The complete Kaposi sarcoma-associated herpesvirus genome induces early-onset, metastatic angiosarcoma in transgenic mice.

Kaposi sarcoma (KS) is the most common cancer in persons living with HIV. It is caused by KS-associated herpesvirus (KSHV). There exists no animal model for KS. Pronuclear injection of the 170,000-bp viral genome induces early-onset, aggressive angiosarcoma in transgenic mice. The tumors are histopathologically indistinguishable from human KS. As in human KS, all tumor cells express the viral latency-associated nuclear antigen (LANA). The tumors transcribe most viral genes, whereas endothelial cells in other organs only transcribe the viral latent genes. The tumor cells are of endothelial lineage and exhibit the same molecular pattern of pathway activation as KS, namely phosphatidylinositol 3-kinase (PI3K)/Akt/mTOR, interleukin-10 (IL-10), and vascular endothelial growth factor (VEGF). The KSHV-induced tumors are more aggressive than Ha-ras-induced angiosarcomas. Overall survival is increased by prophylactic ganciclovir. Thus, whole-virus KSHV-transgenic mice represent an accurate model for KS and open the door for the genetic dissection of KS pathogenesis and evaluation of therapies, including vaccines.

HRAS, EGFR, MET, and RON Genes Are Recurrently Activated by Provirus Insertion in Liver Tumors Induced by the Retrovirus Myeloblastosis-Associated Virus 2.

Myeloblastosis-associated virus 2 (MAV-2) is a highly tumorigenic simple avian retrovirus. Chickens infected in ovo with MAV-2 develop tumors in the kidneys, lungs, and liver with a short latency, less than 8 weeks. Here we report the results of molecular analyses of MAV-2-induced liver tumors that fall into three classes: hepatic hemangiosarcomas (HHSs), intrahepatic cholangiocarcinomas (ICCs), and hepatocellular carcinomas (HCCs). Comprehensive inverse PCR-based screening of 92 chicken liver tumors revealed that in ca. 86% of these tumors, MAV-2 provirus had integrated into one of four gene loci: HRAS, EGFR, MET, and RON Insertionally mutated genes correlated with tumor type: HRAS was hit in HHSs, MET in ICCs, RON mostly in ICCs, and EGFR mostly in HCCs. The provirus insertions led to the overexpression of the affected genes and, in the case of EGFR and RON, also to the truncation of exons encoding the extracellular ligand-binding domains of these transmembrane receptors. The structures of truncated EGFR and RON closely mimic the structures of oncogenic variants of these genes frequently found in human tumors (EGFRvIII and sfRON).IMPORTANCE These data describe the mechanisms of oncogenesis induced in chickens by the MAV-2 retrovirus. They also show that molecular processes converting cellular regulatory genes to cancer genes may be remarkably similar in chickens and humans. We suggest that the MAV-2 retrovirus-based model can complement experiments performed using mouse models and provide data that could translate to human medicine.

Angiosarcoma in HIV-negative patients is not associated with HHV-8

Abstract: BACKGROUND: Angiosarcoma is an aggressive, malignant neoplasm of vascular or lymphatic origin. Herpes virus 8 (HHV-8) is a member of the herpes family with a tropism for endothelial cells and it has been proven to induce vascular neoplasms, such as Kaposi's sarcoma. The role of HHV-8 in the pathogenesis of angiosarcoma has not been well defined. OBJECTIVE: To investigate the relationship between the presence of HHV-8 and angiosarcoma. METHODS: In this study, the team investigated the relationship between the presence of HHV-8, as determined by polymerase chain reaction, and angiosarcoma, using samples from patients with epidemic Kaposi's sarcoma as controls. RESULTS: While all control cases with epidemic Kaposi's sarcoma were positive for HHV-8, none of the angiosarcoma cases was. CONCLUSION: These findings support most previous studies that found no association between HHV-8 and angiosarcoma.

Angiosarcoma in HIV-negative patients is not associated with HHV-8.

