High MIB-1 Labeling Index Research Articles

30 Year-Old Male with Headaches

30 Year-Old Male with Headaches

Congenital glioblastoma coexisting with vascular developmental anomaly

Congenital central nervous tumours form a unique group of neoplasms. They are different from other tumour groups not only due to the onset time but also to their histopathology, anatomic location, and biologic behaviour. Congenital glioblastoma is one of the rarest types of congenital brain tumours and is uncommon in the prenatal period. We report a rare case of congenital glioblastoma detected prenatally by ultrasound examination and magnetic resonance imaging at 26 gestational weeks. Based on MRI findings and consultation of a team of specialists, pregnancy was terminated at 28 weeks. The newborn presented hydrops foetal. The child died shortly after birth due to cardiorespiratory insufficiency. At autopsy a large tumour with a spongy-like appearance was found. The tumour involved nearly the whole right cerebral hemisphere and led to marked hydrocephalus. In the histological and immunohistochemical examination, the tumour presented features of glioblastoma. Neoplastic cells were immunopositive for GFAP, S-100 protein and negative for neuronal markers. Frequent mitoses and high MIB-1 labelling index were seen in the tumour areas. The coexistence of tumour and vascular developmental anomaly was stated. The conglomerates of numerous, distended, thin-walled foetal-like blood vessels were located beside the tumour tissue, which presented disturbance in differentiation and maturation of the vascular net. Such coexistence of malignant glioma with vascular developmental anomaly is unique.

Papillary glioneuronal tumor—a rare entity: report of four cases and brief review of literature

Papillary glioneuronal tumors (PGNT) have been recently included as a distinct entity in the WHO classification of tumors of the central nervous system. Their molecular pathogenesis is not clear. In the current study, we present the morphological, immunohistochemical, and molecular features of four cases of PGNT reported over the past 11 years. Over a period of 11 years (January 2000-February 2010), there were four cases of PGNT, which were reviewed for histomorphological features. TP53 and IDH1 mutations were assessed using antibodies against p53 protein and for mutant IDH1(R132H) protein, respectively. Immunohistochemistry was also performed for epidermal growth factor receptor (EGFR) protein. Fluorescence in situ hybridization assay was used for analyzing 1p/19q deletion status. All the tumors showed the characteristic biphasic morphology. Rare findings included minigemistocyte-like cells in one, angiomatous areas in three, focal necrosis in one, and a high MIB-1 labeling index of 12 and 13 %, respectively, in two of the cases. All lacked EGFR, IDH1 expression, and 1p/19q deletions. Interestingly, antibody for p53 labeled the tumor cells, mainly those showing glial differentiation, in two cases. At a mean follow-up of 30 months, there was no evidence of disease progression except in one case which recurred after 24 months. PGNT are rare CNS neoplasms. Despite showing focal morphological features reminiscent of oligodendroglial tumors and presence of astrocytic component, they usually lack the common genetic alterations involved in the pathogenesis of gliomas. Multi-institutional pooling of cases may aid in elucidating their oncogenetic pathway.

Mixed angiosarcoma, clear cell adenocarcinoma and mature teratoma elements in an ovarian tumor: A case report and literature review

Malignant transformation of a mature teratoma in the ovary is a rare event, with an approximate rate of only 1-2%. Here, we report an ovarian tumor with a unique combination of epithelial and non-epithelial malignant components, including mature teratoma elements. A 59 year-old postmenopusal woman underwent total hysterectomy and bilateral salpingo-oophorectomy to remove a huge solid mass of the right ovary. The ovarian tumor was 16 × 12 × 4.5 cm in dimensions, composed of red-brown and greyish-white tissue with several cystic areas. Microscopically, atypical cells immunopositive for both CD31 and CD34 formed irregular ectatic vascular patterns with a high MIB-1 labeling index in red-brown areas. In contrast, tubule-cystic and papillary structures were lined by HNF-1β-immunopositive atypical cuboidal and hobnail cells with clear cytoplasm in greyish-white areas. In addition, normal-looking epithelial and stromal components, including mature squamous, cuboidal and ciliated epithelial cells, and adipose tissues, were observed in red-brown areas, suggesting an ovarian tumor combining angiosarcoma, clear cell adenocarcinoma, and mature teratoma features. We could demonstrate identical X-chromosome inactivation patterns among all three components by human androgen receptor gene (HUMARA) assays, pointing to complex inter-relationships regarding their pathogenesis. These observations suggest that a malignant tumor composed of two characteristic phenotypes arose in mature teratoma.

