Primary effusion lymphoma in an elderly patient effectively treated by lenalidomide: case report and review of literature

Primary effusion lymphoma: therapeutic strategies targeting viral and cellular mechanisms

INTRODUCTION

Primary effusion lymphoma (PEL) is a rare subtype of B-cell lymphoma primarily affecting immunocompromised and elderly individuals. Given the dismal survival rates associated with traditional treatments, studying novel therapeutic approaches to improve patient outcomes is critical.

AREAS COVERED

This review focuses on developing therapeutic options for PEL that target particular viral and cellular mechanisms involved in PEL pathogenesis. Since the CHOP regimen was associated with a lower median survival rate, alternative treatments, including stem cell transplantation, have also been explored, but have generally produced unsatisfactory results. Therefore, novel therapeutic agents are under investigation, including antiretroviral drugs targeting viral pathways and treatments targeting particular cellular processes, such as DNA damage, epigenetics, apoptotic, and immune-modulatory pathways showing promising outcomes in preclinical and clinical research, increasing PEL treatment efficacy while minimizing toxicity. In this review, we conducted a comprehensive literature search using PubMed, and Google Scholar for studies published between 1989 and 2024.

EXPERT OPINION

Further research is needed to refine the appropriate combination methods and strategies behind drug interactions. Targeted therapies could be investigated further to improve therapeutic efficacy and reduce toxicity in this type of lymphoma.

Repurposing alcohol-abuse drug disulfiram for the treatment of KSHV-infected primary effusion lymphoma by activating antiviral innate immunity

Cancer remains a leading cause of global mortality, characterized by high treatment costs, and generally poor prognoses. Developing new anti-cancer drugs requires substantial investment, extended development timelines, and a high failure rate. Therefore, repurposing existing US Food and Drug Administration (FDA)-approved drugs for other diseases as potential anti-cancer therapies offers a faster and more cost-effective approach. Primary effusion lymphoma (PEL) is an aggressive B-cell malignancy linked to Kaposi's sarcoma-associated herpesvirus (KSHV) infection. In this study, we identified that disulfiram (DSF), an FDA-approved medication for alcohol dependence, acts as a potent inhibitor of KSHV-positive PEL. DSF suppresses PEL cell proliferation by inducing apoptosis through the activation of innate antiviral immunity. Remarkably, DSF effectively impedes KSHV reactivation and virion production in both PEL and endothelial cells. Inhibition of TANK binding kinase 1 (TBK1) or interferon regulatory factor 3 (IRF3), essential activators of antiviral innate immunity, reverses DSF's effects on PEL cell survival and KSHV reactivation. Furthermore, DSF treatment significantly hinders the initiation and progression of PEL tumors in a xenograft mouse model, with this effect notably abolished by TBK1 depletion. Our findings highlighted DSF as a promising therapeutic agent for targeting persistent KSHV infection and treating PEL tumors.

HIV/AIDS Associated Lymphoma: Review

Lymphoma is one of the hematologic malignancies that occur at a higher rate in human immunodeficiency virus-infected individuals. It is one of the most frequent neoplastic causes of death in those individuals. Non-Hodgkin's lymphoma and Hodgkin's lymphomas are acquired immunodeficiency syndrome defining lymphoma and non-acquired immunodeficiency syndrome defining lymphoma, respectively. Non-Hodgkin's lymphoma is the most common type of lymphoma in human immunodeficiency virus-positive people. The lymphoma that develops in patients infected with the human immunodeficiency virus/acquired immunodeficiency syndrome is heterogeneous in terms of morphology, pathogenesis pathways, and cellular derivation. A narrative review was conducted on the basis of relevant literature on the current topic to summarize the current epidemiology, pathogenesis, laboratory diagnosis, and treatment of lymphoma in human immunodeficiency virus-infected patients. The finding showed that although the incidence of non-Hodgkin's lymphoma has decreased after the advent of highly active antiretroviral therapy, it has remained higher in human immunodeficiency virus-infected people than in the general population. On the other hand, the incidence of Hodgkin's lymphoma has increased after the introduction of highly active antiretroviral therapy. Therefore, it is recommended that people living with human immunodeficiency virus/ acquired immunodeficiency syndrome be screened for the development of lymphoma to increase their survival time and quality of life, and further research is required regarding the pathogenesis, treatment, and laboratory diagnosis of human immunodeficiency virus/ acquired immunodeficiency syndrome-associated lymphoma.

