Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “sarcoma”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources

Molecular epidemiology of Kaposi's sarcoma herpesvirus (KSHV) in Cuban and German patients with Kaposi's sarcoma (KS) and asymptomatic sexual contacts.

Kaposi's sarcoma (KS) shows a distinct geographical and ethnic distribution. The variable K1 gene serves to differentiate the KSHV subtypes A-E, M, N, and Q. Phylogenetic characterization of 19 classical and epidemic German KS specimens revealed the Eurasian KSHV subtypes C (n = 13, including 6 classical KS) and A (n = 6), while 27 Cuban specimens showed a variety of different subtypes (A: n = 16, 4 being A5; C: n = 8; B: n = 2; and the new subtype E: n = 1). Three pairs of isolates from KS patients and peripheral blood mononuclear cells (PBMC) of their sexual partners without KS were studied for the first time and found identical, strongly arguing for sexual transmission of KSHV in this unique cohort. The unique ethnic background of the Cuban population may explain the variety of different KSHV strains.

Adult↗

Differential viral protein expression in Kaposi's sarcoma-associated herpesvirus-infected diseases: Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease.

Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) is linked to KS, primary effusion lymphomas (PEL), and a subset of multicentric Castleman's disease (MCD). Transcript mapping studies using PEL cell lines have allowed preliminary classification of viral gene expression into constitutive (class I) and inducible (class II/III) categories. To determine whether viral gene expression differs in vivo, we examined tissue sections of KSHV-infected disorders, using specific antibodies against proteins that are representative of the different expression classes of KSHV genes. ORF73/LANA appears to be a surrogate marker for KSHV infection because it is constitutively expressed in vitro and in vivo in all KSHV-infected cells. Expression of vIRF1, vIL6, and PF-8 proteins in the infected B cells of MCD lymph nodes reproduces the expression pattern observed in TPA-stimulated KSHV-infected B-cell lines. In contrast, the protein expression of the inducible viral genes that we tested in KS and PEL biopsies is restricted to PF-8 and vIL6, respectively. The tightly restricted expression of KSHV proteins in vivo differs from the dysregulated expression of inducible KSHV genes in vitro and suggests that viral gene expression in KSHV-infected cell lines does not accurately reflect what occurs in diseased tissues. These differences may be related to either cell-specific or immune restriction of viral replication.

Castleman Disease↗

Kaposi's sarcoma following chemotherapy for testicular cancer in a homosexual man: demonstration of cytomegalovirus RNA in sarcoma cells.

A 35-year-old white Jewish homosexual man who had undergone surgery and chemotherapy for an embryonal carcinoma of the testis subsequently developed Kaposi's sarcoma. The neoplasm involved the skin as well as visceral tissues. Tissue derived from a biopsy specimen of one of the skin lesions was used in the in situ hybridization technique for the detection of genetic material. Cytomegalovirus messenger RNA was identified in the neoplastic Kaposi cells in the skin. The significance of this finding is discussed.

Cytomegalovirus↗

Prognostic factors in the treatment of Ewing's sarcoma. The Ewing's Sarcoma Study Group of the German Society of Paediatric Oncology CESS 81.

From 1981 up to February 1985, a total of 93 protocol patients entered the study CESS 81. The protocol recommended an initial 18-week period of polychemotherapy (VACA) followed by local therapy and two additional cycles of chemotherapy. Local therapy consisted either of radical surgery or of incomplete resection plus postoperative irradiation with 36 Gy or of radiotherapy alone (46 and 60 Gy). Centrally located lesions were always irradiated with 60 Gy. This article summarizes the data after 5 years. Data of 93 patients were analysed in October 1986 after a median follow-up of 37 months. The projected 5-year survival is 50%. The relapse rate was 42%, distant relapses occurred in 19%, local (plus distant) relapses in 23%. Most of the relapses occurred during the first 3 years of observation. Failure rate was high in patients undergoing irradiation alone (44%). Initial tumour mass (greater than 100 ml) and histopathologic response to initial chemotherapy were identified as major prognostic factors. Tumour site and type of local therapy were not significant if patients were categorised by tumour volume. In small lesions, surgery and radiotherapy were equally effective. In large lesions greater than 100 ml volume, a trend towards a better prognosis in surgically treated patients was observed. The results of CESS 81 emphasize the importance of permanent local control in Ewing's sarcoma even in the presence of systemic control by an effective multi-drug chemotherapy.

