Junji Wasa

MRI Features in the Differentiation of Malignant Peripheral Nerve Sheath Tumors and Neurofibromas

OBJECTIVE The objective of this study was to identify the MRI criteria that best differentiate malignant peripheral nerve sheath tumors from benign neurofibromas. MATERIALS AND METHODS We retrospectively analyzed MR images obtained for 41 histologically diagnosed cases of malignant peripheral nerve sheath tumor and 20 cases of neurofibroma that had been treated at four tertiary institutions. Twenty of the patients with malignant peripheral nerve sheath tumors and 14 patients with neurofibromas developed the disease in association with neurofibromatosis 1. The MR images were evaluated with regard to tumor size, signal intensity, heterogeneity of T1- and T2-weighted MR images, enhancement pattern, definition of margins, presence of perilesional edemalike zone, and presence of intratumoral cystic lesions. RESULTS Significant differences between malignant peripheral nerve sheath tumors and neurofibromas were noted for the largest dimension of the mass, peripheral enhancement pattern, perilesional edemalike zone, and intratumoral cystic lesion. In cases associated with neurofibromatosis 1, heterogenicity on T1-weighted images was also significant in differentiating neurofibroma from malignant peripheral nerve sheath tumor. The presence of two or more of the four features suggestive of malignancy indicated malignant peripheral nerve sheath tumor with a sensitivity of 61% and a specificity of 90%. CONCLUSION The MR features described in this study are useful for distinguishing malignant peripheral nerve sheath tumors from neurofibromas. If a tumor has two or more of the four statistically significant features, it can be considered to be highly suspicious of malignancy and should be subjected to a biopsy for early diagnosis.

Inhibition of hyaluronan synthesis in breast cancer cells by 4‐methylumbelliferone suppresses tumorigenicity in vitro and metastatic lesions of bone in vivo

Hyaluronan (HA) has been shown to play crucial roles in the tumorigenicity of malignant tumors. Previous studies demonstrated that inhibition of HA suppressed the tumorigenicity of various malignant tumors including breast cancer. 4‐methylumbelliferone (MU) has been reported to inhibit HA synthesis in several cell types. However, few studies have focused on the effects of HA inhibition in breast cancer cells by MU, nor the effects on bone metastasis. We hypothesized that MU would suppress the progression of bone metastasis via inhibition of HA synthesis. Here, we investigated the effects of MU on HA expression in MDA‐MB‐231 breast cancer cell line in addition to their tumorigenicity in vitro and in vivo. HAS2 mRNA expression was downregulated after 6 and 24 hr treatment with MU. Quantitative analysis of HA revealed that MU significantly inhibited the intracellular and cell surface HA. MU significantly inhibited cell growth and induced apoptosis as determined by cell proliferation and TUNEL assays, respectively. Phosphorylation of Akt was suppressed after 12 and 24 hr treatment with MU. MU treatment also inhibited cell motility as well as cell invasiveness. MU also inhibited cell growth and motility in murine fibroblast cell line NIH3T3. In vivo, administration of MU inhibited the expansion of osteolytic lesions on soft X‐rays in mouse breast cancer xenograft models. HA accumulation in bone metastatic lesions was perturbed peripherally. These data suggest that MU might be a therapeutic candidate for bone metastasis of breast cancer via suppression of HA synthesis and accumulation.

Inhibition of hyaluronan retention by 4-methylumbelliferone suppresses osteosarcoma cells in vitro and lung metastasis in vivo.

Background:Hyaluronan (HA) plays crucial roles in the tumourigenicity of many types of malignant tumours. 4-Methylumbelliferone (MU) is an inhibitor of HA synthesis. Several studies have shown its inhibitory effects on malignant tumours; however, none have focused on its effects on osteosarcoma.Methods:We investigated the effects of MU on HA accumulation and tumourigenicity of highly metastatic murine osteosarcoma cells (LM8) that have HA-rich cell-associated matrix, and human osteosarcoma cell lines (MG-63 and HOS).Results:In vitro, MU inhibited HA retention, thereby reducing the formation of functional cell-associated matrices, and also inhibited cell proliferation, migration, and invasion. Akt phosphorylation was suppressed by MU (1.0 mM). In vivo, although MU showed only a mild inhibitory effect on the growth of the primary tumour, it markedly inhibited (75% reduction) the development of lung metastasis. Hyaluronan retention in the periphery of the primary tumour was markedly suppressed by MU.Conclusion:These findings suggested that MU suppressed HA retention and cell-associated matrix formation in osteosarcoma cells, resulting in a reduction of tumourigenicity, including lung metastasis. 4-Methylumbelliferone is a promising therapeutic agent targeting both primary tumours and distant metastasis of osteosarcoma, possibly via suppression of HA retention.

