Advances in the pathobiology and treatment of Kaposi sarcoma

Modulation of diverse oncogenic signaling pathways by oroxylin A: An important strategy for both cancer prevention and treatment

BACKGROUND

Regardless of major advances in diagnosis, prevention and treatment strategies, cancer is still a foreboding cause due to factors like chemoresistance, radioresistance, adverse side effects and cancer recurrence. Therefore, continuous development of unconventional approaches is a prerequisite to overcome foregoing glitches. Natural products have found their way into treatment of serious health conditions, including cancer since ancient times. The compound oroxylin A (OA) is one among those with enormous potential against different malignancies. It is a flavonoid obtained from the several plants such as Oroxylum indicum, Scutellaria baicalensis and S. lateriflora, Anchietea pyrifolia, and Aster himalaicus.

PURPOSE

The main purpose of this study is to comprehensively elucidate the anticancerous effects of OA against various malignancies and unravel their chemosensitization and radiosensitization potential. Pharmacokinetic and pharmacodynamic studies of OA have also been investigated.

METHOD

The literature on antineoplastic effects of OA was searched in PubMed and Scopus, including in vitro and in vivo studies and is summarized based on a systematic review protocol prepared according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The term "oroxylin A" was used in combination with "cancer" and all the title, abstracts and keywords appeared were considered.

RESULTS

In Scopus, a total of 157 articles appeared out of which 103 articles that did not meet the eligibility criteria were eliminated and 54 were critically evaluated. In PubMed, from the 85 results obtained, 26 articles were eliminated and 59 were included in the preparation of this review. Mounting number of studies have illustrated the anticancer effects of OA, and its mechanism of action.

CONCLUSION

OA is a promising natural flavonoid possessing wide range of pleiotropic properties and is a potential anticancer agent. It has a great potential in the treatment of multiple cancers including brain, breast, cervical, colon, esophageal, gall bladder, gastric, hematological, liver, lung, oral, ovarian, pancreatic and skin. However, lack of pharmacokinetic studies, toxicity assessments, and dose standardization studies and adverse effects limit the optimization of this compound as a therapeutic agent.

Kaposi sarcoma

Kaposi sarcoma (KS) is a low-grade vascular tumor associated with Kaposi sarcoma herpesvirus/human herpesvirus 8 (KSHV/HHV8) infection. Kaposi sarcoma lesions predominantly present at mucocutaneous sites, but may involve all organs and anatomic locations. Recognized epidemiologic-clinical forms of KS include classic, African (endemic), AIDS-associated (epidemic), and iatrogenic KS. New clinical manifestations have been described, such as antiretroviral therapy-related KS regression or flares. Kaposi sarcoma lesions evolve from early (patch stage) macules into plaques (plaque stage) that grow into larger nodules (tumor stage). Newer histologic variants include anaplastic, hyperkeratotic, lymphangioma-like, bullous, telangiectatic, ecchymotic, keloidal, pyogenic granuloma-like, micronodular, intravascular, glomeruloid and pigmented KS, as well as KS with sarcoidlike granulomas and KS with myoid nodules. Latency-associated nuclear antigen (HHV8) is the most specific immunohistochemical marker available to help distinguish KS from its mimics. Since KS remains one of the most common AIDS-defining malignancies, it is important that pathologists be able to recognize KS and its contemporary manifestations.

HIV/AIDS-associated Kaposi's sarcoma with multiple skin-mucosal disseminations following ultraviolet (puva) photochemotherapy

HIV/AIDS infection in Bulgaria has spread over about 1200 registered patients and it is supposed that the number of the undetected cases is four times higher. Kaposi's sarcoma is rarely observed in our country and no cutaneous-mucosal dissemination is reported for the time being.

AIM

The aim of the study is to present a case of disseminated Kaposi's sarcoma in a HIV/ AIDS patient who underwent Psoralen--UVA radiation treatment (PUVA) for total alopecia.

METHODS

HIV was proved through ELISA and Western blot (InnoLia HIV I/II Score). PCR method (COBAS-Amplicor HIV-1 MT, 1,5) was used to determine viral load (VL). Monitoring was realized by flow-cytometric phenotype analysis of the immune cells. Biopsy of a skin lesion was performed for histomorphological analysis. Computed axial tomography (CAT) of the visceral organs was also applied.

