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PubMed2004

Primary vertebral osteosarcoma: imaging findings.

PURPOSE: To evaluate patient age and sex and location and imaging appearances of primary vertebral osteosarcoma (PVOS) compared with histologic subtypes. MATERIALS AND METHODS: Retrospective review (1915-2001) of imaging findings in patients with histologically proved primary osteosarcoma of vertebral column was performed. Two radiologists in consensus reviewed findings for location, origin site, matrix pattern, and spinal canal invasion and compared them with histologic subtypes. Radiation-induced, Paget, metastatic, and multifocal osteosarcoma were excluded. RESULTS: Of 4,887 osteosarcoma cases, 198 (4%) were PVOS arising from vertebral column. There were 103 female and 95 male patients (age range, 8-80 years; median age, 34.5 years). Involvement included cervical (27 patients), thoracic (66 patients), lumbar (64 patients), and sacral (41 patients) spine. Adequate imaging findings were available in 69 patients, and involvement of two levels was seen in 12 (17%). In nonsacral spine, most tumors (44 cases) arose from posterior elements, with partial involvement of vertebral body. Lesions confined to vertebral body were less frequent (12 cases). Sacral tumors involved body and sacral ala. The most common histologic subtypes were osteoblastic (47 patients), chondroblastic (12 patients), telangiectatic (four patients), fibroblastic (four patients), small cell (one patient), and epithelioid (one patient). The majority (55 cases) demonstrated osteoid matrix mineralization; 17 showed marked mineralization. Five cases with marked mineralization were confined to vertebral body, with "ivory vertebra" appearance. Purely lytic pattern was seen in 14 (20%) cases. Lytic pattern was seen in four (100%) telangiectatic, three (75%) fibroblastic, three (25%) chondroblastic, three (6%) conventional osteoblastic, and one (100%) small-cell subtypes. Invasion of spinal canal was common (84% of cases). Appearance simulating osteoblastoma without soft-tissue mass was present (seven cases). Pathologic compression fractures were identified (seven patients). CONCLUSION: This study provides age and sex distribution and location and imaging features in a large series of PVOS.

Adolescent↗
PubMed1992

Osteosarcoma after chemotherapy: evaluation with contrast material-enhanced subtraction MR imaging.

A new magnetic resonance (MR) technique, gadolinium-enhanced subtraction MR imaging, was developed to evaluate the response of patients with osteosarcoma to chemotherapy. Ten patients, who had received chemotherapy for osteosarcoma of the lower extremity, underwent MR imaging 3 days before surgery. After routine MR imaging was performed, subtraction MR was performed in the plane in which the tumor was best visualized. With gadopentetate dimeglumine (0.1 mmol per kilogram) on a standard MR console, subtraction images were created by subtracting precontrast images from gadolinium-enhanced T1-weighted images. The time of maximal tumoral vascular uptake was 1 1/2 minutes after injection, and, therefore, the subtracted image obtained at this time was used for evaluation of viable tumor. Independently, radiologists and histopathologists examined their respective studies for viable tumor to differentiate responders from nonresponders. Four of 10 osteosarcomas were classified as good responders because they appeared as nonenhancing masses, with or without enhancing thin lines, or small nodules (< or = 3 mm wide). At histopathologic examination, all were good responders with less than 3% viable tumor. Six of 10 osteosarcomas were classified as nonresponders because they appeared as enhancing high-signal-intensity masses measuring more than 3 mm in width. Five tumors had between 18% and 43% viable tumor cells.

Adolescent↗
PubMed2006

Overexpression of COX-2 in human osteosarcoma cells decreases proliferation and increases apoptosis.

