Proteins encoded by genes involved in chromosomal alterations in lymphoma and leukemia: clinical value of their detection by immunocytochemistry

miR-142: A Master Regulator in Hematological Malignancies and Therapeutic Opportunities

MicroRNAs (miRNAs) are a type of non-coding RNA whose dysregulation is frequently associated with the onset and progression of human cancers. miR-142, an ultra-conserved miRNA with both active -3p and -5p mature strands and wide-ranging physiological targets, has been the subject of countless studies over the years. Due to its preferential expression in hematopoietic cells, miR-142 has been found to be associated with numerous types of lymphomas and leukemias. This review elucidates the multifaceted role of miR-142 in human physiology, its influence on hematopoiesis and hematopoietic cells, and its intriguing involvement in exosome-mediated miR-142 transport. Moreover, we offer a comprehensive exploration of the genetic and molecular landscape of the miR-142 genomic locus, highlighting its mutations and dysregulation within hematological malignancies. Finally, we discuss potential avenues for harnessing the therapeutic potential of miR-142 in the context of hematological malignancies.

NPM1-Mutated Acute Myeloid Leukemia: Recent Developments and Open Questions

Somatic mutations in the nucleophosmin (NPM1) gene occur in approximately 30% of de novo acute myeloid leukemias (AMLs) and are relatively enriched in normal karyotype AMLs. Earlier World Health Organization (WHO) classification schema recognized NPM1-mutated AMLs as a unique subtype of AML, while the latest WHO and International Consensus Classification (ICC) now consider NPM1 mutations as AML-defining, albeit at different blast count thresholds. NPM1 mutational load correlates closely with disease status, particularly in the post-therapy setting, and therefore high sensitivity-based methods for detection of the mutant allele have proven useful for minimal/measurable residual disease (MRD) monitoring. MRD status has been conventionally measured by either multiparameter flow cytometry (MFC) and/or molecular diagnostic techniques, although recent data suggest that MFC data may be potentially more challenging to interpret in this AML subtype. Of note, MRD status does not predict patient outcome in all cases, and therefore a deeper understanding of the biological significance of MRD may be required. Recent studies have confirmed that NPM1-mutated cells rely on overexpression of HOX/MEIS1, which is dependent on the presence of the aberrant cytoplasmic localization of mutant NPM1 protein (NPM1c); this biology may explain the promising response to novel agents, including menin inhibitors and second-generation XPO1 inhibitors. In this review, these and other recent developments around NPM1-mutated AML, in addition to open questions warranting further investigation, will be discussed.

Co-Detection of EBV and Human Polyomavirus JCPyV in a Case of AIDS-Related Multifocal Primary Central Nervous System Diffuse Large B-Cell Lymphoma

The human neurotropic Polyomavirus JCPyV is the widespread opportunistic causative pathogen of the fatal demyelinating disease progressive multifocal leukoencephalopathy; however, it has also been implicated in the oncogenesis of several types of cancers. It causes brain tumors when intracerebrally inoculated into rodents, and genomic sequences of different strains and expression of the viral protein large T-Antigen have been detected in a wide variety of glial brain tumors and CNS lymphomas. Here, we present a case of an AIDS-related multifocal primary CNS lymphoma in which JCPyV genomic sequences of the three regions of JCPyV and expression of T-Antigen were detected by PCR and immunohistochemistry, respectively. No capsid proteins were detected, ruling out active JCPyV replication. Sequencing of the control region revealed that Mad-4 was the strain of JCPyV present in tumor cells. In addition, expression of viral proteins LMP and EBNA-1 from another ubiquitous oncogenic virus, Epstein-Barr, was also detected in the same lymphocytic neoplastic cells, co-localizing with JCPyV T-Antigen, suggesting a potential collaboration between these two viruses in the process of malignant transformation of B-lymphocytes, which are the site of latency and reactivation for both viruses.

High frequency of BCL2 gene rearrangement-negative follicular lymphoma in northwestern Italy

BCL2 rearrangement is reported to be an early pathogenetic event in follicular lymphoma (FL) and it is considered as a reliable marker in the follow up of the disease. We aimed to investigate the frequency of BCL2 rearrangement in FLs from northwestern Italy, to evaluate their clinicopathological features, and to investigate alternative genetic aberrations in BCL2-negative FLs. We collected a series of 76 consecutive FLs diagnosed between 2013 and 2016. All lymphomas underwent histopathological review. Interphasic fluorescent in situ hybridization (FISH) was performed with break apart probes targeting BCL2, IGH, BCL6 and MYC on paraffin embedded (PE) and fresh frozen (FF) specimens. 1p36 region and p53 locus in BLC2-negative cases were investigated using dual color probes. Karyotype analysis was available in a subset of cases. BCL2 rearrangements were detected in 39 cases (51,3%). Of the remaining 37, 6 showed IGH rearrangement, and were further tested: 1 showed variant BCL2 translocation, 1 had BCL6 rearrangement, and the other 4 were negative for further gene rearrangements. FISH on FF specimens detected small BCL2+ clones in cases otherwise categorized as BCL2-. 1p36 and p53 deletion were observed in 1 and 8 BCL2- FLs, respectively. Karyotype analysis documented 3q, 1p and BCL6 alternative abnormalities in 3 cases. In conclusion, BCL2 rearrangement is not a constant finding in FL, its frequency being probably affected by geographical factors. Thus, it should not be considered as a reliable molecular marker in the follow up of the disease, unless it is found to be present at the initial diagnosis of FL. Alternative genetic aberrations exist in BCL2-negative cases.

A comparison of the International Consensus and 5th World Health Organization classifications of mature B-cell lymphomas

Several editions of the World Health Organization (WHO) classifications of lympho-hemopoietic neoplasms in 2001, 2008 and 2017 served as the international standard for diagnosis. Since the 4th WHO edition, here referred as WHO-HAEM4, significant clinico-pathological, immunophenotypic and molecular advances have been made in the field of lymphomas, contributing to refining diagnostic criteria of several diseases, to upgrade entities previously defined as provisional and to identify new entities. This process has resulted in two recent classifying proposals of lymphoid neoplasms, the International Consensus Classification (ICC) and the 5th edition of the WHO classification (WHO-HAEM5). In this paper, we review and compare the two classifications in terms of diagnostic criteria and entity definition, with focus on mature B-cell neoplasms. The main aim is to provide a tool to facilitate the work of pathologists, hematologists and researchers involved in the diagnosis and treatment of lymphomas.

Confirmation of lung adenocarcinoma as the primary cancer with detection of EML4-ALK rearrangement using next-generation sequencing: a case study

We report a female patient, who presented as a carcinoma of unknown primary site with multiple tumors in breast, lung, stomach, and ovary, was confirmed to be lung adenocarcinoma as primary cancer through detecting EML4-ALK rearrangement by the next generation sequencing (NGS). The patient was treated with crizotinib and resulted in significant regression of the primary and metastatic tumors, but resistance to crizotinib was developed 5 months after the treatment. Targeted therapy was, therefore, switched to alectinib, one of the second-generation of anaplastic lymphoma kinase (ALK) inhibitors, with excellent therapeutic response till November 16th, 2021. This study suggested that NGS be recommended to detect ALK rearrangement in the patients with carcinoma of unknown primary site, and that resistance to targeted therapy with ALK inhibitors should be considered for personalized precision medicine.

