Osteosarcoma of the femur with skip, lymph node, and lung metastases

Role of bone scintigraphy (bone scan) in skeletal osteosarcoma: A retrospective audit and review from tertiary oncology centre

Introduction

Bone scan is a investigation which uses radionuclide phosphonate compound for whole skeletal survey. In this current study we have done the analysis of the role of bone scan in skeletal osteosarcoma at tertiary oncology care centre.

Material & methods

This is a retrospective study conducted in a tertiary oncology centre from January 2022 to February 2023. A total of 92 patients with skeletal OGS were included in our study undergone 99 mTCcMDP whole body bone scan. 99 mTc MDP was prepared freshly every morning and dose for each patient were calculated as per EANM guidelines. Images were acquired 2-3 h of post injection. All images were acquired at GE infinia dual head machine with peak setting at 140Kev and LEAP collimator. Suspicious lesions on planer bone scan were correlated with SPECT fused with CT. All the bone scans were reviewed retrospectively by two independent nuclear medicine physicians.

Results

In this study group, 86 patients with biopsy proven skeletal OGS underwent 99 mTCcMDP bone scan of which 63 were males and 23 were females (2.7:1) with age of study group ranging from 7years to 48years. Patients referred for bone scan were retrospectively categorized in two groups, first group patients (52) were referred for initial staging of disease and second group of patients (34) were referred for follow-up or re-staging of the disease. Total 09 patients showed distant skeletal metastases on bone scan, out of which 05 were in initial staging group and 04 in follow up group.

Conclusion

Osteosarcoma has propensity to metastasize to many sites in the body however most common site being lung followed by skeletal, nodal and rarely soft tissue metastasis. Bone scan enjoys a optimal sensitivity in case of osteosarcoma to detect skeletal metastasis but have low specificity. However being a cost effective and faster investigation makes it a wise investigation of choice in case of osteosarcoma for skeletal metastasis evaluation.

Initial Evaluation of Focal Bone Lesions: How Do We Do It?

Focal bone lesions are frequent, and management greatly depends on the characteristics of their images. After briefly discussing the required work-up, we analyze the most relevant imaging signs for assessing potential aggressiveness. We also describe the imaging aspects of the various types of lesion matrices and their clinical implications.

Osteogenic Sarcoma Presenting with Skip, Lymph Nodal, Pulmonary, Pleural Metastases and Malignant Effusion: An Unusual Appearance on Bone Scan

Osteogenic sarcoma is an aggressive malignant bone tumor arising from primitive mesenchymal bone-forming cells. Ossification is the characteristic feature of the metastases in osteosarcoma which aids their detection on ^99mTc-MDP bone scintigraphy. Although lung is the most common site of metastasis in osteogenic sarcoma, pleural involvement with effusion and skip metastases are rare. Herein, we report a case of osteogenic sarcoma of distal femur with diffuse calcified pleural thickening leading to malignant pleural effusion, calcified lung, lymph node, and bone metastases illustrated on bone scan.

Pretreatment Prediction of Relapse Risk in Patients with Osteosarcoma Using Radiomics Nomogram Based on CT: A Retrospective Multicenter Study

OBJECTIVE

To develop and externally validate a CT-based radiomics nomogram for pretreatment prediction of relapse in osteosarcoma patients within one year.

MATERIALS AND METHODS

In this multicenter retrospective study, a total of 80 patients (training cohort: 63 patients from three hospitals; validation cohort: 17 patients from three other hospitals) with osteosarcoma, undergoing pretreatment CT between August 2010 and December 2018, were identified from multicenter databases. Radiomics features were extracted and selected from tumor regions on CT image, and then, the radiomics signature was constructed. The radiomics nomogram that incorporated the radiomics signature and clinical-based risk factors was developed to predict relapse risk with a multivariate Cox regression model using the training cohort and validated using the external validation cohort. The performance of the nomogram was assessed concerning discrimination, calibration, reclassification, and clinical usefulness.

