Update on Kaposi's sarcoma and other HHV8 associated diseases. Part 2: pathogenesis, Castleman's disease, and pleural effusion lymphoma

Optical Coherence Tomography as a Valuable Tool for the Evaluation of Cutaneous Kaposi Sarcoma Treated with Imiquimod 5% Cream

Kaposi sarcoma (KS) is a rare disease that was not frequently identified before the widespread occurrence of AIDS. Even today, it remains a challenge for physicians to diagnose, particularly in its early stages, often requiring referral to specialists and further investigations. Dermoscopy, a non-invasive imaging technique, reveals a distinctive rainbow pattern that strongly indicates KS. Moreover, advanced imaging tools like optical coherence tomography (OCT) can provide additional information though specific disease-related patterns have not been fully established yet. These emerging techniques show promise in facilitating early diagnosis of skin-related KS and monitoring the effectiveness of treatments. However, biopsy remains the definitive method for confirming the disease. In this study, we present two cases of cutaneous Kaposi sarcoma, documented using OCT, both before and after treatment with imiquimod 5% cream. The study highlights the potential of OCT in evaluating disease progression and treatment response, as well as the usefulness of dermoscopy in detecting early indicators of KS. By integrating these advanced imaging techniques, the diagnosis and management of cutaneous KS could be improved, leading to timely interventions and better patient outcomes.

GNA14, GNA11, and GNAQ Mutations Are Frequent in Benign but Not Malignant Cutaneous Vascular Tumors

Cutaneous vascular tumors consist of a heterogeneous group of benign proliferations, including a range of hemangiomas and vascular malformations, as well as heterogeneous groups of both borderline and malignant neoplasms such as Kaposi’s sarcoma and angiosarcomas. The genetics of these tumors have been assessed independently in smaller individual cohorts making comparisons difficult. In our study, we analyzed a representative cohort of benign vascular proliferations observed in a clinical routine setting as well as a selection of malignant vascular proliferations. Our cohort of 104 vascular proliferations including hemangiomas, malformations, angiosarcomas and Kaposi’s sarcoma were screened by targeted next-generation sequencing for activating genetic mutations known or assumed to be potentially relevant in vascular proliferations. An association analysis was performed for mutation status and clinico-pathological parameters. Frequent activating hotspot mutations in GNA genes, including GNA14 Q205, GNA11 and GNAQ Q209 were identified in 16 of 64 benign vascular tumors (25%). GNA gene mutations were particularly frequent (52%) in cherry (senile) hemangiomas (13 of 25). In angiosarcomas, activating RAS mutations (HRAS and NRAS) were identified in three samples (16%). No activating GNA or RAS gene mutations were identified in Kaposi’s sarcomas. Our study identifies GNA14 Q205, GNA11 and GNAQ Q209 mutations as being the most common and mutually exclusive mutations in benign hemangiomas. These mutations were not identified in malignant vascular tumors, which could be of potential diagnostic value in distinguishing these entities.

Epidemiology and Genetic Variability of HHV-8/KSHV among Rural Populations and Kaposi's Sarcoma Patients in Gabon, Central Africa. Review of the Geographical Distribution of HHV-8 K1 Genotypes in Africa

Human herpesvirus 8 (HHV-8) is the etiological agent of all forms of Kaposi's sarcoma (KS). K1 gene studies have identified five major molecular genotypes with geographical clustering. This study described the epidemiology of HHV-8 and its molecular diversity in Gabon among Bantu and Pygmy adult rural populations and KS patients. Plasma antibodies against latency-associated nuclear antigens (LANA) were searched by indirect immunofluorescence. Buffy coat DNA samples were subjected to polymerase chain reaction (PCR) to obtain a K1 gene fragment. We studied 1020 persons; 91% were Bantus and 9% Pygmies. HHV-8 seroprevalence was 48.3% and 36.5% at the 1:40 and 1:160 dilution thresholds, respectively, although the seroprevalence of HHV-8 is probably higher in Gabon. These seroprevalences did not differ by sex, age, ethnicity or province. The detection rate of HHV-8 K1 sequence was 2.6% by PCR. Most of the 31 HHV-8 strains belonged to the B genotype (24), while the remaining clustered within the A5 subgroup (6) and one belonged to the F genotype. Additionally, we reviewed the K1 molecular diversity of published HHV-8 strains in Africa. This study demonstrated a high seroprevalence of HHV-8 in rural adult populations in Gabon and the presence of genetically diverse strains with B, A and also F genotypes.

Kaposi’s sarcoma manifested as lower gastrointestinal bleeding in a HIV/HBV-co-infected liver cirrhosis patient: A case report

BACKGROUND

Kaposi’s sarcoma (KS) is one of the most common cancers in human immunodeficiency virus (HIV)-positive patients and leads to a high prevalence of morbidity and mortality. It usually appears as cutaneous or mucous lesions. Patients with visceral KS are asymptomatic and clinically silent. As the disease advances, patients may progress from a normal condition to exhibiting severe symptoms.

CASE SUMMARY

A 27-year-old man presented with a 2-mo history of fever, bearing-down pain, and rectal bleeding. His hepatitis B virus DNA level was 2.7 ×10⁷ IU/mL. Abdominal computed tomography (CT) indicated liver cirrhosis. Before he was admitted to our hospital, he was diagnosed with HIV infection. His CD4 count was 24 cells/μL. Pelvic cavity CT suggested a thickened rectum wall accompanied by multiple enlarged lymph nodes. The patient was initially treated as having haemorrhoidal varices with bleeding, telbivudine for anti-hepatitis B virus treatment, and antibiotics for anti-infection. After half a month of treatment, the patient felt that his lower lumbus ache and bearing-down pain had not improved, and a colonoscopy was conducted. The result revealed a rectal mass that was histologically confirmed as KS with rectal spindle cells that were positive for cluster of differentiation 117 (CD117), CD34, human herpes virus 8, and CD31. He was administered systemic chemotherapy with 36 mg/d liposomal doxorubicin six times. The patient experienced no sign of lower gastrointestinal bleeding again.

CONCLUSION

This case highlights the diagnosis of primary KS with lower gastrointestinal bleeding in HIV-positive patients, which means visceral KS could not be excluded. The gold standard relies on colonoscopy and biopsy findings.

Non-Neoplastic and Benign Tumoral Lesions of the Thymic Gland: A Review and Update

The thymus is a dynamic organ that undergoes changes throughout life and can demonstrate a myriad of pathologic alterations. A number of benign entities of the thymus prove to be diagnostic dilemmas owing to their resemblance and association with true thymic tumors. These are usually discovered incidentally on routine imaging and most patients are either asymptomatic or present with signs and symptoms of compression of adjacent organs. The radiologic appearance of these lesions varies from simple cysts to complex masses that are suspicious for malignancy. The diagnosis is usually made purely on morphologic grounds, however, immunohistochemical stains can help rule out possible differential diagnoses. Surgical removal is usually curative in these lesions and recurrences are rare. The prognosis is excellent, however, some of these lesions may be associated with myasthenia gravis and/or thymomas. In this review, we describe non-neoplastic lesions and benign tumoral lesions of the thymus, with emphasis on the clinical, radiologic, and pathologic features. The differential diagnosis of each entity is also discussed.