Straight to the Point-The Novel Strategies to Cure Pediatric AML

Although the outcome has improved over the past decades, due to improved supportive care, a better understanding of risk factors, and intensified chemotherapy, pediatric acute myeloid leukemia remains a life-threatening disease, and overall survival (OS) remains near 70%. According to French-American-British (FAB) classification, AML is divided into eight subtypes (M0–M7), and each is characterized by a different pathogenesis and response to treatment. However, the curability of AML is due to the intensification of standard chemotherapy, more precise risk classification, improvements in supportive care, and the use of minimal residual disease to monitor response to therapy. The treatment of childhood AML continues to be based primarily on intensive, conventional chemotherapy. Therefore, it is essential to identify new, more precise molecules that are targeted to the specific abnormalities of each leukemia subtype. Here, we review abnormalities that are potential therapeutic targets for the treatment of AML in the pediatric population.

Total Flavonoids of Drynariae Rhizoma Improve Glucocorticoid-Induced Osteoporosis of Rats: UHPLC-MS-Based Qualitative Analysis, Network Pharmacology Strategy and Pharmacodynamic Validation

BACKGROUND

Glucocorticoid-induced osteoporosis (GIOP) is a common form of secondary osteoporosis caused by the protracted or a large dosage of glucocorticoids (GCs). Total flavonoids of Drynariae rhizoma (TFDR) have been widely used in treating postmenopausal osteoporosis (POP). However, their therapeutic effects and potential mechanism against GIOP have not been fully elucidated.

METHODS

Ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC-ESIQ-TOF-MS) experiments were performed for qualitative analysis. We performed hematoxylin-eosin (HE) staining and microcomputed tomography (micro-CT) analysis to detect the changes in bone microstructure. The changes in biochemical parameters in the serum samples were determined by performing an enzyme-linked immunosorbent assay (ELISA). The prediction results of network pharmacology were verified via quantitative real-time polymerase chain reaction (qRT-PCR) to elucidate the potential mechanism of TFDR against GIOP.

RESULTS

A total of 191 ingredients were identified in vitro and 48 ingredients in vivo. In the in-vivo experiment, the levels of the serum total cholesterol (TC), the serum triglyceride (TG), Leptin (LEP), osteocalcin (OC), osteoprotegerin (OPG), bone morphogenetic protein-2 (BMP-2), propeptide of type I procollagen (PINP), tartrate-resistant acid phosphatase (TRACP) and type-I collagen carboxy-terminal peptide (CTX-1) in the TFDR group significantly changed compared with those in the GIOP group. Moreover, the TFDR group showed an improvement in bone mineral density and bone microstructure. Based on the results of network pharmacology analysis, 67 core targets were selected to construct the network and perform PPI analysis as well as biological enrichment analysis. Five of the targets with high "degree value" had differential gene expression between groups using qRT-PCR.

CONCLUSION

TFDR, which may play a crucial role between adipose metabolism and bone metabolism, may be a novel remedy for the prevention and clinical treatment of GIOP.

Cytokines, Genetic Lesions and Signaling Pathways in Anaplastic Large Cell Lymphomas

ALCL is a tumor of activated T cells and possibly innate lymphoid cells with several subtypes according to clinical presentation and genetic lesions. On one hand, the expression of transcription factors and cytokine receptors triggers signaling pathways. On the other hand, ALCL tumor cells also produce many proteins including chemokines, cytokines and growth factors that affect patient symptoms. Examples are accumulation of granulocytes stimulated by IL-8, IL-17, IL-9 and IL-13; epidermal hyperplasia and psoriasis-like skin lesions due to IL-22; and fever and weight loss in response to IL-6 and IFN-γ. In this review, we focus on the biology of the main ALCL subtypes as the identification of signaling pathways and ALCL-derived cytokines offers opportunities for targeted therapies.

Promyelocytic Leukemia Antigen Expression: a Histological Marker for Primary Biliary Cholangitis Diagnosis?

Background and Objectives

Distinguishing primary biliary cholangitis (PBC) from other cholestatic diseases at the histological level could be assisted by new methods, such as immunohistochemical staining of specific antigens.

Methods

We evaluated whether the detection of promyelocytic leukemia protein (PML) can serve as a specific and sensitive marker for PBC diagnosis. Liver biopsies from 26 PBC patients, 20 primary sclerosing cholangitis (PSC), 37 viral hepatitis, 11 non-alcoholic steatohepatitis (NASH) and 5 normal patients were investigated after immunostaining with the anti-PML monoclonal PG-M3, IgG1 antibody.

Results

Immunoreactivity in bile ducts was expressed by the PML-score (quotient of positive ducts to the total number of portal tracts multiplied by 2). PML-score was higher in PBC as compared to controls (P < 0.001). Using a cutoff of 0.18, PML-score proved highly sensitive (84.6%) and specific (89.7%) for confirming PBC as compared to only 5% of PSC, 9.1% of NASH and 13.5% of viral hepatitis patients (P < 0.001). Irrespective of the underlying disease, patients with PML-score > 0.18 were older (P = 0.007), more often females (P < 0.001) with higher ALP (P < 0.001), γ-GT (P = 0.001) and IgM (P < 0.001) compared to the patients with PML-score < 0.18.

Conclusions

We postulate that a simple PML immunohistochemical test could be sufficient for histopathological discrimination of PBC in problematic cases of undefined cholestatic disorders, including small-duct PSC and AMA-negative PBC cases.

NPM1 Biology in Myeloid Neoplasia

PURPOSE OF REVIEW

Nucleophosmin (NPM1) mutations are encountered in myeloid neoplasia and are present in ~ 30% of de novo acute myeloid leukemia cases. This review summarizes features of mutant NPM1-related disease, with a particular emphasis on recent discoveries relevant to disease monitoring, prognostication, and therapeutic intervention.

RECENT FINDINGS

Recent studies have shown that HOX/MEIS gene overexpression is central to the survival of NPM1-mutated cells. Two distinct classes of small molecule drugs, BH3 mimetics and menin-MLL interaction inhibitors, have demonstrated exquisite leukemic cell toxicity in preclinical AML models associated with HOX/MEIS overexpression, and the former of these has shown efficacy in older treatment-naïve NPM1-mutated AML patients. The results of ongoing clinical trials further investigating these compounds will be of particular importance and may alter the clinical management of patients with NPM1-mutated myeloid neoplasms. Significant scientific advancements over the last decade, including improved sequencing and disease monitoring techniques, have fostered a much deeper understanding of mutant NPM1 disease biology, prognostication, and opportunities for therapeutic intervention. These discoveries have led to the development of clinical assays that permit the detection and monitoring of mutant NPM1 and have paved the way for future investigation of targeted therapeutics using emerging cutting-edge techniques.

Diffuse large B-cell lymphoma carrying t(9;14)(p13;q32)/PAX5-immunoglobulin heavy chain gene is characterized by nuclear positivity of MUM1 and PAX5 by immunohistochemistry

We described four patients with diffuse large B-cell lymphoma (DLBCL) carrying t(9;14)(p13;q32) that places the PAX5 adjacent to the immunoglobulin heavy chain (IGH) gene. Ages ranged between 63 and 80, and three were female. One developed a nodal disease, and the other three involved extranodal organs. The lymphoma cells were CD10^- /BCL6^- /MUM1⁺ in three and CD10⁺ /BCL6⁺ /MUM1⁺ in one. BCL2 was weak or negative. All had t(9;14)(p13;q32), and three had additional 14q32/IGH translocations or +der(14)t(9;14)(p13;q32). Fluorescence in situ hybridization using the PAX5 break-apart probe showed that the locus was disrupted between the 5' and 3' probes or within the 5' probe. Immunohistochemistry (IHC) using a monoclonal antibody against PAX5 showed strong nuclear positivity in all four patients. Cell block IHC of a CD30⁺ DLBCL cell line, KIS-1, which carried the t(9;14)(p13;q32) and PAX5-IGH fusion gene, reproduced the CD10^- /BCL6^- /MUM1⁺ immunophenotype, low-level BCL2, and strong nuclear PAX5. Uniform nuclear positivity of MUM1 in all four cases and KIS-1 cells suggest that these lymphomas arose at a late stage of B-cell differentiation, where expression of PAX5 physiologically becomes downregulated. It is therefore possible that high-level PAX5 resulting from t(9;14)(p13;q32) at this stage of differentiation perturbs the plasma cell differentiation program initiated by PAX5 repression, thereby contributing to the development of a fraction of DLBCL.