RESULTS

Kaplan-Meier curves based on the radiomics signature showed a significant difference between the high-risk and the low-risk groups in both training and validation cohorts (P < 0.001 and P = 0.015, respectively). The radiomics nomogram achieved good discriminant results in the training cohort (C-index: 0.779) and the validation cohort (C-index: 0.710) as well as good calibration. Decision curve analysis revealed that the proposed model significantly improved the clinical benefit compared with the clinical-based nomogram (P < 0.001).

CONCLUSIONS

This multicenter study demonstrates that a radiomics nomogram incorporated the radiomics signature and clinical-based risk factors can increase the predictive value of the osteosarcoma relapse risk, which supports the clinical application in different institutions.

Popliteal lymph nodes in patients with osteosarcoma: are they metastatic?

PURPOSE

To evaluate the prevalence, imaging appearance, and significance of popliteal lymph nodes (PLN) on magnetic resonance imaging (MRI) in patients with distal femoral or proximal tibial osteosarcoma (OS).

METHOD AND MATERIALS

This study included consecutive patients with OS presenting from May 2016 to March 2018. Inclusion criteria were patients with distal femoral or proximal tibial OS with MRI and pathology at our institution. On MRI, two radiologists recorded primary tumor features (size, location, signal, extra-compartmental extension), and PLN characteristics (mean size, presence/absence of fatty hilum, mineralization, PET/bone scintigraphy avidity, contrast enhancement, and diffusion restriction). Tumor histology, stage, and clinical follow-up were recorded. Descriptive statistics were provided.

RESULTS

Sixteen patients with OS (age 20 ± 10 (range10-40) years, 10/16 male) were included. Although 81% (13/16) of the patients had PLNs at presentation (size range 0.3-3.6 cm), fewer patients had extra-compartmental spread: intra-articular extension 50% (8/16), skip lesions 19% (3/16), lung metastases 31% (5/16), and osseous metastases 12% (2/16). Four (25% (4/16)) patients had PLN ≥ 1 cm; two were histologically proven reactive. One was presumed metastatic due to rapid development, mineralization, and FDG-avidity on PET/CT. The other ≥ 1 cm PLNs along with all twelve (75% (12/16)) that were < 1 cm in mean diameter were presumed non-metastatic with documented stability for at least 12 months of follow-up.

CONCLUSION

PLNs are frequently visible on MRI in patients with OS but are rarely (prevalence = 6%) metastatic. Features on MRI which may suggest metastatic PLNs include large size > 1 cm and loss of a fatty hilum.

Bone Tumors Occurring in the Soft Tissues: A Review of the Clinical, Imaging, and Histopathologic Findings

Although rare in everyday practice, malignancies that classically arise from bone or cartilage have been reported to arise de novo in various soft tissues in the body, resulting in a diagnostic challenge for the clinician, radiologist, and pathologist. Differential diagnoses of bone tumors often depend on anatomic location of the lesion. For example, the classic location of osteosarcoma is in the metaphysis of long bones about the knee. Histologically osteosarcoma is characterized by tumor cells that directly produce osteoid, bone, or cartilaginous matrix. In extraskeletal osteosarcoma, the clinical and radiologic picture is very different from a conventional osteosarcoma. They occur in older patients, present as a soft tissue mass often coincidentally following trauma and have a worse prognosis. The imaging characteristics are often nonspecific with mineralized elements in a well-defined soft tissue mass. The mineralized elements may or may not be visible. Magnetic Resonance sequences demonstrate a well circumscribed soft tissue mass with hemorrhagic and enhancing solid components. The pathologic features of extraskeletal osteosarcoma on a microscopic scale are identical to that of skeletal lesions. Likewise, conventional chondrosarcomas present in older patients with a growing, painful soft tissue prominence most commonly involving the long tubular bones. In extraskeletal chondrosarcoma however, the presentation is in somewhat younger patients with a painful soft tissue prominence typically in the head (meninges), neck, or upper leg. The pathologic features are most often that of a myxoid chondrosarcoma which is characterized by strands of small cells over a myxoid matrix. Imaging features include chondroid matrix, heterogenous contrast enhancement, and amorphous internal calcification on Computed Tomography. On Magnetic Resonance sequences the matrix has a low signal on all sequences, and variable inhomogeneity depending on grade of the lesion. Other extraskeletal bone tumors include Ewing's sarcoma and osteoid osteoma amongst other lesions. Although these malignancies may be rare clinical entities, they often exhibit characteristic clinical, imaging, and histopathological findings although differing in treatment and prognosis. Knowledge of these and other common mimicking lesions will help guide the clinician and radiologist to make an accurate diagnosis.