RESULTS

The patient's face, chest, back and upper extremities are covered by more than 50 typical for Kaposi's sarcoma skin tumors and several isolated lesions are found in the oral cavity mucosa. The histological results show dilated vascular spaces with large endothelial cells and spindle-like tumor cells in irregularly formed fascicles. Monitoring of the immune cells and the viral load before and after the application of highly active antiretroviral therapy (HAART) showed CD4+ T cell number = 0.147 x 10(9)/l and VL = 216 000 copies HIV-RNA/ml plasma when the disorder was first detected. A very good effect appeared 4 months after the HAART start: the mucous membrane lesions disappeared and the skin tumors decreased by number and dimensions. In the same time the CD4+ T cell number increased up to 0.255 x 10(9)/l and VL values decreased < 400 c/ml.

CONCLUSION

Disseminated form of Kaposi's sarcoma can be provoked by additional immunosuppressive factors like the implementation of PUVA therapy. Early initiation of HAART improves the process and prevents visceral dissemination.

Kaposin-B enhances the PROX1 mRNA stability during lymphatic reprogramming of vascular endothelial cells by Kaposi's sarcoma herpes virus

Kaposi's sarcoma (KS) is the most common cancer among HIV-positive patients. Histogenetic origin of KS has long been elusive due to a mixed expression of both blood and lymphatic endothelial markers in KS tumor cells. However, we and others discovered that Kaposi's sarcoma herpes virus (KSHV) induces lymphatic reprogramming of blood vascular endothelial cells by upregulating PROX1, which functions as the master regulator for lymphatic endothelial differentiation. Here, we demonstrate that the KSHV latent gene kaposin-B enhances the PROX1 mRNA stability and plays an important role in KSHV-mediated PROX1 upregulation. We found that PROX1 mRNA contains a canonical AU-rich element (ARE) in its 3′-untranslated region that promotes PROX1 mRNA turnover and that kaposin-B stimulates cytoplasmic accumulation of the ARE-binding protein HuR through activation of the p38/MK2 pathway. Moreover, HuR binds to and stabilizes PROX1 mRNA through its ARE and is necessary for KSHV-mediated PROX1 mRNA stabilization. Together, our study demonstrates that kaposin-B plays a key role in PROX1 upregulation during lymphatic reprogramming of blood vascular endothelial cells by KSHV.

Kaposi's sarcoma (KS) is the most common cancer in HIV-positive patients and KS-associated herpes virus (KSHV) was identified as its causing agent. We and others have discovered that when the virus infects endothelial cells of blood vessels, KSHV reprograms the cell type resembling endothelial cells in lymphatic vessels. Although endothelial cells of the blood vascular system and of the lymphatic system share functional similarities, the cell type-reprogramming does not occur under a normal physiological condition. Therefore, cell-fate reprogramming by the cancer-causing virus KSHV provides an important insight into the molecular mechanism for viral pathogenesis. Our current study investigates the molecular mechanism underlying the KSHV-mediated cell fate reprogramming. We identified that a KSHV latent gene kaposin-B plays an important role in KSHV-mediated regulation of PROX1 to promote PROX1 mRNA stability. This study will provide a better understanding on the tumorigenesis and pathogenesis of KS with a potential implication toward new KS therapy.

Non-HIV-related Kaposi's sarcoma in former colonists/expatriates in Central Africa

Two cases of Kaposi's sarcoma (KS) that occurred in patients who had no evident risk factors for KS but who were former colonists/expatriates in Central Africa are reported. The occurrence of KS in this setting may represent a hitherto unrecognized epidemiological form of KS.

Kaposi sarcoma: a continuing conundrum

Kaposi sarcoma (KS) remains a challenge. Its classic or Mediterranean form tends to be benign. In transplant recipients it may be less so. As part of the AIDS pandemic, of which it was an original defining component, it may be life-threatening. It is due to human herpesvirus-8, which is necessary but not sufficient to produce the disease. KS has a low prevalence in the general population of the United States and United Kingdom, with an intermediate rate in Italy and Greece, and a high one in parts of Africa. In Italy, hot spots include its southern regions, the Po River Valley, and Sardinia, possibly related to a high density of blood-sucking insects. An important challenge is to treat KS patients without immunocompromising them. The potential of effective anti-herpes virus therapy and the use of sirolimus in transplantation recipients have added new opportunities for KS prevention.

