Claudia Mannu

Molecular Profiling Improves Classification and Prognostication of Nodal Peripheral T-Cell Lymphomas: Results of a Phase III Diagnostic Accuracy Study

PURPOSE The differential diagnosis among the commonest peripheral T-cell lymphomas (PTCLs; ie, PTCL not otherwise specified [NOS], angioimmunoblastic T-cell lymphoma [AITL], and anaplastic large-cell lymphoma [ALCL]) is difficult, with the morphologic and phenotypic features largely overlapping. We performed a phase III diagnostic accuracy study to test the ability of gene expression profiles (GEPs; index test) to identify PTCL subtype. METHODS We studied 244 PTCLs, including 158 PTCLs NOS, 63 AITLs, and 23 ALK-negative ALCLs. The GEP-based classification method was established on a support vector machine algorithm, and the reference standard was an expert pathologic diagnosis according to WHO classification. RESULTS First, we identified molecular signatures (molecular classifier [MC]) discriminating either AITL and ALK-negative ALCL from PTCL NOS in a training set. Of note, the MC was developed in formalin-fixed paraffin-embedded (FFPE) samples and validated in both FFPE and frozen tissues. Second, we found that the overall accuracy of the MC was remarkable: 98% to 77% for AITL and 98% to 93% for ALK-negative ALCL in test and validation sets of patient cases, respectively. Furthermore, we found that the MC significantly improved the prognostic stratification of patients with PTCL. Particularly, it enhanced the distinction of ALK-negative ALCL from PTCL NOS, especially from some CD30+ PTCL NOS with uncertain morphology. Finally, MC discriminated some T-follicular helper (Tfh) PTCL NOS from AITL, providing further evidence that a group of PTCLs NOS shares a Tfh derivation with but is distinct from AITL. CONCLUSION Our findings support the usage of an MC as additional tool in the diagnostic workup of nodal PTCL.

Molecular profiling of blastic plasmacytoid dendritic cell neoplasm reveals a unique pattern and suggests selective sensitivity to NF-kB pathway inhibition

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare disease of controversial origin recently recognized as a neoplasm deriving from plasmacytoid dendritic cells (pDCs). Nevertheless, it remains an orphan tumor with obscure biology and dismal prognosis. To better understand the pathobiology of BPDCN and discover new targets for effective therapies, the gene expression profile (GEP) of 25 BPDCN samples was analyzed and compared with that of pDCs, their postulated normal counterpart. Validation was performed by immunohistochemistry (IHC), whereas functional experiments were carried out ex vivo. For the first time at the molecular level, we definitely recognized the cellular derivation of BPDCN that proved to originate from the myeloid lineage and in particular, from resting pDCs. Furthermore, thanks to an integrated bioinformatic approach we discovered aberrant activation of the NF-kB pathway and suggested it as a novel therapeutic target. We tested the efficacy of anti-NF-kB-treatment on the BPDCN cell line CAL-1, and successfully demonstrated by GEP and IHC the molecular shutoff of the NF-kB pathway. In conclusion, we identified a molecular signature representative of the transcriptional abnormalities of BPDCN and developed a cellular model proposing a novel therapeutic approach in the setting of this otherwise incurable disease.

Minimal residual disease after conventional treatment significantly impacts on progression-free survival of patients with follicular lymphoma: the FIL FOLL05 trial.