Overexpression of cyclooxygenase-2 (COX-2) is generally considered to promote tumorigenesis. To investigate a potential role of COX-2 in osteosarcoma, we overexpressed COX-2 in human osteosarcoma cells. Saos-2 cells deficient in COX-2 expression were retrovirally transduced or stably transfected with murine COX-2 cDNA. Functional expression of COX-2 was confirmed by Northern and Western analyses and prostaglandin production. Overexpression of COX-2 reduced cell numbers by 50% to 70% compared with controls. Decreased proliferation in COX-2-overexpressing cells was associated with cell cycle prolongation in G(2)-M. Apoptosis, measured by both Annexin V binding assay and terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling staining, was increased in cells overexpressing COX-2, and the increase was not reversed by treatment with NS-398, indicating that the effects were not mediated by prostaglandins. Retroviral COX-2 overexpression in two other human osteosarcoma cell lines, U2OS and TE85, also decreased cell viability. However, in the human colon carcinoma HCT-116 cell line, which is deficient in COX-2, retroviral overexpression of COX-2, at similar efficiency as in Saos-2 cells, increased resistance to apoptosis. Reactive oxygen species (ROS), measured by flow cytometry, were increased by COX-2 overexpression in Saos-2 cells but not in HCT-116 cells. Inhibition of peroxidase activity, but not of COX activity, blocked the ROS increase. Antioxidants blocked the increase in ROS and the increase in apoptosis due to COX-2 overexpression in Saos-2 cells. Our results suggest that (a) COX-2 overexpression in osteosarcoma cells may increase resistance to tumorigenesis by increasing ROS to levels that decrease cell viability and (b) the effects of COX-2 overexpression are cell type/tissue dependent.

Antioxidants↗
PubMed2004

High-level expression of the coxsackievirus and adenovirus receptor messenger RNA in osteosarcoma, Ewing's sarcoma, and benign neurogenic tumors among musculoskeletal tumors.

PURPOSE: The sensitivity of human tumor tissues to infection with recombinant adenoviruses correlates with the expression of the coxsackievirus and adenovirus receptor (CAR). CAR has been shown to function as the primary receptor for adenoviruses and to play a critical role in adenovirus entry into host cells. It is important for clinical gene therapy to determine the expression level of CAR in tumor tissues. EXPERIMENTAL DESIGN: We analyzed the expression of CAR mRNA in 154 musculoskeletal tumor tissues from 154 patients and 10 normal mesenchymal tissues from 3 patients using reverse transcription-PCR and real-time quantitative PCR. An adenovirus infection assay was performed in two cell lines that were established from CAR-positive osteosarcoma tissue and CAR-negative malignant fibrous histiocytoma tissue. RESULTS: Ninety-nine of 154 tumors were detected as CAR positive by reverse transcription-PCR. We found that the expression levels of CAR mRNA varied markedly between different tumors as determined by real-time quantitative PCR. CAR mRNA was expressed at high levels in osteosarcoma, Ewing's sarcoma, neurofibroma, and schwannoma; at intermediate levels in exostosis, giant cell tumor, liposarcoma, synovial sarcoma, malignant peripheral nerve sheath tumor, and hemangioma; and at low levels in alveolar soft part sarcoma and desmoid. Whereas the osteosarcoma cell line that expressed a high level of CAR mRNA, like its parent tumor, had a high efficiency of adenovirus infection, the malignant fibrous histiocytoma cell line with almost undetectable expression of CAR mRNA, like its parent tumor, had a low efficiency of infection. CONCLUSIONS: Our data showed the great variations in CAR mRNA expression among human musculoskeletal tumors and mesenchymal tissues and implicated the potential usefulness of adenoviral vectors in gene therapy for osteosarcoma, Ewing's sarcoma, neurofibroma, and schwannoma. Efficient transduction with adenovirus for gene therapy could be realized in appropriate, sensitive tumor types.

Adenoviridae↗
PubMed2005

Interleukin-12 up-regulates Fas expression in human osteosarcoma and Ewing's sarcoma cells by enhancing its promoter activity.