Clinical and Therapeutic Implications of Epstein-Barr Virus in HIV-Related Lymphomas

The incidence of lymphomas is increased in people living with HIV (PLWH). Aggressive B-cell non-Hodgkin lymphomas (NHLs) are the most common and are considered an AIDS-defining cancer (ADC). Although Hodgkin lymphoma (HL) is not considered an ADC, its incidence is also increased in PLWH. Among all HIV-related lymphomas (HRL), the prevalence of Epstein-Barr virus (EBV) is high. It has been shown that EBV is involved in different lymphomagenic mechanisms mediated by some of its proteins, contributing to the development of different lymphoma subtypes. Additionally, cooperation between both HIV and EBV can lead to the proliferation of aberrant B-cells, thereby being an additional lymphomagenic mechanism in EBV-associated HRL. Despite the close relationship between EBV and HRL, the impact of EBV on clinical aspects has not been extensively studied. These lymphomas are treated with the same therapeutic regimens as the general population in combination with cART. Nevertheless, new therapeutic strategies targeting EBV are promising for these lymphomas. In this article, the different types of HRL are extensively reviewed, focusing on the influence of EBV on the epidemiology, pathogenesis, clinical presentation, and pathological characteristics of each lymphoma subtype. Moreover, novel therapies targeting EBV and future strategies to treat HRL harboring EBV are discussed.

Pomalidomide restores immune recognition of primary effusion lymphoma through upregulation of ICAM-1 and B7-2

Pomalidomide (Pom) is an immunomodulatory drug that has efficacy against Kaposi’s sarcoma, a tumor caused by Kaposi’s sarcoma-associated herpesvirus (KSHV). Pom also induces direct cytotoxicity in primary effusion lymphoma (PEL), a B-cell malignancy caused by KSHV, in part through downregulation of IRF4, cMyc, and CK1α as a result of its interaction with cereblon, a cellular E3 ubiquitin ligase. Additionally, Pom can reverse KSHV-induced downregulation of MHCI and co-stimulatory immune surface molecules ICAM-1 and B7-2 on PELs. Here, we show for the first time that Pom-induced increases in ICAM-1 and B7-2 on PEL cells lead to an increase in both T-cell activation and NK-mediated cytotoxicity against PEL. The increase in T-cell activation can be prevented by blocking ICAM-1 and/or B7-2 on the PEL cell surface, suggesting that both ICAM-1 and B7-2 are important for T-cell co-stimulation by PELs. To gain mechanistic insights into Pom’s effects on surface markers, we generated Pom-resistant (PomR) PEL cells, which showed about 90% reduction in cereblon protein level and only minimal changes in IRF4 and cMyc upon Pom treatment. Pom no longer upregulated ICAM-1 and B7-2 on the surface of PomR cells, nor did it increase T-cell and NK-cell activation. Cereblon-knockout cells behaved similarly to the pomR cells upon Pom-treatment, suggesting that Pom’s interaction with cereblon is necessary for these effects. Further mechanistic studies revealed PI3K signaling pathway as being important for Pom-induced increases in these molecules. These observations provide a rationale for the study of Pom as therapy in treating PEL and other KSHV-associated tumors.

Primary effusion lymphoma (PEL) is an aggressive B-cell lymphoma caused by Kaposi’s sarcoma-associated herpesvirus (KSHV). KSHV encodes various genes that enable infected cells to evade recognition and elimination by the immune system. PEL cells are poorly recognized by T-cells and NK cells, partly due to KSHV-induced downregulation of immune stimulatory surface molecules ICAM-1 and B7-2. We previously found that a cereblon-binding immunomodulatory drug pomalidomide (Pom) can restore the levels of these markers on PELs. Here, we show that the increases in ICAM-1 and B7-2 induced by Pom leads to a functional increase in the recognition and killing of PELs by both T-cells and NK cells. Further, exposure of both the PEL cells and T-cells to Pom lead to an even higher T-cell stimulation providing strong evidence that Pom could help PEL patients by providing specific immune-stimulatory effect. We further perform mechanistic studies and show that Pom’s cellular binding partner cereblon as well as the PI3K pathway are important for Pom-mediated increases in these surface markers.

