Yoshinao Oda

c-kit and PDGFRA mutations in extragastrointestinal stromal tumor (gastrointestinal stromal tumor of the soft tissue).

Extragastrointestinal stromal tumor (EGIST) is a unique tumor that occurs outside the gastrointestinal tract. EGIST shows a c-kit expression and histologic appearance similar to those of gastrointestinal stromal tumor (GIST). Most GISTs have gain-of-functional mutation of the c-kit gene, and some have mutation of the platelet-derived growth factor receptor-alpha (PDGFRA) gene. However, the frequency of mutation of those genes in EGISTs remains unclear. We examined the clinicopathologic features, prognostic factors, and c-kit and PDGFRA mutation in 39 cases of EGIST. Tumors with high mitotic counts (≥5/50 high power fields) or a high Ki-67 labeling index (≥10%) were significantly correlated with worse prognoses. The c-kit mutation was found in the juxtamembrane domain (exon 11) and the extracellular domain (exon 9) in 12 of 29 cases (41.4%) and 2 of 29 cases (6.9%), respectively. The PDGFRA gene mutation was found at the juxtamembrane domain (exon 12) and the tyrosine kinase domain (exon 18) in one case each. The pattern of kit and PDGFRA mutation in EGIST was essentially similar to that in GIST. Our results suggest that the c-kit and PDGFRA mutations play an important role in the tumorigenesis of EGIST. High mitotic counts and a high Ki-67 labeling index may be useful for predicting the aggressive biologic behavior in EGIST. Furthermore, STI-571, targeting c-kit and PDGFR tyrosine kinase, seems to be a possible therapeutic strategy for EGISTs, especially advanced cases.

Parotid gland tumors: can addition of diffusion-weighted MR imaging to dynamic contrast-enhanced MR imaging improve diagnostic accuracy in characterization?

PURPOSE To determine the value of adding diffusion-weighted (DW) magnetic resonance (MR) imaging to dynamic contrast material-enhanced MR imaging when distinguishing between benign and malignant parotid tumors. MATERIALS AND METHODS This retrospective study was approved by the institutional review board, and the informed consent requirement was waived. The authors analyzed MR images of 50 lesions (36 benign, 14 malignant) in 47 patients. DW MR imaging and dynamic contrast-enhanced MR imaging were performed in all patients. Time-intensity curve (TIC) patterns were categorized as follows: type A, time to peak was more than 120 seconds; type B, time to peak was 120 seconds or less with high washout ratio (> or = 30%); type C, time to peak was 120 seconds or less with low washout ratio (< 30%); and type D, flat. The apparent diffusion coefficient (ADC) values were measured on DW MR images. Sensitivity, specificity, accuracy, and positive and negative predictive values were calculated for type A, B, and D tumors regarded as benign and for type C tumors regarded as malignant. On the basis of DW MR imaging results, ADC threshold values between pleomorphic adenomas and carcinomas and between Warthin tumors and carcinomas were selected. Diagnostic accuracy was compared before and after modification diagnosis referring to the ADC value obtained with the McNemar test. P < .05 was considered to indicate a significant difference. RESULTS ADC threshold values were 1.4 x 10(-3) mm(2)/sec between pleomorphic adenomas and carcinomas and 1.0 x 10(-3) mm(2)/sec between Warthin tumors and carcinomas. Accuracy (82% vs 94%) and positive predictive value (67% vs 92%) significantly improved with the addition of ADC values in the evaluation of patients with type B or C tumors. CONCLUSION A persistent or flat TIC pattern on dynamic contrast-enhanced MR images indicates benign disease, but there is added value from including the ADC value in the evaluation of tumors that show a plateau or washout TIC pattern.

Inflammatory myofibroblastic tumor versus IgG4-related sclerosing disease and inflammatory pseudotumor: a comparative clinicopathologic study.