Pineal parenchymal tumor of intermediate differentiation with marked elevation of MIB-1 labeling index

We report a case of pineal parenchymal tumor (PPT) in an 11-year-old girl. Brain magnetic resonance imaging (MRI) revealed a large tumor (48mm) located in the pineal region with heterogeneous enhancement after gadolinium administration. The patient underwent tumor removal with craniotomy; only partial tumor resection could be performed because of massive intratumoral bleeding. Histopathological examination of the tumor showed lobular proliferation of round cells with moderate atypia. Cellularity varied by area, and focal Homer Wright rosettes were identified. Examination of tumor cells revealed a few mitoses (two mitotic figures per 10 high-powered fields), and immunohistochemical staining revealed positivity for synaptophysin, slight positivity for neurofilament protein (NFP) with antibody clone 2F11, and strong positivity for NFP with clone NF-M+H. The pathological diagnosis was pineal parenchymal tumor of intermediate differentiation grade II according to World Health Organization criteria despite a high (22%) MIB-1 labeling index (LI). The patient had a favorable clinical course after an intensified chemotherapy regimen designed for pineoblastoma and radiotherapy administered to the entire neuraxis, followed by stereotactic radiotherapy. In conclusion, MIB-1 LI could be a useful tool for deciding therapeutic strategies for PPT treatment when there is a discrepancy between clinical findings and pathological grading.

Maximun Standard Uptake Value At the Biopsy Site During 18f-Fluorodeoxyglucose Positron Emission Tomography Does Not Predict the Proliferation Potential of Tumor Cells in Extranodal Natural Killer/T-Cell Lymphoma, Nasal Type

Abstract 5216 Background:Extranodal natural killer (NK)/T cell lymphoma, nasal type (ENKL) is a distinct subtype of non-Hodgkin lymphoma. ENKL is extremely rare in the United States of America and in Europe, but is rather common in East Asia. The overall prognosis is usually poor when compared to that of B cell lymphoma. Ki-67 is a nuclear antigen expressed by dividing cells. Thus, the Ki-67 proliferation index ((MIB-1) labeling index) indicates the proliferation potential of tumor cells. In recent studies (Ann Oncol. 2007; 18: 1382–1387, J Clin Oncol. 2006; 24: 2472–2479, Anticancer Res. 2008; 28: 1113–1118), a high MIB-1 labeling index was associated with poor prognosis in non-Hodgkin lymphoma, T-cell lymphoma, and localized ENKL. We recently reported that the maximum standard uptake value (SUVmax) of the biopsy site during 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) reflects tumor aggressiveness in the cases of non-Hodgkin lymphoma (Leuk Lymph. 2010; 51: 279–283). The positive rate of FDG-PET was reported to be 100% in ENKLs (Ann Oncol. 2007; 18: 1685–1690). In this study, we studied the biopsy sites of patients with untreated ENKL to clarify the correlation between SUVmax at the biopsy site and the proliferation potential of tumor cells. Patients and Methods:Between 1998 and 2011, 22 patients were newly diagnosed with ENKL at Yokohama City University Hospital and Kanagawa Cancer Center. In 17 cases, the tumors were staged by positron emission tomography (PET) or PET/computed tomography (CT) and were simultaneously biopsied. Variations in SUVmax among institutions and the underestimations derived from small tumors, which are limitations of PET performed in multicenter studies, were adjusted using a phantom study. The difference in accuracy of SUVmax between 2 institutions was less than 2%. One patient was excluded because the biopsy site was not scanned by PET or PET/CT. The biopsy specimens were reviewed by 2 hematopathologists (S. S. and K. T.) in accordance with the World Health Organization (WHO) classification, and the proliferation potential of lymphoma cells was evaluated by measuring the MIB-1 labeling index. One patient was excluded because the diagnosis made by central review was not compatible with ENKL. Two patients were excluded because the biopsy specimens were very small and the MIB-1 labeling index could not be evaluated. Consequently, we studied 15 extranodal biopsy specimens from 13 patients with untreated ENKL, for whom complete data were available. The patients included 10 males and 3 females with a median age of 52 years (range, 18–82 years). Results:For the 15 ENKL specimens included, the biopsy site was the nasal cavity in 7 cases, the pharynx in 4, and the skin in 4, respectively. The measured MIB-1 labeling index ranged from 0.44% to 77.44%. The MIB-1 labeling index for 7 patients was more than 60% and for 2 patients was less than 20%. The SUVmax at the biopsy sites ranged from 2.1 to 20.8. The SUVmax at the biopsy site was not correlated with the MIB-1 labeling index (r = −0.33, P = 0.22). The SUVmax was also not correlated with the MIB-1 labeling index/tumor cell proportion in the biopsy specimens (r = 0.18, P = 0.52). Conclusion:The SUVmax during FDG-PET does not predict the proliferation potential of ENKLs. Disclosures:No relevant conflicts of interest to declare.