Lenalidomide in Combination with Arsenic Trioxide: an Effective Therapy for Primary Effusion Lymphoma

Primary effusion lymphoma (PEL) is a rare aggressive subset of non-Hodgkin B cell lymphoma. PEL is secondary to Kaposi sarcoma herpes virus (KSHV) and predominantly develops in serous cavities. Conventional chemotherapy remains the treatment of choice for PEL and yields high response rates with no significant comorbidities. Yet, chemotherapy often fails in achieving or maintaining long-term remission. Lenalidomide (Lena), an immunomodulatory drug, displayed some efficacy in the treatment of PEL. On the other hand, arsenic trioxide (ATO) in combination with other agents effectively treated a number of blood malignancies, including PEL. In this study, we present evidence that the combination of ATO/Lena significantly enhanced survival of PEL mice, decreased the volume of exacerbated ascites in the peritoneum, and reduced tumor infiltration in organs of treated animals. In ex vivo treated PEL cells, ATO/Lena decreased the proliferation and downregulated the expression of KSHV latent viral proteins. This was associated with decreased NF-κB activation, resulting in reactivation of viral replication, downregulation of interleukin-6 (IL-6) and IL-10, inhibition of vascular endothelial growth factor, and apoptosis. Our results elucidate the mechanism of action of ATO/Lena and present it as a promising targeted therapeutic modality in PEL management, which warrants further clinical investigation.

Primary effusion lymphoma in human immune deficiency (HIV)-negative non-organ transplant immunocompetent patients

Primary effusion lymphoma (PEL) is a rare non‐Hodgkin's lymphoma most commonly occurring in the context of human immune deficiency (HIV) infection. Herpes virus 8 (HHV‐8) has been associated with PEL and considered to be the etiologic agent. In addition, most cases (60%‐90%) also show evidence of Epstein‐Barr virus (EBV) infection. We describe here an elderly man who was HIV seronegative and immunocompetent, and presented with worsening weakness and ascites. The diagnosis of PEL was rendered cytologically and supported by the results of flow cytometry. The presence of HHV‐8 was demonstrated by immunohistochemistry, whereas EBV‐associated genetic material was absent by EBER ISH. No lymphadenopathy or organ involvement with lymphoma was found. Systemic chemotherapy with lenalidomide was started given the poor prognosis and commodities of severe coronary artery disease; however, the patient did not respond and succumbed to his disease in 4 months. We present detailed cytologic and clinical findings of this very rare occurrence, and review literature of all reported PEL cases of HIV‐negative, nontransplant, immunocompetent patients.

Mechanistic Insights into Chemoresistance Mediated by Oncogenic Viruses in Lymphomas

Viral lymphomagenesis induced by infection with oncogenic viruses, such as Kaposi’s sarcoma associated herpesvirus (KSHV), Epstein–Barr virus (EBV) and human T-cell leukemia virus (HTLV-1), represents a group of aggressive malignancies with a diverse range of pathological features. Combined chemotherapy remains the standard of care for these virus-associated lymphomas; however, frequent chemoresistance is a barrier to achieving successful long-term disease-free survival. There is increasing evidence that indicates virus-associated lymphomas display more resistance to cytotoxic chemotherapeutic agents than that observed in solid tumors. Although the tumor microenvironment and genetic changes, such as key oncogene mutations, are closely related to chemoresistance, some studies demonstrate that the components of oncogenic viruses themselves play pivotal roles in the multidrug chemoresistance of lymphoma cells. In this review, we summarize recent advances in the understanding of the mechanisms through which oncogenic viruses mediate lymphoma cell chemoresistance, with a particular focus on KSHV and EBV, two major oncogenic viruses. We also discuss the current challenges to overcome these obstacles in the treatment of virus-associated lymphomas.

High-dose Therapy and Autologous Hematopoietic Cell Transplantation as Consolidation Treatment for Primary Effusion Lymphoma

BACKGROUND

Primary effusion lymphoma (PEL) is a rare type of non-Hodgkin lymphoma. The limited disease-free survival after chemotherapy has resulted in a poor prognosis. The outcomes data for high-dose therapy followed by autologous hematopoietic cell transplantation (auto-HCT) for PEL are limited owing to the rarity of the disease.

PATIENTS AND METHODS

The present study included 9 patients with PEL from 2 major academic centers. Of these patients, 4 had received auto-HCT after high-dose therapy. Of the 9 patients, 8 (89%) had immunodeficiency (7 with human immunodeficiency virus seropositivity; 1, a solid organ transplant recipient) at the diagnosis. Human herpesvirus-8 by immunohistochemistry was positive in 8 patients. Anthracycline-based combination chemotherapy was used as first-line treatment in 7 patients; 4 underwent auto-HCT after attaining first complete remission.

RESULTS

The median follow-up of the surviving patients was 25 months (95% confidence interval [CI], 8%-29%). The 2-year progression-free and overall survival for the 8 patients who had received treatment was 58% (95% CI, 22%-95%) and 73% (95% CI, 41%-100%), respectively. The 2-year progression-free and overall survival for the patients who had received auto-HCT was 50% (95% CI, 1%-99%) and 75% (95% CI, 33%-100%), respectively. Of the 4 auto-HCT recipients, all had been in first complete remission at the time of autografting. The cumulative incidence of relapse was 50% (95% CI, 19%-100%). No deaths were attributable to auto-HCT at 2 years after autografting.