Inflammatory pseudotumor (IPT) is a heterogeneous group of lesions occurring in various organs, which is histologically characterized by fibroblastic and myofibroblastic proliferation with inflammatory infiltrate. Inflammatory myofibroblastic tumor (IMT) is a neoplastic counterpart of IPT, which shows aberrant expression of ALK and its gene translocation. In contrast, the concept “immunoglobulin (Ig)G4-related IPT” in the lung, liver, and pancreas has recently been proposed as a member of IgG4-related sclerosing disease. In this study, we compared the histopathologic features with an emphasis on IgG4 expression between 22 cases of IMT and 16 cases of IgG4-related sclerosing disease, including chronic sclerosing sialadenitis (n=8), mass-forming autoimmune pancreatitis (n=3), sclerosing cholangitis (n=1), retroperitoneal fibrosis (n=2), and chronic sclerosing dacryoadenitis (n=2). Bland-looking spindle cell proliferation with fibrosis and inflammatory infiltrate of lymphocytes and plasma cells was the common morphologic feature in both lesions. Obstructive phlebitis was observed in all of the IgG4-related sclerosing lesions, but in only 1/22 (4.5%) of IMT. The immunohistochemical expression of ALK was observed in 15/22 (68.2%) of IMT and 0/16 (0%) of IgG4-related sclerosing disease. The number of IgG4-positive plasma cells and the ratio of IgG4+/IgG+ plasma cells were each significantly lower in IMT than in IgG4-related sclerosing disease [mean 6.4/HPF vs. 178.3/HPF (P<0.0001), 3.0% vs. 67.5% (P<0.0001), respectively]. The results suggest that IgG4 does not play an important role in the pathogenesis of IMT. In addition, the evaluation of IgG4+ plasma cells and the ratio of IgG4+/IgG+ plasma cells and the presence of obstructive phlebitis may be useful for the differential diagnosis between IMT and IgG4-related sclerosing disease.

CXCR4 and VEGF expression in the primary site and the metastatic site of human osteosarcoma: analysis within a group of patients, all of whom developed lung metastasis.

The chemokine, CXCL12, and its receptor, CXCR4, have recently been shown to play an important role in metastasis of several kinds of carcinoma. It has also been demonstrated that VEGF regulates both the expression of CXCR4 and invasiveness in breast cancer cell lines. We compared the immunohistochemical expression of CXCR4 and VEGF between the primary site and a concordant pulmonary metastatic site in 30 osteosarcoma patients, all of which had undergone thoracotomy. Microvessel density (MVD) as shown by immunostaining of CD34 and proliferative activity with MIB-1 monoclonal antibody was also evaluated. CXCR4 expression (primary, 33.3% positive vs metastatic, 66.6% positive; P=0.0097) and MVD (primary, 29.86±6.87/0.26 mm2 vs metastatic, 43.32±8.65/0.26 mm2; P=0.0015) in the metastatic site were both significantly increased compared with those in the primary site, whereas no difference between primary and metastatic sites was observed with regard to VEGF expression. There was a significant positive correlation between immunohistochemical CXCR4 and VEGF expression (P=0.0269). In total population, the MIB-1-labeling index (LI) was significantly higher in tumors, which showed immunoreactivity for VEGF (MIB-1-LI in VEGF-positive tumors, 24.29±5.4 vs VEGF-negative tumors, 18.33±4.16; P=0.034). Furthermore, those patients with VEGF-positive primary tumors had a significantly worse prognosis compared with the patients with VEGF-negative primary tumors (P=0.0053). Our results suggested that CXCR4 expression was associated with metastatic progression, and immunohistochemical VEGF expression in the primary site had predictive value for the osteosarcoma patients, who developed lung metastasis.

Endometrial stromal sarcomas and related high-grade sarcomas : immunohistochemical and molecular genetic study of 31 cases

Classification and terminology of non–low-grade endometrial sarcomas, which show significant nuclear atypia, have been controversial. Currently, these tumors seem to be classified all together into “undifferentiated endometrial sarcoma (UES).” However, it remains unclear whether these non–low-grade sarcomas are universally “undifferentiated.” We divided these sarcomas morphologically into undifferentiated endometrial sarcoma with nuclear uniformity (UES-U) and undifferentiated endometrial sarcoma with nuclear pleomorphism (UES-P), and compared their molecular genetic and immunohistochemical profiles. Eighteen low-grade endometrial stromal sarcomas (ESS-LG), 7 UES-U, and 6 UES-P were examined. All the patients with ESS-LG were still alive, either with or without disease, whereas 4 of the 5 patients with advanced stage UES-U and all 3 of the patients with advanced stage UES-P had died of the disease. JAZF1-JJAZ1 fusion transcript was detected in 6 (50%) out of 12 ESS-LG and in 1 (33%) of 3 UES-U, whereas it was not detected in any of the cases of UES-P. ESS-LG and UES-U frequently showed positive immunoreaction for estrogen receptor (ESS-LG: 94%, UES-U: 57%) and progesterone receptor (ESS-LG: 94%, UES-U: 57%), whereas all the UES-P were negative for these receptors. Nuclear β-catenin expression was more frequently recognized in ESS-LG (47%) and UES-U (85%), compared with UES-P (33%). Moreover, nuclear accumulation of p53 and TP53 gene missense mutations were limited to 3 UES-P cases. Our data suggest that UES-U shares some molecular genetic and immunohistochemical characteristics with ESS-LG, but UES-P considerably differs from ESS-LG.