Computerized texture analysis of pulmonary nodules in pediatric patients with osteosarcoma: Differentiation of pulmonary metastases from non-metastatic nodules

OBJECTIVE

To retrospectively evaluate the value of computerized 3D texture analysis for differentiating pulmonary metastases from non-metastatic lesions in pediatric patients with osteosarcoma.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board. The study comprised 42 pathologically confirmed pulmonary nodules in 16 children with osteosarcoma who had undergone preoperative computed tomography between January 2009 and December 2014. Texture analysis was performed using an in-house program. Multivariate logistic regression analysis was performed to identify factors for differentiating metastatic nodules from non-metastases. A subgroup analysis was performed to identify differentiating parameters in small non-calcified pulmonary nodules. The receiver operator characteristic curve was created to evaluate the discriminating performance of the established model.

RESULTS

There were 24 metastatic and 18 non-metastatic lesions. Multivariate analysis revealed that higher mean attenuation (adjusted odds ratio [OR], 1.014, P = 0.003) and larger effective diameter (OR, 1.745, P = 0.012) were significant differentiators. The analysis with small non-calcified pulmonary nodules (7 metastases and 18 non-metastases) revealed significant inter-group differences in various parameters. Logistic regression analysis revealed that higher mean attenuation (OR, 1.007, P = 0.008) was a significant predictor of non-calcified pulmonary metastases. The established logistic regression model of subgroups showed excellent discriminating performance in the ROC analysis (area under the curve, 0.865).

CONCLUSION

Pulmonary metastases from osteosarcoma could be differentiated from non-metastases by using computerized texture analysis. Higher mean attenuation and larger diameter were significant predictors for pulmonary metastases, while higher mean attenuation was a significant predictor for small non-calcified pulmonary metastases.

Regulatory mechanism of microRNA-128 in osteosarcoma tumorigenesis and evolution through targeting SASH1

Osteosarcoma, which commonly occurs in young individuals, is a type of malignant tumor of growing bones. MicroRNAs (miRNAs) have been found to be involved in various cancer-related processes. In the present study, it was reported that miRNA-128 (miR-128) was overexpressed in pathological tissues from patients with osteosarcoma. The present study investigated the possible regulatory mechanism of miR-128 on the progression of osteosarcoma and offered a foundation for clinical therapeutics in osteosarcoma. First, the expressions levels of miR-128 and its target gene, SAM and SH3 domain-containing 1 (SASH1), were measured in tissues from patients with osteosarcoma, and their correlation with osteosarcoma in terms of the pathological level were examined. The effects of miR-128 on osteosarcoma cell proliferation and apoptosis were examined, and its regulation of the expression levels of SASH1 and associated proteins was analyzed. Subsequently, the association between SASH1 and miR-128 was evaluated using a dual luciferase gene reporter assay. Finally, an in vivo xenograft tumor mouse model of osteosarcoma was established to confirm the in vitro results. The results demonstrated a higher expression of miR-128 in pathological tissues, compared with that in normal tissues. From examining the patient osteosarcoma tissues, marked correlations were found between the expression of miR-128 and that of SASH1, particularly with tumor size, invasion depth, lymph node metastasis, and tumor-node-metastasis stage. Compared with the negative control group and blank control group, the results showed that the inhibition of miR-128 led to a lower cell proliferation rate and higher apoptotic rate in MG-63 cells (P<0.05). Additionally, the expression of B-cell lymphoma 2 (Bcl-2) was downregulated in the miR-128-inhibited group, compared with that in the control group, whereas the expression levels of SASH1, Bcl-2-associated X protein and caspase-3 were upregulated in the group with miR-128 inhibition (P<0.05). SASH1 was confirmed as a direct target of miR-128 using a dual luciferase gene reporter assay. Finally, the downregulation of miR-128 was found to induce tumor suppressive effects on xenograft tumor models of osteosarcoma in mice in vivo. The results of the present study suggested that miR-128 may regulate the tumorigenesis and evolution of osteosarcoma through targeting SASH1.