CONCLUSION

Despite the small sample size, our data have shown that consolidative auto-HCT is safe and effective and should be considered for eligible patients with PEL after demonstration of an objective response to induction chemotherapy. However, the high relapse rate remains a concern and warrants the development of new strategies to mitigate post-transplantation relapse.

Hiv and Lymphoma: from Epidemiology to Clinical Management

Patients infected with human immunodeficiency virus (HIV) are at increased risk for developing both non-Hodgkin’s lymphoma (NHL) and Hodgkin’s lymphoma (HL). Even if this risk has decreased for NHL after the introduction of combination antiretroviral therapy (cART), they remain the most common acquired immune deficiency syndrome (AIDS)-related cancer in the developed world. They are almost always of B-cell origin, and some specific lymphoma types are more common than others. Some of these lymphoma types can occur in both HIV-uninfected and infected patients, while others preferentially develop in the context of AIDS. HIV-associated lymphoma differs from lymphoma in the HIV negative population in that they more often present with advanced disease, systemic symptoms, and extranodal involvement and are frequently associated with oncogenic viruses (Epstein-Barr virus and/or human herpesvirus-8). Before the introduction of cART, most of these patients could not tolerate the treatment strategies routinely employed in the HIV-negative population. The widespread use of cART has allowed for the delivery of full-dose and dose-intensive chemotherapy regimens with improved outcomes that nowadays can be compared to those seen in non-HIV infected patients. However, a great deal of attention should be paid to opportunistic infections and other infectious complications, cART-chemotherapy interactions, and potential cumulative toxicity. In the context of relatively sparse prospective and randomized trials, the optimal treatment of AIDS-related lymphomas remains a challenge, particularly in patients with severe immunosuppression. This paper will address epidemiology, pathogenesis, and therapeutic strategies in HIV-associated NHL and HL.

Management and Outcomes of HIV-Associated Primary Effusion Lymphoma: A Single Center Experience

BACKGROUND

Primary effusion lymphoma (PEL) is a rare malignancy usually associated with HIV infection. Management and outcomes are poorly understood.

METHODS

The medical records of all patients diagnosed with HIV-associated PEL at our institution between 1999 and 2014 were reviewed. Patients were followed till death, treatment failure or loss of follow-up.

RESULTS

Twelve patients with PEL were identified during the 15 year study period; 9 had HIV infection. All 9 were male; median age was 45 years. All presented with local symptoms and were diagnosed with PEL a median of 11 years after HIV diagnosis. Location was pleural (3), pericardial (3), peritoneal (1) and extracavitatory (2). By definition, all had Ann Arbor stage 4 at diagnosis. Median follow-up was 34 months. Two patients had poor performance status and were unable to get chemotherapy. Seven patients had a complete remission (CR) and two died within 1 month of diagnosis. The median CD4 levels at PEL diagnosis in patients with poor versus good outcomes were 54 cells/mm3 (range, 26-82 cells/mm3) and 211 cells/mm3 (range, 73-800 cells/mm3). In contrast, the median lactate dehydrogenase (LDH) levels at PEL diagnosis with poor versus good prognosis were 1074 U/L (range, 703-1445 U/L) and 283 U/L (range, 156-760 U/L).

CONCLUSIONS

Given its rarity, our knowledge of PEL relies solely on case reports and case series. Prompt HAART and chemotherapy may be effective in HIV- associated PEL and good outcomes are possible. LDH and CD4 may be possible prognostic factors in PEL.

Survival of patients with CD20-negative variants of large B-cell lymphoma: an analysis of the National Cancer Data Base

Using records from the National Cancer Data Base, we studied overall survival of CD20-negative variants of diffuse large B-cell lymphoma (DLBCL): primary effusion (PEL, N = 228), plasmablastic (PBL, N = 481), ALK-positive large B-cell (ALK + LBLC, N = 15), and human herpesvirus-8-positive DLBCL (HHV8 + DLBCL, N = 77). Three-year survival was 27% for PEL, 40% for PBL, 34% for ALK + LBCL, and 63% for HHV8 + DLBCL. Compared with unspecified DLBCL, and adjusting for clinical characteristics (including the HIV status), survival was significantly worse for PEL (hazard ratio [HR], 1.58; 95% confidence interval [CI], 1.31-1.90), PBL (HR 1.66; 95% CI, 1.41-1.95), and ALK + LBCL (HR, 2.70; 95% CI, 1.27-5.75), but not for HHV8 + DLBCL (HR, 0.89; 95% CI, 0.54-1.45). The HIV status was not an independent prognostic factor in PEL, PBL, or HHV8 + DLBCL. Advanced stage was prognostic for PBL (p = .0002), but not for ALK + LBCL (p = .96), or HHV8 + DLBCL (p = .28). In PEL and PBL survival significantly differed according to primary site. Novel therapeutic approaches are urgently needed for these rare diseases.