Nucleophosmin1 (NPM1) abnormality in hematologic malignancies, and therapeutic targeting of mutant NPM1 in acute myeloid leukemia

Nucleophosmin (NPM1) is an abundant nucleolar protein that is implicated in a variety of biological processes and in the pathogenesis of several human malignancies. For hematologic malignancies, approximately one-third of anaplastic large-cell non-Hodgkin’s lymphomas were found to express a fusion between NPM1 and the catalytic domain of anaplastic lymphoma receptor tyrosine kinase. About 50–60% of acute myeloid leukemia patients with normal karyotype carry NPM1 mutations, which are characterized by cytoplasmic dislocation of the NPM1 protein. Nevertheless, NPM1 is overexpressed in various hematologic and solid tumor malignancies. NPM1 overexpression is considered a prognostic marker of recurrence and progression of cancer. Thus, NPM1 abnormalities play a critical role in several types of hematologic malignancies. This has led to intense interest in the development of an NPM1 targeting strategy for cancer therapy. The aim of this review is to summarize present knowledge on NPM1 origin, pathogenesis, and therapeutic interventions in hematologic malignancies.

Unraveling Tumor Heterogeneity in an Apparently Monolithic Disease: BCL2 and Other Players in the Genetic Landscape of Nodal Follicular Lymphoma

Follicular lymphoma (FL) is the most common form of non-Hodgkin lymphoma in Western countries. Although traditionally considered a well-defined, easy to diagnose lymphoproliferative disorder, in the last few years it has become clear that it is in fact composed of many different clinicopathological entities, encompassing a variegated and complex genetic background. This has led to the inclusion of specific FL variants and separate entities in the latest update of the WHO classification. However, even in the context of classical FL, many aspects of intra- and inter-tumoral heterogeneity have been recognized, with a major influence on diagnosis and clinical practice at different time points during the course of the disease. This review focuses on the molecular cytogenetic heterogeneity in classical FL from precursors and early development to progression and transformation, in terms of both clonal heterogeneity and unusual genetic features. Several factors have been investigated and suggested to contribute to the broad spectrum of clinicopathological, phenotypic, and genetic features observed in otherwise morphologically classical cases. Among them, deregulation of the epigenetic machinery and interactions with tumor microenvironment seem to play a pivotal role, together with genetic aberrations involving well-known molecular pathways and mechanisms physiologically operating in the germinal center. In the era of personalized medicine, precision diagnostics based both on understanding of the complex interplay among all these factors and on novel developments will become crucial to predict the outcome and guide the treatment of FL patients.

RNA Analysis as a Tool to Determine Clinically Relevant Gene Fusions and Splice Variants

CONTEXT

- Technologic advances have contributed to the increasing relevance of RNA analysis in clinical oncology practice. The different genetic aberrations that can be screened with RNA include gene fusions and splice variants. Validated methods of identifying these alterations include fluorescence in situ hybridization, immunohistochemistry, reverse transcription-polymerase chain reaction, and next-generation sequencing, which can provide physicians valuable information on disease and treatment of cancer patients.

OBJECTIVE

- To discuss the standard techniques available and new approaches for the identification of gene fusions and splice variants in cancer, focusing on RNA analysis and how analytic methods have evolved in both tissue and liquid biopsies.

DATA SOURCES

- This is a narrative review based on PubMed searches and the authors' own experiences.

CONCLUSIONS

- Reliable RNA-based testing in tissue and liquid biopsies can inform the diagnostic process and guide physicians toward the best treatment options. Next-generation sequencing methodologies permit simultaneous assessment of molecular alterations and increase the number of treatment options available for cancer patients.

Current Status of Proteomics in Ewing's Sarcoma

Ewing's sarcoma is an extremely rare mesenchymal malignancy of the bone, which predominantly occurs in children and young adolescents. Ewing's sarcoma is characterized by chromosomal translocations resulting in the formation of chimeric fusions between the EWS gene and transcription factors of the ETS family, such as EWS-FLI-1. The clinical outcome of Ewing's sarcoma remains poor, and novel therapeutic approaches are required. Proteomic analyses have been applied to identify the functions of the fusion gene product, and a novel mechanism of EWS-FLI-1 turnover has been proposed. Furthermore, proteomics has revealed the regulation of IL-6 secretion by EWS-FLI-1, which may promote malignant behavior in tumor cells. In addition, proteomic approaches have been used to assess the effects of unique genes and drugs on Ewing's sarcoma and to determine specific biomarker candidates for the prediction of drug resistance and recurrence. By identifying the proteins relevant to the molecular backgrounds of clinical characters of Ewing's sarcoma, we can understand the biology of Ewing's sarcoma and develop clinical applications. Fundamental research systems such as tumor cell and tissue biobanks and databases are required to make effective use of the limited clinical materials and promote research into Ewing's sarcoma.

Clinicopathological Analysis of 320 Cases of Diffuse Large B-cell Lymphoma Using the Hans Classifier

The estimation of clinical prognosis for diffuse large B-cell lymphoma (DLBCL) with a quick, cost-efficient method is necessary because of the clinical heterogeneity of this disease, which leads to death, relapsed or refractory disease in approximately 40% of patients. We analyzed 320 cases diagnosed from 2007 to 2013 treated with R-CHOP therapy at Tokai University Hospital and associated institutions. DLBCL was classified according to the cell-of-origin using the Hans algorithm [germinal center B-cell-like (GCB) vs non-GCB subtypes], and into 6 subgroups derived from combinations of CD10, BCL6 and MUM1 markers. The percentage of GCB and non-GCB (NGCB) subtypes was 35% and 65%, respectively. GCB-DLBCL was characterized by lower BCL2 immunohistochemical expression, extranodal sites ＜1, better therapeutic response, and favorable overall survival (OS) and progression free survival (PFS) (P＜0.01). The most frequent subgroup was NGCB-1 (CD10^-BCL6⁺MUM1⁺, 51%) followed by GCB-1 (CD10⁺BCL6^+or-MUM1⁺, 21%), NGCB-2 (CD10^-BCL6^-MUM1⁺, 13%), GCB-2 (CD10⁺BCL6^+or-MUM1^-, 10%), GCB-3 (CD10^-BCL6⁺MUM1^-, 4%) and NGCB-3 (CD10^-BCL6^-MUM1^-, 2%). In comparison with GCB-2 and GCB-3 (both MUM1^-), the GCB-1 (MUM1⁺) was characterized by favorable PFS (5-year PFS 84% vs 65%, OR 0.368, P＜0.05), independent of high LDH (associated with unfavorable PFS, OR 7.04, P＜0.01) in the multivariate analysis. This predictive value of MUM1 was independent of CD10. Interestingly, triple-negative NGCB-3 tended to have a more favorable prognosis than the other NGCB subgroups. In conclusion, the Hans classifier is a valid method to evaluate the prognosis of DLBCL NOS. In the GCB subtypes, GCB subtypes, MUM1-positivity is associated with a more favorable outcome (PFS).