Purpose: The role of the minimal residual disease (MRD) in follicular lymphoma is still debated. In this study, we assessed whether the BCL2/IGH rearrangement could have a prognostic role in patients receiving R-CHOP, R-FM, or R-CVP. Experimental Design: DNAs from 415 patients among the 504 cases enrolled in the FOLL05 trial (NCT00774826) were centralized and assessed for the BCL2/IGH at diagnosis, at the end of treatment, and after 12 and 24 months. Results: At diagnosis, the molecular marker was detected in 53% of cases. Patients without molecular marker or with a low molecular tumor burden (<1 × 10−4 copies) showed higher complete remission (CR) rate and longer progression-free survival (PFS; 3-year PFS 80% vs. 59%; P = 0.015). PFS was significantly conditioned by the PCR status at 12 and 24 months, with 3-year PFS of 66% for MRD− cases versus 41% for those MRD+ at 12 months (P = 0.015), and 84% versus 50% at 24 months (P = 0.014). The MRD negativity at 12 and 24 months resulted in an improved PFS both in CR and in partial remission (PR) patients (3-year PFS = 72% for cases CR/PCR− vs. 32% for those CR/PCR+ vs. 62% for those PR/PCR− and 25% for patients in PR/PCR+; P = 0.001). The prognostic value of MRD at 12 and 24 months of follow-up was confirmed also in multivariate analysis. Conclusions: In this study, standardized molecular techniques have been adopted and applied on bone marrow samples from a large cohort. Data reported show that the MRD detection is a powerful independent predictor of PFS in patients with follicular lymphoma receiving conventional chemoimmunotherapy. Clin Cancer Res; 20(24); 6398–405. ©2014 AACR.

Pathobiology of hodgkin lymphoma.

Despite its well-known histological and clinical features, Hodgkins lymphoma (HL) has recently been the object of intense research activity, leading to a better understanding of its phenotype, molecular characteristics, histogenesis, and possible mechanisms of lymphomagenesis. There is complete consensus on the B-cell derivation of the tumor in most cases, and on the relevance of Epstein-Barr virus infection and defective cytokinesis in at least a proportion of patients. The REAL/WHO classification recognizes a basic distinction between lymphocyte predominance HL (LP-HL) and classic HL (cHL), reflecting the differences in clinical presentation and behavior, morphology, phenotype, and molecular features. cHL has been classified into four subtypes: lymphocyte rich, nodular sclerosing, with mixed cellularity, and lymphocyte depleted. The borders between cHL and anaplastic large-cell lymphoma have become sharper, whereas those between LP-HL and T-cell-rich B-cell lymphoma remain ill defined. Treatments adjusted to the pathobiological characteristics of the tumor in at-risk patients have been proposed and are on the way to being applied.

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.

Prognostic Markers in Peripheral T-Cell Lymphoma

Based on their own experience and knowledge of the literature, the authors review the pathobiological characteristics of peripheral T-cell lymphomas (PTCLs), focusing on the available prognostic indicators. The International Prognostic Index (IPI), which is based on age, performance status, lactate dehydrogenase [LDH], stage, and extranodal involvement, appears to be efficient as a prognostic index for PTCLs, at least in part and especially for certain PTCL subtypes. However, it is not so satisfactory for the two commonest PTCLs, PTCL not otherwise specified (PTCL/NOS) and angioimmunoblastic T-cell lymphoma (AITL), for which novel scores, possibly based on the biologic features of the tumors, have been explored. An Italian cooperative group proposed a revision of the IPI for PTCL unspecified (PTCL-U), the Prognostic Index for PTCL-U (PIT), which includes age, performance status, LDH, and bone marrow involvement. The PIT apparently offered some advantages, but they were not confirmed in subsequent studies. A clinical-biological score (the Bologna score) was then proposed, including tumor proliferation and clinical features (age, LDH, and performance status). This score appears promising and offers the intriguing advantage of integrating biological and clinical elements, but independent validation on a large series is still warranted. More recently, gene expression profiling has been used to identify novel molecular prognostic factors. In particular, inactivation of the NFκB pathway, high expression of proliferation-associated genes, and cytotoxic molecular phenotype seem to be associated with a worse outcome. So far, however, none of these indicators has been validated in an independent series. Finally, various reports have dealt specifically with the prognostication of NK-derived tumors, including nasal and nasal-type lymphomas. Both the IPI and dedicated models have turned out to be of prognostic relevance for these tumors. In conclusion, although the IPI is somewhat effective for PTCL prognostication, novel scores that are more refined and possibly disease-specific are warranted. The validation process for several models, including clinical-pathological and molecular models, is now ongoing.

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

Currently, 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.

