Hiroshi Hashimoto

Molecular Alterations of h-warts/LATS1 Tumor Suppressor in Human Soft Tissue Sarcoma

h-warts/LATS1 is a human homolog of the Drosophila warts tumor suppressor gene, which functions as a component of the mitotic apparatus. LATS1-deficient (Lats1−/−) mice have been reported to develop ovarian stromal tumors and soft tissue sarcomas. We investigated the status of the h-warts/LATS1 in 50 human soft tissue sarcomas to address its potential function as a tumor suppressor in human sarcoma development. In our RT-PCR assay, 7 (14%) (3 of 4 myxoid liposarcomas, 3 of 7 leiomyosarcomas, 1 of 9 malignant fibrous histiocytomas) of 50 sarcomas examined had no or a reduced expression of the h-warts/LATS1, indicating down-regulated gene expression. We further analyzed alterations of the h-warts/LATS1 in these seven sarcomas. Using microsatellite markers for chromosome 6q23-25.1, to which the h-warts/LATS1 is localized, an allelic loss of this locus was detected in one leiomyosarcoma, in which a missense point mutation of the h-warts/LATS1 was detected by PCR single-strand conformation polymorphism. Clusters of CpG dinucleotides in a 5′ putative promoter region were hypermethylated in the other six sarcomas. Our data suggest that the molecular alterations of the h-warts/LATS1 could be of pathologic importance in human sarcomagenesis.

Juxta-articular myxoma and intramuscular myxoma are two distinct entities: Activating Gsα mutation at Arg 201 codon does not occur in juxta-articular myxoma

Juxta-articular myxoma is a rare myxoid tumor of soft tissue that bears a close histologic resemblance to intramuscular myxoma but is distinguished from the latter by its clinical setting and behavior. Activating missense mutations at the Arg 201 codon of the Gsα gene ultimately leading to increased levels of cyclic adenosine monophosphate have been implicated in McCune-Albright syndrome and sporadic fibrous dysplasia of bone. Recently, we have demonstrated that the same Gsα mutations occur in intramuscular myxomas associated with fibrous dysplasia of bone (Mazabrauds syndrome) as well as in sporadic intramuscular myxoma. The overlapping histologic appearances of juxta-articular myxoma and intramuscular myxoma prompted us to investigate whether there is a relationship between the two entities. We studied this possibility by looking for Gsα mutations in juxta-articular myxoma using polymerase chain reaction (PCR) to amplify appropriate genomic DNA fragments extracted from formalin-fixed, paraffin-embedded specimens of five juxta-articular myxomas, followed by single-strand conformation polymorphism analysis. Using these techniques, no aberrant bands were detected in any of the five juxta-articular myxomas, indicating that they lack Gsα mutations. Moreover, DNA sequencing of the PCR products of two JAMs showed no abnormalities. We conclude that juxta-articular myxomas, in contrast to intramuscular myxomas, do not involve Arg 201 mutations of the Gsα gene, indicating that they represent distinct entities with different underlying molecular mechanisms.

Gene expression of TrkC (NTRK3) in human soft tissue tumours

TrkC is a member of the Trk family of tyrosine kinase receptors and plays an important role in the development and maintenance of neural tissues. Although a variety of non‐neuronal tissues have also been shown to express TrkC, the status of TrkC in soft tissue tumours has been poorly investigated, except for a small fraction of tumours including congenital/infantile fibrosarcoma characterized by an ETV6–NTRK3 (also known as Tel–TrkC) fusion gene. To broaden knowledge about the TrkC status in human neoplasms, the expression of TrkC transcripts was assessed in 51 soft tissue tumours of variable lines of differentiation by reverse transcription‐polymerase chain reaction (RT‐PCR), using primer sets flanking their extracellular domain, the tyrosine kinase domain, and the intracellular domain of a truncated variant (Trunc 1) described previously. In 44 of the 51 tumours, TrkC transcripts, including alternatively spliced isoforms, were detected. The truncated transcripts (Trunc 1) were co‐expressed in 40 of the 44 tumours and were expressed in one tumour without native TrkC gene expression. In two of the remaining six tumours, part of the sequence coding the tyrosine kinase domain of TrkC appeared to be truncated. Using a 3′ rapid amplification of cDNA ends (3′RACE) method, another truncated isoform (Trunc 2) was isolated from one of the tumours, in which the TrkC transcript was terminated with a novel 160‐base pair sequence. This truncated isoform was identified in nine of the 51 tumours examined by RT‐PCR using primers for Trunc 2. There was no clear correlation between the types of TrkC isoforms detected and histological types or grades of the tumours. These results suggest that human soft tissue tumours widely express TrkC, irrespective of their cellular lineage, morphology, and biological behaviour. Dysregulated TrkC expression may enhance overgrowth or transformation of various mesenchymal cells. Copyright

Specific but variable expression of h-caldesmon in leiomyosarcomas: an immunohistochemical reassessment of a novel myogenic marker.