Prognostic Significance of in situ Phenotypic Marker Expression in Diffuse Large B-cell Lymphomas

Diffuse large B-cell lymphomas (DLBCL) are the most common lymphoid malignancies, and encompass all malignant lymphomas characterized by large neoplastic cells and B-cell derivation. In the last decade, DLBCL has been subjected to intense clinical, phenotypic and molecular studies, and were found to represent a heterogeneous group of tumors. These studies suggested new disease subtypes and variants with distinct clinical characteristics, morphologies, immunophenotypes, genotypes or gene expression profiles, associated with distinct prognoses or unique sensitivities to particular therapy regimens. Unfortunately, the reliability and reproducibility of the molecular results remains unclear due to contradictory reports in the literature resulting from small sample sizes, referral and selection biases, and variable methodologies and cut-off levels used to determine positivity. Here, we review phenotypic studies on the prognostic significance of protein expression profiles in DLBCL and reconsider our own retrospective data on 301 primary DLBCL cases obtained on a previously validated tissue microarray in light of powerful statistical methods of determining optimal cut-off values of phenotypic factors for prediction of outcome.

Immunohistochemical profile and prognostic significance in primary central nervous system lymphoma: Analysis of 89 cases

The majority of primary central nervous system lymphomas (PCNSLs) are diffuse large B cell lymphoma, characterized by poor prognosis. In the present study, the expression of cluster of differentiation (CD)10, B cell lymphoma (BCL)-6, multiple myeloma-1 (MUM-1), BCL-2, CD138 and Ki-67 was analyzed by immunohistochemistry in 89 Chinese PCNSL cases, and the potential prognostic significance was evaluated. CD10, BCL-6, MUM-1, BCL-2 and CD138 were positive in 16.9 (15/89), 51.7 (46/89), 92.1 (82/89), 73.3 (63/86) and 0% (0/65) of all cases, respectively. According to the Hans algorithm, 71 patients (79.8%) were classified into the non-germinal center B cell-like (non-GCB) group, indicating a post-germinal center origin of PCNSL. The median follow-up time of 73 patients was 13 months [95% confidence interval (CI), 10.93-15.08]. The median overall survival (OS) time was 45.3 months (95% CI, 25.01-65.59) and the median progression-free survival (PFS) time was 30.0 months (95% CI, 13.43-46.57). Age (>60 years) was associated with a shorter OS time (P=0.009). Ki-67 (cutoff point 90%) was associated with shorter OS (P=0.037) and shorter PFS (P=0.039) times. No other immunohistochemical markers were associated with prognosis. On multivariate analysis, age (>60 years) was associated with shorter OS time (P=0.038), but immunophenotype and expression status of Ki-67, CD10, BCL-6 and BCL-2 did not predict prognosis. In conclusion, high Ki-67 expression may predict poor prognosis in PCNSL. The present study was limited by its sample size and short follow-up time. This requires more evidence to further clinical study.

Molecular Analysis of Genetic Markers for Non-Hodgkin Lymphomas

Molecular analysis complements the clinical and histopathologic tools used to diagnose and subclassify hematologic malignancies. The presence of clonal antigen-receptor gene rearrangements can help to confirm the diagnosis of a B or T cell lymphoma and can serve as a fingerprint of that neoplasm to be used in identifying concurrent disease at disparate sites or recurrence at future time points. Certain lymphoid malignancies harbor a characteristic chromosomal translocation, a finding that may have significant implications for an individual's prognosis or response to therapy. The polymerase chain reaction (PCR) is typically used to detect antigen-receptor gene rearrangements as well as specific translocations that can be supplemented by fluorescence in situ hybridization (FISH) and karyotype analysis. © 2017 by John Wiley & Sons, Inc.

TRIg: a robust alignment pipeline for non-regular T-cell receptor and immunoglobulin sequences

BACKGROUND

T cells and B cells are essential in the adaptive immunity via expressing T cell receptors and immunoglogulins respectively for recognizing antigens. To recognize a wide variety of antigens, a highly diverse repertoire of receptors is generated via complex recombination of the receptor genes. Reasonably, frequencies of the recombination events have been shown to predict immune diseases and provide insights into the development of immunity. The field is further boosted by high-throughput sequencing and several computational tools have been released to analyze the recombined sequences. However, all current tools assume regular recombination of the receptor genes, which is not always valid in data prepared using a RACE approach. Compared to the traditional multiplex PCR approach, RACE is free of primer bias, therefore can provide accurate estimation of recombination frequencies. To handle the non-regular recombination events, a new computational program is needed.

RESULTS

We propose TRIg to handle non-regular T cell receptor and immunoglobulin sequences. Unlike all current programs, TRIg does alignments to the whole receptor gene instead of only to the coding regions. This brings new computational challenges, e.g., ambiguous alignments due to multiple hits to repetitive regions. To reduce ambiguity, TRIg applies a heuristic strategy and incorporates gene annotation to identify authentic alignments. On our own and public RACE datasets, TRIg correctly identified non-regularly recombined sequences, which could not be achieved by current programs. TRIg also works well for regularly recombined sequences.

CONCLUSIONS

TRIg takes into account non-regular recombination of T cell receptor and immunoglobulin genes, therefore is suitable for analyzing RACE data. Such analysis will provide accurate estimation of recombination events, which will benefit various immune studies directly. In addition, TRIg is suitable for studying aberrant recombination in immune diseases. TRIg is freely available at https://github.com/TLlab/trig .

Genetic Immunization: A New Monoclonal Antibody for the Detection of BCL-6 Protein in Paraffin Sections

Genetic immunization can be combined with hybridoma technology to generate high-affinity monoclonal antibodies (MAbs). A new anti-BCL-6 MAb (GI191E/A8) was produced by cloning full-length BCL-6 cDNA into a eukaryotic vector and delivering this into mouse epidermis using a helium gene gun. A comparative study was made of the specificity and the effects of formalin fixation on immunohistochemistry quality of GI191E/A8 and two other anti-BCL-6 MAbs. To evaluate its possible application to differential diagnosis of lymphomas, two tissue microarrays (89 diffuse large B-cell lymphomas and 24 B-cell chronic lymphocytic leukemia cases) were stained with GI191E/A8 and another anti-BCL-6 MAb produced by conventional means. Using GI191E/A8, the detection of BCL-6 protein was significantly increased, and its specificity was independent of formalin-fixation time. Using automatic quantified analysis, the correlation between the two anti-BCL-6 MAbs tested was identical in cases with overexpression or absence of BCL-6. In cases with intermediate BCL-6 protein expression, detection with GI191E/A8 was more sensitive. A significant association of higher BCL-6 expression and longer median overall survival times in diffuse large B-cell lymphomas was found. Using conventionally produced MAbs in the same patient group, the association was not significant.

Toward Personalized Lymphoma Immunotherapy: Identification of Common Driver Mutations Recognized by Patient CD8+ T Cells

PURPOSE

A fundamental challenge in the era of next-generation sequencing (NGS) is to design effective treatments tailored to the mutational profiles of tumors. Many newly discovered cancer mutations are difficult to target pharmacologically; however, T-cell-based therapies may provide a valuable alternative owing to the exquisite sensitivity and specificity of antigen recognition. To explore this concept, we assessed the immunogenicity of a panel of genes that are common sites of driver mutations in follicular lymphoma, an immunologically sensitive yet currently incurable disease.