BACKGROUND:: Angiosarcoma is an aggressive, malignant neoplasm of vascular or lymphatic origin. Herpes virus 8 (HHV-8) is a member of the herpes family with a tropism for endothelial cells and it has been proven to induce vascular neoplasms, such as Kaposi's sarcoma. The role of HHV-8 in the pathogenesis of angiosarcoma has not been well defined. OBJECTIVE:: To investigate the relationship between the presence of HHV-8 and angiosarcoma. METHODS:: In this study, the team investigated the relationship between the presence of HHV-8, as determined by polymerase chain reaction, and angiosarcoma, using samples from patients with epidemic Kaposi's sarcoma as controls. RESULTS:: While all control cases with epidemic Kaposi's sarcoma were positive for HHV-8, none of the angiosarcoma cases was. CONCLUSION:: These findings support most previous studies that found no association between HHV-8 and angiosarcoma.

Kaposi sarcoma following postmastectomy lymphedema.

Classical Kaposi sarcoma (KS) usually appears on lower extremities accompanied or preceded by local lymphedema. However, the development in areas of chronic lymphedema of the arms following mastectomy, mimicking a Stewart-Treves syndrome, has rarely been described. We report an 81-year-old woman who developed multiple, erythematous to purple tumors, located on areas of post mastectomy lymphedema. Histopathological examination evidenced several dermal nodules formed by spindle-shaped cells that delimitated slit-like vascular spaces with some red cell extravasation. Immunohistochemically, the human herpesvirus type 8 (HHV-8) latent nuclear antigen-1 was detected in the nuclei of most tumoral cells confirming the diagnosis of KS. Lymphedema could promote the development of certain tumors by altering immunocompetence. Although angiosarcoma (AS) is the most frequent neoplasia arising in the setting of chronic lymphedema, other tumors such as benign lymphangiomatous papules (BLAP) or KS can also develop in lymphedematous limbs. It is important to establish the difference between AS and KS because their prognosis and treatment are very different. Identification by immunohistochemistry of HHV-8 is useful for the distinction between KS and AS or BLAP.

Sarcomas other than Kaposi sarcoma occurring in immunodeficiency: interpretations from a systematic literature review.

PURPOSE OF REVIEW: In immunodeficiency, an increased sarcoma risk is confirmed for Kaposi's sarcoma. Whether rates of other sarcoma subtypes are elevated in the setting of immunodeficiency is not known. We therefore reviewed published case reports on HIV and AIDS patients and organ transplant recipients with sarcomas. For comparison, we assessed sarcomas in the U.S. general population using Surveillance Epidemiology End Results (SEER) data. RECENT FINDINGS: A total of 176 non-Kaposi sarcoma were identified, 75 in people with HIV and AIDS and 101 in transplant recipients. Leiomyosarcomas (n = 101) were the most frequently reported sarcomas, followed by angiosarcomas (n = 23) and fibrohistiocytic tumors (n = 17). Leiomyosarcomas were reported with two age peaks, in children and young adults. Epstein-Barr virus (EBV) was detected in the tumor cells in 85 and 88% of leiomyosarcomas in HIV-infected people and transplant recipients, respectively. Angiosarcomas and fibrohistiocytic tumors were most frequently reported in men. Among kidney transplant recipients, 20% of sarcomas arose at the site of an arteriovenous fistula. In comparison, leiomyoscarcomas, angiosarcomas, and fibrohistiocytic tumors comprised 16.9, 3.8, and 18.7% of sarcomas in the U.S. general population. SUMMARY: Leiomyosarcoma and angiosarcoma may occur disproportionately in immunodeficiency. Leiomyosarcomas appear causatively linked to EBV, whereas angiosarcomas might be correlated with an arteriovenous fistula. Additional studies are necessary to understand the contribution of immunodeficiency to the cause of these sarcomas.

Infrequent detection of papillomaviral DNA within canine cutaneous squamous cell carcinomas, haemangiosarcomas and healthy skin on the ventrum of dogs.

