Ikuo Kudawara

Orphan receptor tyrosine kinase ROR2 as a potential therapeutic target for osteosarcoma

Osteosarcoma is the most prevalent bone malignant tumor in children and adolescents, and displays heterogeneous histology and high propensity for distant metastasis. Although adjuvant chemotherapy remarkably improved treatment outcome over the past few decades, prognosis for osteosarcoma patients with pulmonary metastasis is still unsatisfactory. To identify novel therapeutic targets for osteosarcoma, we investigated the gene expression profile of osteosarcomas by cDNA microarray analysis and found transactivation of receptor tyrosine kinase‐like orphan receptor 2 (ROR2) expression in the majority of osteosarcoma samples. Treatment of osteosarcoma cell lines with siRNA against ROR2 significantly inhibited cell proliferation and migration. We also identified wingless‐type MMTV integration site family, member 5B (WNT5B) as a putative ROR2 ligand and that the physiological interaction of WNT5B and ROR2 could enhance cell migration, indicating the possible roles of ROR2 and WNT5B in the metastatic property of osteosarcoma cells. Taken together, our findings revealed that the WNT5B/ROR2 signaling pathway is a promising therapeutic target for osteosarcoma. (Cancer Sci 2009; 100: 1227–1233)

Prognostic significance of activated AKT expression in soft-tissue sarcoma.

Purpose: AKT is a serine/threonine kinase which is important in tumorigenesis. Several molecules involved in AKT pathway are dysregulated in various kinds of human cancers. Patients and Methods: Ninety-three patients (53 males and 40 females), ages ranging from 19 to 77 years (median, 57 years), with localized soft-tissue sarcomas arising in the trunk and extremities, were analyzed. Immunoperoxidase procedure (avidin-biotin complex method) was done on paraffin-embedded sections with anti–phosphorylated AKT (Thr308), anti–phosphorylated p44/42 extracellular signal–regulated kinase 1 and 2 (ERK1/2) (Thr202/Tyr204), anti–phosphorylated forkhead in rhabdomyosarcoma (FKHR) (Ser256), and anti-Ki 67 antibodies. Expression levels of phosphorylated AKT (p-AKT), phosphorylated ERK1/2 (p-ERK1/2), and phosphorylated FKHR (p-FKHR) were categorized as either weaker (level 1) or equal to or stronger (level 2) compared with those in the endothelial cells of the same specimens. Percentage of cells showing intranuclear staining with Ki-67 was shown as the Ki-67 labeling index (LI). Cases were divided into two groups: level 1, Ki-67 LI < 20%; level 2, Ki-67 LI ≥ 20%. Results: Twenty-six (28.0%), 6 (6.5%), and 46 (44.1%) of the tumors showed level 2 expression for p-AKT, p-ERK1/2, and Ki-67 LI, respectively. Tumors with level 2 p-AKT expression showed a higher ratio of level 2 p-FKHR expression (P < 0.01). Multivariate analysis revealed p-AKT expression and Ki-67 LI to be independent prognosticators for overall survival, and p-AKT expression for disease-free survival. Conclusion: p-AKT expression level is a significant prognosticator in soft-tissue sarcoma.

Cystic synovial sarcomas: imaging features with clinical and histopathologic correlation.

ObjectiveTo characterize the radiological and clinicopathologic features of cystic synovial sarcoma.Design and patientsSeven patients with primary cystic synovial sarcoma were evaluated. Computed tomography (CT) and magnetic resonance (MR) imaging were undertaken at the first presentation. The diagnosis of synovial sarcoma was made on the basis of histological examinations followed by molecular analysis. Radiological and clinicopathologic findings were reviewed.ResultsCT showed well-defined soft tissue mass without cortical bone erosion and invasion. Calcification was seen at the periphery of the mass in three cases. T2-weighted MR images showed multilocular inhomogeneous intensity mass in all cases, five of which showed fluid-fluid levels. On gross appearance, old and/or fresh hematomas were detected in six cases. In the one remaining case, microscopic hemorrhage in the cystic lumen was proven. Four cases had poorly differentiated areas. In five cases prominent hemangiopericytomatous vasculature was observed. Histologic grade was intermediate in one tumor and high in six. One case had a history of misdiagnosis for tarsal tunnel syndrome, one for lymphadenopathy, two for sciatica and two for hematoma.ConclusionAll cystic synovial sarcomas demonstrated multilocularity with well-circumscribed walls and internal septae. Synovial sarcoma should be taken into consideration in patients with deeply situated multicystic mass with triple signal intensity on T2-weighted MR imaging.