EXPERIMENTAL DESIGN

Exon capture and NGS were used to interrogate tumor samples from 53 patients with follicular lymphoma for mutations in 10 frequently mutated genes. For 13 patients, predicted mutant peptides and proteins were evaluated for recognition by autologous peripheral blood T cells after in vitro priming.

RESULTS

Mutations were identified in 1-5 genes in 81% (43/53) of tumor samples. Autologous, mutation-specific CD8(+) T cells were identified in 23% (3/13) of evaluated cases. T-cell responses were directed toward putative driver mutations in CREBBP and MEF2B. Responding T cells showed exquisite specificity for mutant versus wild-type proteins and recognized lymphoma cells expressing the appropriate mutations. Responding T cells appeared to be from the naïve repertoire, as they were found at low frequencies and only at single time points in each patient.

CONCLUSIONS

Patients with follicular lymphoma harbor rare yet functionally competent CD8(+) T cells specific for recurrent mutations. Our results support the concept of using NGS to design individualized immunotherapies targeting common driver mutations in follicular lymphoma and other malignancies. Clin Cancer Res; 22(9); 2226-36. ©2015 AACR.

Recurrent FGFR3-TACC3 fusion gene in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is one of the most common head and neck malignancies and exhibits regional differences in incidence. Because many fusion genes have been discovered in different types of tumors over the past few years, we aimed to investigate the existence of a fusion gene in primary NPC patients using RNA-seq. In this study, for the first time, we found that fibroblast growth factor receptor 3-transforming acidic coiled-coil-containing protein 3 (FGFR3-TACC3) fusion transcripts are recurrently detected in NPC. The presence of this fusion gene was also detected in head and neck cancer, esophageal squamous cell carcinoma (ESCC), and lung cancer. Furthermore, we found certain new isoforms of the FGFR3-TACC3 fusion transcripts, such as a gene fusion between exon 18 of FGFR3 and exon 6 or exon 14 of TACC3 and agene fusion between exon 19 of FGFR3 and exon 11 of TACC3. In addition, we showed that the FGFR3-TACC3 fusion gene promotes cell proliferation, colony formation, and transforming ability in vitro, whereas the FGFR3-TACC3 K508M mutant or treatment with the FGFR inhibitor PD173074 abrogates these effects, suggesting that FGFR3-TACC3 most likely exerts its effects through activation of FGFR kinase activity. This activation likely leads to the development of NPC. Additionally, FGFR3-TACC3 could trigger activation of the ERK and Akt signaling pathways, whereas FGFR3-TACC3 K508M mutant could not, suggesting that these 2 signaling pathways might be involved in the function of FGFR3-TACC3. Taken together, our data demonstrated the oncogenic role of FGFR3-TACC3 in vitro, indicating that FGFR3-TACC3 may be useful as a diagnostic marker and therapeutic target in cancers.

BCL6 expression correlates with the t(1;19) translocation in B-lymphoblastic leukemia

OBJECTIVES

Study to date suggests that BCL6 protein expression in B-cell neoplasia predominates in germinal center-derived tumors, but less is known regarding its expression in B-lymphoblastic leukemia. Therefore, we designed a comprehensive study of BCL6 expression in B-lymphoblastic leukemia.

METHODS

BCL6, LMO, and HGAL protein expression in B-lymphoblastic leukemia was investigated using immunohistochemical staining of paraffin-embedded bone marrow specimens. Cryptic TCF3(E2A)-PBX1 rearrangements were investigated using interphase fluorescence in situ hybridization.

RESULTS

Six (12%) of 52 B-lymphoblastic leukemias demonstrated BCL6 protein expression, with B-cell lymphoblastic leukemias containing a t(1;19) translocation demonstrating the strongest staining (three of three). Additional t(1;19) cases beyond the screening study showed similar results. Public microarray expression database mining showed that BCL6 messenger RNA expression levels in B-lymphoblastic leukemia correlated with the protein expression findings. Finally, other markers of B-cell development correlated with BCL6 expression in t(1;19) B-lymphoblastic leukemia cases, with LMO2 and HGAL proteins expressed in six (67%) of nine and eight (89%) of nine cases, respectively.

CONCLUSIONS

BCL6 expression is present in a subset of B-lymphoblastic leukemias, especially in cases containing the 1;19 translocation. Investigation for TCF3(E2A)-PBX1 rearrangements may be useful in BCL6-positive B-lymphoblastic leukemia.

Multiple genetic alterations in primary cutaneous large B-cell lymphoma, leg type support a common lymphomagenesis with activated B-cell-like diffuse large B-cell lymphoma

Primary cutaneous large B-cell lymphoma, leg type has been individualized from nodal diffuse large B-cell lymphoma. The objective of this study was to screen primary cutaneous large B-cell lymphoma, leg type for genetic alterations recently described in nodal diffuse large B-cell lymphoma. Skin biopsies from 23 patients were analyzed for IRF4, BCL2, BCL6, and MYC expression. FISH testing was performed for BCL2, BCL6, MYC with separation probes and for CDKN2A and PRDM1/BLIMP1 deletion. Multiple sequential FISH analyses with up to six probes were performed to define samples with multiple cytogenetic alterations. MYD88 mutations were studied by Sanger sequencing. All cases but one displayed at least one genetic alteration (96%). Nine patients exhibited a single genetic mutation and 12 combined several alterations (52%). We observed a split for BCL2, BCL6, or MYC in 1/23, 6/23, and 3/23 of cases, respectively. No double-hit lymphoma was observed. CDKN2A deletion was detected by FISH in only 5/23 cases. BLIMP1 and/or 6q deletion was observed at a higher rate in 10/20 of cases. No correlation between rearrangement and immunohistochemical expression was found for BCL2 or MYC. FISH tracking of sequential hybridizations showed that several alterations were carried by the same nuclei. The p.L265P MYD88 mutation was found in 11/18 (61%) of cases. Contrary to most cutaneous lymphomas that rarely harbor primary genetic alteration of their nodal histological equivalent, primary cutaneous large B-cell lymphoma, leg type seems to be a 'cutaneous counterpart' of activated B-cell-like diffuse large B-cell lymphoma with a similar cytogenetic profile and a high rate of MYD88 oncogenic L265P mutation. This also suggests a common lymphomagenesis with NF-κB activation, strong IRF4 expression and terminal B-cell differentiation blockage. Our data support the use of therapies targeting NF-κB, as most patients displayed disease progression and resistance to conventional therapies.

Hope and fear for interferon: the receptor-centric outlook on the future of interferon therapy

After several decades of intense clinical research, the great promise of Type I interferons (IFN1) as the anticancer wonder drugs that could cure or, at the very least, curb the progression of various oncological diseases has regrettably failed to deliver. Severe side effects and low efficacy of IFN1-based pharmaceutics greatly limited use of these drugs and further reduced the enthusiasm of clinical oncologists for future optimization of IFN1-based therapeutic modalities. Incredibly, extensive clinical studies to assess the efficacy of IFN1 alone or in combination with other anticancer drugs have not been paralleled by an equal scope in defining the determinants that confer cell sensitivity or refractoriness to IFN1. Given that all effects of IFN1 on malignant and benign cells alike are mediated by its receptor, the mechanisms regulating these receptor cell surface levels should play a paramount role in shaping the magnitude and duration of IFN1-elicited effects. These mechanisms and their role in controlling IFN1 responses, as well as an ability of a growing tumor to commandeer these events, are the focus of our review. We postulate that activation of numerous signaling pathways leading to elimination of IFN1 receptor occurs in cancer cells and benign cells that contribute to tumor tissue. We further hypothesize that activation of these eliminative pathways enables the escape from IFN1-driven suppression of tumorigenesis and elicits the primary refractoriness of tumor to the pharmaceutical IFN1.