Kaposi sarcoma in Southern Finland (2006-2018)

BACKGROUND

Kaposi sarcoma (KS) age-standardized incidence rate is below 0.3 per 100,000 in Nordic countries. Data on KS in Finland have been sparse.

METHODS

A retrospective review of all the patients with KS cases managed in the Helsinki University Central Hospital between 2006 and 2018.

RESULTS

Forty patients (median age at diagnosis 45 years, 38 males) were included. About 2.5 new cases were diagnosed per year (incidence 0.16 /100,000). The different subtypes of KS were: human immunodeficiency virus (HIV) (65%), classical KS (30%), and immunodepression (5%). Patients with HIV were significantly younger, more likely to have cutaneous lesions of the face, the trunk, and mucosal lesions, and KS within lymph nodes and inner organs. KS was diagnosed at the same time as HIV in 77% of cases, 28% with CD4-cell level above 300 cells/mm³ . Among the patients with classical KS (n = 12), 75% were of Finnish origin, 41% had a second primary malignancy diagnosed, and 25% had noninsulin dependent diabetes mellitus. Among HIV patients, 27% had another AIDS-related illness, 7% of the patients developed lymphoproliferative disorders, and 7% a hemophagocytic syndrome. Patients with HIV were always treated with antiviral therapy, with pegylated liposomal doxorubicin in 57% of the cases. Local radiotherapy was the main treatment for other KS types. None of the 5 deaths during follow-up was related to KS.

CONCLUSIONS

Classical KS (KS-CLA) occurs among native Finns, frequently with other present malignancies. Screening of HIV and other malignancies is warranted in new cases of KS.

Activation and counteraction of antiviral innate immunity by KSHV: an Update

The innate immune responses triggering production of type I interferons and inflammatory cytokines constitute a nonspecific innate resistance that eliminates invading pathogens including viruses. The activation of innate immune signaling through pattern recognition receptors (PRRs) is by sensing pathogen-associated molecular patterns derived from viruses. According to their distribution within cells, PRRs are classified into three types of receptors: membrane, cytoplasmic, and nuclear. Kaposi's sarcoma-associated herpesvirus (KSHV), a large DNA virus, replicates in the nucleus. Its genome is protected by capsid proteins during transport in the cytosol. Multiple PRRs are involved in KSHV recognition. To successfully establish latent infection, KSHV has evolved to manipulate different aspects of the host antiviral innate immune responses. This review presents recent advances in our understanding about the activation of the innate immune signaling in response to infection of KSHV. It also reviews the evasion strategies used by KSHV to subvert host innate immune detection for establishing a persistent infection.

Antiangiogenic Activity of Chemopreventive Drugs

Tumors growing within the host form dynamic aberrant tissue that consists of host components, including the stroma, an expanding vasculature and often chronic inflammation, in addition to the tumor cells themselves. These host components can contribute to, rather than limit, tumor expansion, whereas deprivation of vessel formation has the potential to confine tumors in small, clinically silent foci. Therapeutic inhibition of vessel formation could be best suited to preventive strategies aimed at the suppression of angiogenesis in primary tumors in subjects at risk, or of micrometastases after surgical removal of a primary tumor. Our analysis of potential cancer chemopreventive molecules including N-acetylcysteine, green tea flavonoids and 4-hydroxyphenyl-retinamide has identified antiangiogenic activities that could account -at least in part - for the tumor prevention effects observed with these compounds. These drugs appear to target common mechanisms of tumor angiogenesis that may permit identification of critical targets for antiangiogenic therapy and antiangiogenic chemoprevention.

Diagnostic value of medical thoracoscopy in malignant pleural effusion induced by non-Hodgkin's lymphoma

Malignant pleural effusion (MPE) appears in up to 20% of patients with non-Hodgkin's lymphoma (NHL). The present study aimed to assess the efficacy of medical thoracoscopy (MT) in the diagnosis of patients with MPE induced by NHL. Between July 2005 and June 2014, 833 patients with pleural effusions of unknown etiology underwent MT in Beijing Chaoyang Hospital (Beijing, China), where diagnostic thoracocentesis or/and blind pleural biopsy had failed to yield an answer. Demographic, radiographic, thoracoscopic, histological and immunophenotyping data of 10 NHL patients with MPE were then retrospectively analyzed. Under medical thoracoscopy, pleural nodules (in n=6 patients), hyperemia (n=5), plaque-like lesions (n=4), pleural thickening (n=3), cellulose (n=3), ulcer (n=2), adhesion (n=2), and scattered hemorrhagic spots (n=1) were observed on the surface of parietal pleura. Histopathological and immunohistochemical analysis of pleural biopsy samples led to a correct diagnosis of B-cell NHL in 7 patients and T-lymphoblastic NHL in 2 patients. Data from the present study demonstrated that pleural biopsy through MT achieved a definite diagnosis of NHL in 9 out of 10 (90%) patients with MPE induced by NHL. Therefore, MT is a useful method for diagnosing MPE induced by NHL.

Occurrence of renal cell carcinoma and hematologic malignancies (predominantly lymphoid) in individuals and in families

The relationship between renal cell cancer (RCC) and hematologic malignancy (HM) in the same individual has been reported for more than 20 years, and is noted in SEER database studies. Family histories suggest a familial association as well. This study evaluates the occurrence of renal cell cancer and hematologic malignancies in individual patients and families, and the occurrence of age-of-onset anticipation among generations. Family history data from our familial patient registry, including more than 700 pedigrees of familial hematologic malignancies, and 700 patients with renal cell cancer, were reviewed. Twenty-six patients with a personal history of both RCC and HM are reported. Seventy four patients with RCC are noted to have 95 family members with HM. Consistent with past reports, there was male predominance among the patients with both diseases (71 %), and among the RCC patients' relatives with HM (57 %). Also consistent was a predominance of lymphoid malignancies in those with both diseases (92 %) and in the HMs among family members of RCC patients (79 %). The majority (95 %) of HM relatives were first or second degree relatives of the patient with RCC. Thirty of 34 parent/child pairs demonstrated age of onset anticipation in which the child developed either disease at a younger age than the parent. The co-occurrence of RCC and HM in the same patient has been shown to be significantly greater than expected. Families also appear to have an increased association. The appearance of anticipation suggests that genetic factors may be significant in this association of RCC and HM.

Castleman Disease of the Thorax: Clinical, Radiologic, and Pathologic Correlation: From the Radiologic Pathology Archives

Castleman disease is a complex lymphoproliferative disease pathologically divided into two subtypes, the hyaline vascular variant (HVV) and the plasma cell variant (PCV). The HVV is the most common, is thought to represent a benign neoplasm of lymph node stromal cells, and is treated with surgical resection. It is most commonly found in the mediastinum, where it classically appears as a unicentric, avidly enhancing mass at computed tomography (CT) and magnetic resonance imaging. This appearance can mimic other avidly enhancing mediastinal masses, and location, clinical history, laboratory data, and nuclear medicine single photon emission CT (SPECT) and positron emission tomography (PET) studies can help narrow the differential diagnosis. Multicentric Castleman disease (MCD), which in the majority of cases is composed of the PCV, is an aggressive lymphoproliferative disorder associated with human herpesvirus infection, interleukin 6 dysregulation, and other systemic disorders. While it can be difficult to differentiate MCD from lymphoma, the presence of avidly enhancing lymph nodes can suggest the diagnosis. The purpose of this article is to review the clinical, immunologic, and pathologic findings associated with both unicentric Castleman disease and MCD and discuss how the imaging findings correlate with the pathophysiology of the disease.