Primary desmoplastic cutaneous leiomyosarcoma associated with high MIB-1 labeling index: A teaching case giving rise to diagnostic difficulties on a small biopsy specimen

A case of primary desmoplastic cutaneous leiomyosarcoma is reported. A flat and elevated tan plaque, measuring 30 mm × 20 mm, was noticed in the left back of a 74-year-old Japanese male 6 months before the resection. The biopsy specimen showed an overgrowth of desmoplastic fibrocollagenous stroma, focally admixed with a less cellular proliferation of spindle cells having mildly pleomorphic nuclei, but no mitotic figures, arranged in small clusters or appearing as individual cells. Based on these features, we interpreted it as a benign keloid-like lesion. A local resection was done, and gross examination revealed a poorly demarcated grayish tumor lesion, replacing the entire dermis and extending into the subcutis. Microscopic findings demonstrated a sparsely cellular proliferation of atypical spindle cells having cigar-shaped or multi-nucleated pleomorphic nuclei and abundant eosinophilic cytoplasm with few mitotic hot spots, arranged in interlacing bundles, alternating with scattered tumor cells within an abundant desmoplastic stroma. Immunohistochemically, these atypical cells were positive for α-smooth muscle actin, HHF-35, desmin, and caldesmon, and MIB-1 labeling index was greater than 10%. Therefore, we finally made a diagnosis of desmoplastic leiomyosarcoma as a very rare variant of cutaneous leiomyosarcoma. We should be aware that owing to its characteristic features, pathologists might misinterpret it as benign when examining only small or inadequate specimens. It is thus suggested that a large panel of antibodies including smooth muscle cell markers and MIB-1 in immunohistochemistry are useful and adjunctive diagnostic aids for recognizing malignancy, especially in diagnostically difficult cases such as ours.

Dural Metastasis of Atypical Extraventricular Neurocytoma with the Codeletion of Chromosomes 1p/19q

Extraventricular neurocytoma (EVN) is a rare neoplasm described in the 2007 World Health Organization classification of tumours of the nervous system. Due to the rarity of the tumour, there is limited literature available. The clinical characteristics, pathological features, biological behaviour and outcome of EVN remain unclear, and there are challenges regarding its diagnosis and management. The present case was a 75-year-old man who had been experiencing slow responses to stimuli for 1 month prior to hospital admission. A diagnosis of atypical EVN was made on the basis of pathology and immunohistochemistry results. Atypical pathological features included vascular proliferation, the presence of mitosis and a high MIB-1 (an antibody against Ki-67) labelling index. The disease recurred 7 months after the initial complete resection and radiation treatment, presenting with dural metastasis and codeletion of chromosomes 1p/19q. The present case history and treatment course are discussed with respect to the literature.