Clinical implications of serum C-reactive protein levels in malignant fibrous histiocytoma.

Paraneoplastic syndromes (PNSs) associated with mesenchymal tumors are uncommon. Previous reports sporadically described inflammatory PNSs with elevated serum C‐reactive protein (CRP) levels and leukocytosis in patients with inflammatory malignant fibrous histiocytoma (MFH) of soft tissue; however, the relationship between other subtypes of MFH and PNS has not been extensively investigated. Forty‐six patients with primary MFH of soft tissues who underwent radical surgery were retrospectively analyzed. These patients were divided into 2 groups according to preoperative serum CRP level: normal (<1.0 mg/dl) and elevated (≥1.0 mg/dl). The correlation between serum CRP level and several clinicopathologic factors was analyzed. Correlation between preoperative serum CRP level and metastasis‐free and overall survival was also investigated by univariate and multivariate analyses. Elevated preoperative serum CRP levels were found in 65% of patients with a mean of 3.7 mg/dl. There were statistically significant relationships regarding tumor size, depth, histologic subtypes, grade, stage and metastatic rate among normal and elevated CRP groups (p < 0.001, p < 0.02, p < 0.005, p < 0.001, p < 0.001 and p < 0.05, respectively). When the tumor was removed, the elevated CRP level subsided into the normal range and other abnormal laboratory findings diminished in all cases. In 11/14 relapsed cases that showed elevated CRP preoperatively, the serum CRP level re‐elevated with tumor relapse. The normal CRP group showed significantly more favorable prognosis than the elevated CRP group in metastasis‐free and overall survival on univariate analysis (p < 0.02, p < 0.05, respectively). Patients with MFH frequently present with an inflammatory PNS, such as elevated serum CRP level, which can be a useful marker of disease activity and a valuable prognostic indicator.

Novel fully interconnected porous hydroxyapatite ceramic in surgical treatment of benign bone tumor

BackgroundLarge bone defects remaining after curettage of benign bone tumors should be filled with a substitute to restore mechanical strength. In 2000, we developed a fully interconnected porous calcium hydroxyapatite ceramic (IPCHA, NEOBONE) and have utilized it as a bone substitute. IP-CHA has a finely organized, three-dimensional interconnecting pore structure. The large interconnecting channels (average diameter 40 μm) permit easy penetration of tissue into the deep pores, so IP-CHA can itself induce local bone repair processes. The purpose of this study was to evaluate the clinical outcomes with the use of IP-CHA as bone substitute after curettage of benign bone tumors.MethodsWe reviewed the results of 71 patients with benign bone tumors sequentially treated by curettage followed by implantation of IP-CHA between 2000 and 2006. There were 29 women and 42 men, with a mean age of 28 years. Assessment was based on radiography at each time point during the follow-up. Radiographic findings were classified into five stages: stage 0, no change; stage 1, slight bone formation; stage 2, moderate bone formation; stage 3, consolidation; stage 4, absorption.ResultsIn 70 of 74 operated lesions, radiographs showed that implanted IP-CHA proceeded to stage 2 or more within an average of 8 months after the surgery. In addition, 17 lesions proceeded to stage 4 within 35 months after surgery, on average. However, there were 10 local recurrences, which is similar to the recurrence rate for such tumors treated with or without implantation of CHAs and reflects the biological nature of each tumor.ConclusionsIn this study, we utilized IP-CHA as a bone substitute after curettage of benign bone tumors and demonstrated its usefulness in the clinical situation. IP-CHA comparatively exhibited excellent bone formation at an early stage although the problem of recurrence of the tumor remained. We conclude that IP-CHA is a useful bone substitute for the treatment of benign bone tumors.