Tissue microarray in a subset of South African patients with DLBCL

Tissue samples from 93 de novo diffuse large B-cell lymphoma patients seen between 1995 and 2009 randomly receiving either standard combination chemotherapy (CHOP, n=48) or the identical program with rituximab (n=45) were subtyped using an investigational immunohistochemical (IHC) based tissue microarray (TMA) and contrasted to the approximately corresponding categories as defined either by Hans and associates using a three marker panel into germinal or non-germinal centre subtypes or by Choi and colleagues with two additional antibodies into germinal centre (GCB) or activated B-cells (ABC). Each of these primary subdivisions was further evaluated for expression of BCL2 and LMO2 both of which are recognised to predicate response. The addition of rituximab to the uniform drug regimen did not show any significant improvement in 5 years overall (63% versus 59%, p 0.68) or event-free survival (42% versus 39%, p 0.94), for CHOP versus R-CHOP comparisons. Similarly no differences were evident in subtype analysis. Interestingly however, when segregated on the Choi criteria, cytotoxic drugs alone showed a non-significant trend in improved survival (74% versus 55%, p 0.32) as well as event-free survival (44% versus 40%, p 0.42) for the germinal centre as opposed to the activated B-cell subtype. Nevertheless not even a small difference could be demonstrated in the presence of the anti CD 20 monoclonal antibody. According to Choi, both regimens (chemotherapy or immunotherapy antibody) revealed similar results to the Hans algorithm on 5 years OS as well as 3 year EFS when comparing GCB versus ABC or non-GCB subgroups. BCL2 and LMO2 marker expression of the respective immunohistochemical (IHC) subtype, despite small sample size, revealed the following. Analysis by Choi criteria on survival for BCL2, no matter for which subsets (GCB or ABC) or treatment modality (chemotherapy with or without the addition of rituximab) showed no difference in 5 years OS or EFS. In contrast, a significant difference for better EFS (p=0.0015) in the BCL2 positive group of the ABC subgroups subtypes treated with rituximab containing chemotherapy. For LMO2 similar results on survival outcome were seen thus showing no difference in 5 years OS or EFS - regardless of subtype or treatment modality. Also here, this was contrasted by better EFS (p=0.039) in the LMO2 positive group of ABC subtypes when treated with the rituximab containing regimen. The use of the IHC based TMA methodology has shown to be a simple, cost effective and a robust alternative to gene expression profiling (GEP) which is currently regarded as the gold standard for the classification in lymphomas. It provides a useful prognostic tool in stratifying DLBCL or other entities in future, even when frozen tissue samples are not available for GEP analysis. With the current budgetary limitations in South African public hospitals chemotherapy protocols for lymphoproliferative disorders exclude agents such as rituximab. Local therapeutic drug committees consider the approximately 15% overall survival benefit seen at 5 years for DLBCL when rituximab is added to combination chemotherapy as too marginal for justifying the arising additional expenses. Accordingly, demonstration that a specific molecular subtype accounts for superior outcome, when using these regimens, is needed. Such an option would provide convincing evidence for the use of immunochemotherapy in a resource constrained setting.

Novel real-time polymerase chain reaction assay for simultaneous detection of recurrent fusion genes in acute myeloid leukemia

The recent World Health Organization classification recognizes different subtypes of acute myeloid leukemia (AML) according to the presence of several recurrent genetic abnormalities. Detection of these abnormalities and other molecular changes is of increasing interest because it contributes to a refined diagnosis and prognostic assessment in AML and enables monitoring of minimal residual disease. These genetic abnormalities can be detected using single RT-PCR, although the screening is still labor intensive and costly. We have developed a novel real-time RT-PCR assay to simultaneously detect 15 AML-associated rearrangements that is a simple and easily applicable method for use in clinical diagnostic laboratories. This method showed 100% specificity and sensitivity (95% confidence interval, 91% to 100% and 92% to 100%, respectively). The procedure was validated in a series of 105 patients with AML. The method confirmed all translocations detected using standard cytogenetics and fluorescence in situ hybridization and some additional undetected rearrangements. Two patients demonstrated two molecular rearrangements simultaneously, with BCR-ABL1 implicated in both, in addition to RUNX1-MECOM in one patient and PML-RARA in another. In conclusion, this novel real-time RT-PCR assay for simultaneous detection of multiple AML-associated fusion genes is a versatile and sensitive method for reliable screening of recurrent rearrangements in AML.

Anaplastic lymphoma kinase as a therapeutic target

INTRODUCTION

Anaplastic lymphoma kinase (ALK), a tyrosine kinase receptor, has been initially identified through its involvement in chromosomal translocations associated with anaplastic large cell lymphoma. However, recent evidence that aberrant ALK activity is also involved in an expanding number of tumor types, such as other lymphomas, inflammatory myofibroblastic tumor, neuroblastomas and some carcinomas, including non-small cell lung carcinomas, is boosting research progress in ALK-targeted therapies.

AREAS COVERED

The first aim of this review is to describe current understandings about the ALK tyrosine kinase and its implication in the oncogenesis of human cancers as a fusion protein or through mutations. The second goal is to discuss its interest as a therapeutic target and to provide a review of the literature regarding ALK inhibitors. Mechanisms of acquired resistance are also reviewed.

EXPERT OPINION

Several ALK inhibitors have recently been developed, offering new treatment options in tumors driven by abnormal ALK signaling. However, as observed with other tyrosine kinase inhibitors, resistance has emerged in patients treated with these agents. The complexity of mechanisms of acquired resistance recently described suggests that other therapeutic options, including combination of ALK and other kinases targeted drugs, will be required in the future.

MicroRNA-142 is mutated in about 20% of diffuse large B-cell lymphoma

MicroRNAs (miRNAs) are short 18–23 nucleotide long noncoding RNAs that posttranscriptionally regulate gene expression by binding to mRNA. Our previous miRNA profiling of diffuse large B-cell lymphoma (DLBCL) revealed a mutation in the seed sequence of miR-142-3p. Further analysis now showed that miR-142 was mutated in 11 (19.64%) of the 56 DLBCL cases. Of these, one case had a mutation in both alleles, with the remainder being heterozygous. Four mutations were found in the mature miR-142-5p, four in the mature miR-142-3p, and three mutations affected the miR-142 precursor. Two mutations in the seed sequence redirected miR-142-3p to the mRNA of the transcriptional repressor ZEB2 and one of them also targeted the ZEB1 mRNA. However, the other mutations in the mature miR-142-3p did not influence either the ZEB1 or ZEB2 3′ untranslated region (3′ UTR). On the other hand, the mutations affecting the seed sequence of miR-142-3p resulted in a loss of responsiveness in the 3′ UTR of the known miR-142-3p targets RAC1 and ADCY9. In contrast to the mouse p300 gene, the human p300 gene was not found to be a target for miR-142-5p. In one case with a mutation of the precursor, we observed aberrant processing of the miR-142-5p. Our data suggest that the mutations in miR-142 probably lead to a loss rather than a gain of function. This is the first report describing mutations of a miRNA gene in a large percentage of a distinct lymphoma subtype.

Lineage switching in acute leukemias: a consequence of stem cell plasticity?