Deregulation of KSHV latency conformation by ER-stress and caspase-dependent RAD21-cleavage

Kaposi’s sarcoma (KS)-associated herpesvirus (KSHV) is a human gammaherpesvirus recognized as the principal causative agent of KS and primary effusion lymphoma (PEL). KSHV establishes persistent latent infection in B lymphocytes where viral gene expression is restricted, in part, by a cohesin-dependent chromosome conformation. Here, we show that endoplasmic reticulum (ER) stress induces a rapid, caspase-dependent cleavage of cohesin subunit RAD21. ER stress-induced cleavage of RAD21 correlated with a rapid and strong viral lytic transcriptional activation. This effect was observed in several KSHV positive PEL cells, but not in other B-cells or non-B-cell models of KSHV latency. The cleaved-RAD21 does not dissociate from viral genomes, nor disassemble from other components of the cohesin complex. However, RAD21 cleavage correlated with the disruption of the latency genome conformation as revealed by chromosome conformation capture (3C). Ectopic expression of C-terminal RAD21 cleaved form could partially induce KSHV lytic genes transcription in BCBLI cells, suggesting that ER-stress induced RAD21 cleavage was sufficient to induce KSHV reactivation from latency in PEL cells. Taken together our results reveal a novel aspect for control and maintenance of KSHV genome latency conformation mediated by stress-induced RAD21 cleavage. Our studies also suggest that RAD21 cleavage may be a general regulatory mechanism for rapid alteration of cellular chromosome conformation and cohesin-dependent transcription regulation.

Latent infection with Kasposi’s Sarcoma (KS)-Associated Herpesivirus (KSHV) is linked to malignant transformation of the host cell. KSHV associated pleural effusion lymphomas (PEL) are highly sensitive to endoplasmic reticulum (ER) stress due to underlying defects in ER stress response pathways. We show here that ER stress inducers lead to a rapid activation of KSHV lytic transcripts, and that an underlying mechanism is found in the caspase and calpain-dependent proteolytic cleavage of RAD21. RAD21 is a subunit of the cohesin complex that maintains a chromosome conformation that restricts KSHV lytic cycle transcription. ER stress-induced cleavage of RAD21 alters the KSHV chromosome conformation associated with latency, and a locus-specific increase in RNA polymerase II association and activation. These findings provide new insights into the regulation of KSHV latency and its response to ER stress, and may further the development of selective treatments for KSHV associated PEL and related malignancies.

Restoration of immune surface molecules in Kaposi sarcoma-associated herpes virus infected cells by lenalidomide and pomalidomide

Kaposi sarcoma-associated herpesvirus (KSHV) is the cause of several tumors, including Kaposi sarcoma and primary effusion lymphoma (PEL). Most viruses have evolved means of escaping immune recognition. KSHV downregulates MHC-I expression during lytic infection, and expression of ICAM-1 and B7-2 (CD86) during latent infection, allowing evasion of T cell and natural killer immunity respectively. These effects are largely mediated by two KSHV-encoded proteins, K3 and K5. We show here that lenalidomide (Len) and pomalidomide (Pom) prevent down-regulation of MHC-I during lytic activation, and restore ICAM-1 and B7-2 surface expression in latently infected PEL cells. Importantly, these changes occurred at clinically achievable concentrations and prior to any cytotoxic effects. Exploration of the mechanism revealed that Pom blocked lytic down-regulation of MHC-I induced by transfection with K3 but not K5. Although Pom alone did not significantly increase HLA mRNA expression in PEL cells, it did blunt the butyrate-induced decrease in MHC-I mRNA expression and decreased the upregulation of K3 mRNA in lytic cells. Virus-induced tumors express foreign antigens, but immunotherapy can be thwarted by viral strategies to evade immune recognition. The effects of Pom and Len described here can prevent these strategies and support the use of these drugs to treat KSHV-induced tumors.