Analysis of factors affecting the long-term functional outcome of patients with skull base meningioma

We analyzed the factors that affect the long-term clinical outcome of a series of patients with skull base meningiomas. Clinical records of 73 patients with cranial base meningiomas were reviewed retrospectively, of whom 13 patients experienced a recurrence at various times following the initial surgery. The mean follow-up time was 90.4 ± 21.2 months (range = 60–124 months). Based on the location of the recurrence, patients with recurrence were divided into peripheral ( n = 6) and central ( n = 7) skull base groups. Of several variables analyzed using a multivariate logistic regression model, “high MIB-1 (Ki-67 proliferation antigen) labeling index” was an independent variable predicting poor long-term functional outcomes. Recurrence of the tumor at the central skull base was also a strong predictor of poor long-term outcomes. An increased proliferative potential, as indicated by a high MIB-1 labeling index, may induce repeated recurrences, eventually leading to worse functional outcomes, particularly for patients with central skull base meningiomas.

A pediatric intramedullary spinal cord tumor with unusual solid-cystic and papillary features: A case report

Spinal cord tumors are rare in children. We report a novel case of pediatric intramedullary spinal cord tumor with unusual solid-cystic and papillary features. Clinically, the patient presented at the age of 3 years with motor deficit and urinary incontinence, and MRI demonstrated multilocular cystic lesions in the thoracic spine. Histologically the tumor consisted of solid, sheet-like components and branching papillary structures, and immunohistochemistry demonstrated positive reactivity for epithelial membrane antigen, cytokeratins (7, AE1/3, CAM5.2), E-cadherin and transthyretin, and negativity for GFAP, S-100 protein, synaptophysin and neurofilament. These histological and immunohistochemical findings appeared to be unique, and were not compatible with the features of classical ependymoma or choroid plexus papilloma. The clinical behavior, characterized by relatively rapid tumor regrowth after surgical resection and a relatively high MIB-1 labeling index, suggest that this tumor might have had moderate malignant potential. This pediatric case appears to be particularly informative with regard to the tumor biology or tumorigenesis of intramedullary spinal cord tumor with unusual solid-cystic and papillary features.

Clinico-pathological feature of pilomyxoid astrocytomas: Three case reports

Pilomyxoid astrocytoma (PMA) is a newly identified variant of pilocytic astrocytoma (PA). We report three cases of PMA with comparison to seven cases of PA in terms of their clinicopathological features. The three cases occurred at the ages of 2, 36 and 6 years, and their tumors were located in the left basal ganglia, the pineal gland, and the cerebellum, respectively. They were diagnosed PMA by surgical specimens that showed a characteristic monomorphous architecture with an angiocentric growth pattern and myxoid background. One patient developed localized relapse at 6 months after the surgery, but the other patients remained alive without tumor progression more than 5 years after treatment. In analysis of the immunohistochemical association in PMA and PA, no specific staining was found to be useful for differential diagnosis of PMA from PA. The expression of biomarkers including O-6-methylguanine-DNA methyltransferase, p53, MIB-1, and EGF receptor neither distinguished PMA from PA nor correlated with outcome. But almost all PMA and PA that demonstrated prominent positivity for nestin showed a high MIB-1 labelling index (LI), and four of these five patients suffered a relapse in the early phase. These results suggest that immunohistochemical expression of nestin and MIB-1 LI may correlate with the aggressiveness of the tumor in PA and PMA.