HHV8/KSHV-Positive Lymphoproliferative Disorders and the Spectrum of Plasmablastic and Plasma Cell Neoplasms: 2015 SH/EAHP Workshop Report-Part 3

OBJECTIVES

The 2015 Workshop of the Society for Hematopathology/European Association for Haematopathology aimed to review immunodeficiency-related lymphoproliferative disorders with plasmablastic and plasma cell differentiation.

METHODS

The workshop panel reviewed human herpes virus 8 (HHV8)/Kaposi sarcoma herpesvirus (KSHV)-associated lesions and other lesions exhibiting plasma cell differentiation, including plasmablastic proliferations with features of myeloma/plasmacytoma, plasmablastic neoplasms presenting in extranodal sites and effusion-based lymphomas, and rendered a consensus diagnosis.

RESULTS

The spectrum of HHV8/KSHV-associated proliferations ranged from multicentric Castleman disease (MCD) to MCD with plasmablastic aggregates to HHV8+ diffuse large B-cell lymphoma and germinotrophic lymphoproliferative disorder. Comparisons across effusion-based lymphomas with and without HHV8/KSHV and plasmablastic lymphomas in immunodeficient and immunocompetent patients were discussed.

CONCLUSIONS

The presence or absence of HHV8/KSHV is a defining feature in disorders associated with Castleman disease, although their differential diagnosis and recognition of progression may be challenging. Plasmablastic proliferations overlap with myeloma/plasmacytoma as well as extranodal and effusion-based lymphomas. The involvement of Epstein-Barr virus is typically variable.

EBV reactivation as a target of luteolin to repress NPC tumorigenesis

Nasopharyngeal carcinoma (NPC) is a malignancy derived from the epithelial cells of the nasopharynx. Although a combination of radiotherapy with chemotherapy is effective for therapy, relapse and metastasis after remission remain major causes of mortality. Epstein-Barr virus (EBV) is believed to be one of causes of NPC development. We demonstrated previously that EBV reactivation is important for the carcinogenesis of NPC. We sought, therefore, to determine whether EBV reactivation can be a target for retardation of relapse of NPC. After screening, we found luteolin is able to inhibit EBV reactivation. It inhibited EBV lytic protein expression and repressed the promoter activities of two major immediate-early genes, Zta and Rta. Furthermore, luteolin was shown to reduce genomic instability induced by recurrent EBV reactivation in NPC cells. EBV reactivation-induced NPC cell proliferation and migration, as well as matrigel invasiveness, were also repressed by luteolin treatment. Tumorigenicity in mice, induced by EBV reactivation, was decreased profoundly following luteolin administration. Together, these results suggest that inhibition of EBV reactivation is a novel approach to prevent the relapse of NPC.

Modulation of gene expression in Kaposi’s sarcoma-associated herpesvirus-infected lymphoid and epithelial cells

Aim: To evaluate the gene expression changes that occur soon after the active infection of two susceptible cell types with human herpesvirus 8 (HHV-8). Materials & methods: The expression profile of 282 human genes involved in the inflammatory process was investigated in HHV-8 A1 or C3 subtype-infected and mock-infected human epithelial cells and lymphoid cells. Results: The HHV-8-induced transcriptional profiles in the epithelial and lymphoid cells were very different. A robust increase in the expression was found in genes belonging to different categories, especially the categories of inflammation response and signal transduction. Conclusion: These results indicate that during early infection, HHV-8 induces a variety of cell type-specific processes, thus providing infection signatures useful as potential targets for therapeutic intervention.

KSHV-Mediated Regulation of Par3 and SNAIL Contributes to B-Cell Proliferation

Studies have suggested that Epithelial-Mesenchymal Transition (EMT) and transformation is an important step in progression to cancer. Par3 (partitioning-defective protein) is a crucial factor in regulating epithelial cell polarity. However, the mechanism by which the latency associated nuclear antigen (LANA) encoded by Kaposi's Sarcoma associated herpesvirus (KSHV) regulates Par3 and EMTs markers (Epithelial-Mesenchymal Transition) during viral-mediated B-cell oncogenesis has not been fully explored. Moreover, several studies have demonstrated a crucial role for EMT markers during B-cell malignancies. In this study, we demonstrate that Par3 is significantly up-regulated in KSHV-infected primary B-cells. Further, Par3 interacted with LANA in KSHV positive and LANA expressing cells which led to translocation of Par3 from the cell periphery to a predominantly nuclear signal. Par3 knockdown led to reduced cell proliferation and increased apoptotic induction. Levels of SNAIL was elevated, and E-cadherin was reduced in the presence of LANA or Par3. Interestingly, KSHV infection in primary B-cells led to enhancement of SNAIL and down-regulation of E-cadherin in a temporal manner. Importantly, knockdown of SNAIL, a major EMT regulator, in KSHV cells resulted in reduced expression of LANA, Par3, and enhanced E-cadherin. Also, SNAIL bound to the promoter region of p21 and can regulate its activity. Further a SNAIL inhibitor diminished NF-kB signaling through upregulation of Caspase3 in KSHV positive cells in vitro. This was also supported by upregulation of SNAIL and Par3 in BC-3 transplanted NOD-SCID mice which has potential as a therapeutic target for KSHV-associated B-cell lymphomas.

Luteolin inhibits Epstein-Barr virus lytic reactivation by repressing the promoter activities of immediate-early genes

The lytic reactivation of Epstein-Barr virus (EBV) has been reported to be strongly associated with several human diseases, including nasopharyngeal carcinoma (NPC). Inhibition of the EBV lytic cycle has been shown to be of great benefit in the treatment of EBV-associated diseases. The administration of dietary compounds is safer and more convenient than other approaches to preventing EBV reactivation. We screened several dietary compounds for their ability to inhibit EBV reactivation in NPC cells. Among them, the flavonoid luteolin showed significant inhibition of EBV reactivation. Luteolin inhibited protein expression from EBV lytic genes in EBV-positive epithelial and B cell lines. It also reduced the numbers of EBV-reactivating cells detected by immunofluorescence analysis and reduced the production of virion. Furthermore, luteolin reduced the activities of the promoters of the immediate-early genes Zta (Zp) and Rta (Rp) and also inhibited Sp1-luc activity, suggesting that disruption of Sp1 binding is involved in the inhibitory mechanism. CHIP analysis revealed that luteolin suppressed the activities of Zp and Rp by deregulating Sp1 binding. Taken together, luteolin inhibits EBV reactivation by repressing the promoter activities of Zp and Rp, suggesting luteolin is a potential dietary compound for prevention of virus infection.

c-Myc and viral cofactor Kaposin B co-operate to elicit angiogenesis through modulating miRNome traits of endothelial cells

BACKGROUND

MicroRNAs (miRNAs) have emerged as master regulators of angiogenesis and other cancer-related events. Discovering new angiogenesis-regulating microRNAs (angiomiRs) will eventually help in developing new therapeutic strategies for tumor angiogenesis and cardiovascular diseases. Kaposi's sarcoma (KS), which is induced by the etiological infectious agent KS-associated herpesvirus (KSHV), is a peculiar neoplasm that expresses both blood and lymphatic endothelial markers and possesses extensive neovasculature. Using KSHV and its proteins as baits will be an efficient way to discover new angiomiRs in endothelial cells. Kaposin B is one of the latent viral genes and is expressed in all KSHV tumor cells. Since Kaposin B is a nuclear protein with no DNA-binding domain, it may regulate gene expression by incorporating itself into a transcription complex.

