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In rare cases, giant cell tumor of bone (GCTB) can undergo primary or secondary malignant transformation to malignant giant cell tumor of bone (MGCTB), but the details of the molecular alterations are still unclear. The present study aimed to elucidate the clinicopathologic and molecular features of MGCTBs based on immunohistochemistry, fluorescence in situ hybridization (FISH) and next generation sequencing (NGS) of nine MGCTBs (five primary and four secondary). Seven (78%) of 9 MGCTBs were immunohistochemically positive for H3.3 G34W. In two (22%) patients, although GCTB components were focally or diffusely positive for H3.3 G34W, their malignant components were entirely negative for H3.3 G34W, which was associated with heterozygous loss of H3F3A by FISH. NGS on four MGCTBs revealed pathogenic mutations in TP53 (n = 3), EZH2 (n = 1) and several other genes. Immunohistochemical analysis of the nine MGCTBs confirmed the p53 nuclear accumulation (n = 5) and loss of H3K27me3 expression (n = 3) and showed that they were mutually exclusive. In addition, four (80%) of five cases of pleomorphic or epithelioid cell-predominant MGCTBs were positive for p53, while three (75%) of four cases of spindle cell-predominant MGCTBs were negative for trimethylation at lysine 27 of histone 3 (H3K27me3). The results suggested that p53 alteration and dysfunction of histone methylation as evidenced by H3K27me3 loss may play an important role in the malignant progression of GCTB, and might contribute to the phenotype-genotype correlation in MGCTB. The combined histologic, immunohistochemical and molecular information may be helpful in part for the diagnosis of challenging cases.

Chondroblastoma (CB) is histologically characterized by oval to polygonal-shaped mononuclear neoplastic cells, multinucleated osteoclastic giant cells, and eosinophilic matrix with occasional calcification. Genetically, the majority of CBs harbor H3F3B p.K36M mutation. Despite the historical nomenclature, it has been reported that the matrix of CB is similar to osteoid rather than true cartilage; however, it remains unclear whether neoplastic cells in CB have the potential for osteoblastic differentiation. To clarify this issue, we immunohistochemically examined the expression of osteogenic and chondrogenic markers (SATB2, RUNX2, p63, and SOX9) as well as H3K36M mutant protein in 33 cases of CB. All 33 cases of CB were positive for H3K36M, while SATB2, RUNX2, p63, and SOX9 were expressed in 30/33 (91%), 33/33 (100%), 29/33 (88%), and 31/32 (97%) CB cases, respectively. Our immunohistochemical results suggest that neoplastic cells in CB frequently express both osteogenic and chondrogenic markers and may have an intermediate feature of osteoblastic and chondroblastic nature.

AimsLiposarcoma is a malignant soft tissue tumour with adipocytic differentiation. Dedifferentiated liposarcoma (DDLS) and myxoid liposarcoma (MLS) are classified as high-grade liposarcomas. Lipid droplet-associated protein (also known as perilipin 1 (PLIN1)) is the predominant perilipin and has utility as a specific marker of adipogenic differentiation. Adipose differentiation-related protein (also known as adipophilin (ADRP)) is ubiquitously expressed in a range of tissues. High ADRP expression is reportedly a poor prognostic factor in several cancer types. However, no previous studies have examined the association between PLIN1 or ADRP expression and prognosis in sarcoma. This study therefore aimed to evaluate the association between PLIN1 or ADRP expression and prognosis in liposarcoma.MethodsIn total, 97 primary resection specimens (53 MLS and 44 DDLS) were examined in this study. PLIN1 and ADRP expression was evaluated by immunohistochemistry. Survival analyses were performed for MLS and DDLS.ResultsOf the 53 MLS specimens, 15 (28.3%) exhibited high PLIN1 expression. PLIN1 expression was not observed in DDLS specimens. High PLIN1 expression was significantly associated with increased disease-free survival (DFS) among patients with MLS (p=0.045). Distinct ADRP expression was observed in 13 of 53 (24.5%) MLS specimens and 5 of 44 (11.4%) DDLS specimens. High ADRP expression was associated with shorter overall survival (OS) in MLS (p=0.042) and DFS and shorter OS in DDLS (p=0.024 and pConclusionsPLIN1 and ADRP expression is associated with poor prognosis in high-grade liposarcoma.