Rhabdoid papillary meningioma: A clinicopathologic case series study

World Health Organization (WHO) grade III meningiomas are subclassified on the basis of their architectural pattern into papillary and rhabdoid subtypes. Some meningiomas even combine papillary architecture with rhabdoid cytology. Additionally, they always show malignant histological features, follow an aggressive clinical course and tend to spread through the CSF after frequent local recurrence. We render the first series of rhabdoid papillary meningioma with review of the literature to further elucidate its biological behavior. From six patients (three male, three female), nine specimens of rhabdoid papillary meningioma were obtained between 1994 and 2010. Correlations of histologic parameters, immunohistochemical study, and clinical features were assessed. The mean age of patients was 44.7 years at their first operation. The mean postoperative follow-up period was 63.2 months. Five patients experienced tumor recurrence, and one of them died from the disease after diffuse leptomeningeal dissemination. The mean time to first recurrence was 28 months. Only one patient was free of tumoral recurrence after an 8-year follow-up. Immunohistochemically, all tumors were positive for vimentin and epithelial membrane antigen. MIB-1 labeling indices were higher following tumor recurrence. The present study expands the clinicopathologic horizon of rhabdoid papillary meningioma and suggests that it will behave aggressively based on its histology and concomitant features of atypia or malignancy or high MIB-1 labeling indices. Close follow-up and aggressive treatments of these tumors are warranted.

Anaplastic Meningioma With Extremely Rapid Recurrence -Case Report-

A 62-year-old woman presented with an uncommon case of anaplastic meningioma manifesting as recent memory disturbance. Magnetic resonance imaging revealed a mass located in the right temporal lobe. She became unconscious because of uncal herniation and underwent urgent surgery. The tumor was completely resected, except for a lesion tightly attached to arteries. Histological examination indicated the presence of anaplastic meningioma with an extremely high MIB-1 labeling index (70%). After 43 days, the patient developed local recurrence and dissemination in the left temporal lobe. The exceptionally high MIB-1 labeling index corresponded with a short tumor doubling time (8.2 days). Whole-brain irradiation and linear accelerator surgery for disseminated lesions were performed, and the tumor growth halted. Although meningiomas rarely show malignant behavior, corresponding to World Health Organization grade III, it is necessary to consider malignant behavior when treating meningiomas.

A comparison of World Health Organization tumor grades at recurrence in patients with non–skull base and skull base meningiomas

Despite a favorable outcome for most patients with WHO Grade I meningiomas, a subset of these patients will have recurrent or progressive disease that advances to a higher grade and requires increasingly aggressive therapy. The goal of this study was to identify clinical characteristics associated with the recurrence of benign meningiomas and their acceleration to atypical and malignant histological types. Records of 216 patients with WHO Grade I, II, or III meningioma that were initially treated between 1965 and 2001 were retrospectively reviewed. Median follow-up was 7.2 years. Patients with non-skull base cranial meningiomas (82 of 105 [78%]) were more likely to have undergone a gross-total resection than patients with skull base meningiomas (32 of 78 [41%]; p < 0.001). Consequently, patients with Grade I non-skull base cranial meningiomas had better 5-year recurrence-free survival (69%) than patients with Grade I skull base meningiomas (56%) or Grade II or III tumors at any site (50%; p = 0.005). Unexpectedly, patients with non-skull base tumors who experienced a recurrence (8 of 22 [36%]) were more likely than patients with skull base tumors (1 of 19 [5%]) to have a higher grade tumor at recurrence (p = 0.024). Furthermore, the median MIB-1 labeling index of Grade I non-skull base cranial meningiomas (2.60%) was significantly higher than that of Grade I skull base tumors (1.35%; p = 0.016). Cranial meningiomas that occur outside of the skull base are more likely to have a higher MIB-1 labeling index and recur with a higher grade than those within the skull base, suggesting that non-skull base cranial tumors may have a more aggressive biology than skull base tumors.

Parasagittal solitary fibrous tumor resembling hemangiopericytoma

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor in the central nervous system, and the clinical behavior of this tumor is similar to that of meningioma. We report the case of a Japanese woman with parasagittal SFT that resembled hemangiopericytoma (HPC). Histological examination revealed that the tumor was highly cellular, with cells containing oval- or spindle-shaped nuclei arranged in sheets or a pattern-less growth mode. Focal vascular proliferation was also observed. Some areas showed intercellular stroma containing remarkable eosinophilic collagens. Tumor cells showed a strong immunoreactivity for CD34 but were negative for S-100 protein and epithelial membrane antigen. MIB-1 labeling index of the tumor was 6.6%. Owing to the high cellularity, high MIB-1 labeling index, and focal vascular proliferation, it was difficult to distinguish this lesion from HPC. However, the tumor was finally diagnosed as SFT on the basis of the strong immunostaining for CD34 and absence of pericellular reticulin.