RESULTS

We demonstrated that c-Myc and Kaposin B form a transcription complex and bind to the miR-221/-222 promoter, thereby affecting their expression and anti-angiogenic ability. By small RNA sequencing (smRNA-Seq), we revealed that 72.1% (173/240) of Kaposin B up-regulated and 46.5% (113/243) of Kaposin B down-regulated known miRNAs were regulated by c-Myc. We also found that 77 novel miRNA were up-regulated and 28 novel miRNAs were down-regulated in cells expressing both c-Myc and Kaposin B compared with cells expressing Kaposin B only. The result was confirmed by RNA-IP-seq data.

CONCLUSIONS

Our study identifies known and novel c-Myc-regulated microRNAs and reveals that a c-Myc-oriented program is coordinated by Kaposin B in KSHV-infected cells.

Molecular biology of KSHV lytic reactivation

Kaposi’s sarcoma-associated herpesvirus (KSHV) primarily persists as a latent episome in infected cells. During latent infection, only a limited number of viral genes are expressed that help to maintain the viral episome and prevent lytic reactivation. The latent KSHV genome persists as a highly ordered chromatin structure with bivalent chromatin marks at the promoter-regulatory region of the major immediate-early gene promoter. Various stimuli can induce chromatin modifications to an active euchromatic epigenetic mark, leading to the expression of genes required for the transition from the latent to the lytic phase of KSHV life cycle. Enhanced replication and transcription activator (RTA) gene expression triggers a cascade of events, resulting in the modulation of various cellular pathways to support viral DNA synthesis. RTA also binds to the origin of lytic DNA replication to recruit viral, as well as cellular, proteins for the initiation of the lytic DNA replication of KSHV. In this review we will discuss some of the pivotal genetic and epigenetic factors that control KSHV reactivation from the transcriptionally restricted latent program.

KSHV reactivation and novel implications of protein isomerization on lytic switch control

In Kaposi’s sarcoma-associated herpesvirus (KSHV) oncogenesis, both latency and reactivation are hypothesized to potentiate tumor growth. The KSHV Rta protein is the lytic switch for reactivation. Rta transactivates essential genes via interactions with cofactors such as the cellular RBP-Jk and Oct-1 proteins, and the viral Mta protein. Given that robust viral reactivation would facilitate antiviral responses and culminate in host cell lysis, regulation of Rta’s expression and function is a major determinant of the latent-lytic balance and the fate of infected cells. Our lab recently showed that Rta transactivation requires the cellular peptidyl-prolyl cis/trans isomerase Pin1. Our data suggest that proline‑directed phosphorylation regulates Rta by licensing binding to Pin1. Despite Pin1’s ability to stimulate Rta transactivation, unchecked Pin1 activity inhibited virus production. Dysregulation of Pin1 is implicated in human cancers, and KSHV is the latest virus known to co-opt Pin1 function. We propose that Pin1 is a molecular timer that can regulate the balance between viral lytic gene expression and host cell lysis. Intriguing scenarios for Pin1’s underlying activities, and the potential broader significance for isomerization of Rta and reactivation, are highlighted.

Lymphoid hyperplasia and lymphoma in KSHV K1 transgenic mice

Growing evidence supports the involvement of human herpervirus 8, Kaposi's sarcoma associated herpesvirus (KSHV), in the pathology of primary effusion lymphoma, multicentric Castleman's disease, and Kaposi's sarcoma, but the exact mechanism of KSHV contribution to the oncogenic process remains elusive. We studied transgenic mice expressing the ORF K1 of KSHV, whose position in the KSHV genome corresponds to known lymphoproliferative genes of other herpesviruses. K1 protein was previously shown to contain a constitutively active ITAM domain, involved in activation of Akt and pro-survival signaling, and to inhibit Fas-mediated apoptosis by interfering with binding of FasL. All this pointed to a possible role of K1 in the pathogenesis of KSHV-associated cancers. K1 transgenic mice (80-90%) developed lymphoid hyperplasia and splenomegaly at 8 and 10 months of age, 25% had confirmed diagnosis of lymphoma, and 50% developed abdominal and/or hepatic tumors by 18 months of age. Histological examination showed loss of splenic architecture and increased cellularity. Lymph nodes showed disrupted architecture with effaced follicles and other pathological changes, including signs of angiofollicular lymphoid hyperplasia. One of the livers showed signs of angiosarcoma. In summary, our histology results revealed pathological changes in K1 transgenic mice similar to lymphoma, Castleman's disease, and angiosarcoma, suggesting that K1 may contribute to the development of KSHV-associated cancers.

Skin cancer in kidney transplant recipients

Morbidity and mortality due to skin cancer is excessively high in renal transplant recipients compared to the general population. This epidemiologic difference is mainly due to the severe immunosuppression that enhances ultraviolet-induced DNA damage and leads to reactivation of potential oncogenic viruses. The most common skin cancer in transplant recipients is squamous cell carcinoma followed by basal cell carcinoma, while in the general population this ratio is reversed. Melanoma and cutaneous lymphoma are relatively rare although they occur more frequently in transplant patients than in the general population. Notably some tumors, such as Kaposi's sarcoma, are seldom encountered in the general population while they are frequently observed in transplant recipients. Local recurrences and visceral spreading are not so uncommon and pose a major issue for quality of life and overall prognosis of these patients. Timely diagnosis is essential and may be challenging, since the accuracy of clinical diagnosis is modest; thus skin biopsy is an essential tool for appropriate management. In this review, we describe the most common types of skin cancer in renal transplant recipients, with a focus on pathogenic issues that account for the different epidemiology and clinical expression of these neoplasms in this population.

Surgical Management of Unicentric Castleman's Disease in the Abdomen

Castleman's disease (CD) is a rare lymphoproliferative disorder that can involve single or multiple lymph nodes in the body. Especially, the localized form of CD is known to be well-controlled by using a surgical resection. On occasion, the surgeon may confront an abdominal and retroperitoneal mass of unknown origin. Thus, we present this case in which we treated a 16-year-old female patient for CD and investigated how to evaluate and manage the situation from the standpoint of CD. Also, we give a review of the pathology, clinical manifestation, diagnosis, and treatment of CD.