BACKGROUND: Canine squamous cell carcinomas (SCCs) most frequently develop on the ventral abdomen and are thought to be caused by ultraviolet (UV) light. Papillomaviruses (PVs) have been associated with cutaneous SCCs in multiple species, including dogs. HYPOTHESIS: That PVs act as cofactors in canine UV-induced SCCs. ANIMALS: The study was performed on skin from the ventrum of 60 dogs. These samples included 20 SCCs, 20 haemangiosarcomas and 20 samples of clinically normal skin. Two canine viral plaques were included as positive controls for PV. METHODS: PCR was used to amplify PV DNA from all samples. Primers used included two sets of consensus primers and two sets of primers that were designed specifically to amplify PV DNA sequences detected in the viral plaques. RESULTS: The MY09/11 consensus primers amplified PV DNA from both viral plaques. One plaque contained a DNA sequence (CfPV-JM) that had been previously reported from a dog with multiple cutaneous SCCs. The other plaque contained a previously unreported PV DNA sequence. No PV DNA was amplified by either consensus primer from any of the ventrum skin samples. Primers designed specifically to amplify the CfPV-JM sequence amplified DNA from one SCC, but no other sample. No PV DNA was amplified using the other specific PCR primer set. CONCLUSIONS AND CLINICAL IMPORTANCE: These results do not support a significant role for PVs in SCC development from the ventrum of dogs. However, they contribute another PV sequence to the list of PVs that have been associated with viral plaque development in dogs.

Bovine papillomavirus E5 oncoprotein binds to the activated form of the platelet-derived growth factor beta receptor in naturally occurring bovine urinary bladder tumours.

Studies regarding the functions of the bovine papillomavirus (BPV) E5 oncoprotein in vivo are lacking and no E5-mediated mechanism underlying epithelial carcinogenesis is known. We have shown that BPV-2 DNA is present in the majority of naturally occurring urinary bladder tumours of cattle and that E5 is expressed in the cancer cells. Here we show that the interaction between the platelet-derived growth factor (PDGF) beta receptor and BPV E5, described in vitro in cultured cells, takes place in vivo in bovine urinary bladder cancers. In these cancers, E5 and PDGF beta receptor colocalize, as shown by confocal microscopy, and physically interact, as shown by coimmunoprecipitation. Furthermore, the PDGF beta receptor associated with E5 is highly phosphorylated, suggesting the functional activation of the receptor upon E5 interaction. Our results demonstrate, for the first time, that E5-PDGF beta receptor interaction occurs during the natural history of bovine urinary bladder tumours, suggesting an important role for E5 in carcinogenesis. Finally, the system provides a suitable animal model of papillomavirus-associated cancer to test therapeutic vaccination against E5. Successful bladder tumour regression would provide a valuable model for therapeutic vaccination against papillomavirus-associated tumours.

Human herpesvirus 8 and angiosarcoma: analysis of 40 cases and review of the literature.

AIMS: To prove a possible involvement of the endotheliotropic human herpesvirus 8 (HHV-8) in the pathogenesis of angiosarcoma in samples from patients in a low HHV-8 seroprevalence area. METHODS: A comprehensive series of angiosarcomas (n = 40) as well as positive and negative control tissues from patients with Kaposi's sarcoma, human immunodeficiency virus (HIV)-associated multicentric Castleman's disease or juvenile haemangioma, respectively, was analysed with two sensitive methods: immunohistochemical staining for the HHV-8 latency-associated nuclear antigen 1 (LANA-1); and polymerase chain reaction (PCR) for HHV-8 VP23 DNA sequences. RESULTS: None of the angiosarcoma cases and none of the negative control samples (juvenile haemangiomas) revealed positive immunohistochemical staining with the LANA-1 antibody. In contrast, HHV-8 LANA-1 was clearly detected in all analysed cases of Kaposi's sarcoma and multicentric Castleman's disease. These results were confirmed by PCR assay at the DNA level. CONCLUSION: In conclusion, the great majority of angiosarcomas investigated to date, including the series of 40 angiosarcomas analysed here, does not contain HHV-8 DNA sequences or protein. This argues against a relevant role of the endotheliotropic HHV-8 in the pathogenesis of angiosarcoma and, for vascular diseases, speaks in favour of a relatively restricted pathogenic role of HHV-8 to Kaposi's sarcoma and multicentric Castleman's disease.

B1 lymphocytes and myeloid dendritic cells in lymphoid organs are preferential extratumoral sites of parvovirus minute virus of mice prototype strain expression.

