CD30+ anaplastic large-cell lymphoma with aberrant expression of CD13: Case report and review of the literature

Exploring ligand dissociation pathways from aminopeptidase N using random acceleration molecular dynamics simulation

Aminopeptidase N (APN) is a zinc-dependent ectopeptidase involved in cell proliferation, secretion, invasion, and angiogenesis, and is widely recognized as an important cancer target. However, the mechanisms whereby ligands leave the active site of APN remain unknown. Investigating ligand dissociation processes is quite difficult, both in classical simulation methods and in experimental approaches. In this study, random acceleration molecular dynamics (RAMD) simulation was used to investigate the potential dissociation pathways of ligand from APN. The results revealed three pathways (channels A, B and C) for ligand release. Channel A, which matches the hypothetical channel region, was the most preferred region for bestatin to dissociate from the enzyme, and is probably the major channel for the inner bound ligand. In addition, two alternative channels (channels B and C) were shown to be possible pathways for ligand egression. Meanwhile, we identified key residues controlling the dynamic features of APN channels. Identification of the dissociation routes will provide further mechanistic insights into APN, which will benefit the development of more promising APN inhibitors. Graphical Abstract The release pathways of bestatin inside active site of aminopeptidase N were simulated using RAMD simulation.

European canine lymphoma network consensus recommendations for reporting flow cytometry in canine hematopoietic neoplasms

BACKGROUND

Flow cytometry (FC) is assuming increasing importance in diagnosis in veterinary oncology. The European Canine Lymphoma Network (ECLN) is an international cooperation of different institutions working on canine lymphoma diagnosis and therapy. The ECLN panel of experts on FC has defined the issue of reporting FC on canine lymphoma and leukemia as their first hot topic, since a standardized report that includes all the important information is still lacking in veterinary medicine.

METHODS

The flow cytometry panel of the ECLN started a consensus initiative using the Delphi approach. Clinicians were considered the main target of FC reports. A panel of experts in FC was interrogated about the important information needed from a report.

RESULTS

Using the feedback from clinicians and subsequent discussion, a list of information to be included in the report was made, with four different levels of recommendation. The final report should include both a quantitative part and a qualitative or descriptive part with interpretation of the salient results. Other items discussed included the necessity of reporting data regarding the quality of samples, use of absolute numbers of positive cells, cutoff values, the intensity of fluorescence, and possible aberrant patterns of antigen expression useful from a clinical point of view.

CONCLUSION

The consensus initiative is a first step toward standardization of diagnostic approach to canine hematopoietic neoplasms among different institutions and countries. This harmonization will improve communication and patient care and also facilitate the multicenter studies necessary to further our knowledge of canine hematopoietic neoplasms. © 2016 International Clinical Cytometry Society.

In vitro and in vivo activity of melflufen (J1)in lymphoma

BACKGROUND

Melphalan has been used in the treatment of various hematologic malignancies for almost 60 years. Today it is part of standard therapy for multiple myeloma and also as part of myeloablative regimens in association with autologous allogenic stem cell transplantation. Melflufen (melphalan flufenamide ethyl ester, previously called J1) is an optimized derivative of melphalan providing targeted delivery of active metabolites to cells expressing aminopeptidases. The activity of melflufen has compared favorably with that of melphalan in a series of in vitro and in vivo experiments performed preferentially on different solid tumor models and multiple myeloma. Melflufen is currently being evaluated in a clinical phase I/II trial in relapsed or relapsed and refractory multiple myeloma.

METHODS

Cytotoxicity of melflufen was assayed in lymphoma cell lines and in primary tumor cells with the Fluorometric Microculture Cytotoxicity Assay and cell cycle analyses was performed in two of the cell lines. Melflufen was also investigated in a xenograft model with subcutaneous lymphoma cells inoculated in mice.

RESULTS

Melflufen showed activity with cytotoxic IC50-values in the submicromolar range (0.011-0.92 μM) in the cell lines, corresponding to a mean of 49-fold superiority (p < 0.001) in potency vs. melphalan. In the primary cultures melflufen yielded slightly lower IC50-values (2.7 nM to 0.55 μM) and an increased ratio vs. melphalan (range 13-455, average 108, p < 0.001). Treated cell lines exhibited a clear accumulation in the G2/M-phase of the cell cycle. Melflufen also showed significant activity and no, or minimal side effects in the xenografted animals.

CONCLUSION

This study confirms previous reports of a targeting related potency superiority of melflufen compared to that of melphalan. Melflufen was active in cell lines and primary cultures of lymphoma cells, as well as in a xenograft model in mice and appears to be a candidate for further evaluation in the treatment of this group of malignant diseases.

Anaplastic large cell lymphoma: twenty-five years of discovery

CONTEXT

The year 2010 commemorates the 25th year since the seminal publication by Karl Lennert and Harald Stein and others in Kiel, West Germany, describing an unusual large cell lymphoma now known as anaplastic large cell lymphoma (ALCL). Investigators at many universities and hospitals worldwide have contributed to our current in-depth understanding of this unique peripheral T-cell lymphoma, which in its systemic form, principally occurs in children and young adults.