Clinical Outcome of Sacral Chordoma With Carbon Ion Radiotherapy Compared With Surgery

PURPOSE To evaluate the efficacy, post-treatment function, toxicity, and complications of carbon ion radiotherapy (RT) for sacral chordoma compared with surgery. METHODS AND MATERIALS The records of 17 primary sacral chordoma patients treated since 1990 with surgery (n = 10) or carbon ion RT (n = 7) were retrospectively analyzed for disease-specific survival, local recurrence-free survival, complications, and functional outcome. The applied carbon ion dose ranged from 54.0 Gray equivalent (GyE) to 73.6 GyE (median 70.4). RESULTS The mean age at treatment was 55 years for the surgery group and 65 years for the carbon ion RT group. The median duration of follow-up was 76 months for the surgery group and 49 months for the carbon ion RT group. The local recurrence-free survival rate at 5 years was 62.5% for the surgery and 100% for the carbon ion RT group, and the disease-specific survival rate at 5 years was 85.7% and 53.3%, respectively. Urinary-anorectal function worsened in 6 patients (60%) in the surgery group, but it was unchanged in all the patients who had undergone carbon ion RT. Postoperative wound complications requiring reoperation occurred in 3 patients (30%) after surgery and in 1 patient (14%) after carbon ion RT. The functional outcome evaluated using the Musculoskeletal Tumor Society scoring system revealed 55% in the surgery group and 75% in the carbon ion RT group. Of the six factors in this scoring system, the carbon ion RT group had significantly greater scores in emotional acceptance than did the surgery group. CONCLUSION Carbon ion RT results in a high local control rate and preservation of urinary-anorectal function compared with surgery.

Successful Treatment With Meloxicam, a Cyclooxygenase-2 Inhibitor, of Patients With Extra-Abdominal Desmoid Tumors: A Pilot Study

TO THE EDITOR: Extra-abdominal desmoid tumors, which are usually sporadic in nature, occur across a wide age range and can arise at virtually any body site, but are mainly found in the extremities and girdles, chest, abdominal wall, and neck. Local growth and invasion may result in pain, deformity, and functional impairment. The potential morbidity of surgery and radiation therapy has led investigators to assess the role of noncytotoxic and cytotoxic chemotherapy. Because extra-abdominal desmoid tumors rarely cause disease-specific death, pharmacologic treatment with fewer complications is desirable. Cyclooxygenase-2 (COX-2) is implicated as a factor in tumor initiation in colonic neoplasia and has also been demonstrated to play a role in the growth of desmoid tumors, with pharmacologic blockade of COX resulting in decreased cell proliferation in desmoid cell cultures in vitro, and COX-2 blockade resulting in smaller desmoid tumors in an in vivo mouse model. Taken together, these results led us to hypothesize that COX-2 might represent an attractive therapeutic target in desmoid tumors, and that meloxicam may have a marked efficacy compared with conventional nonselective nonsteroidal anti-inflammatory drugs. Between 1991 and 2003, excluding those with intra-abdominal, familial adenomatous polyposis–associated, and unresectable tumors, 30 patients were treated with surgery in our institutions. Because the recurrence rate of this group was high (53%) even with a mostly negative surgical margin, since 2003, 22 consecutive extra-abdominal patients have been prospectively treated with meloxicam. Patients with intra-abdominal desmoid tumors and patients less than 16 years of age were excluded. Meloxicam was administered orally at 10 mg/ day. There were no patients with a known history of gastritis or gastric ulcer, and none were receiving hormonal medications. Baseline imaging of desmoid tumors by MRI was obtained before starting treatment. Patients treated with meloxicam have been followed with physical examinations and magnetic resonance imaging and/or computed tomography at the outpatient unit of our department of orthopedic surgery every 3 to 6 months. The efficacy of meloxicam was evaluated according to Response Evaluation Criteria in Solid Tumors (RECIST) measured with magnetic resonance imaging at the latest follow-up. All patients signed an informed consent form, and the protocol was approved by the institutional review board of our

Phosphorylated retinoblastoma protein stimulates DNA polymerase α

Human retinoblastoma (Rb) protein, immunopurified from an extract of recombinant baculovirus infected cells, stimulated 10 – 100-fold the activity of DNA polymerase α from calf thymus or human HeLa cells. Purified Rb protein is composed of two electrophoretically distinguishable forms, i.e., partially phosphorylated and under-phosphorylated forms. Dephosphorylation of Rb protein by protein phosphatase 2A largely diminished its stimulatory effect. On the other hand, a hyperphosphorylated Rb protein, obtained from insect cells overexpressing Rb protein, cyclin E and cyclin-dependent kinase 2 simultaneously, stimulated DNA polymerase α more strongly than the singly-expressed Rb protein. These results indicate that the phosphorylation is crucial for the stimulation. Rb protein isolated from human Burkitt lymphoma Raji cells also stimulated DNA polymerase α. In contrast, Rb protein did not affect eukaryotic DNA primase or Klenow fragment of Escherichia coli DNA polymerase I. By immunoprecipitation using anti-DNA polymerase α antibody, Rb protein in nuclear extract of Raji cells was co-precipitated with DNA polymerase α. This result indicates that DNA polymerase α exists as a complex containing phosphorylated Rb protein in cells. DNA polymerase α specifically bound to a purified Rb protein-immobilized Sepharose column. Rb protein also bound to DNA polymerase α trapped to anti-DNA polymerase α antibody-Sepharose column, suggesting the direct association of these two proteins. These observations suggest a new function of phosphorylated Rb protein in the regulation of DNA replication.