[Lymph node metastasis of osteosarcomas]

Lymph node metastasis of osteosarcomas is a rather rare phenomenon; according to different authors, the incidence of lymph node metastasis is 4 to 11%. The detection of lymph node metastases in osteosarcoma is associated with a significant reduction in the 5-year survival of patients and allows its classification as clinical stage IV tumor. The risk factors for lymph node metastases in patients with bone sarcomas are age (≥64 years), gender (female), nosological entity (undifferentiated pleomorphic sarcoma, osteosarcoma, chondrosarcoma), tumor depth (muscle, bone), and the size of primary tumor (>5 сm). The mechanism of lymph node metastasis of osteosarcomas seems to be related to mesenchymal-to-epithelial transition.

Expression and function of PIM kinases in osteosarcoma

The provirus integrating site Moloney murine leukemia virus (PIM) family of serine/threonine protein kinases is composed of three members, PIM1, PIM2 and PIM3, which have been identified as oncoproteins in various malignancies. However, their role in osteosarcoma (OS) remains largely unknown. This study aimed to examine the expression patterns and the clinical significance of PIM kinases in human OS and their biological effects in human OS cell lines. Immunohistochemical staining was used to detect PIM kinases in archived pathologic material from 43 patients with primary OS; in addition, the effects of PIM knockdown and overexpression on the proliferation, migration and invasion of OS cell lines were determined. We observed that all three PIM kinases were frequently expressed in OS, but only PIM1 positive expression was associated with poorer prognosis regarding overall survival of OS patients. In addition, knockdown of PIM kinases notably inhibited OS cell proliferation, migration and invasiveness, whereas overexpression of PIM kinases resulted in increased OS cell growth and motility. This study suggests that PIM1 could be a valuable prognostic marker in patients with OS, and the biological functions of PIM kinase family in the osteosarcoma cell lines indicate that they could serve as potential therapeutic targets for OS.

TRAF4 enhances osteosarcoma cell proliferation and invasion by Akt signaling pathway

TRAF4, or tumor necrosis factor receptor-associated factor 4, is overexpressed in several cancers, suggesting a specific role in cancer progression. However, its functions in osteosarcoma are unclear. This study aimed to explore the expression of TRAF4 in osteosarcoma tissues and cells, the correlation of TRAF4 to clinical pathology of osteosarcoma, as well as the role and mechanism of TRAF4 in osteosarcoma metastasis. The protein expression levels of TRAF4 in osteosarcoma tissues and three osteosarcoma cell lines, MG-63, HOS, and U2OS, were assessed. Constructed TRAF4 overexpression vectors and established TRAF4 overexpression of the U2OS cell line. Cell proliferation, cell invasion, protein levels, and TRAF4 phosphorylations were assessed following TRAF4 transfection, as well as the effects of TRAF4 siRNA on cell proliferation and invasion. The results show that TRAF4 protein levels in osteosarcoma tissues were significantly higher than that in normal bone tissues. Importantly, an obvious upregulation of TRAF4 was found in carcinoma tissues from patients with lung metastasis compared with patients without lung metastasis. Consistently, a similar increase in TRAF4 mRNA and protein was also demonstrated in the osteosarcoma cell lines MG-63, HOS, and U2OS compared to normal bone cells, hFOB1.19. When TRAF4 was overexpressed in U2OS cells, cell proliferation was significantly enhanced, accompanied by an increase in Ki67 expression and colony formation. Compared with the control and vector-treated groups, TRAF4 transfection increased the invasion potential of U2OS cells (p < 0.05). Interestingly, TRAF4 transfection significantly enhanced the phosphorylation of Akt. After blocking Akt with its specific siRNA, TRAF4-induced cell proliferation and invasion were dramatically attenuated. In summary, our findings demonstrated that TRAF4 enhances osteosarcoma cell proliferation and invasion partially by the Akt pathway. This work suggests that TRAF4 might be an important target in osteosarcoma.