Acute leukemias are the most common cancer in childhood and characterized by the uncontrolled production of hematopoietic precursor cells of the lymphoid or myeloid series within the bone marrow. Even when a relatively high efficiency of therapeutic agents has increased the overall survival rates in the last years, factors such as cell lineage switching and the rise of mixed lineages at relapses often change the prognosis of the illness. During lineage switching, conversions from lymphoblastic leukemia to myeloid leukemia, or vice versa, are recorded. The central mechanisms involved in these phenomena remain undefined, but recent studies suggest that lineage commitment of plastic hematopoietic progenitors may be multidirectional and reversible upon specific signals provided by both intrinsic and environmental cues. In this paper, we focus on the current knowledge about cell heterogeneity and the lineage switch resulting from leukemic cells plasticity. A number of hypothetical mechanisms that may inspire changes in cell fate decisions are highlighted. Understanding the plasticity of leukemia initiating cells might be fundamental to unravel the pathogenesis of lineage switch in acute leukemias and will illuminate the importance of a flexible hematopoietic development.

Immunophenotype classification and therapeutic outcomes of Chinese primary gastrointestinal diffuse large B-cell lymphoma

Background

Recent studies showed that diffuse large B-cell lymphoma (DLBCL) could be classified into germinal centre B cell-like (GCB) and non-germinal centre B cell-like (non-GCB) phenotypes according to CD10,Bcl-6 and MUM1 expression. But primary gastrointestinal DLBCL has rarely been studied. This study was aimed to investigate the relationship between immunophenotypic classification, therapeutic outcomes and the prognosis of patients with primary gastrointestinal DLBCL.

Methods

Between 1998 and 2010, there were 151 patients studied at Shanghai Renji Hospital with a histopathological diagnosis of primary gastrointestinal DLBCL. Immunohistochemistry was performed using EnVision methods for CD10, BCL-6 and MUM1. The clinicopathologic features and follow-up data were analyzed by the Kaplan-Meier method, log-rank test and χ2 test.

Results

According to the expression of CD10, BCL-6 and MUM1, 31.8 % (48/151) of the cases belonged to the GCB subtype and 68.2 % (103/151) belonged to the non-GCB subtype. There was a significant difference of local lymph node metastasis between the GCB and non-GCB groups (P < 0.05). Patients in the GCB group had a better survival rate than those in the non-GCB group (5-year survival rate, 65.2 % vs 36.4 %, P < 0.05). In the GCB group, there was no significant difference in survival rates in patients receiving R-CHOP and CHOP therapy (P > 0.05). In the non-GCB group, the survival rate in patients treated with R-CHOP therapy was significantly longer than those treated with CHOP therapy (5-year survival rate, 62.8 % vs 30.8 %, P < 0.05).

Conclusions

The immunophenotype classification of gastrointestinal DLBCL, which is closely related to local lymph node metastasis, is found to have prognostic significance. Immunophenotype classification is also useful in selecting the chemotherapy protocol.

Comprehensive gene expression profiling and immunohistochemical studies support application of immunophenotypic algorithm for molecular subtype classification in diffuse large B-cell lymphoma: a report from the International DLBCL Rituximab-CHOP Consortium Program Study

Gene expression profiling (GEP) has stratified diffuse large B-cell lymphoma (DLBCL) into molecular subgroups that correspond to different stages of lymphocyte development-namely germinal center B-cell like and activated B-cell like. This classification has prognostic significance, but GEP is expensive and not readily applicable into daily practice, which has lead to immunohistochemical algorithms proposed as a surrogate for GEP analysis. We assembled tissue microarrays from 475 de novo DLBCL patients who were treated with rituximab-CHOP chemotherapy. All cases were successfully profiled by GEP on formalin-fixed, paraffin-embedded tissue samples. Sections were stained with antibodies reactive with CD10, GCET1, FOXP1, MUM1 and BCL6 and cases were classified following a rationale of sequential steps of differentiation of B cells. Cutoffs for each marker were obtained using receiver-operating characteristic curves, obviating the need for any arbitrary method. An algorithm based on the expression of CD10, FOXP1 and BCL6 was developed that had a simpler structure than other recently proposed algorithms and 92.6% concordance with GEP. In multivariate analysis, both the International Prognostic Index and our proposed algorithm were significant independent predictors of progression-free and overall survival. In conclusion, this algorithm effectively predicts prognosis of DLBCL patients matching GEP subgroups in the era of rituximab therapy.

Anaplastic large-cell lymphoma

The concept of anaplastic large-cell lymphoma (ALCL) has changed over the years because of a stream of new information and novel understanding regarding the cell of origin, biology, genetics, and clinical features of these neoplasms. This new information has led to the current classification proposed by the expert reviewers of the World Health Organization. The objective of this review is to present the most updated information on the cytologic and histologic features of these entities, with a special reference to diagnostic algorithms. A detailed description of the genetic aberrations and the pathogenetic mechanisms leading to transformation is presented. The clinical features of ALCL and novel tailored strategies are briefly illustrated.

Molecular cytogenetics of lymphoma: where do we stand in 2010?

For the past 20 years most malignant lymphomas have been classified as clinicopathological entities, each with its own combination of clinical, morphological, immunophenotypic and molecular genetic characteristics. Molecular and cytogenetic abnormalities can be detected by a wide range of techniques, ranging from conventional karyotyping to single nucleotide polymorphism analysis. In this review, we consider the common genetic abnormalities found in lymphoma and discuss the advantages and disadvantages of individual techniques used in their detection. Finally, we discuss briefly possible novel developments in the field of lymphoma diagnostics.

Pathobiology of anaplastic large cell lymphoma

The authors revise the concept of anaplastic large cell lymphoma (ALCL) in the light of the recently updated WHO classification of Tumors of Hematopoietic and Lymphoid Tissues both on biological and clinical grounds. The main histological findings are illustrated with special reference to the cytological spectrum that is indeed characteristic of the tumor. The phenotype is reported in detail: the expression of the ALK protein as well as the chromosomal abnormalities is discussed with their potential pathogenetic implications. The clinical features of ALCL are presented by underlining the difference in terms of response to therapy and survival between the ALK-positive and ALK-negative forms. Finally, the biological rationale for potential innovative targeted therapies is presented.

Monoclonal antibodies against nucleophosmin mutants: potentials for the detection of acute myeloid leukemia

Nucleophosmin (NPM1) gene mutations resulting in cytoplasmic delocalization of Nucleophosmin (NPMc+) are the most common genetic alteration in acute myeloid leukemia (AML). Here, we attempted to prepare monoclonal antibodies (mAbs) against NPM1 mutation A (NPM-mA) and investigated the mAbs' clinical utility in immunohistochemical detection of NPMc+AML. The pET-32a-NPM-mA vector with the whole open reading frame of the NPM-mA gene was constructed. E.coli BL21 transformed with the vector were induced to express the NPM-mA recombinant protein. BALB/c mice were immunized with the recombinant NPM-mA. Positive clones were selected by indirect ELISA and the mAbs were obtained. Immunohistochemistry was performed to detect the NPMc+ in bone marrow smears from 10 AML patients with NPM-mA. The results showed that the pET-32a-NPM-mA vector was successfully constructed and the NPM-mA recombinant protein was used to immunize the mice. Two positive clones (2G3 and 3F9) were selected. The mAbs against NPM-mA were raised, but did cross-react with wild type NPM1. The mAbs can be used to detect the cytoplasmic dislocation of NPM1 in all AMLs carrying NPM-mA. Our results show that anti-NPM-mA mAbs were produced. Though they would cross-react with wild type NPM1, the mAbs may still have potential in the detection of NPMc+AMLs.

