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The human homologue of Drosophila disc large tumor suppressor protein (hDlg) is one of the proteins known to act cooperatively in regulating cell polarity and proliferation, suggesting an important connection between epithelial organization and cellular growth control. An abnormal expression of hDlg has been reported in several cancer types. However, the expression of hDlg in soft-tissue sarcomas has not yet been reported. We examined the expression of hDlg immunohistochemically in 46 specimens of malignant fibrous histiocytoma (MFH). The expression of hDlg was negative in 19 specimens, weak in 4, moderate in 16, and strong in 7. The patients with a weak or negative expression of hDlg had a significantly shorter metastasis-free survival rate and disease-free survival rate in comparison with those with a strong or moderate expression in both univariate analysis (p=0.0287 and 0.0237, respectively; log-rank test) and multivariate analysis (p=0.0087 and 0.0126, respectively; Cox proportional hazards regression model). Moreover, the patients with a weak or negative expression of hDlg had a significantly shorter overall survival rate in comparison with those with a strong or moderate expression in a univariate analysis (p=0.0214; log-rank test). This is the first report to demonstrate that a reduced expression of hDlg protein is an independent negative prognostic factor for MFH.

Osteosarcoma (OS) is the most common primary malignant tumor of the bone and often forms pulmonary metastases, which are the most important prognostic factor. For further elucidation of the mechanism underlying the progression and metastasis of human OS, a culture system mimicking the microenvironment of the tumor in vivo is needed. We report a novel three-dimensional (3D) alginate spheroid culture system of murine osteosarcoma. Two different metastatic clones, the parental Dunn and its derivative line LM8, which has a higher metastatic potential to the lungs, were encapsulated in alginate beads to develop the 3D culture system. The beads containing murine OS cells were also transplanted into mice to determine their metastatic potential in vivo. In this culture system, murine OS cells encapsulated in alginate beads were able to grow in a 3D structure with cells detaching from the alginate environment. The number of detaching cells was higher in the LM8 cell line than the Dunn cell line. In the in vivo alginate bead transplantation model, the rate of pulmonary metastasis was higher with LM8 cells compared with that of Dunn cells. The cell characteristics and kinetics in this culture system closely reflect the original malignant potential of the cells in vivo.

We present a case of malignant melanoma with a rhabdoid phenotype in a 44-year-old female with a quite unique and aggressive clinical course. Rhabdoid features are defined by characteristics such as sheets or solid trabeculae of neoplastic cells with large, vesicular, round to bean-shaped nuclei, prominent centrally located nucleoli, and abundant eccentric cytoplasm. Although various histological differential diagnoses were cited for the present case that showed 'rhabdoid features', most of them were excluded on the basis of the clinical history, tumor location, clinical behavior, and a broad panel of immunohistochemical stains. In the present case, the immunohistochemical findings were positive for vimentin, S-100 protein, melan-A, and EMA, but negative for HMB45, cytokeratin, CD34 and desmin. In addition, the positive expression of BAF47 was also recognized. These findings lead to the conclusion that this quite unique aggressive soft tissue tumor should therefore be diagnosed as malignant melanoma with a rhabdoid phenotype.

Rhabdomyosarcoma is a common malignant soft tissue that frequently involves bone and major neurovascular structures and resection of deep-seated rhabdomyosarcoma can cause severe dysfunction in the affected limbs. Based on the mouse osteosarcoma model, we developed a new surgical approach involving photodynamic surgery (PDS), photodynamic therapy (PDT) and radiodynamic therapy (RDT) using acridine orange (AO). Six rhabdomyosarcoma cases were treated using this new modality after confirming the effectiveness of AO-PDT on human rhabdomyosarcoma cell lines. All patients had almost normal limb function after surgery, with only one recurrence. Based on these results, AO-PDS, PDT and RDT can be used to preserve excellent limb function in patients with rhabdomyosarcoma involving major nerves and vessels or bones.

Bone metastasis is one of the most severe cancer complications. To analyze the mechanism of bone metastasis, we established highly invasive cell lines from the human breast cancer cell line MDA-MB-231 using an in vitro sequential selection system. The cell lines, MDA-231-S10 and MDA-231-S5, were more invasive and more motile than the parental cell line. Moreover, MDA-231-S10 metastasized to bone more often when inoculated into the arterial circulation of nude mice. MDA-231-S10-bearing nude mice had a significantly poorer prognosis, and their bony metastatic tumors grew more rapidly than those of the mice bearing the parental cell line (MDA-231-P). Given that a high expression of matrix metalloproteinase (MMP) is reported to be associated with cancer invasiveness, we examined MMP expression. Our results showed that the expression of MMP-3, -5, -7, -9, -13 and -14 was decreased on Multiplex real-time quantitative RT-PCR analysis in the two new cell lines. The zymographic analysis showed no MMP-2 activity and a decreased MMP-9 activity in MDA-231-S10. However, the expression of MMP-1 in MDA-231-S10 was increased. We therefore concluded that MMP-1 plays a crucial role in breast cancer bone metastasis. Furthermore, our MDA-231-derived cell lines are useful analytical models of MMP-1- associated breast cancer bone metastasis.