Apurinic/apyrimidinic endonuclease 1 regulates angiogenesis in a transforming growth factor β-dependent manner in human osteosarcoma

Angiogenesis plays an important role in tumor growth and metastasis and has been reported to be inversely correlated with overall survival of osteosarcoma patients. It has been shown that apurinic/apyrimidinic endonuclease 1 (APE1), a dually functional protein possessing both base excision repair and redox activities, is involved in tumor angiogenesis, although these mechanisms are not fully understood. Our previous study showed that the expression of transforming growth factor β (TGFβ) was significantly reduced in APE1-deficient osteosarcoma cells. Transforming growth factor β promotes cancer metastasis through various mechanisms including immunosuppression, angiogenesis, and invasion. In the current study, we initially revealed that APE1, TGFβ, and microvessel density (MVD) have pairwise correlation in osteosarcoma tissue samples, whereas TGFβ, tumor size, and MVD were inversely related to the prognosis of the cohort. We found that knocking down APE1 in osteosarcoma cells resulted in TGFβ downregulation. In addition, APE1-siRNA led to suppression of angiogenesis in vitro based on HUVECs in Transwell and Matrigel tube formation assays. Reduced secretory protein level of TGFβ of culture medium also resulted in decreased phosphorylation of Smad3 of HUVECs. In a mouse xenograft model, siRNA-mediated silencing of APE1 downregulated TGFβ expression, tumor size, and MVD. Collectively, the current evidence indicates that APE1 regulates angiogenesis in osteosarcoma by controlling the TGFβ pathway, suggesting a novel target for anti-angiogenesis therapy in human osteosarcoma.

Popliteal lymph node metastasis of tibial osteoblastic osteosarcoma

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Lymph node metastasis of osteosarcoma, which is a rare entity.

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Metastatic patterns could not be clearly explained.

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The effects of lymph node metastasis on prognosis are also not clearly defined and further studies are needed.

INTRODUCTION

We report a case with lymph node metastasis of osteosarcoma, which is a rare entity in comparison to hematogeneous lung or bone metastasis.

PRESENTATION OF CASE

Twenty-seven years old male patient referred to our clinic complaining of ongoing left knee pain and swelling since one month without a history of prior trauma. Magnetic resonance imaging (MRI) revealed a mass of malignant nature which causes more prominent expansion and destruction of the bone distally with periosteal reaction. A lymphadenomegaly 16 mm × 13 mm in diameter was also present in the popliteal fossa having the same signal pattern with the primary lesion. Thirteen weeks following the first referral of the patient, wide resection and reconstruction with modular tumor prosthesis was performed. Popliteal lymph node was excised through the same incision. Pathologic examination of the resected speciman reported osteoblastic osteosarcoma. The lymph node extirpated from the popliteal fossa was reported to be a metastasis of the primary tumor.

DISCUSSION

Osteosarcoma of the long bones is the most common primary malignant bone neoplasm of both childhood and adulthood. Osteosarcomas commonly metastasize hematogeneously to the lungs and bones. Lymph node metastasis is a rare entity. Similar studies report rates between 2.3% and 4%. It is not clearly explained, how lymph node metastasis in osteosarcoma occurs despite lack of lymphatic drainage in normal cortical and spongious bone.

CONCLUSION

Lymph node metastasis of osteosarcoma is a rare entity and metastatic patterns could not be clearly explained. On the other hand, the effects of lymph node metastasis on prognosis are also not clearly defined and further studies are needed.