Adolescent↗

Five-year results in Ewing's sarcoma. The Scandinavian Sarcoma Group experience with the SSG IX protocol.

The first Scandinavian protocol for Ewing's sarcoma, SSG IV, resulted in a local control rate of 74% and 5-year metastasis-free survival (MFS) of 43%. The second protocol, SSG IX, was started in order to improve upon these results. It featured four chemotherapy cycles, each consisting of two courses of VAI (vincristine, doxorubicin, ifosfamide) alternating with one course of PAI (cisplatin, doxorubicin, ifosfamide) at 3-weekly intervals. Total treatment time was 35 weeks. Local therapy was given at week 9. Inoperable or non-radically operated patients received hyperfractionated accelerated radiotherapy 1.5 Gy twice daily between chemotherapy courses to a total dose of 42-60 Gy, depending on surgical radicality and tumour localisation. 88 patients were included (58 male, 30 female, mean age 20 years; range 5-65 years). The tumour (73 M0 and 15 M1) was located centrally in 31 patients (35%), in the extremities in 34 (39%) and other sites in 23 (26%) of cases. The median size of tumour was 10 cm (range 2-23), soft tissue was invaded in 87%. Surgery was the local therapy for 60 (68%) patients: amputation in 8 and local excision in 52. The surgical margins were wide in 35 patients, marginal in 14 and intralesional in 3. Radiotherapy was given to 17 non-radically operated patients postoperatively and to 28 patients with inoperable tumours primarily. Histological responses were evaluated in 52 patients. 9 local recurrences were observed (10%). Distant metastases developed in 24 M0 patients (33%). The estimated 5-year MFS was 58% and overall survival (OS) 70% for M0 and 27% and 28% for M1 patients, respectively. Survival was favourable in patients with non-metastatic extremity tumours (90%) and tumours operated with wide margins (90%). Patients with a total necrosis after chemotherapy had a better OS than those with a partial or poor response (P=0.003). The toxicity (World Health Organisation) was acceptable (gastrointestinal G1-2; haematological G3-4). The SSG IX protocol gave better local control and survival rates than the SSG IV. Whether this is due to a higher therapeutic efficacy of the present protocol cannot be ascertained in this comparison with a historical control.

Adolescent↗

Analysis of growth factor-dependent signalling in human epithelioid sarcoma cell lines. clues To the role of autocrine, juxtacrine and paracrine interactions in epithelioid sarcoma.

Human epithelioid sarcoma (ES) is an extremely aggressive soft tissue tumour of unknown histogenesis. Although growth factor-dependent signalling cascades significantly affect the biological behaviour of malignant tumours, little is known so far about their role in human ES. The present investigation, therefore, analyses the coexpression and function of different growth factors and their receptors in the human ES cell line GRU-1 and its clonal subpopulations (GRU-1A, GRU-1B and GRU-1C). As shown by Northern blot, flow cytometry, immunocytochemistry and MTT assay, all ES cell lines expressed transforming growth factor (TGF)-alpha and the epidermal growth factor receptor (EGF-R). Although no response to exogenous TGF-alpha was observed, antagonistic anti-EGF-R antibodies (at 20 microg/ml) induced significant (P<0.05) growth inhibition in all cell lines. All cell lines showed coexpression of platelet-derived growth factor (PDGF)-A and the corresponding receptors. Neutralisation of ES-derived PDGF by anti-hPDGF antibodies resulted in significant (P<0.05) growth inhibition of all clonal subpopulations. Although all cell lines expressed TGF-beta(1) as well as TGF-beta type I and type II receptors (TGF-BI-R and TGF-BII-R), growth inhibition (P<0.05) by exogenous TGF-beta(1) was achieved in the clonal subpopulations only and not in the parental cell line. No ES cell line expressed acidic fibroblast growth factor (FGF) but stimulation of FGF type 3 and type 4 receptors (FGF-3R and FGF-4R) by exogenous acidic FGF (aFGF) resulted in a marked (P<0.05) acceleration of proliferation in all cell lines. In conclusion, our investigation suggests an intricate network of autocrine, juxtacrine and paracrine signalling between ES tumour cells and adjacent non-neoplastic stromal cells.

Blotting, Northern↗

Randomised phase II trial of pegylated liposomal doxorubicin (DOXIL/CAELYX) versus doxorubicin in the treatment of advanced or metastatic soft tissue sarcoma: a study by the EORTC Soft Tissue and Bone Sarcoma Group.