h-Caldesmon is considered a novel specific marker for tumors with smooth muscle differentiation. To reassess its diagnostic use, the authors evaluated the immunohistochemical expression of h-caldesmon and other myogenic markers (calponin, &agr;-smooth muscle actin, HHF35, and desmin) in 30 leiomyosarcomas (external soft tissues [15], retroperitoneum [8], uterus [5], other sites [2]), 26 myofibroblastic lesions, and 26 fibrohistiocytic tumors of varying biologic potential and histology. In contrast with previous data, h-caldesmon was expressed only in 11 (36%) of the 30 leiomyosarcomas analyzed, whereas they consistently expressed actins and frequently expressed calponin (86%) and desmin (76%). Leiomyosarcomas with the expression of h-caldesmon were well or moderately differentiated and primarily confined to the retroperitoneum or uterus. All but one leiomyosarcomas in the external soft tissues examined were negative for h-caldesmon, and the h-caldesmon-negative tumors showed moderately to poorly differentiated morphology. All myofibroblastic lesions examined were negative for h-caldesmon despite their constant expressions of at least one of the other markers. h-Caldesmon was not expressed in fibrohistiocytic tumors either, although focal positivity for the other markers was seen in subsets of the tumors. Thus, h-caldesmon can be regarded as a specific myogenic marker. However, one should be aware that the expression of h-caldesmon in leiomyosarcomas can be more variable according to their locations and/or extent of smooth muscle differentiation than considered previously.

Extraskeletal myxoid chondrosarcoma arising in the finger

Extraskeletal myxoid chondrosarcoma (EMCS) is a rare soft tissue sarcoma and usually occurs in deep soft tissues, especially of the proximal extremities and limb girdles. We present an unusual case of the tumor arising in the finger. The diagnosis was confirmed by molecular detection of a characteristic EWS-CHN/TEC fusion gene transcript. Molecular detection of the tumor specific fusion gene could be a valuable aid for the final diagnosis of EMCS, particularly in cases with unusual clinicopathological features.

Immunohistochemical Expression of Metallothionein in Human Bladder Cancer: Correlation With Histopathological Parameters And Patient Survival

PURPOSEnWe assessed metallothionein expression and its patterns of distribution as possible prognostic variables in bladder cancer with regard to histopathological parameters.nnnMATERIALS AND METHODSnWe stained 91 formalin fixed, paraffin embedded tissue specimens of bladder cancer from 91 patients with no history of treatment using an immunohistochemical technique for metallothionein. Relationships between immunoreactivity for metallothionein and histopathological parameters were examined. In addition, these parameters, including metallothionein, were evaluated as potential prognostic markers.nnnRESULTSnMetallothionein was detected in 33 of 91 bladder cancers (36.3%). There were significant relationships of metallothionein expression with high grade, high stage and nonpapillary growth pattern tumors. There was no specific correlation of metallothionein expression with the interval to intravesical recurrence. In the 31 patients who underwent radical cystectomy a significant relationship between metallothionein immunoreactivity and cancer specific survival was found.nnnCONCLUSIONSnOur findings suggest that a close correlation exists of metallothionein expression with histopathological parameters and metallothionein expression can be a useful prognostic variable for bladder cancer.

Intranasal pericytic tumors (glomus tumor and sinonasal hemangiopericytoma-like tumor) : Report of two cases with review of the literature

An intranasal glomus tumor and a sinonasal hemangiopericytoma‐like tumor are reported. Both patients were elderly women suffering from nasal bleeding, and presented with a polypoid mass arising in the nasal septum. Microscopically, the glomus tumor displayed a proliferation of uniform rounded or cuboidal epithelioid cells arranged in sheets and interrupted by a rich vasculature with a characteristic configuration mimicking the normal glomus bodies, while the sinonasal hemangiopericytoma‐like tumor featured a perivascular proliferation of spindle‐ to oval‐shaped cells that were arranged in short fascicles. Both tumors shared immunohistochemical features supporting their myoid differentiation by the expression of vimentin, α‐smooth muscle actin and muscle‐specific actin, albeit with no immunoreaction to desmin. Both the intranasal glomus tumor and sinonasal hemangiopericytoma‐like tumor are characterized by a perivascular growth pattern and myoid differentiation, having a close relation to the ‘perivascular myomas’, which was recently designated.

Comparative study of novel endoluminal ultrasonography and conventional transurethral ultrasonography in staging of bladder cancer

Abstractu2003 Background:u2002 Recent advances in ultrasonic techniques have improved the image quality and diagnostic accuracy for staging of bladder cancer. The aim of this study was to assess the feasibility and usefulness of endoluminal ultrasonography (ELUS) in staging of bladder cancer, and to compare them with those of conventional transurethral ultrasonography (TUUS).

Dimethylsulfoxide enhances the absorption of chemotherapeutic drug instilled into the bladder

SummaryWe examined the effect of dimethylsulfoxide (DMSO) on the absorption of a chemotherapeutic drug instilled into the bladder. Female Wistar rats with bladder tumors underwent intravesical instillation of normal saline (S group) or 50% DMSO (D group) prior to the administration of pirarubicin (tetrahydropyranyl-Adriamycin). The absorption of pirarubicin was estimated histologically by observing its fluorescence. In the S group, fluorescence of pirarubicin was observed only in the epithelial layer of normal or hyperplastic regions and in the cells of superficial layers of the tumor. In the D group fluorescence was observed in the entire bladder wall of normal or hyperplastic regions and extended to deeper regions of the tumors than in the S group. These findings indicate enhancement of the absorption of pirarubicin by pretreatment with DMSO.

Reversal of acquired cisplatin resistance by modulation of metallothionein in transplanted murine tumors

Background: The platinum‐based chemotherapeutic agent cisplatin is involved in a broad spectrum of activities against human systemic malignancies. However, acquired resistance to cisplatin reduces its clinical efficacy. Elucidation of the molecular basis of cisplatin resistance is required to improve the effectiveness of cisplatin. In the present study, the mechanism of acquired resistance to cisplatin was studied in C3H mice inoculated with MBT‐2 murine bladder tumor cells.