Neoadjuvant and adjuvant chemotherapy with high-dose ifosfamide, doxorubicin, cisplatin and high-dose methotrexate in non-metastatic osteosarcoma of the extremities: a phase II trial in Japan

Abstract From 1997 to 2003, 40 patients (all <40 years of age) with non-metastatic osteosarcoma of the extremities were treated with OOS-D and definitive surgery. Two cycles of doxorubicin 90 mg/m2 plus cisplatin 120 mg/m2 and ifosfamide 15 g/m2 were given as neoadjuvant chemotherapy, and two cycles of doxorubicin/cisplatin and ifosfamide, and two cycles of high-dose methotrexate (10–12 g/m2) were given post-operatively. All patients underwent limb salvage surgeries, and 66% showed good response to neoadjuvant chemotherapy. With a median follow-up period of 117 months, 31 of the evaluable 40 patients were continuously disease-free, 7 were currently alive with no evidence of disease, and 2 died of disease. There was no local recurrence. The 5-year event-free and overall survival rates were 83 and 98%, respectively. The 10-year event-free and overall survival rates were 80 and 95%, respectively. The major form of toxicity was haematological one.

Frequent expression of smooth muscle markers in malignant fibrous histiocytoma of bone

Background/Aims: Malignant fibrous histiocytoma (MFH) of bone, a relatively rare primary malignant bone tumour, is a distinct clinicopathological entity as opposed to MFH derived from soft tissue. Although the true histogenesis of this condition is still controversial, a considerable number of cases of MFH in soft tissue show positive immunohistochemical reactivity for muscle markers such as desmin, common muscle actin (HHF35), and α smooth muscle actin (SMA), suggesting that MFH cells are myofibroblastic in nature. Methods: This study investigated immunoreactivity for several different muscle markers in 19 cases of MFH of bone together with reverse transcription polymerase chain reaction (RT-PCR) analysis on frozen tissue samples that were available in four cases, and compared the data with those found in 11 cases of osteosarcoma and 11 cases of soft tissue MFH treated over the same period. Results: Immunohistochemistry revealed that MFH of bone showed relatively frequent expression of smooth muscle markers, including calponin (nine cases), α-SMA (nine cases), and SM22α (18 cases), and this was confirmed by RT-PCR analysis. However, only one, two, and three cases of MFH of bone showed positive staining for desmin, MyoD1, and HHF35, respectively. Similarly, 11 osteosarcoma cases were relatively frequently positive for α-SMA (five cases), calponin (four cases), and SM22α (seven cases), and less frequently positive for desmin (one case), MyoD1 (none), and HHF35 (none). In contrast, very few MFH of soft tissue cases (n = 11) showed positive reactivity for all of these muscle markers. It has recently been reported that human bone marrow stromal cells also express various kinds of smooth muscle markers including α-SMA and calponin. Conclusions: These results suggested that MFH of bone may derive from mesenchymal stromal cells in bone marrow and has a more myofibroblastic differentiation than soft tissue MFH.

In vivo inhibition of tumour growth by dexamethasone in murine osteosarcomas

This study was performed to determine whether glucocorticoid (GC) is an effective inhibitor of tumour growth in murine osteosarcoma (OS) in vivo. The effects of dexamethasone (DEX) on the growth of this tumour were studied in male C3H/He mice. The animals received a dose of 1.25 or 5 microg/g of DEX in 0.1 ml of steroid solution daily intraperitoneally (i.p.) for 14 days. In each DEX-treated group, significant inhibition of the tumour growth curve was seen in a dose- dependent manner compared with the control group (P<0.0001). The percentage of proliferative cell nuclear antigen (PCNA)-positive cells was 22.7% in the 5 microg/g DEX treatment group compared with 67.6% in the control group (P=0.009). Furthermore, mifepristone, a GC receptor antagonist, blocked the inhibition of tumour growth induced by DEX. In the control group, tumour cells showed positive reactivity for nuclear glucocorticoid receptors (GR) by immunohistochemistry. The results of this study indicate that tumour growth inhibition by DEX in murine osteosarcoma may be via GR.

Plexiform schwannoma of the foot

Abstract. The present report describes a plexiform schwannoma involving the subcutis of the foot in an 8-year-old boy. Gross findings revealed thin fibrous septa in a multilobulated tumor that was partly separated into free body-like nodules in the subcutis. Preoperative CT and MRI failed to delineate this multinodular architecture or free bodies. This is a case presentation including the CT and MR findings associated with plexiform schwannoma.

Granular cell tumor of the subcutis: CT and MRI findings

Abstract Three cases of granular cell tumor (GCT) of the subcutis are presented. Computed tomography showed a mass isodense with muscle with an ill-defined margin. Magnetic resonance imaging showed a mass with inhomogeneous low signal intensity on both T1- and T2-weighted images. Another characteristic feature of subcutaneous GCT is its attachment in part to muscle. Histological examination confirmed the diagnosis in all cases.