The IRTA1 molecule is selectively expressed in nodal and extranodal marginal zone lymphomas

La diagnosi di linfoma non Hodgkin B della zona marginale si basa su criteri morfologici e sulla sostanziale negatività per marcatori immunoistochimici espressi in altri sottotipi di linfoma B. L’ obiettivo di questo lavoro è stato, quindi, quello di ricercare una molecola specifica associata ai linfomi della zona marginale. Materiali e Metodi. Sono stati esaminati 2.104 linfomi periferici di entità nosologia eterogenea mediante un anticorpo monoclonale, diretto contro la molecola IRTA1, che riconosce la zona marginale nei tessuti linfoidi umani. Risultati. Si è riscontrata espressione di IRTA1 nel 93% dei linfomi della zona marginale ad insorgenza extranodale e nel 74% di quelli primitivi linfonodali suggerendo la possibilità che questi linfomi possano originare dalle cellule perifollicolari o monocitoidi IRTA1+ riscontrabili nei linfonodi reattivi. La valutazione immunoistochimica mediante doppia colorazione (IRTA1/bcl6), ha inoltre dimostrato come vi sia una modulazione fenotipica nelle cellule marginali neoplastiche nel momento in cui esse colonizzano i follicoli linfoidi e durante la loro circolazione nei centri germinativi. Le cellule marginali neoplastiche che differenziano in senso plasmacellulare perdono l’ espressione di IRTA1 Discussione. In conclusione, tali evidenze hanno permesso di ampliare la conoscenza sulla biologia dei linfomi marginali e sottolineano come IRTA1 sia il primo marcatore diagnostico positivo per queste neoplasie.Diagnosis of marginal zone lymphomas (MZLs) is based on morphological criteria and negativity for markers characteristically detectable in other B-cell lymphomas. Searching for a molecule specifically associated to MZLs, we immunostained 2,104 peripheral lymphomas of various types with a monoclonal antibody against IRTA1 that recognizes the equivalents of marginal zone in human lymphoid tissues other than spleen. IRTA1 expression was mostly restricted to extranodal (93%) and nodal MZLs (73%) and to lymphomas with marginal zone differentiation. Extranodal MZL cells with the strongest IRTA1 expression were usually located adjacent to epithelia, mimicking the IRTA1 expression pattern of normal and acquired mucosa-associated lymphoid tissue (MALT). The cytological features, growth pattern and IRTA1 positivity we observed in nodal MZLs suggest they may derive from the IRTA1+ perifollicular B-cells or monocytoid B-cells detectable in reactive lymph nodes. Double immunostaining for IRTA1/BCL6 allowed to track colonization of B-cell follicles by MZL cells and to document modulation of their phenotype (e.g. acquisition of BCL6) during recirculation through germinal centers. MZL cells differentiating to plasma cells usually lost IRTA1. These results further expand our knowledge on the biology of MZLs and highlight IRTA1 as the first positive marker for MZLs, enabling more accurate diagnosis of these neoplasms

Progression in Ph-Chromosome-Negative Myeloproliferative Neoplasms: An Overview on Pathologic Issues and Molecular Determinants

Progression in Ph-chromosome-negative myeloproliferative neoplasms (MPN) develops with variable incidence and time sequence in essential thrombocythemia, polycythemia vera, and primary myelofibrosis. These diseases show different clinic-pathologic features and outcomes despite sharing deregulated JAK/STAT signaling due to mutations in either the Janus kinase 2 or myeloproliferative leukemia or CALReticulin genes, which are the primary drivers of the diseases, as well as defined diagnostic criteria and biomarkers in most cases. Progression is defined by the development or worsening of marrow fibrosis or the progressive increase in the marrow blast percentage. Progression is often related to additional genetic aberrations, although some can already be detected during the chronic phase. Detailed scoring systems for clinical usage that are mostly applied in patients with primary myelofibrosis have been defined, and the most recent ones include cytogenetic and molecular parameters with prognostic significance. Additional different clinic-pathologic changes have been reported that may occur during the course of the disease and that are, at present, classified as WHO-defined types of progression, although they likely represent such an event. The present review is meant to provide an updated overview on progression in Ph-chromosome-negative MPN, with a major focus on the pathologic side

The evolution of clonality testing in the diagnosis and monitoring of hematological malignancies

none14noCurrently, distinguishing between benign and malignant lymphoid proliferations is based on a combination of clinical characteristics, cyto/histomorphology, immunophenotype and the identification of well-defined chromosomal aberrations. However, such diagnoses remain challenging in 10-15% of cases of lymphoproliferative disorders, and clonality assessments are often required to confirm diagnostic suspicions. In recent years, the development of new techniques for clonality detection has allowed researchers to better characterize, classify and monitor hematological neoplasms. In the past, clonality was primarily studied by performing Southern blotting analyses to characterize rearrangements in segments of the IG and TCR genes. Currently, the most commonly used method in the clinical molecular diagnostic laboratory is polymerase chain reaction (PCR), which is an extremely sensitive technique for detecting nucleic acids. This technique is rapid, accurate, specific, and sensitive, and it can be used to analyze small biopsies as well as formalin-fixed paraffin-embedded samples. These advantages make PCR-based approaches the current gold standard for IG/TCR clonality testing. Since the completion of the first human genome sequence, there has been a rapid development of technologies to facilitate high-throughput sequencing of DNA. These techniques have been applied to the deep characterization and classification of various diseases, patient stratification, and the monitoring of minimal residual disease. Furthermore, these novel approaches have the potential to significantly improve the sensitivity and cost of clonality assays and post-treatment monitoring of B- and T-cell malignancies. However, more studies will be required to demonstrate the utility, sensitivity, and benefits of these methods in order to warrant their adoption into clinical practice. In this review, recent developments in clonality testing are examined with an emphasis on highly sensitive systems for improving diagnostic workups and minimal residual disease assessments.noneA. Gazzola; C. Mannu; M. Rossi; M. A. Laginestra; M. R. Sapienza; F. Fuligni; M. Etebari; F. Melle; E. Sabattini; C. Agostinelli; F. Bacci; C. A. Sagramoso Sacchetti; S. A. Pileri; P. P. PiccalugaA. Gazzola; C. Mannu; M. Rossi; M. A. Laginestra; M. R. Sapienza; F. Fuligni; M. Etebari; F. Melle; E. Sabattini; C. Agostinelli; F. Bacci; C. A. Sagramoso Sacchetti; S. A. Pileri; P. P. Piccalug