A case of multicentric Castleman's disease in HIV infection with the rare complication of acquired angioedema

Multicentric Castleman's disease (MCD), a polyclonal lymphoproliferative disorder of unknown aetiology, is a well-recognised complication of HIV disease. We present a case of MCD in an HIV-positive patient that is unusual on two counts: our patient's MCD first presented in the context of an immune restoration inflammatory syndrome (IRIS), following the initiation of highly active antiretroviral therapy (HAART). In addition, her MCD was associated with the unusual complication of acquired angioedema (AAE), which resolved following treatment of the MCD. While AAE is frequently found to have an underlying diagnosis of a lymphoproliferative disease, this is the first reported case linking AAE to MCD.

Castleman's disease and primary effusion lymphoma in a HIV-positive patient

We present a case of primary effusion lymphoma (PEL) occurring simultaneously with Castleman's disease in the same patient. Castleman's disease is distinct from PEL, although both are associated with HHV-8. Other cases have debated whether the coexistence of PEL and Castleman's disease is a recurrence of an original PEL tumour in an extracavitary site, or a secondary HHV-8-associated lymphoma distinct from primary PEL. Our case, along with those described previously, show that co-occurrence of PEL and Castleman's disease is possible and plausible. PEL needs to be included in the differential diagnosis in any HIV-positive patient who presents with a pleural effusion, and diagnosis requires only a simple thoracentesis and appropriate immunohistochemistry.

The inflammatory kinase MAP4K4 promotes reactivation of Kaposi's sarcoma herpesvirus and enhances the invasiveness of infected endothelial cells

Kaposi's sarcoma (KS) is a mesenchymal tumour, which is caused by Kaposi's sarcoma herpesvirus (KSHV) and develops under inflammatory conditions. KSHV-infected endothelial spindle cells, the neoplastic cells in KS, show increased invasiveness, attributed to the elevated expression of metalloproteinases (MMPs) and cyclooxygenase-2 (COX-2). The majority of these spindle cells harbour latent KSHV genomes, while a minority undergoes lytic reactivation with subsequent production of new virions and viral or cellular chemo- and cytokines, which may promote tumour invasion and dissemination. In order to better understand KSHV pathogenesis, we investigated cellular mechanisms underlying the lytic reactivation of KSHV. Using a combination of small molecule library screening and siRNA silencing we found a STE20 kinase family member, MAP4K4, to be involved in KSHV reactivation from latency and to contribute to the invasive phenotype of KSHV-infected endothelial cells by regulating COX-2, MMP-7, and MMP-13 expression. This kinase is also highly expressed in KS spindle cells in vivo. These findings suggest that MAP4K4, a known mediator of inflammation, is involved in KS aetiology by regulating KSHV lytic reactivation, expression of MMPs and COX-2, and, thereby modulating invasiveness of KSHV-infected endothelial cells.

Kaposi's sarcoma (KS) is a tumour caused by Kaposi's sarcoma herpesvirus (KSHV) and dysregulated inflammation. Both factors contribute to the high angiogenicity and invasiveness of KS. Various cellular kinases have been reported to regulate the KSHV latent-lytic switch and thereby virus pathogenicity. In this study, we have identified a STE20 kinase family member – MAP4K4 – as a modulator of KSHV lytic cycle and invasive phenotype of KSHV-infected endothelial cells. Moreover, we were able to link MAP4K4 to a known mediator of inflammation and invasiveness, cyclooxygenase-2, which also contributes to KSHV lytic replication. Finally, we could show that MAP4K4 is highly expressed in KS lesions, suggesting an important role for this kinase in tumour development and invasion.

Carcinogenic viruses and solid cancers without sufficient evidence of causal association

Viral infections are important risk factors for tumor development in humans. Selected types of cancers, either lymphomas or carcinomas, for which there is sufficient evidence in humans of a causal association with specific viruses, have been identified. Experimental and clinical data on the possible association of other tumor types and carcinogenic viruses are presently controversial. In this article, we review the current evidence on the relationship between breast, colorectal and lung cancers and carcinogenic viruses. The majority of the publications reviewed do not provide definitive evidence that the viruses studied are associated with breast, colon and lung cancers. However, since this association may be clinically relevant for some tumor subtypes (i.e., lung cancer and papillomaviruses), there is an urgent need for further investigation on this topic. Using innovative laboratory techniques for viral detection on well-defined tumor types, National and International networks against cancer should encourage and organize concerted research programs on viruses and solid cancer association.

Clinical characteristics and outcomes of HIV-infected children diagnosed with Kaposi sarcoma in Malawi and Botswana

BACKGROUND

Kaposi sarcoma (KS) is the most common HIV-associated malignancy in sub-Saharan Africa. The presentation and outcomes of pediatric KS are not well understood.

PROCEDURE

We performed a retrospective cohort analysis of 81 HIV-infected children with KS at the Baylor Children's Clinical Centres of Excellence in Malawi and Botswana from March 2003 to October 2009.

RESULTS

Eighty-one children with KS were identified whose median age was 8.0 (inter-quartile range 5.1-11.3) years. KS lesions were presented primarily on the skin (83%), lymph nodes (52%), and oral mucosa (41%). Occasionally disease was limited to the lymph nodes only (10%). Severe immunosuppression (70%), anemia (29%), and thrombocytopenia (17%) were common laboratory findings. Highly active antiretroviral therapy (HAART) was administered to 94% of children, including 77% who received HAART plus chemotherapy. KS immune reconstitution inflammatory syndrome (IRIS) occurred in 22%. Disease status 12 months after KS diagnosis was determined for 69 children: 43% were alive and 57% had died. Severe immunosuppression was independently associated with mortality in multivariate analysis (OR = 4.3; 95% CI 1.3-14.6; P = 0.02).

CONCLUSION

KS occurs in a significant number of HIV infected children in sub-Saharan Africa. Pediatric KS is distinct from KS in adults. Lymph node involvement was a common manifestation of KS in children, and severe immunosuppression was associated with the highest mortality risk. Though overall mortality was high in children with KS, patients did achieve clinical remission in settings with limited diagnostic and therapeutic resources.

Dangerous liaisons: molecular basis for a syndemic relationship between Kaposi's sarcoma and P. falciparum malaria

The most severe manifestations of malaria (caused by Plasmodium falciparum) occur as a direct result of parasitemia following invasion of erythrocytes by post-liver blood-stage merozoites, and during subsequent cyto-adherence of infected erythrocytes to the vascular endothelium. However, the disproportionate epidemiologic clustering of severe malaria with aggressive forms of endemic diseases such as Kaposi's sarcoma (KS), a neoplasm that is etiologically linked to infection with KS-associated herpesvirus (KSHV), underscores the significance of previously unexplored co-pathogenetic interactions that have the potential to modify the overall disease burden in co-infected individuals. Based on recent studies of the mechanisms that P. falciparum and KSHV have evolved to interact with their mutual human host, several new perspectives are emerging that highlight a surprising convergence of biological themes potentially underlying their associated co-morbidities. Against this background, ongoing studies are rapidly constructing a fascinating new paradigm in which the major host receptors that control parasite invasion (Basigin/CD147) and cyto-adherence (CD36) are, surprisingly, also important targets for exploitation by KSHV. In this article, we consider the major pathobiological implications of the co-option of Basigin/CD147 and CD36 signaling pathways by both P. falciparum and KSHV, not only as essential host factors for parasite persistence but also as important mediators of the pro-angiogenic phenotype within the virus-infected endothelial microenvironment. Consequently, the triangulation of interactions between P. falciparum, KSHV, and their mutual human host articulates a syndemic relationship that points to a conceptual framework for prevalence of aggressive forms of KS in malaria-endemic areas, with implications for the possibility of dual-use therapies against these debilitating infections in resource-limited parts of the world.

