Primary body cavity-based AIDS-related lymphomas
Five patients with advanced AIDS developed a unique type of high grade primary body cavity-based non-Hodgkin's lymphoma (NHL). The lymphomas were exclusively in serous effusions with no detectable mass disease in the body cavities and no lymphadenopathy or organomegaly. All of the lymphomas exhibited virtually identical morphology, which could not be precisely classified, but appeared to bridge features of large cell immunoblastic and anaplastic large cell lymphomas. Immunophenotypically the lymphoma cells lacked expression of any B- or T-lymphocyte antigens, but expressed CD45 and the activation antigens CD30, CD38, CD71, and HLA-DR. Clonally rearranged immunoglobulin heavy chain and kappa light chain genes were identified by Southern blot analysis. Molecular studies also revealed Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) genomes and germline configuration of the c-myc protooncogene. In two cases studied cytogenetically, the lymphoma cells manifested complex chromosome abnormalities. These lymphomas are clinically and biologically unique and found predominantly in patients with advanced AIDS, in many cases with pre-existing Kaposi's sarcoma.
- "In PEL, genetic lesions commonly seen in other types of AIDS-related lymphomas are absent, with no MYC or BCL6 gene rearrangements, and no mutations of the RAS oncogene or the TP53 tumor suppressor gene.5,22,23,24 The presence of multiple chromosomal abnormalities suggests that secondary genetic events contribute to neoplastic transformation of PEL cells.24 During latency, HHV8 expresses microRNAs that promote cellular survival, for example, by augmenting nuclear factor-κB activity induced by vFLIP, by targeting IκB, or by preventing cell-cycle arrest through targeting p21 mRNA.5,20 "
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ABSTRACT: Primary effusion lymphoma (PEL) is a human herpes virus 8 (HHV8)-positive large B-cell neoplasm that presents as an effusion with no detectable tumor in individuals with human immunodeficiency virus infection or other immune deficiencies. PEL is an aggressive neoplasm with a poor prognosis. PEL cells show diverse morphologies, ranging from immunoblastic or plasmablastic to anaplastic. The immunophenotype of PEL is distinct, but its lineage can be misdiagnosed if not assessed thoroughly. PEL cells usually express CD45, lack B- and T-cell-associated antigens, and characteristically express lymphocyte activation antigens and plasma cell-associated antigens. Diagnosis of PEL often requires the demonstration of a B-cell genotype. HHV8 must be detected in cells to diagnose PEL. In most cases, PEL cells also harbor the Epstein-Barr virus (EBV) genome. Similar conditions associated with HHV8 but not effusion-based are called "extracavitary PELs." PELs should be differentiated from HHV8-negative, EBV-positive, body cavity-based lymphomas in patients with long-standing chronic inflammation; the latter can occur in tuberculous pleuritis, artificial pneumothorax, chronic liver disease and various other conditions. Despite their morphological similarity, these various lymphomas require different therapeutic strategies and have different prognostic implications. Correct diagnosis is essential to manage and predict the outcome of patients with PEL and related disorders.
Available from: Renaud Mahieux
- "Infection with Kaposi sarcoma associated herpesvirus (KSHV) (also known as Human Herpesvirus Type 8 (HHV-8)) , is linked to all forms of Kaposi sarcoma, primary effusion lymphoma (PEL) [2–4], and some forms of multicentric Castelman’s disease (MCD) [5,6]. PEL is a monoclonal/oligoclonal, rare, aggressive and body cavity-based B-cell lymphoma, accounting for approximately 3% of AIDS-related lymphomas [7,8]. "
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ABSTRACT: Kaposi sarcoma-associated herpesvirus (KSHV) is the etiologic agent of primary effusion lymphomas (PEL). PEL cell lines infected with KSHV, but negative for Epstein-Barr virus have a tumorigenic potential in non-obese diabetic/severe combined immunodeficient mice and result in efficient engraftment and formation of malignant ascites with notable abdominal distension, consistent with the clinical manifestations of PEL in humans.
Using this preclinical mouse model, we demonstrate that the combination of arsenic trioxide and interferon-alpha (IFN) inhibits proliferation, induces apoptosis and downregulates the latent viral transcripts LANA-1, v-FLIP and v-Cyc in PEL cells derived from malignant ascites. Furthermore, this combination decreases the peritoneal volume and synergistically increases survival of PEL mice.
These results provide a promising rationale for the therapeutic use of arsenic/IFN in PEL patients.
Available from: Maqbool Ahmed
- "Despite advances in therapeutic regimes for the treatment of aggressive NHL over the last decade, PELs are still refractory to conventional systemic chemotherapy with a mean overall survival of 3 months . The suggested benefit of high-dose Methotrexate in association with CHOP (Cyclophosphamide, Doxorubicin, Prednisolone and Vincristine)-like regimens is negatively balanced by the hampered toxicity of Methotrexate in the presence of serous effusions . "
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ABSTRACT: A number of constitutively activated signaling pathways play critical roles in the survival and growth of primary effusion lymphoma cells (PELs) including NFkB and PI3/AKT kinase cascades. NFkBis constitutively activated in a number of malignancies, including multiple myeloma, Burkitt's lymphoma and diffuse large cell B-cell lymphoma. However, its role in primary effusion lymphoma has not been fully explored.
We used pharmacological inhibition and gene silencing to define the role of NFkB in growth and survival of PEL cells. Inhibition of NFkB activity by Bay11-7085 resulted in decreased expression of p65 in the nuclear compartment as detected by EMSA assays. In addition, Bay11-7085 treatment caused de-phosphorylation of AKT and its downstream targets suggesting a cross-talk between NFkB and the PI3-kinase/AKT pathway. Importantly, treatment of PEL cells with Bay11-7085 led to inhibition of cell viability and induced apoptosis in a dose dependent manner. Similar apoptotic effects were found when p65 was knocked down using specific small interference RNA. Finally, co-treatment of PEL cells with suboptimal doses of Bay11-7085 and LY294002 led to synergistic apoptotic responses in PEL cells.
These data support a strong biological-link between NFkB and the PI3-kinase/AKT pathway in the modulation of anti-apoptotic effects in PEL cells. Synergistic targeting of these pathways using NFKB- and PI3-kinase/AKT-inhibitors may have a therapeutic potential for the treatment of PEL and possibly other malignancies with constitutive activation of these pathways.
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