Oncocytic choroid plexus carcinoma: case report

Herein, we report an unusual choroid plexus carcinoma with extensive oncocytic transformation. A 13-month-old girl presented with acute lethargy which quickly progressed to coma. A CT scan of the head revealed impending herniation due to hemorrhage within an intracranial tumor. An MRI scan showed a large, partly cystic and highly vascular left lateral ventricular mass. A near total resection was achieved. Microsections revealed a WHO Grade III choroid plexus carcinoma with extensive oncocyti c transformation. A minor portion of the moderately to poorly differentiated tumor exhibited classical microscopic features of choroid plexus carcinoma, including marked nuclear atypia, brisk mitotic activity (78/10 HPF), a high MIB-1 labeling index (44%) and zones of necrosis. In contrast, the large, eosinophilic, cytologically malignant but granular-appearing oncocytes comprising the majority of the lesion showed scant (1/10 HPF) mitotic activity and only a low MIB-1 labeling index (5%). A subsequent recurrence at 1 year consisted entirely of non-oncocytic tumor. Choroid plexus carcinoma with oncocytic transformation has not been previously reported. The remarkable extent of this alteration and its clinical significance remains to be determined.

The expression level of sphingosine-1-phosphate receptor type 1 is related to MIB-1 labeling index and predicts survival of glioblastoma patients

Although there are many reports on the clinical use of the MIB-1 labeling index (LI), which is a measure of proliferative activity in astrocytomas; its significance varies between studies. There are no known molecules that are directly linked to the MIB-1 LI in astrocytomas. We evaluated the clinical value of the MIB-1 LI in our human glioblastoma cases and determined the molecules that possibly influenced the MIB-1 LI. An immunohistochemical study of the MIB-1 protein was performed and MIB-1 LIs of 38 glioblastomas were determined. In the same cases, epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor-alpha (PDGFRA), and sphingosine-1-phosphate receptor type 1 (S1P(1)), which are known regulators of glioma cell proliferation, were detected and quantified by quantitative real-time-PCR or western blotting. Kaplan-Meier survival curves for 38 patients with glioblastomas showed that a high MIB-1 LI correlated with poor survival (P < 0.05). Among the molecules tested, only the low expression of S1P(1) was significantly correlated with the high MIB-1 LI in glioblastomas (P < 0.05). Multivariate analysis revealed that the S1P(1) expression level was a significant prognostic factor. Our results indicate that the MIB-1 LI is an important prognostic factor in human glioblastomas. Furthermore, downregulation of S1P(1) expression increases proliferative activity, and thus enhances the malignancy of glioblastomas, resulting in a poor survival.

Brain surface spindle cell glioma in a patient with medically intractable partial epilepsy: A variant of monomorphous angiocentric glioma?

We report a case of brain surface angiocentric glioma in a 6-year-old Japanese boy with medically intractable partial epilepsy. MRI showed somewhat ill-defined high-signal lesions on fluid-attenuated inversion recovery and T2-weighted imagings of the right occipitoparietal cortex. At surgery, a yellowish tumor was localized in the superficial cortex. Histologically, the tumor was predominantly composed of elongated astrocytic cells forming rings around blood vessels. Tumor cells circumferential to vessels predominanted in low cellurarity areas, whereas radial alignment with perivascular pseudorosettes was observed in more cellular regions. These perivascular pseudorosettes closely resembled those of ependymoma. The tumor cells showed variable cytoplasmic immunoreactivity with GFAP. These findings were more likely monomorphous angiocentric glioma, which was first described by Wang et al. in 2005. However, in our case the tumor had a small foci of polymorphous appearance and a comparatively high MIB-1 labeling index (8%). Therefore, the present case may be an atypical form of monomorphous angiocentric glioma. However, no de novo anaplastic monomorphous angiocentric glioma similar to our case has yet been reported in the literature. It remains to be determined whether the behavior of monomorphous angiocentric glioma is an example of benign biological characteristics or whether it more closely resembles a low-grade malignant tumor.