Therapeutic potential of hyaluronan oligosaccharides for bone metastasis of breast cancer

Hyaluronan (HA) oligosaccharides were reported to have suppressive effects on various malignant tumors via disruption of receptor HA interactions. However, no studies have focused on the effects of HA oligosaccharides on bone metastasis of breast cancer. In this study, we clarified the effective size of HA oligosaccharides required to inhibit cell growth in the highly invasive breast cancer cell line, MDA‐MB‐231 cells. Based on the results of cell growth assay, we subsequently analyzed the effects of HA tetrasaccharides, HA decasaccharides, and high molecular weight HA on the other breast cancer cell behaviors in vitro and breast cancer bone metastasis in vivo. HA decasaccharides significantly inhibited cell growth, motility, and invasion, whereas tetrasaccharides did not. HAS2 mRNA expression was altered after the treatment with both tetrasaccharides and decasaccharides. Phosphorylation of Akt was suppressed after 1 h treatment with HA decasaccharides, and the effect was partially reversed by anti‐CD44 monoclonal antibody. In vivo, local application of HA decasaccharides inhibited the expansion of osteolytic lesions in tibia on soft X‐rays using mouse bone metastasis model of breast cancer. Histological analysis revealed HA accumulation in bone metastatic lesions was perturbed by decasaccharides. These results suggest that HA oligosaccharides suppressed progression of bone metastasis in breast cancer via interruption of endogenous HA–CD44 interaction, and as such, can be a novel therapeutic candidate to limit bone metastasis of breast cancer.

Versican V1 isoform regulates cell-associated matrix formation and cell behavior differentially from aggrecan in Swarm rat chondrosarcoma cells

Versican, a large chondroitin sulfate proteoglycan that binds hyaluronan and is composed of large extracellular matrix aggregates, has been shown to correlate with tumor progression. No studies have examined the roles of versican in chondrosarcoma nor compared them to those of aggrecan. In clinical specimens of human chondromatous tumors, versican expression was significantly increased in malignant tumors, moreover, as the tumor grade increased. To clarify the roles of versican in chondrosarcoma, versican splicing variant 1, variant 3 or only GFP was stably transfected to Swarm rat chondrosarcoma cells with Trap‐In System. Forced expression of versican V1 isoform in Swarm rat chondrosarcoma cells induced a marked increase of cell‐associated matrix compared to V3‐, GFP‐ transfected or RCS cells. Versican was immunolocalized in a fashion similar to that of hyaluronan and more diffusively than aggrecan. Anchor‐dependent and ‐independent growth was not affected by versican isoform expression, whereas cell motility and migration were significantly enhanced by V1 isoform transfection. Tumors formed in vivo with V1‐transfected cells exhibited more myxomatous area and included more spindle shaped cells. These results support the concept that versican has the capacity to form more extensive cell‐associated matrix than aggrecan, and the prominent matrix formation alters the cell behavior of chondrosarcoma more aggressively. These observations suggest that versican expression may serve as a marker of tumor grade determination in chondrosarcoma and possibly help to decide on therapeutic targets in higher grades of chondrosarcoma.

Vascularized fibular flaps enhance histological repair in pasteurized autogenous bone graft.

The healing process of structural pasteurized autogenous bone graft has not been studied in detail. The purpose of this investigation was to assess the reparative process of pasteurized bone graft histologically, and clarify the factors influencing the outcome. From among 51 cases using pasteurized autogenous bone graft since 1992, 10 specimens were retrieved after lower extremity reconstruction of tibia or femur with or without simultaneous fibula flap, and subjected to the analysis. Regeneration of the grafted bone was assessed as the ratio of the number of viable cells to that of whole cells. Pasteurized bone combined with a vascularized fibula showed markedly better repair. Long duration from implantation to retrieval was associated with a better reparative process with vascularized fibula (P = 0.03), whereas other factors had no significant impact. This study demonstrated that pasteurized autogenous bone graft remained structurally stable for many years, although facilitators such as the combined use of a vascularized fibula are required to promote regeneration of the graft.

Nodular Fasciitis of the Finger and Hand: Case Report

Nodular fasciitis rarely arises in the hand. We describe 4 cases that were histologically diagnosed as nodular fasciitis on biopsy specimens arising in the hands. The masses of 2 patients were excised due to rapid growth. Both of these patients had no recurrence. The other 2 patients were followed without surgical excision, and the masses partially regressed without functional impairment.