OBJECTIVE

To summarize our current knowledge of the clinical and pathologic features of systemic and primary cutaneous ALCL. Particular emphasis is given to the biology and pathogenesis of ALCL.

DATA SOURCES

Search of the medical literature (Ovid MEDLINE In-Process & Other Non-Indexed Citations and Ovid MEDLINE: 1950 to Present [National Library of Medicine]) and more than 20 years of diagnostic experience were used as the source of data for review.

CONCLUSIONS

Based on immunostaining for activation antigen CD30 and the presence of dysregulation of the anaplastic lymphoma kinase gene (2p23), the diagnosis of ALCL has become relatively straightforward for most patients. Major strides have been made during the last decade in our understanding of the complex pathogenesis of ALCL. Constitutive NPM-ALK signaling has been shown to drive oncogenesis via an intricate network of redundant and interacting pathways that regulate cell proliferation, cell fate, and cytoskeletal modeling. Nevertheless, pathomechanistic, therapeutic, and diagnostic challenges remain that should be resolved as we embark on the next generation of discovery.

A practical approach to the flow cytometric detection and diagnosis of T-cell lymphoproliferative disorders

The flow cytometric analysis of T-cell malignancies is difficult due to the heterogeneity of T-cells and the lack of convenient methods to detect T-cell clonality. Neoplastic T-cells are most often detected by their altered level of surface antigen expression, and detection requires an extensive knowledge of the phenotype of normal T-lymphocytes. This review focuses on the methods to distinguish malignant T-cells from their normal counterparts and the phenotypic features of the T-cell lymphoproliferative disorders.

CD13+ anaplastic large cell lymphoma with leukemic presentation and additional chromosomal abnormality

Anaplastic large cell lymphoma (ALCL) is a highly malignant neoplasm characterized by pleomorphic appearance, different immunophenotypes and variable sites of involvement. Expression of myeloid-associated markers in anaplastic large cell lymphomas may mislead the medical team and result in delay of diagnosis due to unusual phenotype. It is important to diagnose this type of tumors and distinguish it from myeloid neoplasms (extramedullary myeloid cell tumors and histiocytic tumors) since therapy and prognosis are significantly different.A 16-year-old female patient presented with fever, lymphadenopathy, and high white blood cell count. Diagnosing a CD13+ ALCL with leukemic presentation with additional cytogenetic abnormality (duplication 5q35) was a significant diagnostic challenge.This combination of features, unusual for lymphoma, should be considered in differential diagnosis of myeloid neoplasms and fatal infections.

Expression of ALK protein, mRNA and fusion transcripts in anaplastic large cell lymphoma

Systemic anaplastic large cell lymphoma (ALCL) can be divided into two subgroups, anaplastic lymphoma kinase (ALK)-positive and ALK-negative, based on the expression of ALK protein. Expression of this protein is due to genetic alterations of ALK at 2p23. Overall, observations on ALK protein, ALK mRNA, ALK-associated genetic alterations and their relationships, to one another are not often reported in the literature. In this study, we investigated the expression of ALK protein, mRNA and fusion transcripts involving ALK and their relationships in ALCL and analyzed formalin-fixed, paraffin-embedded tissues. Forty-five human cases were analyzed with immunohistochemistry for the ALK protein and RT-PCR for ALK mRNA and seven kinds of ALK involved fusion transcripts. Our results showed that the expression of ALK protein, ALK mRNA and ALK fusion transcripts were significantly related to one another (P<0.01). Consistent with the expression of ALK protein, patients presenting with ALK mRNA or ALK involved fusion transcripts were significantly younger than those lacking ALK gene alteration (P<0.01). This study demonstrates expression of both ALK protein and ALK mRNA are positively correlated with expression of ALK-associated fusion transcripts. Combined detection of ALK protein, ALK mRNA and ALK fusion transcripts can complement each other to aid in the diagnosis of ALCL.

Flow cytometric immunophenotyping for hematologic neoplasms

Flow cytometric immunophenotyping remains an indispensable tool for the diagnosis, classification, staging, and monitoring of hematologic neoplasms. The last 10 years have seen advances in flow cytometry instrumentation and availability of an expanded range of antibodies and fluorochromes that have improved our ability to identify different normal cell populations and recognize phenotypic aberrancies, even when present in a small proportion of the cells analyzed. Phenotypically abnormal populations have been documented in many hematologic neoplasms, including lymphoma, chronic lymphoid leukemias, plasma cell neoplasms, acute leukemia, paroxysmal nocturnal hemoglobinuria, mast cell disease, myelodysplastic syndromes, and myeloproliferative disorders. The past decade has also seen refinement of the criteria used to identify distinct disease entities with widespread adoption of the 2001 World Health Organization (WHO) classification. This classification endorses a multiparametric approach to diagnosis and outlines the morphologic, immunophenotypic, and genotypic features characteristic of each disease entity. When should flow cytometric immunophenotyping be applied? The recent Bethesda International Consensus Conference on flow cytometric immunophenotypic analysis of hematolymphoid neoplasms made recommendations on the medical indications for flow cytometric testing. This review discusses how flow cytometric testing is currently applied in these clinical situations and how the information obtained can be used to direct other testing.