Due to their oncolytic properties and apathogenicity, autonomous parvoviruses have attracted significant interest as possible anticancer agents. Recent preclinical studies provided evidence of the therapeutic potential of minute virus of mice prototype strain (MVMp) and its recombinant derivatives. In a murine model of hemangiosarcoma, positive therapeutic outcome correlated with high intratumoral expression of MVMp-encoded genes in tumors and lymphoid organs, especially in tumor-draining lymph nodes. The source and relevance of this extratumoral expression, which came as a surprise because of the known fibrotropism of MVMp, remained unclear. In the present study, we investigated (i) whether the observed expression pattern occurs in different tumor models, (ii) which cell population is targeted by the virus, and (iii) the immunological consequences of this infection. Significant MVMp gene expression was detected in lymphoid tissues from infected tumor-free as well as melanoma-, lymphoma-, and hemangiosarcoma-bearing mice. This expression was especially marked in lymph nodes draining virus-injected tumors. Fluorescent in situ hybridization analysis, multicolor fluorescence-activated cell sorting, and quantitative reverse transcription-PCR revealed that MVMp was expressed in rare subpopulations of CD11b (Mac1)-positive cells displaying CD11c+ (myeloid dendritic cells [MDC]) or CD45B (B220+ [B1 lymphocytes]) markers. Apart from the late deletion of cytotoxic memory cells (CD8+ CD44+ CD62L-), this infection did not lead to significant alteration of the immunological profile of cells populating lymphoid organs. However, subtle changes were detected in the production of specific proinflammatory cytokines in lymph nodes from virus-treated animals. Considering the role of B1 lymphocytes and MDC in cancer and immunological surveillance, the specific ability of these cell types to sustain parvovirus-driven gene expression may be exploited in gene therapy protocols.

Demonstration of human herpesvirus 8 in a case of primary vaginal epithelioid angiosarcoma by in situ hybridization, electron microscopy, and polymerase chain reaction.

We demonstrate the presence of human herpesvirsus 8 (HHV-8) in a primary vaginal location of angiosarcoma (AS) by polymerase chain reaction (PCR), in situ hybridization, and ultrastructural direct visualization of viral particles. The latter two techniques for the first time confirm HHV-8 detection in an AS by PCR; these results contribute to the debate caused by the controversial data produced by the almost exclusive use of PCR for investigating the possible presence of HHV-8 in AS, and its possible implications. Moreover, the investigated AS is the seventh published primary vaginal one, and the fourth unrelated to radiotherapy. Interestingly, the affected patient had used a ring pessary for 10 years because of an uterovaginal prolapse.

A Kaposi-like variant of splenic angiosarcoma lacking association with human herpesvirus 8.

We report the case of a Kaposi-like variant of splenic angiosarcoma in a 28-year-old woman. The tumor featured a Kaposi sarcoma-like spindle cell proliferation with slit formation and markedly dilated spongelike vascular channels filled with erythrocytes. Thirteen months following the initial splenectomy, metastatic lesions were found in the patient's liver and bone marrow. The proliferating cells were positive for factor VIII-associated antigen and CD34. The human herpesvirus 8 genome, which is regarded as a diagnostic feature of Kaposi sarcoma, was not detected by polymerase chain reaction analysis. Although the histologic findings were similar, this Kaposi-like variant of splenic angiosarcoma must be considered distinct from Kaposi sarcoma.

Absence of Kaposi's sarcoma-associated virus (human herpesvirus-8) sequences in angiosarcoma.

Kaposi's sarcoma-associated virus (human herpesvirus-8 [HHV8]) sequences have been identified in both AIDS-associated and AIDS-non-associated Kaposi's sarcoma, but data relating to the detection of HHV8 sequences in angiosarcoma are variable. One study showed HHV8 sequences in 29% (7/24) of angiosarcomas, but others have not confirmed these results. We evaluated 33 angiosarcomas for HHV8 sequences to determine the frequency of this virus in angiosarcomas and its possible pathogenetic significance. Five cases of Kaposi's sarcoma from HIV-positive patients were used as positive controls. Five additional cases of Kaposi's sarcoma collected approximately 40-50 years ago were also analysed, and three were HHV8 positive. None of the angiosarcomas revealed HHV8 sequences after the standard 35 cycles of PCR. In 6 cases, nested PCR revealed the presence of HHV8 sequences. These results were not reproducible when outer primers (based on sequences outside of the earlier PCR products) were used for amplification. This suggests that the HHV8 sequences detected in 6 cases represent a low level of contamination. In contrast, HHV8 sequences were found in all Kaposi's sarcomas with well-preserved DNA after standard 35-cycle PCR amplification. These findings confirm a close association between Kaposi's sarcoma and HHV8 infection and suggest that HHV8 is not involved in the pathogenesis of angiosarcoma.