Pathogenetic and diagnostic significance of microRNA deregulation in peripheral T-cell lymphoma not otherwise specified

Peripheral T-cell lymphomas not otherwise specified (PTCLs/NOS) are rare and aggressive tumours whose molecular pathogenesis and diagnosis are still challenging. The microRNA (miRNA) profile of 23 PTCLs/NOS was generated and compared with that of normal T-lymphocytes (CD4+, CD8+, naive, activated). The differentially expressed miRNA signature was compared with the gene expression profile (GEP) of the same neoplasms. The obtained gene patterns were tested in an independent cohort of PTCLs/NOS. The miRNA profile of PTCLs/NOS then was compared with that of 10 angioimmunoblastic T-cell lymphomas (AITLs), 6 anaplastic large-cell lymphomas (ALCLs)/ALK+ and 6 ALCLs/ALK−. Differentially expressed miRNAs were validated in an independent set of 20 PTCLs/NOS, 20 AITLs, 19 ALCLs/ALK− and 15 ALCLs/ALK+. Two hundred and thirty-six miRNAs were found to differentiate PTCLs/NOS from activated T-lymphocytes. To assess which miRNAs impacted on GEP, a multistep analysis was performed, which identified all miRNAs inversely correlated to different potential target genes. One of the most discriminant miRNAs was selected and its expression was found to affect the global GEP of the tumours. Moreover, two sets of miRNAs were identified distinguishing PTCL/NOS from AITL and ALCL/ALK−, respectively. The diagnostic accuracy of this tool was very high (83.54%) and its prognostic value validated.

Systemic Epstein-Barr-virus-positive T cell lymphoproliferative childhood disease in a 22-year-old Caucasian man: A case report and review of the literature

IntroductionSystemic Epstein-Barr-virus-positive T cell lymphoproliferative disease of childhood is an extremely rare disorder, characterized by clonal proliferation of Epstein-Barr-virus-infected T cells with an activated cytotoxic phenotype. The disease is more frequent in Asia and South America, with only few cases reported in Western countries. A prompt diagnosis, though often difficult, is a necessity due to the very aggressive clinical course of the disease.Case presentationWe report the clinicopathological features of fulminant T cell lymphoproliferative disease that arose in the setting of acute primary Epstein-Barr virus infection. Our patient, a 23-year-old man, presented to our facility with persisting fever, hepatosplenomegaly and severe pancytopenia. On bone marrow biopsy, an abundant lymphoid infiltrate was observed. Immunophenotypic and molecular studies revealed that the atypical lymphoid cells displayed a CD8+, Epstein-Barr-encoded-RNA-positive T cell phenotype with clonal rearrangement of the T cell receptor genes, the final diagnosis being systemic Epstein-Barr-virus-positive T cell lymphoproliferative disease. On reviewing the literature we found only 14 similar cases, all presenting with very aggressive clinical courses and requiring extensive phenotyping and molecular techniques for final diagnosis.ConclusionThough extremely rare, this disease can occur in Europe, and a comprehensive diagnostic approach is thus recommended in all case of Epstein-Barr-virus-positive lymphoproliferative disorders. Unfortunately, at present no specific treatment is available; however, prompt administration of anti- Epstein-Barr virus treatment and rapid attempts to control the hemophagocytic syndrome are indicated.

Biology and treatment of follicular lymphoma

Follicular lymphoma (FL) is the second most common lymphoid tumor. It is composed of elements resembling those of normal germinal centers. In particular, it is constituted by small centrocytes and large centroblasts, typically CD10+, CD19+, CD20+, CD79a+ and BCL6+, with follicular growth pattern. The molecular hallmark of FL is the t(14;18)(q32;q21) translocation, which leads to inappropriate BCL2 expression. This feature, other than representing a pathogenetic primary event, constitutes a suitable diagnostic marker, as well as a target for minimal residual disease monitoring and, hopefully, future therapies. Clinically, FL presents with indolent behavior, characterized by prompt response to initial therapy but almost invariably subsequent relapses. Novel approaches, including stem cell transplantation, monoclonal antibodies and innovative agents, should be then considered for improving long-term results.