HMGB1 promotes cellular proliferation and invasion, suppresses cellular apoptosis in osteosarcoma

Osteosarcoma is the most common primary malignant bone tumor in children and adolescents. Unfortunately, treatment failures are common due to the metastasis and chemoresistance, but the underlying molecular mechanism remains unclear. Accumulating evidence indicated that the deregulation of DNA-binding protein high-mobility group box 1 (HMGB1) was associated with the development of cancer. This study aimed to explore the expression of HMGB1 in osteosarcoma tissues and its correlation to the clinical pathology of osteosarcoma and to discuss the role of HMGB1 in the development of osteosarcoma. The results from RT-PCR and Western blot showed that the expression rate of HMGB1 messenger RNA (mRNA) and the expression of HMGB1 in the osteosarcoma tissues were significantly higher than those in normal bone tissue (p < 0.05), the expression rate of HMGB1 mRNA and the expression of HMGB1 in the carcinoma tissues with positive lung metastasis were significantly higher than those without lung metastasis (p < 0.05), and with increasing Enneking stage, the expression rate of HMGB1 mRNA and the expression of HMGB1 also increased (p < 0.05). In order to explore the role of HMGB1 in osteosarcoma, the expression of HMGB1 in the human osteosarcoma MG-63 cell line was downregulated by the technique of RNA interference. Western blot results showed that the protein expression of HMGB1 was significantly decreased in the MG-63 cells from HMGB1-siRNA transfection group (p < 0.05), which suggested that HMGB1 was successfully downregulated in the MG-63 cells. Then the changes in proliferation, apoptosis, and invasion of MG-63 cells were examined by MTT test, PI staining, annexin V staining, and transwell chamber assay. Results showed that the abilities of proliferation and invasion were suppressed in HMGB1 knockdown MG-63 cells, and the abilities of apoptosis were enhanced in HMGB1 knockdown MG-63 cells. The expression of cyclin D1, MMP-9 was downregulated in HMGB1 knockdown MG-63 cells, and the expression of caspase-3 was upregulated in HMGB1 knockdown MG-63 cells. Taken together, the overexpression of HMGB1 in osteosarcoma might be related to the tumorigenesis, invasion, and metastasis of osteosarcoma, which might be a potential target for the treatment of osteosarcoma.

Atypical Presentation of High-Grade Intramedullary Osteosarcoma with Bilateral Cervical, Supraclavicular, and Axillary Lymphadenopathy: A Case Report and Literature Review

Osteosarcoma typically presents with primary site pain. The authors report a case of extensive metastatic osteosarcoma without any complaint of primary site pain during initial presentation. The 23-year-old female patient presented with simultaneous multiple cervical, supraclavicular, and axillary lymphadenopathy, as well as two large subcutaneous fat tumours. Despite initial excision biopsy of cervical lymph nodes, the diagnosis of osteosarcoma was only clinched after open biopsy of the right distal femur lesions and further histological evaluation. Though the patient was promptly started on neo-adjuvant chemotherapy and achieved excellent histological response to treatment, the disease had relapsed quickly and she succumbed to the disease one year after initial presentation. This report highlights the need to be vigilant in the workup and investigation of osteosarcoma, as the presenting symptoms may be more heterogenous than the conventional teaching of primary site pain.

Role of positron emission tomography/computed tomography in bone malignancies

This article presents an overview of positron emission tomography combined with computed tomography (PET/CT) imaging of bone tumors for the practicing radiologist. The clinical roles and utility of (18)F-labeled fluorodeoxyglucose PET/CT in patients with primary bone tumors, osseous metastases, and multiple myeloma are reviewed. The clinical and research data supporting the utility of PET/CT in the evaluation of skeletal malignancies continues to grow.

Synergistic apoptotic effect of crocin and cisplatin on osteosarcoma cells via caspase induced apoptosis

Crocin is well-known traditional Chinese medicine which is extracted from saffron. However, its role in osteosarcoma has not been well understood. Therefore, we used crocin and cisplatin individually or jointly on MG63 and OS732 cells so as to explore whether crocin could induce cellular apoptosis and suppress the ability of invasion of osteosarcoma cells. Cell survival rates, changes of cellular shape, cell apoptosis and cell invasion were analyzed, respectively, by 3-(4,5)-dimethylthiahiazo (-z-y1)-2,5-di- phenytetrazoliumromide (MTT) assay, inverted phase contrast microscope and fluorescence microscope, flow cytometry, and Transwell invasion chamber methods. The expressions of caspase-3 and caspase-8 were detected by Western blot. The survival rate of combined application was significantly lower than that of the individual application. Apoptosis-inducing effect of combined application was much stronger than that of individual application. The invasion ability of MG63 and OS732 cells was restrained significantly in the combined group compared with the individual group and control group. Combined group has the effect of up-regulating the expressions of cleaved-caspase-3 and caspase-8. The results suggested that combination of crocin and cisplatin has a strong killing effect on osteosarcoma cells and suppresses the ability of invasion of MG63 and OS732 cells which might be related to up-regulate the expression of caspase-3 and caspase-8.