LEARNING OBJECTIVES

At the conclusion of this learning activity, participants should be able to provide the most recent information about Kaposi sarcoma in the context in which it occurs. Its classic or Mediterranean form, its pattern in transplant recipients and others iatrogenically immunosuppressed, and its occurrence as a potentially life-threatening part of the AIDS pandemic will be stressed. Its etiology and transmission will be discussed in detail to facilitate understanding of Kaposi sarcoma and of human herpesvirus-8 infection in the general population of the United States and United Kingdom, in Italy and Greece, and in certain parts of Africa. Its therapy, including the concept of doing it without immunocompromising the patient, will be stressed. New opportunities for Kaposi sarcoma prevention will also be discussed.

Malignant tumors of blood vessels: angiosarcomas, hemangioendotheliomas, and hemangioperictyomas

Sarcomas that arise from or resemble the components of blood vessels are uncommon and include angiosarcomas, hemangioendotheliomas, and hemangiopericytomas. This article reviews the management of these three types of sarcomas. Diagnosis can sometimes be difficult, with the diagnosis of hemangiopericytoma versus solitary fibrous tumor currently in debate. Each of these sarcomas subtypes has certain unique clinical traits. The mainstay of treatment is surgical resection, sometimes combined with radiation therapy. Adjuvant chemotherapy is unproven but can be considered. For patients with advanced disease, various chemotherapeutic regimens may result in meaningful responses in a minority of patients.

Spinal Kaposi sarcoma presenting without cutaneous manifestations. Case report

Kaposi sarcoma (KS) is one of the most common tumors in patients with human immunodeficiency virus (HIV), which characteristically presents with cutaneous lesions. The authors report a rare case of spinal KS with no cutaneous manifestation in a 32-year-old man with the acquired immunodeficiency syndrome who presented with abdominal pain. A computed tomography scan revealed incidental lesions in his lumbar spine, and additional imaging studies revealed numerous lesions in the lumbosacral spine and pelvis. An open biopsy was performed, and histopathological examination of the lesion confirmed the diagnosis of KS. At the time of presentation, the patient had no skin lesion or any other manifestation indicative of KS. The authors suggest that in HIV-positive patients who present with spinal lesions, KS should be included in the differential diagnosis.

Immunohistological evaluation of immune cell infiltrate in cutaneous Kaposi's sarcoma

Typically, Kaposi's sarcoma (KS) also presents with immune cell infiltrates. This study does immunophenotype characterization for demographics of some of these cells to test the hypothesis that 'development of end-stage (nodular/tumor) KS is associated with numeric alteration in immune cell infiltrates.' Fifteen cases of classic-KS (nodular/tumor) and 20 normal biopsies were examined using antigen-antibody reactions and immunoperoxidase staining for histiocytes (CD68), B cells (CD20) and T cells (CD3). Variations between normal and lesions were observed with significant increases in immune cell infiltrates (2.3+/-0.6 vs. 6.4+/-0.4); CD68(+) (4.0+/-1.0 vs. 7.0+/-0.5); CD3(+) (3.0+/-1.1 vs. 10.1+/-0.8); and CD20(+) (0.0+/-0.0 vs. 0.3+/-0.0). Increased density of immune cells in the nodular lesions of KS may reflect increased antigenicity of these lesions; the increase in T cells suggests enhanced T cell activity in KS. However, these issues should be tested by further studies.

In vivo-restricted and reversible malignancy induced by human herpesvirus-8 KSHV: a cell and animal model of virally induced Kaposi's sarcoma

Transfection of a Kaposi's sarcoma (KS) herpesvirus (KSHV) Bacterial Artificial Chromosome (KSHVBac36) into mouse bone marrow endothelial-lineage cells generates a cell (mECK36) that forms KS-like tumors in mice. mECK36 expressed most KSHV genes and were angiogenic, but they didn't form colonies in soft agar. In nude mice, mECK36 formed KSHV-harboring vascularized spindle cell sarcomas that were LANA+/podoplanin+, overexpressed VEGF and Angiopoietin ligands and receptors, and displayed KSHV and host transcriptomes reminiscent of KS. mECK36 that lost the KSHV episome reverted to nontumorigenicity. siRNA suppression of KSHV vGPCR, an angiogenic gene upregulated in mECK36 tumors, inhibited angiogenicity and tumorigenicity. These results show that KSHV malignancy is in vivo growth restricted and reversible, defining mECK36 as a biologically sensitive animal model of KSHV-dependent KS.