Methylseleninic acid and sodium selenite induce severe ER stress and subsequent apoptosis through UPR activation in PEL cells

Selenium compounds such as methylseleninic acid (MSA) and sodium selenite (SS) have been widely evaluated as potential anti-cancer agents in the clinical setting. Primary effusion lymphoma (PEL) is a non-Hodgkin's B-cell lymphoma, associated with immunosuppressed individuals, such as post-transplant or AIDS patients. Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of PEL and Kaposi's sarcoma. Here, we found that MSA and SS markedly inhibited the growth of PEL cells compared with KSHV-uninfected B cells. MSA and SS caused ER stress, inducing the unfolded protein response (UPR) pathway in PEL cells that resulted in pro-apoptotic UPR, and finally apoptosis. The expression of UPR-related molecules (GRP78 and GADD34) and pro-apoptotic UPR molecules (CHOP, Bim, or Puma) were augmented in PEL cells treated with MSA or SS. In addition, these compounds induced the activation of caspase-4, an ER stress specific caspase, as well as caspase-3,-7, and -9 in PEL cells. We confirmed that thapsigargin which is an inducer of ER stress, dramatically decreased the viability of PEL cells, compared with KSHV-uninfected Ramos cells. We also investigated whether MSA or SS caused oxidization of cellular proteins in PEL cells. MSA and SS increased the levels of oxidative proteins in PEL cells, and the anti-oxidant agent (N-acetyl-l-cysteine) restored cell viability and suppressed caspase-7 activation in PEL cells treated with MSA or SS. Finally, we confirmed that MSA and SS induced neither lytic replication nor viral production in PEL cells. Taken together, MSA and SS could serve as lead compounds for the development of novel and effective drugs against PEL without the risk of de novo KSHV production.

Phase II Trial of Lenalidomide in HIV-Infected Patients with Previously Treated Kaposi's Sarcoma: Results of the ANRS 154 Lenakap Trial

Lenalidomide, an oral immunomodulating agent, has shown promising activity in HIV-infected individuals with Kaposi's sarcoma (KS). This single-arm, multicenter, open-label, Gehan's two-stage phase II trial evaluated the efficacy and safety of lenalidomide in HIV-infected patients with progressive KS despite previous chemotherapy (NCT01282047, ANRS 154 Lenakap trial). The primary endpoint was the rate of partial response (PR) or complete response (CR) at week 24, evaluated by both the study investigators and the patients using the Physical Global Assessment (PGA). AIDS Clinical Trials Group (ACTG) criteria for KS treatment evaluation were used as a secondary endpoint. The data and safety monitoring board recommended that enrollments be halted on April 24, 2013, because of lack of responses. We enrolled 12 antiretroviral-treated HIV-infected men with progressive KS despite previous chemotherapy. Their HIV plasma viral load was <50 copies/ml and their median CD4 cell count 444/mm³. One patient stopped taking lenalidomide because of hives at week 1 and a second patient died at week 7. The remaining 10 patients were assessable at week 24, when none had PGA-defined CR or PR and one had ACTG-defined PR. There were no additional PGA responses at week 48, but an additional three patients had ACTG responses, for a total of four patients with ACTG PR at week 48 (40%; 95% confidence interval: 12.2-73.8). Fourteen grade 3-4 adverse events were considered at least possibly related to lenalidomide during a total of 101 cycles. Lenalidomide was well tolerated in antiretroviral experienced patients with progressive KS previously treated with chemotherapy. The ACTG-defined response rate at week 48 was 40%, while it was 0% using PGA criteria.

The Aurora kinase inhibitors in cancer research and therapy

Compounds that affect enzymatic function of kinases are valuable for the understanding of the complex biochemical processes in cells. Aurora kinases (AURKs) play a key role in the control of the mitosis. These kinases are frequently deregulated in different human cancers: overexpression, amplifications, translocations and deletions were reported in many cancer cell lines as well as patient tissues. These findings steered a rigorous hunt for small-molecule AURK inhibitors not only for research purposes as well as for therapeutic uses. In this review, we describe a number of AURK inhibitors and their use in cancer research and/or therapy. We hope to assist researchers and clinicians in deciding which inhibitor is most appropriate for their specific purpose. The review will also provide a broad overview of the clinical studies performed with some of these inhibitors (if such studies have been performed).