SASH1 regulates proliferation, apoptosis, and invasion of osteosarcoma cell

SASH1, a member of the SLY-family of signal adapter proteins, is a candidate tumor suppressor in breast and colon cancer. The SASH1 protein possesses both the SH3 and SAM domains, indicating that it may play an important role in intracellular signal transduction. Reduced expression of SASH1 is closely related to tumor growth, invasion, metastasis, and poor prognosis. However, the biological role of SASH1 remains unknown in osteosarcoma. To unravel the function of SASH1, we explored the expression of SASH1 in osteosarcoma tissues and its correlation to the clinical pathology of osteosarcoma and analyzed the relationship between SASH1 expression and cell cycle, apoptosis and invasion of osteosarcoma MG-63 cells, using the flow cytometry analysis and transwell invasion chamber experiments. Furthermore, the effect of SASH1 on the expression of cyclin D1, caspase-3, matrix metalloproteinase (MMP)-9 were observed by western blot. Our results showed that the expression rate of SASH1 mRNA in osteosarcoma tissues was significantly lower than that in normal bone tissue (p = 0.000), that the expression rate of SASH1 mRNA in the carcinoma tissues from patients with lung metastasis was significantly lower than that from patients without lung metastasis (p = 0.041), and that the expression rate of SASH1 mRNA also decreased with increasing Enneking stage (p = 0.032). However, the mRNA expression of SASH1 in osteosarcoma was independent of the patient's gender, age, and tumor size (p = 0.983, 0.343, 0.517, respectively). The SASH1 protein displayed a down-regulation in osteosarcoma tissues compared to normal bone tissue (p = 0.000), displayed a down-regulation in osteosarcoma tissues from patients with lung metastasis compared to from patients without lung metastasis (p = 0.000), and displayed a gradual decrease with increasing Enneking stage (p = 0.000). In addition, the MG-63 cells from pcDNA3.1-SASH1 group exhibited significantly reduced cell viability, proliferation, and invasive ability compared to the empty vector group and blank control group (p = 0.023, 0.001, respectively), and there was no difference between the empty vector group and blank control group. The pcDNA3.1-SASH1 group displayed significantly more apoptotic cells than the empty vector group and blank control group (p = 0.004). The expression of cyclin D1, MMP-9 displayed a down-regulation in MG-63 cells from pcDNA3.1-SASH1 group compared to the empty vector group and blank control group (p = 0.000, 0.001, respectively) and the expression levels of caspase-3 displayed an up-regulation in MG-63 cells from pcDNA3.1-SASH1 group compared to the empty vector group and blank control group (p = 0.000). Taken together, these data indicated that the overexpression of SASH1 might be associated with the inhibition of growth, proliferation, and invasion of MG-63 cells and the promotion of apoptosis of MG-63 cells.