Survival in synovial sarcoma. A multivariate study of prognostic factors with special emphasis on the comparison between early death and long-term survival

A retrospective study of 56 patients with synovial sarcoma was done to search for possible prognostic factors affecting survival. In a univariate analysis, age (≥20 years), site (proximal), large tumor size (≥5 cm), mitotic rate of more than 15 per 10 per high-power fields (hpf), high nuclear grade, tumor necrosis of more than 50%, the presence of rhabdoid cells, a small number of mast cells (<20/10 hpf), and a high stage according to the criteria of the American Joint Committee (AJC) staging of soft tissue sarcoma, significantly decreased survival (log-rank test; p < 0.05). Moreover, when comparing the 10-year survival (11 patients) and the deaths within 1 year (12 patients), size, high nuclear grade, presence of rhabdoid cells, tumor necrosis, and stage were all considered to be significant prognostic factors (two-sided chi-square test; p < 0.01). In a multivariate analysis (Coxs model), stage was the only strong predictor of a poor prognosis (p = 0.011). We therefore concluded that large tumor size, high nuclear grade, the presence of rhabdoid cells, extensive tumor necrosis, and a high AJC stage were adverse prognostic factors in synovial sarcoma.

Extrarenal rhabdoid tumors of soft tissue: Clinicopathological and molecular genetic review and distinction from other soft‐tissue sarcomas with rhabdoid features

Malignant rhabdoid tumor (MRT) of the soft tissue is a rare and highly aggressive tumor that occurs in infancy or childhood. It predominantly involves a deep axial location such as the neck or paraspinal region. Microscopically, the tumor is composed of a diffuse proliferation of rounded or polygonal cells with eccentric nuclei, prominent nucleoli and glassy eosinophilic cytoplasm containing hyaline‐like inclusion bodies, arranged in sheets and nests. These characteristic ‘rhabdoid cells’ are also present in certain soft‐tissue sarcomas such as synovial sarcoma, extraskeletal myxoid chondrosarcoma and leiomyosarcoma. The existence of rhabdoid cells in these other sarcomas is correlated with a worse prognosis for the patients. Cytogenetic and molecular analyses have shown abnormalities in the long arm of chromosome 22 and alteration of the hSNF5/INI1 (SMARCB1) gene in renal, extrarenal and intracranial MRT. This gene alteration has been considered to be a specific molecular event in MRT, but a recent study has also demonstrated frequent alteration of this gene in proximal‐type epithelioid sarcoma (ES). Both MRT of soft tissue and proximal‐type ES show immunoreactivity for vimentin, cytokeratin and epithelial membrane antigen. The tumor cells of proximal‐type ES are also occasionally positive for CD34 and β‐catenin, whereas MRT of soft tissue has no immunoreaction for these markers. Detailed clinicopathological and immunohistochemical evaluations are necessary to distinguish MRT of soft tissue from proximal‐type ES, because these tumors demonstrated a similar morphology and the same gene alteration.

Localization and quantification of proliferating cells during rat fracture repair: detection of proliferating cell nuclear antigen by immunohistochemistry.

Bilateral femurs of 12‐week‐old female Sprague‐Dawley rats were fractured, and the fractured femurs were harvested 36 h, 3, 7, 10, and 14 days after the fracture. Localization of cell proliferation in the fracture calluses was investigated using immunohistochemistry with antiproliferating cell nuclear antigen (PCNA) monoclonal antibodies. Thirty‐six hours after the fracture, many PCNA‐positive cells were observed in the whole callus. The change was not limited to mesenchymal cells at the fracture site where the inflammatory reaction had occurred, but extended in the periosteum along almost the entire femoral diaphysis where intramembranous ossification was initiated. On day 3, periosteal cells or premature osteoblasts in the newly formed trabecular bone during intramembranous ossification still displayed intense staining. On day 7, many premature chondrocytes and proliferating chondrocytes were PCNA positive. Endochondral ossification appeared on days 10 and 14, and the premature osteoblasts and endothelial cells in the endochondral ossification front were stained with anti‐PCNA antibodies. Quantification of PCNA‐positive cells was carried out using an image analysis computer system, obtaining a PCNA score for each cellular event. The highest score was observed in the periosteum early after the fracture near the fracture site. Immunohistochemistry using anti‐PCNA antibodies showed that the distribution of proliferating cells and the degree of cell proliferation varied according to the time lag after the fracture, suggesting the existence of local regulatory factors such as growth factors, and that significant cell proliferation was observed at the beginning of each cellular event.

Pleomorphic leiomyosarcoma: clinicopathologic and immunohistochemical study with special emphasis on its distinction from ordinary leiomyosarcoma and malignant fibrous histiocytoma.