CAELYX/DOXIL, pegylated liposomal doxorubicin, has shown antitumour activity and reduced toxicity compared with standard doxorubicin in other tumour types. In this prospective randomised trial, 94 eligible patients with advanced soft-tissue sarcoma (STS) were treated, 50 with CAELYX (50 mg/m(2) by a 1 h intravenous (i.v.) infusion every 4 weeks) and 44 with doxorubicin (75 mg/m(2) by an i.v. bolus every 3 weeks). Histological subtypes were evenly matched, 33% were leiomyosarcoma (CAELYX: 18; doxorubicin: 13). Primary disease sites were well matched. CAELYX was significantly less myelosuppressive, only 3 (6%) patients had grade 3 and 4 neutropenia, versus 33 (77%) on doxorubicin; febrile neutropenia occurred in 7 (16%) patients given doxorubicin, but only 1 (2%) given CAELYX. 37 (86%) patients on doxorubicin had grade 2-3 alopecia, but only 3 (6%) on CAELYX, and the major toxicity with CAELYX was to the skin. Palmar-plantar erythrodysesthesia with CAELYX was grade 1: 4 (8%) patients, grade 2: 11 (22%) patients, grade 3: 9 (18%) patients and grade 4: 1 (2%) patient. Other non-haematological grade 3 and 4 toxicities were rare. Confirmed responses were observed with both agents: CAELYX: complete response (CR) 1 (uterine), partial response (PR) 4 (response rate (RR) 10%); and doxorubicin: CR 1, PR 3 (RR of 9%); with the best response being stable disease (NC) in 16 and 18 patients, respectively. The reason for the low response rate is unknown, but it may be due partly to a high proportion of gastrointestinal stromal tumours. In conclusion, CAELYX has equivalent activity to doxorubicin in STS with an improved toxicity profile and should be considered for further investigation in combination with other agents such as ifosfamide.

Adult↗

Gemcitabine in advanced adult soft-tissue sarcomas. A phase II study of the EORTC Soft Tissue and Bone Sarcoma Group.

Gemcitabine (2'-deoxy-2'-difluorocytidine monohydrochloride) at a dose of 1250 mg/m(2) was given as a 30-min intravenous (i.v.) infusion on days 1 and 8 in a 3-weekly schedule to 32 patients with advanced soft-tissue sarcoma (STS) failing first-line chemotherapy. One patient was ineligible due to a delay between the previous chemotherapy and the start of treatment. Of the eligible patients, median age was 53 years (range 23-73 years). The predominant histological subtype was leiomyosarcoma in 12 patients (38%). The median number of cycles was three (range 1-8 cycles) with a median total dose of gemcitabine of 6.25 g/m(2) (range 1.25-19.97 g/m(2)). The relative dose intensity of gemcitabine was 96% (range 50-103%). Treatment was tolerated very well with non-complicated haematological toxicity as the most frequently observed side-effect. Only one partial tumour response was documented, giving a response rate of 3.23% (95% Confidence Interval (CI): 0.08-16.2%). The median overall survival was 268 days (95% CI: 129-377) and the median time to progression was 45 days (95% CI: 41-79). These results indicate that gemcitabine given at this dose and schedule is not active as second-line therapy in advanced STS.

Adult↗

Ifosfamide and continuous infusion etoposide in advanced adult soft tissue sarcoma. A Scandinavian Sarcoma Group Phase II Study.

The purpose of this study was to evaluate tumour response and toxicity to ifosfamide and continuous infusion etoposide in metastatic or locally advanced soft tissue sarcoma, with dose escalations under G-CSF (granulocyte colony-stimulating factor) support. Of 92 eligible patients (median age 51 years), 85% had tumours of high-grade malignancy and 82% had metastatic disease. Chemotherapy, the baseline dose, consisted of etoposide 600 mg/m2 as a 72 h infusion and ifosfamide 1500 mg/ m2/day for 3 days, followed by G-CSF support (VIG regimen). Stepwise 10% dose escalations were performed depending on haematological toxicity. For patients considered operable after induction chemotherapy, surgical resection of all identifiable residual tumour was attempted. Complete and partial response rates were 11% and 31%, for an overall response rate of 42% (95% CI 31-52%). Forty-eight per cent of courses were dose escalated by a median of 20%. Complete responders had significantly higher, and patients with progressive disease had significantly lower, dose levels than other patients. None of 20 patients with liver metastases responded despite high dose levels. Compared to a preceding pilot study, the addition of G-CSF led to significantly higher dose levels, improved schedule adherence and less haematological toxicity, but no apparent increase in response rate. In view of the modest dose of ifosfamide applied in this study, it is possible that the prolonged infusion of etoposide made a significant contribution to the regimen's antitumour activity, although this can only be determined definitively in a randomised study.