Role of infectious agents in the carcinogenesis of brain and head and neck cancers

This review concentrates on tumours that are anatomically localised in head and neck regions. Brain cancers and head and neck cancers together account for more than 873,000 cases annually worldwide, with an increasing incidence each year. With poor survival rates at late stages, brain and head and neck cancers represent serious conditions. Carcinogenesis is a multi-step process and the role of infectious agents in this progression has not been fully identified. A major problem with such research is that the role of many infectious agents may be underestimated due to the lack of or inconsistency in experimental data obtained globally. In the case of brain cancer, no infection has been accepted as directly oncogenic, although a number of viruses and parasites are associated with the malignancy. Our analysis of the literature showed the presence of human cytomegalovirus (HCMV) in distinct types of brain tumour, namely glioblastoma multiforme (GBM) and medulloblastoma. In particular, there are reports of viral protein in up to 100% of GBM specimens. Several epidemiological studies reported associations of brain cancer and toxoplasmosis seropositivity. In head and neck cancers, there is a distinct correlation between Epstein-Barr virus (EBV) and nasopharyngeal carcinoma (NPC). Considering that almost every undifferentiated NPC is EBV-positive, virus titer levels can be measured to screen high-risk populations. In addition there is an apparent association between human papilloma virus (HPV) and head and neck squamous cell carcinoma (HNSCC); specifically, 26% of HNSCCs are positive for HPV. HPV type 16 was the most common type detected in HNSCCs (90%) and its dominance is even greater than that reported in cervical carcinoma. Although there are many studies showing an association of infectious agents with cancer, with various levels of involvement and either a direct or indirect causative effect, there is a scarcity of articles covering the role of infection in carcinogenesis of brain and head and neck cancers. We review recent studies on the infectious origin of these cancers and present our current understanding of carcinogenic mechanisms, thereby providing possible novel approaches to cancer treatment.

Upregulation of human β-defensin-3 and cathelicidin LL-37 in Kaposi's sarcoma

Background: Kaposi’s sarcoma (KS) is a rare neoplasm of lymphatic endothelial cells. Human herpes virus 8 (HHV-8) is considered to be a necessary, but not sufficient causal agent of KS and additional cofactors remain unknown. In this study we evaluated the expression of human β defensin (HBD)-3 and LL-37 in cutaneous lesions of KS in comparison to the healthy skin of normal subjects.

Methods: We performed a quantitative immunohistochemical study of HBD-3 and LL-37 on skin lesions from 18 patients having KS, and on healthy skin from 12 normal controls.

Results: HBD-3 and LL-37 were significantly upregulated in epidermal and dermal specimens of all KS patients in comparison to normal skin of healthy controls. The immunostaining score of dermal HBD-3 was significantly higher in nodular lesions (9.6 ± 2.4) versus plaque lesions (4.1 ± 2.2), P = 0.001. Also the immunostaining score of dermal LL-37 was significantly higher in nodular lesions versus plaque lesions (P = 0.001).

Conclusions: We have demonstrated for the first time that HBD-3 and LL-37 are significantly upregulated in lesional skin of KS in comparison to the skin of healthy controls. The obtained data suggest a possible involvement of these antimicrobial peptides in the pathogenesis of KS. However, the biological significance of HBD-3 and LL-37 in KS lesions needs further research.

Castleman disease in a pediatric liver transplant recipient: a case report and literature review

Castleman disease is a rare hematologic disorder, closely linked to the HHV-8, and most commonly observed in immunocompromised individuals. Thirteen months following a liver transplant for CPS-1 defect, a 15-month-old boy presented with fevers, anemia, and growth retardation. Abdominal CT scan showed splenomegaly and generalized lymphadenopathy. Histology of chest wall lymph nodes revealed a mixed CD3+ T-cell and CD20+ B-cell population with atretic germinal centers consistent with multicentric Castleman disease. Qualitative DNA PCR detected HHV-8 in the resected lymph node and in the blood, supporting the diagnosis. Immunosuppression was tapered, and he was transitioned from tacrolimus to sirolimus. His graft function remained stable, and repeat imaging showed regression of the lymphadenopathy. The child is living one yr after Castleman disease diagnosis with a well-functioning graft. Castleman disease is a potential complication of solid organ transplant and HHV-8 infection. Reduction in immunosuppression and switch to sirolimus may be an effective strategy to treat this condition.

Surgery in Castleman's disease: a systematic review of 404 published cases

OBJECTIVES

We undertook a systematic review of 404 published cases of Castleman's disease to identify the role of the surgeon beyond assistance in tissue-based diagnosis.

BACKGROUND

Castleman's disease is a rare primary disease of the lymph node caused by infection with herpesviridae. Little is known about the role of surgery in this condition.

DATA SOURCES

Medline, Embase, Cochrane Database of Systematic Reviews, ISI Thompson Web of Knowledge, and hand search of articles' bibliography.

STUDY SELECTION

Of the 1791 citations identified through the initial electronic search and screened for possible inclusion, 488 articles were retained after title and abstract reviews. Of these, 239 were accepted for this review.

DATA EXTRACTION

A complete dataset containing age, gender, centricity (unicentric vs multicentric), histopathologic type (hyaline vascular [HV] vs plasma cell [PC]), anatomical location of the only focus in unicentric Castleman's disease (UCD) or the dominant focus in multicentric Castleman's disease (MCD), nature of the surgical approach (resective vs diagnostic), and outcome (disease-free survival [DFS] vs death due to disease) was extracted.

RESULTS

A resective or debulking surgical approach was described in 77.0% of all patients, but was far more common in unicentric (262/278; 94.2%) than multicentric (49/126; 38.9%) disease (χ² 146.8; P < 0.0001). Unicentric disease had a significantly higher overall survival (95.3% vs 61.1%; χ² 55.7; P < 0.0001), 3 year DFS (89.7% vs 55.6%; χ² 27.8; P < 0.0001), and 5 year DFS (81.2% vs 34.4%; χ² 28.6; P < 0.0001) than multicentric disease. Failure to treat unicentric disease by resective surgery resulted in a significant mortality (17.6% vs 3.8% χ²; P < 0.05). In multicentric disease, outcomes are comparable between debulking surgery alone, immunochemotherapy alone, or a combination of both (28.0% vs 28.9% vs 50.0%; P = nonsignificant).

CONCLUSIONS

Surgery is the gold standard for treatment of unicentric Castelman's disease. The role of debulking surgery in human immunodeficiency virus (-) MCD needs to be evaluated in prospective studies.