Oncologic Complications of Human Immunodeficiency Virus Infection: Changing Epidemiology, Treatments, and Special Considerations in the Era of Highly Active Antiretroviral Therapy

Although highly active antiretroviral therapy (HAART) has revolutionized the treatment of human immunodeficiency virus (HIV)-positive patients, malignancies in the setting of HIV infection remain an appreciable problem. We evaluated the changing epidemiology of HIV-related malignancies, optimal neoplastics and their effect on viral dynamics, and evidence regarding drug interactions between chemotherapy and antiretrovirals. A MEDLINE search (January 1966-June 2006) was performed to identify clinical trials, review articles, and meta-analyses; abstracts from HIV conferences were also searched. Survival of patients with HIV-related malignancies has substantially improved since the advent of HAART. Chemotherapy for malignancies in the HIV-positive population generally resembles that for the HIV-negative population, with trials revealing an elevated frequency of toxicities in HIV-positive patients. Studies of antineoplastics have shown no long-term adverse effects on viral dynamics in terms of immunologic or virologic HIV markers. Limited pharmacokinetic data with antineoplastics and antiretrovirals suggest possible changes in some pharmacokinetic parameters, but these results should be interpreted cautiously because of the small numbers of patients enrolled in the trials. Researchers also report an increased frequency of chemotherapy-related toxicities when HAART was coadministered with antineoplastics. This increase was likely due to impairment of cytochrome P450 metabolism of antineoplastics by protease inhibitors. Because of the survival benefits of HAART, the integration of antiretrovirals with chemotherapy is now preferred for patients with HIV-related malignancies. However, because the metabolic pathways of many of these agents are similar, the effectiveness of antineoplastic therapy and its related toxicities should be vigilantly monitored in this patient population.

Matrix metalloproteinases in the progression and regression of Kaposi's sarcoma

BACKGROUND

Matrix metalloproteinases (MMPs) are associated with Kaposi's sarcoma (KS) tumorigenesis. To date, only a few MMPs have been studied in KS lesions. Their role in KS regression has not been investigated. The aim of this study was to evaluate the expression of multiple MMPs in developing and pharmacologically regressed KS lesions.

METHODS

Nine samples of acquired immune deficiency syndrome (AIDS)-related and classic cutaneous KS lesions at various histological stages were studied. Regressing KS lesions from three patients treated with systemic therapy were procured after one and two cycles of chemotherapy. Tissue sections from all specimens were immunostained using monoclonal antibodies to MMP-1, MMP-2, MMP-3, MMP-7, MMP-9, MMP-13, and MMP-14.

RESULTS

KS lesional cells were immunoreactive for all MMPs, except MMP-14. Admixed inflammatory cells were immunoreactive for MMP-1, MMP-2, MMP-7, MMP-9, and MMP-13. The MMP immunoprofile in residual KS lesional cells was unaltered in regressed lesions. Increased extracellular matrix (ECM) and macrophage immunoreactivity for MMPs was identified in regressed specimens.

CONCLUSIONS

These data show that developing KS lesional cells express collagenases (MMP-1, MMP-13), gelatinases (MMP-2, MMP-9), stromelysin-1 (MMP-3), and matrilysin (MMP-7) but not the membrane-type MMP-14. This MMP expression profile is retained by residual KS cells and also expressed by infiltrating macrophages in regressed KS lesions. Pantanowitz L, Dezube BJ, Hernandez-Barrantes S, Tahan SR, Dabbous MK. Matrix metalloproteinases in the progression and regression of Kaposi's sarcoma.

Role of environmental factors in the pathogenesis of classic and African-endemic Kaposi sarcoma

Kaposi sarcoma (KS) is a mesenchymal tumour associated with human herpesvirus-8 (HHV-8) infection. However, the incidence of HHV-8 infection is far higher than the prevalence of KS, suggesting that viral infection per se is not sufficient for the development of aggressive phenotype and that one or more additional cofactors are required. The great geographical variation in African-endemic and classic KS incidence points to a role for environmental factors in the etiology of Kaposi sarcoma. However, there are few unequivocably established environmental factors involved in KS pathogenesis. This review focuses on the environmental factors thought to be associated with KS, more particularly iron exposure and facilitation of transmission of HHV-8 infection by contact with blood-sucking arthropods.