Interleukin-12 (IL-12) has shown significant antitumor activity in several preclinical animal tumor models. Our previous studies showed that IL-12 inhibited tumor growth in human osteosarcoma and Ewing's sarcoma animal model. Decreased Fas expression in osteosarcoma increased the lung metastatic potential. In this study, we further examined the mechanism of IL-12 antitumor activity and showed that IL-12 significantly increased Fas expression in both human osteosarcoma cells LM7 and Ewing's sarcoma cells TC71. Up-regulation of Fas expression increased their sensitivity to Fas-induced cell apoptosis. Constructs of the Fas promoter linked to a luciferase reporter gene were used to determine the promoter activity. IL-12 increased Fas promoter activity 4.2- and 4.9-fold in TC71 and LM7 cells, respectively. Time course studies have shown that recombinant IL-12 stimulated Fas promoter activity at 2 hours, reached the peak level at 4 hours, and then declined at 24 hours. To investigate whether IL-12 specifically enhanced Fas promoter activity, we determined whether another gene (E1A) was able to stimulate Fas promoter activity. We also evaluated effect of IL-12 on the topoisomerase IIalpha promoter. The results indicated that E1A but not IL-12 stimulated topoisomerase IIalpha promoter activity. E1A failed to increase Fas promoter activity. We also found that kappaB-Sp1 element at position -295 to -286 in Fas promoter was essential for IL-12-induced activation, and nuclear factor-kappaB transcription factor was activated after IL-12 treatment in TC71 cells. These results indicate that IL-12 up-regulates Fas expression in human osteosarcoma and Ewing's sarcoma by enhancing Fas promoter activity. Understanding this mechanism may lead to new therapeutic approaches for the treatment of sarcoma involving the use of IL-12.

Animals↗
PubMed2002

Acridine orange excited by low-dose radiation has a strong cytocidal effect on mouse osteosarcoma.

The study was conducted to clarify the cytocidal effect of combination therapy consisting of administration of acridine orange (AO), which is a photosensitizer, and radiation therapy using in vitro and in vivo mouse osteosarcoma models. The results revealed that AO combined with low-dose X-ray irradiation of about 1-5 Gy had a strong cytocidal effect on the cultured mouse osteosarcoma cells regardless of their chemosensitivity, and that this combination therapy inhibited growth of the in vivo mouse osteosarcoma by induction of tumor necrosis. This effect was inhibited by L-histidine, but not by mannitol. These findings suggested that AO might be excited by X-rays and kill osteosarcoma cells through the release of singlet oxygen, which is toxic to living cells. This mechanism is similar to that of photodynamic therapy with AO.

Acridine Orange↗
PubMedDate not supplied

Possible involvement of bcl-2 suppression in wild-type p53 gene-dependent cell growth repression in rat osteosarcoma cells.

We recently obtained 3 cloned cell lines demonstrating the p53 mutation from a lung metastatic nodule of a rat transplantable osteosarcoma. In this study, we applied wild-type p53 gene transfer to the rat osteosarcoma cells by lipofection to investigate the effects on cell growth, expression of genes such as waf1/p21, bcl-2, and bax, and nucleosomal DNA fragmentation due to apoptosis. Reconstitution of the p53 gene inhibits cellular growth, and this growth-suppressive effect is partly due to apoptosis involving bcl-2 gene suppression in this tumor type. This rat osteosarcoma model is similar in biologic behavior to human cases and thus is very suitable for further investigation of tumorigenesis and gene therapy for osteosarcoma.

Animals↗
PubMed2003

Neuroendocrine-immune surveillance of osteosarcoma: emerging hypothesis.

Osteosarcoma is a bone-forming cancer predominantly found in children and adolescents more often than in adults. Osteosarcoma of the gnathic apparatus is relatively rare in the young population, and this condition becomes a concern of clinical dentists for predominantly the middle-aged and aging patient groups. Osteosarcomas are invaded by lymphocytes, which exhibit signs of activation. The immune processes that are engaged within the malignant bone matrix involve the production of cytokines, which regulate the process of apoptotic programmed cell death. This paper discusses the mechanisms by which apoptosis of osteosarcoma cells is modulated by the neuroendocrine-immune system, and potential physiological implications.