Anaplastic large cell lymphoma: a flow cytometric analysis of 29 cases

We report our experience with flow cytometric (FC) analysis of 29 cases of anaplastic large cell lymphoma (ALCL). Morphologic analysis of processed cytocentrifuged preparations demonstrated neoplastic cells in 28 cases. In 25 of these, an aberrant lymphoid population was detected by FC analysis. The majority showed high orthogonal light scatter, similar to monocytes or granulocytes. Of the antigens CD2, CD3, CD4, CD5, and CD7, 5 cases expressed 1, 8 expressed 2, 6 expressed 3, 3 expressed 4, and 3 expressed all 5. CD4 was expressed most commonly (20/25 [80%]), followed by CD2 (18/25 [72%]), CD3 (10/25 [40%]), and CD5 and CD7 (8/25 [32%] each). CD45 was expressed in 23 of 25 cases and CD13 in 7 of 9. Of 21 cases, 13 were anaplastic lymphoma kinase (ALK)+, all of which were CD4+, vs 5 of 8 ALK - cases (P = .042). Most ALCLs can be detected and characterized by multiparameter FC analysis. However, light scatter gating on typical lymphoid regions may yield false-negative results in a substantial number of cases.

Pediatric CD56+ anaplastic large cell lymphoma: a review of the literature

CONTEXT

Anaplastic large cell lymphomas (ALCLs) are a heterogeneous group of CD30+ large cell lymphomas that, according to the World Health Organization classification, are defined as being of T-cell origin, based on immunophenotype, and/or the finding of a T-cell gene rearrangement by molecular studies. Most cases express cytotoxic granule-associated proteins. Relatively recent data have suggested that some T-cell ALCLs are derived from cytolytic CD4+ cells, gammadelta T cells, or natural killer-like (CD56+ or CD57+) T cells. We encountered a pediatric case of CD56+, anaplastic lymphoma kinase-positive ALCL of apparent natural killer-like T-cell origin (showing positivity for CD2, cytoplasmic CD3, surface CD3 partial positivity, CD7, CD8, CD56, TIA-1, and granzyme B). The patient had initial lymph node and multiple sites of cutaneous involvement and an aggressive clinical course with multiple recurrences after varying periods of complete remission.

OBJECTIVE

To review the current pediatric literature regarding the incidence, differential diagnosis, and clinical course of such cases.

DATA SOURCES

Relevant articles indexed in PubMed (National Library of Medicine) between 1975 and 2006.

CONCLUSIONS

Our review did not confirm a uniformly aggressive clinical course in pediatric cases of CD56+ ALCLs. Such cases suggest the usefulness of the analysis of CD56-positivity in additional cases of ALCL in an attempt to accrue additional information on this condition. Future accrual of such cases may address whether such cases should be treated more aggressively or with possible targeted therapeutic regimens.

Update on extranodal lymphomas. Conclusions of the Workshop held by the EAHP and the SH in Thessaloniki, Greece

Classification and proper treatment of extranodal lymphoma is hindered by the diversity of lymphoma types and the relative rarity of many of these tumour types. In order to review controversial issues in extranodal lymphoma diagnosis, a joint Workshop of the European Haematopathology Association (EAHP) and the Society for Hematopathology (SH) was held, where 99 selected cases were reviewed and discussed. This Workshop summary is focused on the most controversial aspect of cutaneous B-cell lymphoma, other extranodal B-cell lymphomas, plasmablastic lymphoma and anaplastic large-cell lymphoma in extranodal sites, and makes practical recommendations about diagnosis and therapeutic approaches.

Aminopeptidase-N/CD13 (EC 3.4.11.2) inhibitors: chemistry, biological evaluations, and therapeutic prospects

Aminopeptidase N (APN)/CD13 (EC 3.4.11.2) is a transmembrane protease present in a wide variety of human tissues and cell types (endothelial, epithelial, fibroblast, leukocyte). APN/CD13 expression is dysregulated in inflammatory diseases and in cancers (solid and hematologic tumors). APN/CD13 serves as a receptor for coronaviruses. Natural and synthetic inhibitors of APN activity have been characterized. These inhibitors have revealed that APN is able to modulate bioactive peptide responses (pain management, vasopressin release) and to influence immune functions and major biological events (cell proliferation, secretion, invasion, angiogenesis). Therefore, inhibition of APN/CD13 may lead to the development of anti-cancer and anti-inflammatory drugs. This review provides an update on the biological and pharmacological profiles of known natural and synthetic APN inhibitors. Current status on their potential use as therapeutic agents is discussed with regard to toxicity and specificity.