A revision of the nearly 8-year-old World Health Organization classification of the lymphoid neoplasms and the accompanying monograph is being published. It reflects a consensus among ...hematopathologists, geneticists, and clinicians regarding both updates to current entities as well as the addition of a limited number of new provisional entities. The revision clarifies the diagnosis and management of lesions at the very early stages of lymphomagenesis, refines the diagnostic criteria for some entities, details the expanding genetic/molecular landscape of numerous lymphoid neoplasms and their clinical correlates, and refers to investigations leading to more targeted therapeutic strategies. The major changes are reviewed with an emphasis on the most important advances in our understanding that impact our diagnostic approach, clinical expectations, and therapeutic strategies for the lymphoid neoplasms.
Since the publication of the Revised European-American Classification of mature lymphoid neoplasms in 1994, subsequent updates of the classification of mature lymphoid neoplasms have been generated ...through iterative international efforts to achieve broad consensus among hematopathologists, geneticists, molecular scientists, and clinicians. Significant progress in the characterization of malignancies of the immune system in the last years, with many new insights provided by genomic studies, have led to the current proposal. We have followed the same process that was successfully used for the 3rd and 4th editions of the WHO classification of hematological neoplasms. The definition, recommended studies, and criteria for the diagnosis of many entities have been extensively refined. Some categories considered provisional are now upgraded to definite entities. Terminology of some diseases has been revised to adapt nomenclature to the current knowledge of their biology, but these modifications have been restricted to well-justified situations. Major findings from recent genomic studies have impacted the conceptual framework and diagnostic criteria for many disease entities. These changes will have an impact on optimal clinical management. The conclusions of this work are summarized in this report as the proposed International Consensus Classification (ICC) of mature lymphoid, histiocytic, and dendritic cell tumors.
Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematologic malignancy for which there is still no effective therapy. In order to identify genetic alterations useful for ...a new treatment design, we used whole-exome sequencing to analyze 14 BPDCN patients and the patient-derived CAL-1 cell line. The functional enrichment analysis of mutational data reported the epigenetic regulatory program to be the most significantly undermined (
<0.0001). In particular, twenty-five epigenetic modifiers were found mutated (e.g.
was the most frequently affected (28.6% of cases). To evaluate the impact of the identified epigenetic mutations at the gene-expression and Histone H3 lysine 27 trimethylation/acetylation levels, we performed additional RNA and pathology tissue-chromatin immunoprecipitation sequencing experiments. The patients displayed enrichment in gene signatures regulated by methylation and modifiable by decitabine administration, shared common H3K27-acetylated regions, and had a set of cell-cycle genes aberrantly up-regulated and marked by promoter acetylation. Collectively, the integration of sequencing data showed the potential of a therapy based on epigenetic agents. Through the adoption of a preclinical BPDCN mouse model, established by CAL-1 cell line xenografting, we demonstrated the efficacy of the combination of the epigenetic drugs 5'-azacytidine and decitabine in controlling disease progression
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Tiacci, Falini, and colleagues discovered
BRAF
mutations in nearly all patients with hairy-cell leukemia. Now, their group, along with U.S. investigators, has found response rates of 90% or higher ...among patients treated with the BRAF inhibitor vemurafenib.
Hairy-cell leukemia is a chronic mature B-cell cancer with unique clinicopathologic and biologic features.
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–
4
Purine analogues (cladribine and pentostatin) induce durable complete responses in approximately 80% of patients with this cancer.
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,
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However, in 30 to 50% of patients, the disease relapses and there is a progressively worse response to purine analogues,
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,
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which can also cause cumulative myelotoxic effects and immune suppression. Thus, new therapeutic approaches are needed.
Tiacci and colleagues found that the V600E mutation of BRAF, a kinase commonly mutated in solid tumors,
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was the key genetic lesion of hairy-cell leukemia,
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,
11
and Chung et al. . . .
The International Peripheral T-Cell Lymphoma Project was undertaken to better understand the subtypes of T-cell and natural killer (NK) -cell lymphomas.
Angioimmunoblastic T-cell lymphoma (AITL) was ...diagnosed according to the 2001 WHO criteria by a central review process consisting of panels of expert hematopathologists. Clinical, pathologic, immunophenotyping, treatment, and survival data were correlated.