TRAF6 regulates proliferation, apoptosis, and invasion of osteosarcoma cell

TRAF6, a unique tumor necrosis factor receptor-associated factor (TRAF) family member, possesses a unique receptor-binding specificity that results in its crucial role as the signaling mediator for TNF receptor superfamily and interleukin-1 receptor/Toll-like receptor superfamily. TRAF6 plays an important role in tumorigenesis, invasion and metastasis. This study aimed to explore the expression of TRAF6 in osteosarcoma tissues and its correlation to the clinical pathology of osteosarcoma and to discuss the relationship between TRAF6 expression and osteosarcoma invasion. These data will provide the experimental base for the biological treatment of osteosarcoma in the future. Using RT-PCR and Western blot, the results showed that the expression rate of TRAF6 mRNA in osteosarcoma tissues was significantly higher than that in normal bone tissue (p < 0.05), that the expression rate of TRAF6 mRNA in the carcinoma tissues from patients with lung metastasis was significantly higher than that from patients without lung metastasis (p < 0.05), and that the expression rate of TRAF6 mRNA also increased with increasing Enneking stage (p < 0.05). However, the mRNA expression of TRAF6 in osteosarcoma was independent of the patient's gender, age, and tumor size (p > 0.05). The TRAF6 protein displayed an up-regulation in osteosarcoma tissues compared to normal bone tissue (p < 0.05), displayed an up-regulation in osteosarcoma tissues from patients with lung metastasis compared to from patients without lung metastasis (p < 0.05), and displayed a gradual increase with increasing Enneking stage (p < 0.05). By the technique of RNA interference, the expression of TRAF6 in the human osteosarcoma MG-63 cell line was down-regulated, and the invasive ability of MG-63 cells was examined. The results showed that TRAF6 protein expression was significantly decreased in the MG-63 cells from TRAF6 siRNA-transfected group (p < 0.05), and the proliferation ability of MG-63 cells and the number of MG-63 cells that passed through the Transwell chamber were significantly lower than that in the non-transfected control group as well as the transfected control group (p < 0.05). In addition, the percentage of MG-63 cells undergoing apoptosis was significantly higher in the TRAF6 siRNA-transfected group compared with the non-transfected control group as well as the transfected control group (p < 0.05). The expression of p-p65, cyclin D1, MMP-9 was down-regulated in the MG-63 cells from TRAF6 siRNA-transfected group. The expression of caspase 3 was up-regulated in the MG-63 cells from TRAF6 siRNA-transfected group compared to the non-transfected control group as well as the transfected control group (p < 0.05). To make a long story short, the overexpression of TRAF6 in osteosarcoma might be related to the tumorigenesis, invasion of osteosarcoma.

Radionuclide detection of multiple soft tissue metastases of osteosarcoma masquerading as bone metastasis

OBJECTIVE

The aim of this work was to report an unusual case of multiple soft tissue metastases of osteosarcoma detected using bone scan and confirmed by CT scan.

CLINICAL PRESENTATION AND INTERVENTION

A 15-year-old patient with a history of osteogenic sarcoma presented with fatigue and loss of appetite in addition to a painless swelling of the distal left lower extremity. Bone scan and chest CT scan were performed for restaging purposes. The bone scan revealed multiple bone metastases and suspected tumor recurrence in the left lower extremity in addition to multiple extraosseous hot spots. The latter findings were assessed as ossified soft tissue metastases after considering the performed CT scan.

CONCLUSION

This case showed the double role of bone scan in osteosarcoma in simultaneously assessing the bone status and tumor spread in soft tissue. The benefit of a comparison of bone scan findings with other modalities was also demonstrated.

Overexpression of ZEB1 relates to metastasis and invasion in osteosarcoma

BACKGROUND

This study aimed to investigate the expression of ZEB1 in osteosarcoma tissues and to discuss the relationship between ZEB1 expression and osteosarcoma metastasis.

METHODS

Using RT-PCR and Western blotting, the mRNA and protein expressions of ZEB1 in the osteosarcoma and normal bone tissues were detected. Using the RNA interference technique, the expression of ZEB1 in the human osteosarcoma MG-63 cell line was downregulated, and the changes in the invasion of MG-63 cells were examined.

RESULTS

The positive mRNA expression rate of ZEB1 in the osteosarcoma tissues was significantly higher than that in normal bone tissue (P < 0.05). The protein expression level of ZEB1 in the sarcoma tissues from patients with positive lung metastasis was significantly higher than that from patients without lung metastasis (P < 0.05). After the transfection of ZEB1 siRNA into the MG-63 cells, the protein expression of ZEB1 was significantly reduced (P < 0.05), and the number of cells that passed through the Transwell chamber was significantly lower than that in the non-transfected control group as well as the transfected control group (P < 0.05).

CONCLUSIONS

The overexpression of ZEB1 in osteosarcoma may be related to the carcinogenesis and development as well as metastasis and invasion of osteosarcoma.