Posttransplant Kaposi's sarcoma restricted to the site of a previous deep venous thrombosis: abrupt onset after withdrawal of sirolimus

Kaposi's sarcoma (KS) is an angioproliferative neoplasia associated with human herpesvirus 8 (HHV-8) infection. HHV-8 generates KS by means of the secretion of vascular endothelial growth factor (VEGF) andup-regulation of VEGF receptor, KDR, in endothelial cells. We report a case of KS in a 72-year-old male with a renal transplant who had received immunosuppressant drugs including sirolimus, mycophenolate mofetil, tacrolimus and steroids. KS developed 11 months after transplantation, in relation to deep venous thrombosis and withdrawal of sirolimus due to toxicity. Multiple purple papules and nodules were observed exclusively in the limb affected by thrombosis. Diagnosis of KS was confirmed by biopsy. Progressive withdrawal of prednisone was accompanied by full remission of the tumour. The thrombosis and withdrawal of sirolimus may have acted as cofactors in the development of KS, favouring the activation of the VEGF/KDR autocrine loop. Our experience contributes to further evidence that sirolimus may protect against KS.

The impact of highly active antiretroviral therapy on the incidence and outcomes of AIDS-defining cancers in Southern Alberta

OBJECTIVES

To determine the impact of highly active antiretroviral therapy (HAART) on the incidence and outcomes of Kaposi's sarcoma (KS), non-Hodgkin's lymphoma (NHL) and invasive cervical cancer/dysplasia in a well-defined geographical HIV-infected population between 1984 and 2005.

METHODS

A clinic database search, chart review and verification with public health records were undertaken for all AIDS-defining cancers diagnosed in Southern Alberta before and after the introduction of HAART.

RESULTS

A total of 2,137 patients with 9,265 person-years of HIV follow-up care were reviewed. One hundred and forty-three cases of KS, 64 cases of NHL and 11 cases of invasive cervical cancer/dysplasia were identified. KS and NHL together accounted for 15% of clinical presentations with an AIDS-defining illness that led to the HIV diagnosis. Following the introduction of HAART, the reduced number of severely immunocompromised patients was associated with 92 and 84% reductions in new diagnoses of KS and NHL, respectively, which were seen mainly in clinic patients declining or failing HAART. Crude reductions of 94 and 65% in mortality from KS and NHL, respectively, were also seen. The prevalences of KS, NHL and invasive cervical cancer/dysplasia have recently stabilized at 3, 1 and 5% of the population, respectively.

CONCLUSIONS

The introduction of HAART has dramatically reduced the incidence of KS and NHL and improved survival from these cancers for most patients in HIV care. However, patients still present with KS and NHL leading to their HIV diagnosis.

The TSC2/mTOR pathway drives endothelial cell transformation induced by the Kaposi's sarcoma-associated herpesvirus G protein-coupled receptor

The Kaposi's sarcoma-associated herpesvirus (KSHV), the infectious causative agent of Kaposi's sarcoma (KS), encodes a G protein-coupled receptor (vGPCR) implicated in the initiation of KS. Here we demonstrate that Kaposi's sarcomagenesis involves stimulation of tuberin (TSC2) phosphorylation by vGPCR, promoting the activation of mTOR through both direct and paracrine mechanisms. Pharmacologic inhibition of mTOR with rapamycin prevented vGPCR sarcomagenesis, while overactivation of this pathway was sufficient to render endothelial cells oncogenic. Moreover, mice haploinsufficient for TSC2 are predisposed to vascular sarcomas remarkably similar to KS. Collectively, these results implicate mTOR in KS initiation and suggest that the sarcomagenic potential of KSHV may be a direct consequence of the profound sensitivity of endothelial cells to vGPCR dysregulation of the TSC2/mTOR pathway.

Kaposi's sarcoma–associated herpesvirus/human herpesvirus 8 infection in reactive lymphoid tissues: a model for KSHV/HHV-8–related lymphomas?

We set out to analyze the presence of Kaposi's sarcoma-associated herpesvirus (KSHV)/human herpesvirus 8 (HHV-8) in different neoplasms occurring in East Africa, a region characterized by a high KSHV/HHV-8 seroprevalence rate and endemic Kaposi's sarcoma (KS). Our results suggest that, in endemic regions of Africa, KSHV/HHV-8 is predominantly associated with KS, independently of HIV status. During the course of this study, other important information came to light. We found the presence of KSHV/HHV-8 in 2 cases of lymph nodes partially involved by Burkitt's lymphoma and KS and in 1 case of multicentric Castleman disease. Our immunophenotypic and molecular data seem to suggest 2 different mechanisms of viral infection are at work in lymphoid cells. On one hand, when B cells show a latent phase infection with KSHV/HHV-8, after the germinal center reaction, naive B cells become resting memory B cells, similarly to Epstein-Barr virus-infected B cells. On the other hand, when lytic genes such as vIL6 are expressed in naive B cells, they may be driven to differentiate into plasmablasts without undergoing germinal center reaction. Interestingly, among KSHV/HHV-8-positive cases, in those in which there was also lymphoma, the neoplastic cells were negative for KSHV/HHV-8. This further confirms that KSHV/HHV-8 is involved in the neoplastic transformation of only certain types of lymphoma, probably in relation to their precursor infected cell. In conclusion, the maturation stage of KSHV/HHV-8-positive B cells as well as the type of viral infection may well determine the morphological, phenotypic, and clinical characteristics of KSHV/HHV-8-associated lymphomas.