Pleomorphic leiomyosarcoma (PLMS) was recently described as a morphologic variant of leiomyosarcoma; however, its diagnostic criteria, as shown by morphologic features and biologic behavior, remain controversial. We describe 28 cases of pleomorphic sarcoma with pleomorphic areas in more than two thirds of the tumor and an ordinary leiomyosarcomatous fascicular area covering less than one third as PLMS. PLMS comprised 8.6% of all the leiomyosarcomas (322 cases) registered in our institute. Patients ranged in age from 31 to 89 years (average, 57.9 years). Seventeen patients (60.7%) were male and 11 were female. Tumor location was as follows: the extremities in 17 cases, the retroperitoneum or abdominal cavity in 7 cases, the chest/abdominal wall in 3 cases, and the scalp in 1 case. Histologically, all cases showed at least small foci of fascicles consisting of smooth muscle tumor cells, in addition to pleomorphic areas mimicking storiform–pleomorphic malignant fibrous histiocytoma. The border between pleomorphic and leiomyosarcomatous fascicular areas was sharp in 3 cases, gradual in 2 cases, and blending in 23 cases. Sixteen cases (57.1%) showed a typical storiform pattern, 6 cases revealed extensive stromal hyalinization, 6 cases showed a chronic inflammatory infiltrate, 2 cases had the foci of foamy xanthomatous cells, and 7 cases contained myxoid malignant fibrous histiocytoma-like areas covering less than 50% of the tumor. The tumors had a tendency to be of a morphologically higher grade (10 tumors were French Federation of Cancer Centers grade 2, 18 were grade 3). Five of 28 cases (18%) showed rhabdoid features. Immunohistochemically, all of the 28 tumors examined showed a positive reactivity for at least one smooth muscle marker (desmin, muscle-specific actin, and &agr;-smooth muscle actin) in the leiomyosarcomatous fascicular areas. In the pleomorphic areas the expression of smooth muscle markers (desmin 10 of 28, muscle-specific actin 13 of 28, and &agr;-smooth muscle actin 14 of 28) was significantly reduced, compared with that in leiomyosarcomatous fascicular area (desmin 18 of 28, muscle-specific actin 26 of 28, and &agr;-smooth muscle actin 24 of 28). No significant difference was observed between the MIB-1 labeling index in the leiomyosarcomatous fascicular areas (26.10 on average) and that in the pleomorphic areas (26.17 on average). However, the MIB-1 labeling index in PLMS was significantly higher than that in ordinary leiomyosarcoma (n = 20, 12.86 on average) or storiform–pleomorphic malignant fibrous histiocytoma (n = 16, 16.63 on average). In 23 patients follow-up data were available with a duration of 1–239 months. Eleven patients developed metastases, and lung accounted for the most common site of metastasis (9 cases). Fifteen of 23 patients (65.2%) died of disease. Our results indicate that PLMS should be differentiated from ordinary leiomyosarcoma because of its high proliferative activities and rather aggressive biologic behavior.

MicroRNA-10b is overexpressed in pancreatic cancer, promotes its invasiveness, and correlates with a poor prognosis

BACKGROUND MicroRNAs (miRNAs) have been gaining attention as new, key molecules that contribute to carcinogenesis. In pancreatic cancer, previous profiling analyses of miRNA expression have shown that several miRNAs are differently expressed in normal and cancerous tissues. Several pancreatic cancer-specific miRNAs differed, however, in each analysis. METHODS We investigated the miRNA expression profiles of the pancreatic cancer cell lines CAPAN-1 and CFPAC1 and an immortalized human normal pancreatic ductal epithelial cell line (HPDE) using a high-throughput, TaqMan, qRT-PCR array analysis. We also analyzed the expression levels of this miRNA in microdissected (n = 15) and formalin-fixed, paraffin-embedded (FFPE) (n = 115) samples from pancreatic cancers by quantitative RT-PCR. Finally, we investigated the effects of this miRNA on the invasiveness of pancreatic cancer cells. RESULTS Based on the microarray analysis, miR-372, miR-146a, miR-204, miR-10a, and miR-10b showed particularly large differences (>10-fold changes) between both pancreatic cell lines and HPDE cells. Thirteen of the 15 pancreatic cancer cell lines showed 2.1- to 36.4-fold (median, 15.3-fold) greater levels of miR-10b than HPDE cells. Microdissection analysis revealed that miR-10b exhibited greater expression levels in pancreatic cancer cells (n = 5) than in normal pancreatic ductal cells (n = 10) (P < .020). Analysis of FFPE samples showed that high miR-10b expression was associated with a lesser overall survival (P = .014). Furthermore, miR-10b correlated with the invasiveness of pancreatic cancer cells (P < .01). CONCLUSION miR-10b is overexpressed in pancreatic cancer and may be involved in the invasiveness in pancreatic cancer cells, thereby leading to a poor prognosis.