Adolescent↗
PubMed2005

Acquisition of anoikis resistance in human osteosarcoma cells does not alter sensitivity to chemotherapeutic agents.

BACKGROUND: Chemotherapy-induced cell death can involve the induction of apoptosis. Thus, aberrant function of the pathways involved might result in chemoresistance. Since cell adhesion to the extracellular matrix acts as a survival factor that homeostatically maintains normal tissue architecture, it was tested whether acquisition of resistance to deadhesion-induced apoptosis (anoikis) in human osteosarcoma would result in resistance to chemotherapy. METHODS: Osteosarcoma cell lines (SAOS-2 and TE-85) obtained from ATCC and were maintained in complete Eagle's MEM medium. Suspension culture was established by placing cells in tissue culture wells coated with poly-HEMA. Cell cytotoxicity was determined using a live/dead cytotoxicity assay. Cell cycle/apoptosis analyses were performed using propidium iodide (PI) staining with subsequent FACS analysis. Apoptosis was also assayed by Annexin-FITC/PI staining. RESULTS: Etoposide, adriamycin, vinblastine, cisplatin and paclitaxel were able to induce apoptosis in human osteosarcoma cells SAOS-2 regardless of their anoikis resistance phenotype or the culture conditions (adhered vs. suspended). Moreover, suspended anoikis resistant TE-85 cells (TE-85ar) retained their sensitivity to chemotherapy as well. CONCLUSION: Acquisition of anoikis resistance in human osteosarcoma cells does not result in a generalized resistance to all apoptotic stimuli, including chemotherapy. Moreover, our results suggest that the pathways regulating anoikis resistance and chemotherapy resistance might involve the action of different mediators.

Anoikis↗
PubMed1994

Germline mutations of the p53 tumor suppressor gene in children with osteosarcoma.

PURPOSE: We investigated the possibility that a significant proportion of children with osteosarcoma harbor germline mutations of the p53 tumor suppressor gene and, therefore, this subgroup of pediatric cancer patients should be considered for large-scale predictive testing. PATIENTS AND METHODS: Genomic DNA extracted from peripheral-blood leukocytes from 235 unselected children with osteosarcoma from 33 institutions were screened for the presence of germline p53 mutations using constant denaturant gel electrophoresis (CDGE). Exons 5 through 8 were evaluated in all patients and exon 2 and exon 9 were analyzed in 59 and 95 patients, respectively. Those samples that showed aberrant migration on CDGE were sequenced or analyzed by restriction enzyme digestion of polymerase chain reaction (PCR) products to confirm the nature of the gene alteration. RESULTS: In 18 samples, CDGE showed fragments of the p53 gene with altered electrophoretic mobilities compared with wild-type p53. DNA sequencing showed that 11 samples had an identical, previously described polymorphism. The other seven contained heterozygous p53 mutations located in exon 5 (n = 3), exon 6 (n = 1), exon 7 (n = 1), and exon 8 (n = 2). Six alterations were missense mutations and one was a nonsense mutation. Three of these patients had first-degree relatives with cancer. One of these three kindreds had a family history consistent with Li-Fraumeni syndrome (LFS). CONCLUSION: We identified germline p53 mutations in seven of 235 (3.0%) children with osteosarcoma. Four of these mutations were found in patients who did not have first-degree relatives with cancer. Although genetic transmission of the altered p53 gene could not be tested in this survey because of how it was designed, it is possible that predictive testing for p53 mutations could identify unaffected relatives of gene carriers who also have a high risk for the development of cancer. This study provides evidence for the importance of considering children with osteosarcoma for predictive testing for germline p53 mutations.

Base Sequence↗
PubMed1996

Loss of heterozygosity of the RB gene is a poor prognostic factor in patients with osteosarcoma.