Immunohistochemical surrogates for genetic alterations of CCDN1, PML, ALK, and NPM1 genes in lymphomas and acute myeloid leukemia

The World Health Organization (WHO) classification of lympho-hemopoietic neoplasms is increasingly based on genetic criteria. Detection of tumor-associated primary genetic lesions is usually performed using the polymerase chain reaction (PCR) and/or fluorescence in-situ hybridization (FISH). This review focuses on alternative techniques for detecting genetic lesions in biopsy samples. Immunohistochemical surrogates for the detection of genetic alterations involving the CCND1, PML, anaplastic lymphoma kinase (ALK) and nucleophosmin (NPM1) genes are presented as examples for this approach. Because of their high specificity, rapidity, low costs and ease of performance, these assays have the potential for being extensively applied in developing countries. In some instances (e.g. detection of ALK protein) immunohistochemistry has fully replaced molecular studies for routine diagnosis in paraffin-embedded specimens. Genome wide based discovery of new tumor-associated genetic lesions that are suitable for antibody targeting promises to further expand the application of immunohistochemistry for the molecular classification of hematological neoplasms.

Acute myeloid leukemia with mutated nucleophosmin (NPM1): is it a distinct entity?

After the discovery of NPM1-mutated acute myeloid leukemia (AML) in 2005 and its subsequent inclusion as a provisional entity in the 2008 World Health Organization classification of myeloid neoplasms, several controversial issues remained to be clarified. It was unclear whether the NPM1 mutation was a primary genetic lesion and whether additional chromosomal aberrations and multilineage dysplasia had any impact on the biologic and prognostic features of NPM1-mutated AML. Moreover, it was uncertain how to classify AML patients who were double-mutated for NPM1 and CEBPA. Recent studies have shown that: (1) the NPM1 mutant perturbs hemopoiesis in experimental models; (2) leukemic stem cells from NPM1-mutated AML patients carry the mutation; and (3) the NPM1 mutation is usually mutually exclusive of biallelic CEPBA mutations. Moreover, the biologic and clinical features of NPM1-mutated AML do not seem to be significantly influenced by concomitant chromosomal aberrations or multilineage dysplasia. Altogether, these pieces of evidence point to NPM1-mutated AML as a founder genetic event that defines a distinct leukemia entity accounting for approximately one-third of all AML.

Two novel NPM1 mutations in a therapy-responder AML patient

Nucleophosmin 1 (NPM1) is an abundant phosphoprotein mainly located in the nucleolus but also shuttling between the nucleus and cytoplasm. NPM1 has been proposed to be involved in synthesis and processing of ribosomal RNA, regulation of chromatin structure and transport of rRNA and ribosomal proteins. NPM1 gene is considered to be implicated in human cancer as it is a frequent target of genetic alterations, primarily in haematopoietic neoplasms. We describe a case of a therapy-responder acute myeloid leukaemia (AML) patient bearing two novel NPM1 mutations. Cells' transfection studies indicate that the presence of one of these mutations is associated to an abnormal nucleolar structure, suggesting that NPM1 may contribute to the control of nucleolar integrity.

ROS receptor tyrosine kinase: a new potential target for anticancer drugs

ROS kinase is one of the last two remaining orphan receptor tyrosine kinases with an as yet unidentified ligand. The normal functions of human ROS kinase in different body tissues have not been fully identified so far. However, the ectopic expression, as well as the production of variable mutant forms of ROS kinase has been reported in a number of cancers, such as glioblastoma multiforme, and non-small cell lung cancer, suggesting a role for ROS kinase in deriving such tumors. It is thought also that c-ROS gene may have a role in some cardiovascular diseases, and the fact that homozygous male mice targeted against c-ROS gene are healthy but infertile, has inspired researchers to think about ROS inhibition as a method for development of new male contraceptives. The recent discovery of new selective and potent inhibitors for ROS kinase, along with the development of new specific diagnostic methods for the detection of ROS fusion proteins, raises the importance of using these selective inhibitors for targeting ROS mutations as a new method for treatment of cancers harboring such genes. This review focuses on the ectopic expression of ROS and its fusion proteins in different cancer types and highlights the importance of targeting these proteins for treatment of substantial cancers. It describes also the recent advances in the field of ROS kinase inhibition, and the potential clinical applications of ROS kinase inhibitors.

Molecular analysis of genetic markers for non-Hodgkin lymphomas

Molecular analysis complements the clinical and histopathologic tools used to diagnose and subclassify hematologic malignancies. The presence of clonal antigen-receptor gene rearrangements can help to confirm the diagnosis of a B or T cell lymphoma and can serve as a fingerprint of that neoplasm to be used in identifying concurrent disease at disparate sites or recurrence at future time points. Certain lymphoid malignancies harbor a characteristic chromosomal translocation, a finding that may have significant implications for an individual's prognosis or response to therapy. The polymerase chain reaction (PCR) is typically used to detect antigen-receptor gene rearrangements as well as specific translocations that can be supplemented by fluorescence in situ hybridization (FISH) and karyotype analysis.

The challenge of risk stratification in acute myeloid leukemia with normal karyotype

Cytogenetic aberrations have long been recognized as the most important prognostic variable in acute myeloid leukemia (AML) and are now a major stratification tool for post-remission therapy. Cytogenetics-based stratification improves survival. Patients with AML and normal cytogenetics, the largest single subgroup, have had a very heterogeneous outcome with standard chemotherapy in multiple clinical trials. Hence it is difficult to recommend a "one size fits all" kind of treatment for this heterogeneous population of AML patients. New emerging data from preclinical, retrospective, and large, randomized controlled studies indicate that in addition to cytogenetic abnormalities, many other molecular aberrations are operative in the response to treatment as well as in the risk of relapse. Such molecular markers are being tested for developing targeted therapies and may help in improved stratification of patients in the selection of post-remission therapy. Emerging evidence reveals that at the submicroscopic level, AML with normal cytogenetics may carry poor prognostic genetic lesions or "molecular signatures" as is the case with FLT3 mutations and overexpression of BAALC, ERG or MN1, or may have aberrations that predict better risk as is the case with isolated NPM1 or CEBPA mutations. Later studies have tried to explore the interaction of various prognostically important genes in this group of AML patients. The utility of the evolving data for bedside management of such patients is expected to improve with the wider application of modern tools, using the proposed clinical outcome models, and probably by development of a risk-scoring system based on the relative risk associated with each molecular aberration. The goals include identifying those patients most likely to benefit from upfront allogeneic HSCT and sparing good-prognosis patients from unnecessary transplant-related morbidity. The following is an outline of the most common molecular changes, their impact on the outcome of AML patients with normal cytogenetics and challenges in their wide scale application in risk stratification.

Acute myeloid leukemia with mutated nucleophosmin (NPM1): molecular, pathological, and clinical features

The NPM1 gene encodes for nucleophosmin, a nucleolus-located shuttling protein that is involved in multiple cell functions, including regulation of ribosome biogenesis, control of centrosome duplication and preservation of ARF tumor suppressor integrity. The NPM1 gene is specifically mutated in about 30% acute myeloid leukemia (AML) but not in other human neoplasms. Mutations cause crucial changes at the C-terminus of the NPM1 protein that are responsible for the aberrant nuclear export and accumulation of NPM1 mutants in the cytoplasm of leukemic cells. Diagnosis of AML with mutated NPM1 can be done using molecular techniques, immunohistochemistry (looking at cytoplasmic dislocation of nucleophosmin that is predictive of NPM1 mutations) and Western blotting with antibodies specifically directed against NPM1 mutants. Because of its distinctive molecular, pathological, immunophenotypic and prognostic features, AML with mutated NPM1 (synonym: NPMc+ AML) has been included, as a new provisional entity, in the 2008 World Health Organization (WHO) classification of myeloid neoplasms.