Adolescent↗

The outcome of advanced soft tissue sarcoma patients with complete tumour regression after either chemotherapy alone or chemotherapy plus surgery. The Scandinavian Sarcoma Group experience.

The intensified induction regimens used and the potential use of high-dose consolidation chemotherapy (CT) in advanced soft tissue sarcomas (STS) has focused interest on the outcome of those patients who can achieve complete remission (CR) by current therapy. The files from four institutions with a special interest in STS were studied. 38 adult patients with advanced STS who were converted disease-free by either CT alone (n = 14) or CT followed by surgery (n = 24) were found. The median follow-up time was 29 months. The median disease-free survival (DFS) was 18 months and the estimated 2-year DFS 34%. The median disease-specific survival (DSS) was 40 months and the estimated 2-year DSS 78%. For patients who achieved CR by CT alone, and for patients who were converted to CR by surgery, the corresponding DFS figures were 23 months (estimated 2 year DFS 48%) and 10 months (26%) (P = 0.07), respectively. The histological response to CT significantly predicted outcome in patients subjected to surgery (DFS P value 0.004, DSS P value 0.02). Patients who achieved CR by surgery shortly after having achieved a clinical partial response (PR with early surgery) did better than those who where converted to CR by surgery after protracted CT following a clinical PR (PR with late surgery) (DFS P value 0.02, DSS P value 0.1). Our results confirm that CT alone can induce prolonged DFS in rare patients with advanced STS. In patients subjected to surgery, a good histological response indicates improved outcome.

Adolescent↗

Surgical margins, local recurrence and metastasis in soft tissue sarcomas: 559 surgically-treated patients from the Scandinavian Sarcoma Group Register.

The prognostic importance of surgical margins on local recurrence rates and metastasis-free survival (MFS) was studied in 559 patients with soft tissue sarcoma of the extremities and trunk wall. The patients were all surgically treated, but received no adjuvant treatment. The median follow-up for the survivors was 7.4 (range: 0.1 - 12.5) years. Independent prognostic factors for MFS were analysed by Cox models. The overall 5-year MFS was 0.72 (95% confidence intervals (CI) 0.68 - 0.76). High histopathological malignancy grade (relative risk (RR) 3.0; 95% CI 1.5 - 6.3) and an inadequate surgical margin (RR 2.9; 95% CI 1.8 - 4.6) were independent risk factors for local recurrence. High histopathological malignancy grade and large tumour size (> 7 cm) were the most important risk factors for metastasis. Local recurrence was associated with an increased risk of metastasis (RR 4. 4; 95% CI 2.9-6.8), but an inadequate surgical margin was not a risk factor for metastasis (RR 1.1; 95% CI 0.8-1.7). This study confirms that, as regards metastasis, tumour-related risk factors (malignancy grade and tumour size) are more important risk factors than treatment-related factors. Local recurrence was associated with an increased metastasis rate, whereas inadequate surgical margin was a risk factor for local recurrence but not for metastasis. Hence, the proposed causal association between local recurrence and metastasis is doubtful, and if it exists is a weak association.

Adolescent↗

Potentials for RNAi in sarcoma research and therapy: Ewing's sarcoma as a model.

Existing data identify EWS-FLI1 as indispensable for sustained Ewing's sarcoma growth and as the ideal therapeutic target in this disease. The siRNA may hold great promises as a fusion gene specific agent. RNAi mediated suppression of EWS-FLI1 is likely to result in an altered tumor cell phenotype including changes in chemosensitivity, and a restored differentiation potential. Thus, RNAi may serve as an adjuvant to chemotherapy. As a therapeutic means however, RNAi is hampered by limitations in the delivery of the agent and emergence of resistant clones. In vitro suppression of EWS-FLI1 expression will allow to define the phenotypic characteristics of dormant tumor cells that may give rise to late relapses, enabling improved diagnosis and treatment even of minimal residual disease.