Clinicopathological and immunohistochemical study of extrapleural and pleural solitary fibrous tumors: A special emphasis on the comparison between ordinary tumors and their malignant variant

Solitary fibrous tumors (SFTs) are rare spindle cell tumors that usually arise in the pleura, although they also occur in extrapleural sites. SFTs usually have a favorable clinical course; however, a small number of metastasizing cases have been reported. We evaluated the detailed clinicopathological findings of 20 extrapleural and 16 pleural SFTs. Among them, 6 cases of the histologically malignant variant (4 extrapleural and 2 pleural tumors) were identified. According to the follow-up data, none of the cases, including the 6 malignant tumors, developed metastases in this series. There were no significant differences in the histologic findings between the extrapleural and pleural SFTs. Tumor necrosis was frequently associated with the malignant variant. Immunohistochemically, malignant SFTs revealed more frequent p53 expression (4/6) compared with ordinary SFTs (2/30) (P=0.0027). The MIB-1 labeling index (LI) was significantly higher in malignant SFTs (mean 13.48) than in ordinary SFTs (mean 7.27) (P=0.0023). Our results indicate that tumor necrosis, p53 expression and a high MIB-1 LI are additional parameters of the malignant variant of SFTs, although they do not necessarily have predictive value for biological behavior. Further studies are required to find reliable molecular biomarkers for predicting the clinical outcome of patients with this unique tumor.

Dysadherin Expression as a Significant Prognostic Factor and as a Determinant of Histologic Features in Synovial Sarcoma: Special REFERENCE to its Inverse Relationship With E-cadherin Expression

Dysadherin is a cancer-associated cell membrane glycoprotein, which down-regulates E-cadherin and promotes metastasis. Synovial sarcoma is a very rare mesenchymal tumor that exhibits an epithelial profile. To confirm the diagnosis of synovial sarcoma, we evaluated several immunohistochemical markers, or detected SYT-SSX fusion gene transcript. We studied the clinicopathologic features in 92 synovial sarcoma patients and also assessed the immunohistochemical expression of dysadherin and E-cadherin to examine their possible association with histologic subtype and biologic behavior. Moreover, among 30 patients, for whom frozen materials were available, dysadherin mRNA expression was examined by reverse transcription-polymerase chain reaction and real-time quantitative reverse transcription-polymerase chain reaction analysis. Dysadherin-positive expression was significantly correlated with E-cadherin-reduced expression (P=0.0004). Dysadherin-positive immunostaining was diffusely observed in the membranes of tumor cells in 30/68 (44%) patients with monophasic fibrous type and in 1/2 (50%) patients with poorly differentiated type. However, in biphasic tumors, dysadherin expression in the fibrous component was not diffusely observed, but often sporadically or focally observed [20/22 (91%) patients]. In addition, dysadherin mRNA expression in monophasic fibrous type was significantly higher than in biphasic type (P=0.0079). Synovial sarcoma patients with dysadherin expression survived for a significantly shorter time than those without dysadherin expression (P=0.0006). Patients with combined dysadherin-positive expression and E-cadherin-reduced expression had a significantly worse prognosis than those with other combinations of dysadherin and E-cadherin expression (P=0.0007). SYT-SSX fusion gene transcript was detected in 39 patients. In our series, SYT-SSX fusion type was found to have no correlation with histologic subtype, prognosis, or dysadherin expression. In multivariate analysis, dysadherin immunopositivity (P=0.0411) was an independent adverse prognostic factor, in addition to a high MIB-1 labeling index (> or =10%). We conclude that E-cadherin dysfunction by dysadherin is associated with reduced E-cadherin expression and morphologic change from epithelioid to spindle phenotype. Dysadherin expression is considered to be one of the determinants of histologic subtype in synovial sarcoma. Moreover, dysadherin expression is an excellent and independent prognostic indicator.