Metalloproteinase inhibitors, nonantimicrobial chemically modified tetracyclines, and ilomastat block Bacillus anthracis lethal factor activity in viable cells

Lethal toxin, produced by the bacterium Bacillus anthracis, is a major contributor to morbidity and mortality in animals and humans who have contracted anthrax. One component of this toxin, lethal factor (LF), proteolytically inactivates members of the mitogen-activated protein kinase kinase (MAPKK or MEK) family. In this study we show that CMT-300, CMT-308, and Ilomastat, agents initially characterized as matrix metalloproteinase inhibitors which are in early stages of development as pharmaceuticals, effectively inhibit the zinc metalloproteinase activity of LF. All three inhibitors, CMT-300, CMT-308, and Ilomastat, inhibit LF-mediated cleavage of a synthetic peptide substrate based on the N-terminal domain of MEKs. Inhibition of LF-mediated MEK proteolysis by all three agents was also achieved using lysates of the human monocytoid line MonoMac 6 as sources of MAPKKs and visualization of the extent of cleavage after separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by detection by Western blotting. Finally, we have demonstrated inhibition of intracellular MEKs in viable human monocytes and MonoMac 6 cells by these agents after incubation of the cells with a reconstituted preparation of recombinant lethal toxin. All three agents are effective inhibitors when incubated with LF prior to exposure to cells, while the CMTs, but not Ilomastat, are also effective when added after LF has already entered the viable cell targets. These results offer promise for strategies to combat effects of the lethal toxin of B. anthracis.

The Nikolas Symposia and histiocytosis

Histiocytoses are a group of rare diseases that involve histiocytes (literally tissue cells (Greek), but in reality tissue-resident macrophages and dendritic cells), which are derived from bone-marrow stem cells. Histiocytoses pose problems similar to those of other rare diseases of childhood. Individual physicians see few cases, disease material is hard to collect and families suffer from lack of information and understanding. In this article, we describe how a series of 'think tank' meetings, the Nikolas Symposia, which have concentrated on Langerhans cell histiocytosis, have furthered our understanding of this enigmatic disease.

Kaposi Sarcoma in Solid Organ Transplant Recipients: A Single Center Report

BACKGROUND

Human herpes virus (HHV8) is associated with Castleman's disease, primary effusion lymphoma, and the Kaposi's sarcoma (KS).

PATIENTS AND METHODS

Among 3815 solid organ transplants performed at our center between 1977 and 2003, five patients (0.1%) were identified with KS.

RESULTS

There were one cardiac, one liver, and three renal allograft recipients of median age of 52 (range 38 to 60) years, three of whom were females. Three patients were of Italian and one of Turkish descent; only one patient was a native Austrian. The onset of the disease was 2.0, 7.5, 7.8, 9.4 months, and 22 years posttransplant. Diagnosis of KS was based in all cases on histology. The heart recipient developed a tumor on the planta pedis; one renal recipient, on both legs. The liver and the two remaining renal recipients presented with disseminated disease. Treatment in all cases consisted of reduction in immunosuppression, together with surgery (n = 1), chemotherapy (n = 1), or irradiation (n = 2). Furthermore, immunosuppression was switched in two cases from Tacrolimus to Sirolimus. In the liver recipient a complete response was achieved; he died, however, due to noncompliance followed by graft failure. One renal recipient died without evidence of recurrent disease from myocardial infarction. The cardiac and two renal recipients are alive between 4 months and 17 years with well-functioning grafts and no evidence of recurrent disease.

DISCUSSION

HHV8-associated lesions seem to be extremely rare in the Central European transplant population. Nevertheless, awareness of KS is important for early diagnosis and optimal treatment.