PURPOSE: The usual therapy of osteosarcoma is neoadjuvant chemotherapy, followed by surgery, then by postoperative chemotherapy. There is no prognostic factor to predict, at diagnosis, the histologic response and final outcome. Inactivation of the retinoblastoma-susceptibility gene RB is associated with the pathogenesis of several human cancers. In primary osteosarcomas, loss of heterozygosity (LOH) at the RB locus has been found in greater than 60% of cases. The aim of this study was to determine the potential early prognostic value of LOH of RB gene on the biopsy material at diagnosis. PATIENTS AND METHODS: Forty-seven patients with primary osteosarcoma, treated in four French institutions, were studied. LOH was studied by polymerase chain reaction (PCR) of an informative RB DNA polymorphism. RESULTS: Assessment of LOH at the RB gene could be completed on 34 heterozygous patients only. LOH was found in 24 cases (70%). The event-free survival (EFS) rate at 60 months is 100% for patients without LOH, 43% for all patients with RB LOH, and 65% for nonmetastatic patients with RB LOH. The difference in EFS is highly significant at P = .008 and P = .024, respectively. Histologic response after preoperative chemotherapy did not show significant correlation with LOH status. CONCLUSION: RB gene LOH appears to be an early predictive feature for osteosarcomas that indicates a potential unfavorable outcome. RB LOH study might shortly help to identify high-risk patients earlier. If this is verified, therapy could then be adapted earlier to the individual's real risk of relapse.

Adolescent↗
PubMed1998

Predictive factors of histologic response to primary chemotherapy in osteosarcoma of the extremity: study of 272 patients preoperatively treated with high-dose methotrexate, doxorubicin, and cisplatin.

PURPOSE: In osteosarcoma of the extremity, a strong correlation between chemotherapy-induced necrosis and prognosis has been reported. The aim of this study was to investigate the possible factors that influence histologic response to primary chemotherapy. PATIENTS AND METHODS: In 272 patients with high-grade osteosarcoma of the extremity preoperatively treated with high-dose methotrexate (HDMTX), cisplatin (CDP), and doxorubicin (ADM), the histologic response to chemotherapy was evaluated and graded as complete (no viable tumor cells) or incomplete (persistence of viable tumor cells). Several factors, such as metastatic disease to the lung at diagnosis, sex, age, site and tumor volume, histologic subtype, serum alkaline phosphatase, lactate dehydrogenase (LDH), and methotrexate (MTX) pharmacokinetics were investigated to test their predictive significance on histologic response. RESULTS: Fifty-one patients with localized disease (20.6%) and none of the 25 patients with metastatic disease at presentation had a complete histologic response (P = .006). After multivariate analysis, performed on patients with localized disease only, MTX serum peak (> or = 700 micromol/L) and histologic subtype were proven to be significant predictive factors of histologic response. A complete response was seen in 28.8% of patients with 700 micromol/L or greater MTX serum levels and in 9.9% of those patients with lower levels (P = .001). The chondroblastic subtype was less responsive (6.1% of complete response), compared with the osteoblastic (16.3%), fibroblastic (33.3%), and telangiectatic (42.3%). CONCLUSION: Patients with metastatic osteosarcoma and localized chondroblastic osteosarcoma have a reduced chemosensitivity to primary chemotherapy with MTX, CDP, and ADM. MTX serum peak significantly influences tumor necrosis. A dose adaptation of MTX is recommended to obtain a serum peak of 700 micromol/L or greater when MTX is infused in 6 hours.

Adolescent↗
PubMed2002

Effect of timing of pulmonary metastases identification on prognosis of patients with osteosarcoma: the Japanese Musculoskeletal Oncology Group study.