The incidence of human herpes virus-8 expression in lymph node biopsies from human immunodeficiency virus-positive patients

AIMS

Human immunodeficiency virus (HIV)-related lymphadenopathy is characterized by a wide spectrum of histological changes. Three patterns have been described which correspond to clinical stages of HIV/acquired immune deficiency syndrome (AIDS). Castleman disease is a heterogeneous group of disorders. A recently described variant, multicentric Castleman disease (MCD), of which some cases are associated with human herpes virus-8 (HHV-8), has been reported in both HIV-seropositive and -negative patients. Considerable morphological overlap occurs between one of the patterns of HIV lymphadenopathy and this variant.

METHODS AND RESULTS

This retrospective histopathological study on 95 cases of HIV-reactive lymphadenopathy assessed the incidence of the different patterns and HHV-8 on immunohistochemistry (IHC). Of the 95 cases, 78 (82.1%) were HHV-8-negative, of which 46 (59.0%) were classified as pattern A, 20 (25.6%) as pattern B and 12 (15.4%) as pattern C. Nine (31.0%) of 29 cases with pattern B and 8 (40.0%) of 20 cases with pattern C were HHV-8 positive. In total 15 cases of MCD were diagnosed in this series.

CONCLUSION

This study draws attention to the overlap between HIV lymphadenopathy and MCD. We recommend that cases of HHV-8-associated MCD should be investigated for HIV infection.

A computational profiling of changes in gene expression and transcription factors induced by vFLIP K13 in primary effusion lymphoma

Infection with Kaposi's sarcoma associated herpesvirus (KSHV) has been linked to the development of primary effusion lymphoma (PEL), a rare lymphoproliferative disorder that is characterized by loss of expression of most B cell markers and effusions in the body cavities. This unique clinical presentation of PEL has been attributed to their distinctive plasmablastic gene expression profile that shows overexpression of genes involved in inflammation, adhesion and invasion. KSHV-encoded latent protein vFLIP K13 has been previously shown to promote the survival and proliferation of PEL cells. In this study, we employed gene array analysis to characterize the effect of K13 on global gene expression in PEL-derived BCBL1 cells, which express negligible K13 endogenously. We demonstrate that K13 upregulates the expression of a number of NF-κB responsive genes involved in cytokine signaling, cell death, adhesion, inflammation and immune response, including two NF-κB subunits involved in the alternate NF-κB pathway, RELB and NFKB2. In contrast, CD19, a B cell marker, was one of the genes downregulated by K13. A comparison with K13-induced genes in human vascular endothelial cells revealed that although there was a considerable overlap among the genes induced by K13 in the two cell types, chemokines genes were preferentially induced in HUVEC with few exceptions, such as RANTES/CCL5, which was induced in both cell types. Functional studies confirmed that K13 activated the RANTES/CCL5 promoter through the NF-κB pathway. Taken collectively, our results suggest that K13 may contribute to the unique gene expression profile, immunophenotype and clinical presentation that are characteristics of KSHV-associated PEL.

Plasma-cell type Castleman's disease of the neck and lymphocyte-depletion Hodgkin lymphoma associated with intestinal intussusception in an AIDS patient

A 36-year-old man was diagnosed with plasma-cell type Castleman's disease with the presentation of recurrent lymphadenpathy of the neck. HIV infection was not suspected or confirmed until esophageal candidiasis developed one year later. Meanwhile, surgery was performed for intestinal intussusception and obstruction caused by lymphocyte-depletion Hodgkin lymphoma. However, he died of rapidly progressive pneumonia and disseminated intravascular coagulation associated with intracerebral hemorrhage, which occurred 6 months later during the course of chemotherapy. This case suggests that HIV infection should be considered in patients who present with plasma-cell type Castleman's disease or lymphocyte-depletion Hodgkin lymphoma with extra-nodal involvement in order to conduct appropriate diagnosis and initiate treatment for HIV infection.

Immune reconstitution inflammatory syndrome of Kaposi's sarcoma in an HIV-infected patient

We present a case of Kaposi's sarcoma-related immune reconstitution inflammatory syndrome in an HIV-infected patient who developed fever, worsening pulmonary infiltrates with respiratory distress, and progression of skin tumors at the popliteal region and thigh that resulted in limitation on movement of the right knee joint at 3.5 months following a significant increase of CD4 count after combination antiretroviral therapy.

Kaposi's sarcoma: imaging overview

Kaposi's sarcoma (KS), a low-grade malignancy that is associated with human herpesvirus-8 (HHV-8), is a multifocal tumor that most commonly affects mucocutaneous sites. It might also involve lymph nodes and visceral organs, in particular of the respiratory and gastrointestinal tract, but it can affect every organ system. Four forms of the disease have been recognized: the classic, the endemic, the transplant-associated, and the epidemic form. The endemic form, or African KS, currently accounts for 10%-50% of all cancers in adults and up to 25% of cancers in children in certain parts of Africa. The epidemic form or acquired immune deficiency syndrome (AIDS)-associated KS is a frequent neoplasm in bisexual and homosexual men with AIDS in the United States. Even though in North America and Europe the incidence of KS in men with AIDS has decreased significantly after the introduction of highly active antiretroviral therapy (HAART), in some developing countries, the incidence of KS keeps growing. The pathophysiology, clinical manifestations, imaging findings, and more relevant differential diagnoses are reviewed.

Characterization of Kaposi's Sarcoma-Associated Herpesvirus-Related Lymphomas by DNA Microarray Analysis

Among herpesviruses, γ-herpesviruses are supposed to have typical oncogenic activities. Two human γ-herpesviruses, Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV), are putative etiologic agents for Burkitt lymphoma, nasopharyngeal carcinoma, and some cases of gastric cancers, and Kaposi's sarcoma, multicentric Castleman's disease, and primary effusion lymphoma (PEL) especially in AIDS setting for the latter case, respectively. Since such two viruses mentioned above are highly species specific, it has been quite difficult to prove their oncogenic activities in animal models. Nevertheless, the viral oncogenesis is epidemiologically and/or in vitro experimentally evident. This time, we investigated gene expression profiles of KSHV-oriented lymphoma cell lines, EBV-oriented lymphoma cell lines, and T-cell leukemia cell lines. Both KSHV and EBV cause a B-cell-originated lymphoma, but the gene expression profiles were typically classified. Furthermore, KSHV could govern gene expression profiles, although PELs are usually coinfected with KSHV and EBV.

AIDS-related primary Kaposi sarcoma of the nasopharynx

Primary nasopharyngeal Kaposi sarcoma is extremely rare, as only 1 case has been previously reported in the literature. We report a new case, which occurred in a 37-year-old man with a known history of acquired immune deficiency syndrome (AIDS). The patient presented with complaints of recurrent epistaxis and postnasal hemorrhage. Endoscopic examination detected a bluish, smooth, firm, nonpulsatile mass in the nasopharyngeal wall. Histopathologic findings on biopsy were consistent with Kaposi sarcoma. The tumor was successfully treated with radiotherapy. Kaposi sarcoma should be considered in the differential diagnosis of any AIDS patient who presents with recurrent unilateral nasal bleeding.