Animals↗

Phase II trial of first-line high-dose ifosfamide in advanced soft tissue sarcomas of the adult: a study of the Spanish Group for Research on Sarcomas (GEIS)

BACKGROUND: The agent Ifosfamide (IFOS) is active against soft tissue sarcomas (STS), and patients who progress to IFOS at doses < or = 10 g/m2 show remissions when exposed to high-dose ifosfamide (HDI) (i.e., doses > 10 g/m2), which supports a dose-response relationship for this drug. Because of a lack of first-line studies in adult STS patients, we decided to test the activity and toxicity of HDI in a phase II trial. PATIENTS AND METHODS: Forty-eight patients were enrolled in the study. IFOS was administered at a dose of 14 g/m2 by continuous infusion over six days every four weeks. Granulocyte-macrophage colony-stimulating factor (GM-CSF) at 5 micrograms/kg/day for 10 consecutive days was systematically administered after an episode of neutropenic fever or a delay in hematologic recovery. Patients were treated until progression or the occurrence of severe toxicity, and surgical rescue was attempted when possible. RESULTS: Six pathology-established complete remissions and 11 partial remissions were observed in 45 assessable patients with a response rate of 37.7% (95% CI: 25.5%-50%). Grade 3-4 toxicity (% of cycles) was noted by hemoglobin (17%), leukocyte (75%), granulocyte (75%) and platelet (13%) counts in 158 evaluable cycles. GM-CSF was administered to 28 patients, and 25 suffered one or more episodes of neutropenic fever. Renal toxicity was mild and reversible with some degree of tubular and glomerular dysfunction detected in up to 60% of patients. Grade 3 CNS toxicity was observed in 32% of patients but only one required interruption of therapy. Sixty-four per cent of the patients had asthenia grade 2-3 and 20% were excluded from the study due to excessive toxicity. There was one treatment-related death. CONCLUSIONS: HDI is an active drug in first-line therapy against adult STS. Different administration schedules should be evaluated in an attempt to improve its therapeutic index.

Adult↗

Alveolar soft part sarcoma in children and adolescents: A report from the Soft-Tissue Sarcoma Italian Cooperative Group.

BACKGROUND: Alveolar soft part sarcoma (ASPS) is a rare malignant tumor and little is known about its clinical features and management. We report on a series of 19 pediatric patients managed over 20 years. PATIENTS AND METHODS: Primary conservative surgery was performed in all patients and was radical in nine, non-radical in three; seven patients underwent biopsy alone (3 unresectable tumors, 4 metastatic disease). In two cases radical surgery was performed after primary chemotherapy. Radiotherapy was delivered to 8 patients, chemotherapy to 15. RESULTS: After a median follow-up of 74 months, the five-year survival was 80% for the whole series, 91% for patients with localized disease, 100% for patients with tumor < or = 5 cm, and 31% for those > 5 cm; 16 of 19 patients were alive (12 of 12 with grossly-resected tumor in first continuous remission). Chemotherapy achieved two partial remission among seven evaluable patients. CONCLUSIONS: Pediatric ASPS has a more favorable prognosis than its adult counterpart. In this series, tumor size correlates with metastatic disease at onset and is the major factor influencing survival. Surgery is the mainstay of therapy. The effectiveness of adjuvant therapy remains to be established, though radiotherapy may be advisable in cases of inadequate surgery.

Adolescent↗

Epithelioid sarcoma: an immunohistochemical analysis evaluating the utility of cytokeratin 5/6 in distinguishing superficial epithelioid sarcoma from spindled squamous cell carcinoma.

BACKGROUND: Epithelioid sarcoma (ES) is a rare, aggressive soft tissue tumor characterized by nodular aggregates of epithelioid and/or spindled cells that are immunoreactive to cytokeratins (CKs) and epithelial membrane antigen. ES that arises in the dermis may cause epidermal ulceration and can resemble, clinically, morphologically and immunohistochemically, cutaneous squamous cell carcinoma. CK 5/6 has recently been found to be an excellent marker of squamous cell carcinoma, including spindled variants, but it is not known if this marker can be utilized to distinguish superficial ES from cutaneous spindled squamous cell carcinoma (SSCC). METHODS: Twenty-four cases of ES with typical histologic features and 10 cases of SSCC with ultrastructural evidence of epithelial differentiation were studied. Immunohistochemical analysis using an antibody to CK 5/6 was performed. The extent of immunoreactivity was evaluated in a semiquantitative manner using the following scale: 0, < 5% of cells staining; 1+, 6-25% of cells staining; 2+, 26-50% of cells staining; 3+, 51-75% of cells staining; 4+, > 75% of cells staining. RESULTS: CK 5/6 was expressed in all 10 cases of SSCC, including one case with 3+ staining and six cases with 4+ staining. In contrast, CK 5/6 staining was found only in rare tumor cells (1+ staining) in one of 24 (4%) cases of ES. CONCLUSIONS: CK 5/6 staining is useful in distinguishing superficial ES from cutaneous SSCC.