Of 1,314 patients, 243 (18.5%) were diagnosed with AITL. At presentation, generalized lymphadenopathy was noted in 76% of patients, and 89% had stages III to IV disease. Skin rash was observed in 21% of patients. Hemolytic anemia and hypergammoglobulinemia occurred in 13% and 30% of patients, respectively. Five-year overall and failure-free survivals were 33% and 18%, respectively. At presentation, prognostic models were evaluated, including the standard International Prognostic Index, which comprised the following factors: age ≥ 60 years, stages III to IV disease, lactic dehydrogenase (LDH) > normal, extranodal sites (ENSs) > one, and performance status (PS) ≥ 2; the Prognostic Index for Peripheral T-Cell Lymphoma, comprising: age ≥ 60 years, PS ≥ 2, LDH > normal, and bone marrow involvement; and the alternative Prognostic Index for AITL (PIAI), comprising: age > 60 years, PS ≥ 2, ENSs > one, B symptoms, and platelet count < 150 × 10(9)/L. The simplified PIAI had a low-risk group (zero to one factors), with 5-year survival of 44%, and a high-risk group (two to five factors), with 5-year survival of 24% (P = .0065).
AITL is a rare clinicopathologic entity characterized by an aggressive course and dismal outcome with current therapies.
In this issue of Blood, Wang et al describe the occurrence and pathogenetic relevance of IDH2R172 mutations in angioimmunoblastic T-cell lymphoma (AITL).
Splenic marginal zone B-cell lymphoma (SMZL) is a heterogeneous clinico-biological entity. The clinical course is variable, multiple genes are mutated with no unifying mechanism, and essential ...regulatory pathways and surrounding microenvironments are diverse. We sought to clarify the heterogeneity of SMZL by resolving different subgroups and their underlying genomic abnormalities, pathway signatures, and microenvironment compositions to uncover biomarkers and therapeutic vulnerabilities. We studied 303 SMZL spleen samples collected through the IELSG46 multicenter international study (NCT02945319) by using a multiplatform approach. We carried out genetic and phenotypic analyses, defined self-organized signatures, validated the findings in independent primary tumor metadata and determined correlations with outcome data. We identified 2 prominent genetic clusters in SMZL, termed NNK (58% of cases, harboring NF-κB, NOTCH, and KLF2 modules) and DMT (32% of cases, with DNA-damage response, MAPK, and TLR modules). Genetic aberrations in multiple genes as well as cytogenetic and immunogenetic features distinguished NNK- from DMT-SMZLs. These genetic clusters not only have distinct underpinning biology, as judged by differences in gene-expression signatures, but also different outcomes, with inferior survival in NNK-SMZLs. Digital cytometry and in situ profiling segregated 2 basic types of SMZL immune microenvironments termed immune-suppressive SMZL (50% of cases, associated with inflammatory cells and immune checkpoint activation) and immune-silent SMZL (50% of cases, associated with an immune-excluded phenotype) with distinct mutational and clinical connotations. In summary, we propose a nosology of SMZL that can implement its classification and also aid in the development of rationally targeted treatments.
•SMZL comprises 4 distinct genetically defined molecular clusters and 2 distinct phenotypically defined immune-microenvironment classes.•The molecular-based nosology of SMZL can improve disease classification and discovery of novel biomarkers and therapeutic vulnerabilities.
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•Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a recently recognized non-Hodgkin lymphoma of T-cell origin.•Despite its low incidence, the increasing use of ...breast implants for cosmetic or post-mastectomy reconstruction purposes places BIA-ALC as an emerging and compelling medical challenge.•Multidisciplinary team approach is essential to well define diagnostic workup and treatment.
Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a recently recognized non-Hodgkin lymphoma of T-cell origin. Despite the low incidence of this new disease, the increasing use of breast implants for cosmetic or post-mastectomy reconstruction purposes places BIA-ALC as an emerging and compelling medical challenge. The real BIA-ALCL pathogenesis has not been fully uncovered so far, while different putative causal factors have been proposed. Breast implants with textured surfaces seem to be associated with nearly all cases of BIA-ALCL, while the real the risk of disease development has not been well estimated so far. Late onset, persistent seroma around breast implant represents the classical clinical presentation. Most of the BIA-ALCL patients presents with localized disease, which confers an excellent prognosis. Unlike other non-Hodgkin lymphomas, surgical excision of the mass has a key role in the treatment. For patients with advanced and disseminated diseases, the treatment did not differ from other types of T-cell lymphoma. For these reasons, BIA-ALCL represents an emerging disease which requires multidisciplinary team approach to well define diagnostic workup and treatment for each patient. This review article aims to summarize available data on BIA-ALCL. First, we will outline available data on BIA-ALCL epidemiology, pathogenesis, diagnostic work-up, and treatment. Second, we will point out the potential psychological implications as well as the risk of perception distortion for women with breast implants, especially for those with previous breast cancer. Lastly, we will summarize the current national recommendations regarding textured breast implants and discuss the diagnostic-therapeutic algorithm for BIA-ALCL management.
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