EBV-positive diffuse large B-cell lymphoma of the elderly: a case series from Peru

EBV-positive diffuse large B-cell lymphoma (DLBCL) of the elderly is an entity recently included in the WHO classification of lymphoid tumors. We have reviewed our experience and clinical outcomes of this distinct subtype of DLBCL. Between 2002 and 2009, cases of DLBCL were identified from medical records of the Hospital Nacional Edgardo Rebagliati Martins in Lima, Peru, and underwent pathological evaluation including immunohistochemistry for CD20, CD10, bcl-6, MUM1/IRF4, and EBV-encoded RNA in situ hybridization. Clinical data were gathered, tabulated, and reported descriptively. Survival analyses were performed using Kaplan-Meier estimates. Out of 199 cases of DLBCL, 28 cases of EBV-positive DLBCL of the elderly were identified. The median age was 75 years with male predominance (1.5:1). B-symptoms were present in 43%, advanced stage in 50% and International Prognostic Index (IPI) score > 2 in 57% of patients; 68% of patients had a nongerminal center (NGC) phenotype. The complete response rates to R-CHOP and CHOP were 63% and 33%, respectively. The median overall survival (OS) for the group was 5 months. In the univariate analysis, age ≥70 years, lymphocyte count <1.0 × 10(9) /L, and advanced clinical stage were associated with worse OS in patients treated with chemotherapy with and without rituximab. EBV-positive DLBCL of the elderly is a clinically aggressive entity with a short OS and typically presents with advanced stage, high IPI score, and a NGC phenotype. Further studies are needed to investigate if rituximab-containing regimens are associated with better response and OS rates in EBV-positive DLBCL of the elderly.

Castleman's disease: systematic analysis of 416 patients from the literature

BACKGROUND

Castleman's disease is a rare primary disease of the lymph nodes with limited available clinical information.

METHODS

A systematic literature search identified 416 cases amenable to detailed analysis.

RESULTS

In HIV(-) patients, centricity, pathology type, the presence of symptoms, gender, and age all predict outcome in univariate analyses. The 3-year disease-free survival (DFS) rate for patients with unicentric hyaline vascular disease (49.5% of cases, class I) was 92.5%, versus 45.7% for those with multicentric plasma cell disease (20.2% of cases, class III) and 78.0% for those with any other combination (22.6% of cases, class II) (p < .0001). HIV(+) patients (class IV) exclusively presented with multicentric plasma cell disease and had a 3-year DFS rate of only 27.8%. Kaposi's sarcoma and lymphoma were observed in 59.3% and 9.4% of HIV(+) patients and in 2.6% and 3.6% of HIV(-) patients (p < .0001). Paraneoplastic pemphigus and the syndrome of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes were observed exclusively in HIV(-) patients at a rate of 1.3% and 1.8%, respectively.

CONCLUSION

Clinical, pathological, and viral markers allow for the classification of Castleman's disease into groups with markedly different outcomes and disease associations.

The manipulation of miRNA-gene regulatory networks by KSHV induces endothelial cell motility

miRNAs have emerged as master regulators of cancer-related events. miRNA dysregulation also occurs in Kaposi sarcoma (KS). Exploring the roles of KS-associated miRNAs should help to identify novel angiogenesis and lymphangiogenesis pathways. In the present study, we show that Kaposi sarcoma-associated herpesvirus (KSHV), the etiological agent of KS, induces global miRNA changes in lymphatic endothelial cells (LECs). Specifically, the miR-221/miR-222 cluster is down-regulated, whereas miR-31 is up-regulated. Both latent nuclear antigen (LANA) and Kaposin B repress the expression of the miR-221/miR-222 cluster, which results in an increase of endothelial cell (EC) migration. In contrast, miR-31 stimulates EC migration, so depletion of miR-31 in KSHV-transformed ECs reduces cell motility. Analysis of the putative miRNA targets among KSHV-affected genes showed that ETS2 and ETS1 are the downstream targets of miR-221 and miR-222, respectively. FAT4 is one of the direct targets of miR-31. Overexpression of ETS1 or ETS2 alone is sufficient to induce EC migration, whereas a reduction in FAT4 enhances EC motility. Our results show that KSHV regulates multiple miRNA-mRNA networks to enhance EC motility, which eventually contributes to KS progression by promoting the spread of malignant KS progenitor cells. Targeting KSHV-regulated miRNAs or genes might allow the development of novel therapeutic strategies that induce angiogenesis or allow the treatment of pathogenic (lymph)angiogenesis.

Constitutive NF-kappaB activation confers interleukin 6 (IL6) independence and resistance to dexamethasone and Janus kinase inhibitor INCB018424 in murine plasmacytoma cells

Myeloma cells are dependent on IL6 for their survival and proliferation during the early stages of disease, and independence from IL6 is associated with disease progression. The role of the NF-κB pathway in the IL6-independent growth of myeloma cells has not been studied. Because human herpesvirus 8-encoded K13 selectively activates the NF-κB pathway, we have used it as a molecular tool to examine the ability of the NF-κB pathway to confer IL6 independence on murine plasmacytomas. We demonstrated that ectopic expression of K13, but not its NF-κB-defective mutant or a structural homolog, protected plasmacytomas against IL6 withdrawal-induced apoptosis and resulted in emergence of IL6-independent clones that could proliferate long-term in vitro in the absence of IL6 and form abdominal plasmacytomas with visceral involvement when injected intraperitoneally into syngeneic mice. These IL6-independent clones were dependent on NF-κB activity for their survival and proliferation but were resistant to dexamethasone and INCB018424, a selective Janus kinase 1/2 inhibitor. Ectopic expression of human T cell leukemia virus 1-encoded Tax protein, which resembles K13 in inducing constitutive NF-κB activation, similarly protected plasmacytoma cells against IL6 withdrawal-induced apoptosis. Although K13 is known to up-regulate IL6 gene expression, its protective effect was not due to induction of endogenous IL6 production but instead was associated with sustained expression of several antiapoptotic members of the Bcl2 family upon IL6 withdrawal. Collectively, these results demonstrate that NF-κB activation cannot only promote the emergence of IL6 independence during myeloma progression but can also confer resistance to dexamethasone and INCB018424.

Differentially regulated splice variants and systems biology analysis of Kaposi's sarcoma-associated herpesvirus-infected lymphatic endothelial cells

Alternative RNA splicing greatly increases proteome diversity, and the possibility of studying genome-wide alternative splicing (AS) events becomes available with the advent of high-throughput genomics tools devoted to this issue. Kaposi's sarcoma associated herpesvirus (KSHV) is the etiological agent of KS, a tumor of lymphatic endothelial cell (LEC) lineage, but little is known about the AS variations induced by KSHV. We analyzed KSHV-controlled AS using high-density microarrays capable of detecting all exons in the human genome. Splicing variants and altered exon–intron usage in infected LEC were found, and these correlated with protein domain modification. The different 3′-UTR used in new transcripts also help isoforms to escape microRNA-mediated surveillance. Exome-level analysis further revealed information that cannot be disclosed using classical gene-level profiling: a significant exon usage difference existed between LEC and CD34⁺ precursor cells, and KSHV infection resulted in LEC-to-precursor, dedifferentiation-like exon level reprogramming. Our results demonstrate the application of exon arrays in systems biology research, and suggest the regulatory effects of AS in endothelial cells are far more complex than previously observed. This extra layer of molecular diversity helps to account for various aspects of endothelial biology, KSHV life cycle and disease pathogenesis that until now have been unexplored.