Biomarkers, Tumor↗

Expression of the fibroblast/macrophage marker 1B10 by spindle cells in Kaposi's sarcoma lesions and by Kaposi's sarcoma-derived tumor cells.

BACKGROUND: Kaposi's sarcoma (KS) is a tumor whose ontogenic origin remains a matter of contention. KS tissues are characterized by predominant expression of endothelial markers, while KS-derived cell cultures are usually characterized by expression of mesenchymal non-endothelial cell markers. AIMS: In order to clarify the ontogenic origin of KS cells, we investigated the expression of the fibroblast/macrophage marker 1B10 in KS tissues (AIDS-associated KS, n = 9; classic KS, n = 6; iatrogenic KS, n = 6) and in KS-derived cell cultures. RESULTS: 1B10 was expressed by loosely distributed spindle-shaped cells in early 'patch-stage' KS and by a variable proportion of spindle cells in late 'plaque- and nodular-stage' KS. Using immunohistochemistry and immunoblot analysis, we found that, in vitro, reactivity for 1B10 was uniformly evidenced in fibroblasts and in KS-derived spindle cell cultures, irrespective of their histological or epidemiological setting. By contrast, vascular smooth muscle cells and endothelial cells were negative for 1B10. CONCLUSIONS: These results suggest that the KS spindle cells isolated in vitro may represent a particular subpopulation of the KS spindle cell compartment.

Antigens, Surface↗

Association of pp36, a phosphorylated form of the presumed target protein for the src protein of Rous sarcoma virus, with the membrane of chicken cells transformed by Rous sarcoma virus.

A cellular protein with a molecular mass of approximately 36 kilodaltons is the presumed target protein of the src protein [the transforming protein encoded by Rous sarcoma virus (RSV)]. The cellular location of the phosphorylated 36-kilo-dalton protein (pp36) in chicken embryo fibroblasts transformed by the Schmidt-Ruppin strain of RSV has been investigated. In these studies, two-dimensional electrophoresis was used for detection of the phosphoproteins in total cell extracts and also in fractionated subcellular components. We conclude that pp36 is localized in the plasma membrane, on the basis of the following observations. (i) Fractionation of 32P-labeled cell extracts showed that pp36 is almost exclusively localized in the crude membrane fraction and no appreciable amount was found in nuclear or cytoplasmic fractions. (ii) On further fractionation of the crude membrane fraction, pp36 was localized mostly in the plasma membrane rather than in other membranous fractions. (iii) Isolated plasma membrane by itself phosphorylated the 36-kilodalton protein on incubation with [gamma-32P]ATP.

Animals↗

Restricted expression of Kaposi sarcoma-associated herpesvirus (human herpesvirus 8) genes in Kaposi sarcoma.

Kaposi sarcoma (KS) is the leading neoplasm of HIV-infected patients and is also found in several HIV-negative populations. Recently, DNA sequences from a novel herpesvirus, termed KS-associated herpesvirus (KSHV), or human herpesvirus 8 (HHV-8) have been identified within KS tissue from both HIV-positive and HIV-negative cases; infection with this agent has been proposed as a possible factor in the etiology or pathogenesis of the tumor. Here we have examined the pattern of KSHV/HHV-8 gene expression in KS and find it to be highly restricted. We identify and characterize two small transcripts that represent the bulk of the virus-specific RNA transcribed from over 120 kb of the KSHV genome in infected cells. One transcript is predicted to encode a small membrane protein; the other is an unusual polyadenylylated RNA that accumulates in the nucleus to high copy number. This pattern of viral gene expression suggests that most infected cells in KS are latently infected, with lytic viral replication likely restricted to a much smaller subpopulation of cells. These findings have implications for the therapeutic utility of currently available antiviral drugs targeted against the lytic replication cycle.

Acquired Immunodeficiency Syndrome↗