Effects of ER stress on unfolded protein responses, cell survival, and viral replication in primary effusion lymphoma

Primary effusion lymphoma (PEL), a subtype of non-Hodgkin's B-lymphoma, is an aggressive neoplasm caused by Kaposi's sarcoma-associated herpesvirus (KSHV) in immunosuppressed patients. Endoplasmic reticulum (ER) stress induces activation of the unfolded protein response (UPR), which induces expression of ER chaperones, which in turn decrease ER stress, leading to ER homeostasis. The UPR is necessary for not only ER homeostasis but also persistent infection by, and replication of, many viruses. However, the precise roles and regulation of the UPR in KSHV infection remain poorly understood. Here, we found that IRE1α and PERK were significantly downregulated in PEL cells cultured under normal conditions, compared with KSHV-uninfected B-lymphoma cells. IRE1α and PERK mRNA levels were decreased in PEL cells, and KSHV-encoded LANA and v-cyclin D led to suppressed IRE1α transcription. Thapsigargin-induced ER stress activated the UPR and increased the mRNA levels of UPR-related molecules, including IRE1α and PERK, in PEL cells. However the IRE1α and PERK mRNA levels in PEL cells were lower than those in KSHV-uninfected cells. Furthermore, ER stress induced by brefeldin A and thapsigargin dramatically reduced the viability of PEL cells, compared with KSHV-uninfected cells, and induced apoptosis of PEL cells via the pro-apoptotic UPR through expression of CHOP and activation of caspase-9. In addition to the pro-apoptotic UPR, thapsigargin-induced ER stress enhanced transcription of lytic genes, including RTA, K-bZIP and K8.1, and viral production in PEL cells resulted in induction of the lytic cycle. Thus, we demonstrated downregulation of IRE1α and PERK in PEL cells, transcriptional suppression of IRE1α by LANA and v-cyclin D, apoptosis induction in PEL cells by ER stress, and potentiation of lytic replication by ER stress.

Primary Effusion Lymphoma: Cytological Diagnosis of a Rare Entity--Report of Two Cases in HIV-Uninfected Patients from a Single Institution

BACKGROUND

Primary effusion lymphoma (PEL) is a Kaposi's sarcoma-associated herpesvirus (KSHV)-related large B-cell lymphoma often affecting immunocompromised adults. However, several cases in nonimmunocompromised elderly patients have been reported. It usually occurs as a massive, serosal effusion without tumoral masses and lymphadenopathies. The most frequent diagnostic materials are cytological smears, displaying large lymphocytes with variable morphological aspects but with a specific 'null-cell' phenotype associated with the expression of KSHV-related latency-associated nuclear antigen.

CASES

We report 2 cases of PEL that occurred in elderly, HIV-uninfected patients. In the first case, an 83-year-old man presented with severe dyspnea of 1 week duration. Radiological images documented pericardial effusion causing cardiac tamponade, without lymphadenopathies and solid masses. In the second case, an HIV-uninfected 94-year-old man was affected by anorexia, fatigue, shortness of breath and nonproductive cough. Radiological studies revealed bilateral pleural effusion, without evidence of abnormal lymphadenopathies and lung and/or pleural masses. Thoracentesis was immediately performed. Cytological evaluations of pericardial (first case) and pleural (second case) fluid effusion showed anaplastic and immunoblastic lymphocytes, respectively, expressing LCA/CD45, CD30 and KSHV.

CONCLUSION

Albeit rare, PEL should be kept in mind in the diagnostic algorithm of serosal cytological evaluation in elderly HIV-uninfected patients.

Merkel cell carcinoma presenting as malignant ascites: A case report and review of literature

The most common site of metastasis to ascitic fluid in females is from a mullerian (ovarian) primary, whereas in males it is from the gastrointestinal tract. Metastatic Merkel cell carcinoma (MCC) to the ascitic fluid is extremely rare and may present as a diagnostic challenge on effusion cytology. In a review of the literature, there are only two case reports of metastatic MCC in pleural effusion. To the best of our knowledge, we present the first cytological diagnosis of MCC metastatic to the ascitic fluid. We describe the cytologic findings as well as the immunohistochemical stains supportive of the diagnosis. Given the fatal prognosis of this tumor compared to melanoma and rarity of its occurrence in ascitic fluid, awareness of this tumor and use of immunohistochemical stains are critical in arriving at the diagnosis.

Immunomodulatory drugs target IKZF1-IRF4-MYC axis in primary effusion lymphoma in a cereblon-dependent manner and display synergistic cytotoxicity with BRD4 inhibitors