Lung metastasis is the most crucial event affecting the therapeutic outcome of osteosarcoma. The prevention of lung metastasis is therefore important in improving the prognosis of patients with osteosarcoma. Decorin is a major extracellular matrix protein which has become the focus of various cancer studies. The biological role of decorin in osteosarcoma has yet to be clarified. The aim of this study was to examine the potential of decorin as a novel biological target for the treatment of osteosarcoma. In this study, the LM8 murine osteosarcoma cell line (LM8) with high metastatic potential to the lung was used. The two cell lines established were LM8-DCN which stably expressed human decorin (hDCN) and LM8-mock, established as a control. The LM8-DCN cell line was subcutaneously injected into the backs of mice. Significantly fewer pulmonary metastases were observed in mice with LM8-DCN compared to mice inoculated with LM8 and LM8-mock (P<0.001). In addition, the mice in the LM8-DCN inoculated group survived significantly longer than those in the LM8 and LM8-mock inoculated group, based on the Kaplan-Meier survival analysis and log-rank tests (P<0.005). The effect of decorin on the growth rates, motility and invasion ability of LM8 was investigated in vitro. There was no difference in the morphology and growth rates, but the motility and invasion of LM8 were inhibited by decorin. These results suggest that decorin has the therapeutic potential to prevent lung metastasis in osteosarcoma.

Chronic inflammation is a critical component of carcinogenesis and tumor progression. Reactive nitrogen and oxygen species generated by inflammatory cells form mutagenic DNA lesions, such as 8-nitroguanine, which may play an integral role in inflammation-related carcinogenesis. Hypoxia-inducible factor (HIF)-1alpha has been established as a prognostic biomarker in various tumors, including malignant fibrous histiocytoma (MFH). The aim of this study was to evaluate the impact of 8-nitroguanine formation and HIF-1alpha expression on the prognosis of patients with inflammation-related cancer. Immunohistochemical analyses were employed to examine the distribution of 8-nitroguanine and HIF-1alpha, using clinical specimens from 36 patients with MFH as a model of inflammation-related cancer. 8-Nitroguanine formation was predominantly observed in the nuclei of tumor cells and inflammatory cells in tumor tissues, while HIF-1alpha was expressed in the cytoplasm and nuclei of tumor cells. Little or no immunoreactivity of 8-nitroguanine and HIF-1alpha was observed in adjacent non-tumor tissues. Significantly higher levels of both 8-nitroguanine and HIF-1alpha were observed in the tissue specimens of deceased patients than in those of living subjects. Survival curves analyzed by the Kaplan-Meier method differed significantly between the high- and low-staining groups of 8-nitroguanine (p=0.00003) as well as HIF-1alpha (p=0.01104). These results suggest a significant role of the pathway of iNOS-dependent 8-nitroguanine formation via HIF-1alpha and NF-kappaB on the progression of inflammation-related cancer. In conclusion, 8-nitroguanine is an excellent candidate prognostic and predictive biomarker together with HIF-1alpha in inflammation-related tumor progression.

The vascularized free myocutaneous flap graft, a recent advance in microsurgery, is a very useful reconstruction technique for covering massive soft tissue defects or muscular dysfunction caused by wide resection for malignant soft tissue tumors. We have used this technique to treat many patients after resection for malignant soft tissue tumors. Recently we encountered a case in which a malignant peripheral nerve sheath tumor (MPNST) metastasized to a vascularized free myocutaneous flap used for limb reconstruction surgery after wide resection of a primary lesion. To our knowledge, there have been no previous reports of metastasis of a malignant soft tissue tumor (or any other cancer) to a grafted cutaneous or myocutaneous flap.

We recently encountered a very rare case of periosteal Ewing's sarcoma (PES), which was treated by surgery followed by photodynamic therapy using acridine orange with radiodynamic therapy. No more than 15 cases of PES have been reported previously in literature. In our case, MRI revealed the tumor to be localized on the cortical surface of the proximal humerus. Histopathological examination of biopsy specimens revealed a small round cell sarcoma suggestive of Ewing's sarcoma or PNET, and immunohistochemistry showed positive staining for MIC2. Although fusion genes EWS-FLI1 and EWS-ERG were undetectable, PES was still considered to be the most likely diagnosis. Therefore, we administered preoperative chemotherapy, as a result of which the tumor shrank to 48% of its original volume. With a view to preserve excellent shoulder and upper limb function, we attempted intralesional tumor resection supported by photodynamic therapy using acridine orange with radiodynamic therapy. After surgery followed by postoperative chemotherapy, the patient has, until the time of writing, had no local tumor recurrence and no evidence of metastatic disease, and can move his shoulder fully and throw a ball well. Since it has been reported that PES has a better prognosis and responsiveness to chemotherapy than intramedullary Ewing's sarcoma, we believe that such reduction surgery with photodynamic therapy might be the strategy of choice to obtain satisfactory limb function in cases of PES.