PURPOSE: The prognostic value of the time of identification of lung metastasis was investigated in 280 patients with metastatic lung osteosarcoma as a multi-institutional study of the Japanese Musculoskeletal Oncology Group. PATIENTS AND METHODS: The 280 patients with lung metastasis were divided into four groups: group 1, patients with lung metastasis identified at initial presentation; group 2, those with lung metastasis identified during preoperative chemotherapy; group 3, those with lung metastasis identified during postoperative chemotherapy, and group 4, those with lung metastasis identified after completion of treatment. Survivals of the four groups were compared. Additionally, the effects of number of metastatic nodules, metastasectomy, and the effect of chemotherapy on the primary tumor on survival of the four groups were analyzed. RESULTS: There were 46 patients in group 1, 30 in group 2, 94 in group 3, and 110 in group 4. The overall 2-year survival rates from the time of identification of lung metastasis were 33%, 31%, 24%, and 40% for groups 1, 2, 3, and 4, respectively, whereas the 5-year survival rates were 18%, 0%, 6%, and 31%, respectively. Patients in group 4 thus demonstrated significantly better prognosis than any of the other patients (P <.0001). CONCLUSION: Time of identification of lung metastasis is an important prognostic factor. In terms of clinical behavior, groups 2 and 3 are completely different than group 4. These data ensure the need to stratify stage III osteosarcomas into subgroups according to the time of diagnosis of lung metastases. To improve the survival of osteosarcoma patients, new treatment modalities should be introduced into the treatment armamentarium for lung metastasis from osteosarcoma, especially in groups 1, 2, and 3.

Adolescent↗
PubMed2003

Cytochrome P450 CYP3A4/5 expression as a biomarker of outcome in osteosarcoma.

PURPOSE: Osteosarcoma, the most common pediatric primary bone tumor, is an aggressive malignancy with a tendency for early pulmonary metastasis. A reliable biomarker to predict clinical outcome at diagnosis has not yet been identified. To date, pathological review of neoadjuvant chemotherapy-induced necrosis is the most useful determinant of which patients are likely to develop metastatic disease. There is a clinical need to identify patients who will benefit from more aggressive preoperative therapy or perhaps require less aggressive chemotherapy. More than 30 human P450 isoenzymes have been characterized, with at least nine possessing some clinical relevance. One of these, CYP3A4/5 is involved in metabolic activation and detoxification of a wide number of carcinogens and chemotherapeutic agents, including many drugs that are useful in the treatment of osteosarcomas. MATERIALS AND METHODS: Osteosarcoma tissue microarray blocks containing biopsies from 18 primary tumors were used to analyze the expression of P450s 1A1/2, 1B1, 2B6, 2D6, and 3A4/5 by enzyme-linked avidin-biotin complexed immunohistochemistry. The frequencies of expression were 83%, 67%, and 83% for P450s 1A1/2, 1B1, and 3A4/5, respectively. P450s 2B6 and 2D6 were not detectable. RESULTS: These results were extended by developing a fluorescent-based quantitative immunocytochemistry technique to assess the levels of CYP3A4/5 in 18 paraffin-embedded primary biopsy sections. Expression of CYP3A4/5 was found to be significantly higher in primary biopsies of patients who developed distant metastatic disease compared with biopsies from patients with nonmetastatic disease (P = 0.0004). CONCLUSION: High cytochrome P450 CYP3A4/5 expression may predict metastasis and poor prognosis in osteosarcomas. Its use as a biomarker of therapeutic response will have implications for the treatment of these tumors.

Adolescent↗
PubMed2005

TP53 mutations and outcome in osteosarcoma: a prospective, multicenter study.

PURPOSE: Mutations of the TP53 gene have been associated with resistance to chemotherapy as well as poor prognosis in many different malignancies. This is the first prospective study of the prognostic value of somatic TP53 mutations in patients with newly diagnosed extremity osteosarcoma. PATIENTS AND METHODS: One hundred ninety-six patients with high-grade, nonmetastatic osteosarcoma of the extremities were enrolled from seven tertiary care institutions and observed prospectively for tumor recurrence (median follow-up duration, 44 months). All patients received neoadjuvant or adjuvant chemotherapy and surgery. Tumors were analyzed for the presence of TP53 mutations by polymerase chain reaction single-strand conformation polymorphism analysis and direct DNA sequencing. The association of the status of the TP53 gene with the risk of systemic recurrence was examined using survival analyses with traditional and histologic markers as prognostic factors. RESULTS: Patient age was the only factor that varied with TP53 gene status (P = .05). No relationship was identified between TP53 status and systemic relapse (relative risk, 1.24; P = .41). Analyses based on missense or nonsense mutations gave similar results (P > .10). In multivariate analysis, large (> 9 cm) tumor size (relative risk, 1.9; P = .006) and poor histologic response (< or = 90% necrosis) to chemotherapy (relative risk, 2.14; P = .02) were the only significant independent predictors of systemic outcome. CONCLUSION: We found no evidence that TP53 mutations predict for development of metastases in patients with high-grade osteosarcoma. Identification of other genes that influence chemotherapy response and clinical outcome in osteosarcoma is needed to facilitate further improvements in patient outcomes.