Primary effusion lymphoma (PEL) is an aggressive type of non-Hodgkin lymphoma localized predominantly in body cavities. Kaposi’s sarcoma-associated herpes virus is the causative agent of PEL. PEL is an incurable malignancy and has extremely poor prognosis when treated with conventional chemotherapy. Immunomodulatory drugs (IMiDs) lenalidomide and pomalidomide are FDA approved drugs for the treatment of various ailments. IMiDs display pronounced anti-proliferative effect against majority of PEL cell lines within their clinically achievable concentrations, by arresting cells at G₀/G₁ phase of cell-cycle, and without any induction of KSHV lytic-cycle reactivation. Although microarray examination of PEL cells treated with lenalidomide revealed activation of interferon (IFN) signaling, blocking the IFN pathway did not block the anti-PEL activity of IMiDs. The anti-PEL effects of IMiDs involved cereblon-dependent suppression of IRF4 and rapid degradation of IKZF1, but not IKZF3. Small hairpin-RNA (shRNA) mediated knockdown of MYC enhanced the cytotoxicity of IMiDs. Bromodomain and extraterminal domain (BET) proteins are epigenetic readers which perform a vital role in chromatin remodeling and transcriptional regulation. BRD4, a widely expressed transcriptional coactivator, belongs to BET family of proteins, which has been shown to co-occupy the super-enhancers associated with MYC. Specific BRD4 inhibitors were developed which suppress MYC transcriptionally. Lenalidomide displayed synergistic cytotoxicity with several structurally distinct BRD4 inhibitors (JQ-1, IBET151, and PFI-1). Furthermore, combined administration of lenalidomide and BRD4 inhibitor JQ-1 significantly increased the survival of PEL bearing NOD.SCID mice in an orthotopic xenograft model as compared to either agent alone. These results provide compelling evidence for clinical testing of IMiDs alone and in combination with BRD4 inhibitors for PEL.

Primary effusion lymphoma in the absence of HIV infection--clinical presentation and management

Primary Effusion Lymphoma (PEL) is a rare type of Non-Hodgkin's Lymphoma caused by human herpesvirus type 8, also termed Kaposi's sarcoma-associated herpesvirus. It usually occurs in human immunodeficiency virus (HIV)-infected patients. A subset of patients is not infected with HIV and their treatment remains poorly defined. To clarify treatment issues in HIV-negative PEL patients, we report on two such patients who represent two opposing ends in the spectrum of treatment and review the literature regarding treatment options and patient outcomes. Either repeated cycles of chemotherapy or, surprisingly, drainage of the malignant effusions alone, proved very effective in our patients. The literature reveals additional treatment options which may be effective including immunochemotherapy, stem cell transplantation, antiviral treatment and immunomodulatory and targeted biological therapy. However, no controlled trials were found due to the rarity of the condition. In the absence of controlled trials, treatment decisions in PEL not associated with HIV must remain individual and patient-tailored.

HIV-associated non-Hodgkin lymphoma: viral origins and therapeutic options

HIV infection is associated with an increased risk of malignancy, especially B-cell lymphoid malignancies. Many of these lymphomas are further driven by concomitant infection with viruses such as Epstein-Barr virus or Human Herpesvirus 8, the latter being implicated in uncommon types of lymphomas seen in the setting of HIV-1 infection. Treatment outcomes have improved due to infusional chemotherapy, high-dose chemotherapy, and effective antiretroviral therapy. Successful functional cure of HIV-1 infection has been demonstrated with the use of allogeneic hematopoietic stem cell transplantation. This result spurred a change in the field of HIV-1 management so that, ultimately, the goals of therapy would shift from not only curing the underlying lymphoma, but also curing the HIV-1 infection. Treatment options will be discussed with an emphasis on hematopoietic cell-based therapy for the underlying HIV infection.

Current status of treatment for primary effusion lymphoma

Primary effusion lymphoma (PEL) is a rare and aggressive B-cell non-Hodgkin's lymphoma that usually presents with malignant effusions without tumor masses. An extracavitary or solid variant of PEL has also been described. Human herpes virus 8/Kaposi sarcoma-associated herpes virus (HHV-8/KSHV) is universally associated with the pathogenesis of PEL. More than 70% of cases occur with concurrent Epstein-Barr virus infection, but its relation to the pathogenesis is unknown. Patients are found in the context of immunosuppressive states (HIV-1 infection, post-organ transplantation). PEL is usually treated with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone)-like chemotherapy with antiretroviral therapy if HIV-1 is positive. However, it is generally resistant to chemotherapy with a short median survival of less than 6 months. The optimal treatment for PEL has not been established yet. More intensive chemotherapy, such as dose-adjusted EPOCH (DA-EPOCH; etoposide, prednisone, vincristine, cyclophosphamide and doxorubicin) and CDE (cyclophosphamide, doxorubicin, etoposide) are expected to show a favorable prognosis. Recently, the molecular steps in KSHV/HHV-8-driven oncogenesis have begun to be revealed, and molecular targeting therapies such as proteasome, NF-κB, cytokines and surface antigens would provide evidence for their clinical use.