymphoid tissue (MALT) type (extranodal marginal-zone lymphoma [EMZL]), the nodal marginal zone B-cell lymphoma (NMZL) and the splenic MZL (SMZL). EMZL is relatively common, whereas the remaining two entities are relatively rare disorders. EMZL, especially in its gastric localization, is the most studied MZL, and there are many data both on the underlying genetic lesions and on the role of infectious agents. These data have determined unique approach among all other lymphoma subtypes: the possibility of treating a subset of patients with antibiotics alone as first line of treatment. Indeed, there is compelling evidence that histologic regressions can be achieved in most gastric MALT lymphomas by eradicating Helicobacter pylori infection. However, molecular follow-up studies showed the persistence of the malignant clone in half of the cases in histologic remission after antibiotic treatment and transient, either histologic or molecular, relapses have been reported, too. Hence, a careful long-term follow-up is mandatory after antibiotic treatment. Radiotherapy, chemotherapy, anti-CD20 monoclonal antibodies are effective alternative therapies. The precise role of surgical resection should be redefined in view of the encouraging results of conservative approaches. Differently from EMZL, both SMLZ and NMZL often present with disseminated disease at diagnosis. The therapeutic approach comprises splenectomy, for SMZL, and chemotherapy, but with no consensus about the best treatment. This review addresses the current knowledge on the clinical features and therapeutic approaches for the individual MZLs.