Adolescent↗
PubMed2005

Improved survival associated with postoperative wound infection in dogs treated with limb-salvage surgery for osteosarcoma.

BACKGROUND: Limb-salvage surgery and adjuvant chemotherapy are performed as a treatment of appendicular osteosarcoma in dogs. Approximately 50% of dogs that undergo limb-salvage surgery develop postoperative surgical wound infections. Postoperative surgical infections may affect survival in cancer patients. The purposes of this study were to examine the effect of surgical wound infection on survival, local recurrence, and metastasis in relation to other prognostic factors for dogs with spontaneous osteosarcoma treated with limb-salvage surgery. METHODS: Forty-seven client-owned dogs with osteosarcoma of the distal radius were treated with limb-salvage surgery and adjuvant chemotherapy--either carboplatin or carboplatin and doxorubicin. Hazard ratios were estimated by using the Cox proportional hazard model, and survival functions were estimated by using the Kaplan-Meier product-limit life-table method. RESULTS: Of the 47 dogs in this study, 32 (68%) developed a postoperative wound infection. Infection, dog weight, and extent of the primary tumor (percentage of length) significantly affected survival, and infection and percentage of length significantly affected time to metastasis. None of the variables considered in this study affected local recurrence. Dogs that were diagnosed with an infection were less likely to die (hazard ratio, .446), and dogs with greater body weight and greater percentage length involvement were more likely to die (hazard ratios of 3.37 and 3.66, respectively). CONCLUSIONS: In dogs with osteosarcoma treated with limb-salvage surgery, infection has a positive influence on survival, as does a smaller initial length of radius involved and lower body weight.

Animals↗
PubMed1986

Osteoclast-rich osteosarcoma.

Nine cases of primary osteoclast-rich osteosarcoma, an undifferentiated sarcoma with an overabundance of osteoclasts and a paucity of tumour osteoid, are reported. They comprise about 3% of all primary osteosarcomas and are histologically related to telangiectatic osteosarcoma, another undifferentiated tumour with abundant osteoclasts and scanty osteoid, perhaps being a predominantly solid variant of the latter. Many of the classical radiological features of an osteosarcoma are absent in these cases and differentiation from a benign lesion is sometimes difficult. Typically, an ill-defined margin surrounds a predominantly lytic lesion of the diaphysis or metaphysis of the femur or tibia of a young patient. A soft-tissue mass is not usually present and periosteal reaction is scanty.

Adolescent↗
PubMed1998

Establishment and characterization of two cell lines derived from canine spontaneous osteosarcoma.

Two new canine osteosarcoma cell lines were established. One (OOS) was established from a 10-year-old female maltese dog with mandibular osteosarcoma and the other (HOS) from a 7-year-old male mongrel dog with scapular osteosarcoma. Histopathological types of OOS and HOS were mixed and fibroblastic cell type, respectively. Transmission electron microscopic features of HOS revealed prominent rough endoplasmic reticulum, suggesting higher malignancy comparing to OOS. Doubling time of OOS and HOS were 45.0 +/- 0.5 hr and 42.0 +/- 0.1 hr, respectively. Alkaline phosphatase activities of OOS and HOS were quite low. Histological features of tumor tissues produced by transplantation of these cells into nude mice were identical to those of original osteosarcomas.

Alkaline Phosphatase↗