AimsDedifferentiation is a histological phenomenon characterised by abrupt transition of histology to a sarcomatous component with high-grade malignant potential in solitary fibrous tumour (SFT). The authors histologically reviewed SFT cases to reveal the histological background of dedifferentiated SFTs.MethodsClinicopathological and histopathological findings of 145 SFT cases were reviewed. Immunohistochemical staining and genetic analysis were also performed.ResultsThe non-dedifferentiated components showed a cellular component in 45 of 145 (31%), high mitotic rate (≥4/10 high-powered field) in 12 of 145 (8.2%) tumours, necrosis in 7 of 145 (4.8%) tumours, multinodular growth pattern in 39 of 132 (29.5%) available tumours and intratumoural fibrous septa in 37 of 131 (28.2%). Immunohistochemically, the non-dedifferentiated components were positive for CD34 in 128 of 141 (90.7%), bcl-2 in 101 of 133 (75.9%), nuclear pattern of β-catenin in 64 of 127 (50.3%) and p16 in 22 of 140 (15.7%). Loss of Rb protein expression was detected in 17 of 110 (15.4%) cases. Statistically, cellular component, multinodular structure, p16 overexpression and Rb protein loss were significantly associated with dedifferentiation. Moreover, cellular component and multinodular structure were significantly associated with p16 overexpression and Rb protein loss. All the non-deddifferentiated components showed wild type of p53 expression. The dedifferentiated components of all 10 dedifferentiated tumours presented positivity for p16 in 9 of 10 (90%) and mutational type of p53 in 5 of 10 (50%). Loss of Rb protein expression was detected in 6 of 10 (60%).ConclusionsThe authors propose that cellular or multinodular transformation may be associated with dedifferentiation. They also suggest that cellular and multinodular transformation may be associated with p16 overexpression and Rb downregulation.

Chondrosarcoma is the second most common primary malignant bone tumor, which produces cartilaginous matrix without neoplastic osteoid or bone formation. The histological grade in the WHO Classification of Soft Tissue and Bone (2020 edition) is the most important factor in predicting the clinical outcome of conventional chondrosarcoma, but the lack of clarity in its detailed definition is occasionally problematic. Here, we reviewed conventional chondrosarcoma cases and validated the significance of histological findings. Moreover, we proposed a new scoring system of conventional chondrosarcoma.Clinicopathological features of 60 cases of conventional chondrosarcoma and 21 cases of dedifferentiated chondrosarcoma were reviewed.Moderate to severe nuclear atypia was correlated with distant metastasis. Moderate and severe nuclear atypia, high cellularity, and1 % myxoid change were correlated with adverse overall survival. On the other hand, cases with mild nuclear atypia showed no tumor-related death and no metastases. Based on the above results, we proposed a new scoring system based on nuclear atypia (mild: 0, moderate: +1, severe: +2), cellularity (no and mildly increased cellularity: 0, moderately and diffusely increased cellularity: +1), necrosis [(-): 0, (+): + 1], and chondromyxoid area [(-): 0, (+): + 1]. Each grade was defined as follows: cases with only mild nuclear atypia as grade 1, cases with total score 1-3 excluding mild nuclear atypia as grade 2, and cases with total score 4 or 5 as grade 3. There were 18 cases (30 %) of grade 1 including 5 cases (28 %) of local recurrence, but no metastasis or tumor-related death; 26 cases (43 %) of grade 2 including 2 cases (8 %) of local recurrence, 3 cases (12 %) of metastasis, and 1 case (4 %) of tumor-related death; and 16 cases (27 %) of grade 3 including 4 cases (25 %) of local recurrence, 6 cases (38 %) of metastasis, and 5 cases (31 %) of tumor-related death. There was no statistically significant association between the histological findings and dedifferentiation.From this study, we propose a new histological scoring system for the grading of conventional chondrosarcoma, based on nuclear atypia, cellularity, necrosis, and myxoid change. Using this system, conventional chondrosarcoma may be clearly classified into three grades: grade 1, non-metastasizing; grade 2, metastasizing but rarely life-threatening; and grade 3, frequently metastasizing and life-threatening.

The scientific name Cottus kazika has been used for over a century as valid for the catadromous fourspine sculpin endemic to Japan. However, recent DNA sequence analyses have indicated a sister relationship between two catadromous species, so-called C. kazika and Trachidermus fasciatus with a great phylogenetic divergence, separated from a monophyletic freshwater spawning clade including the other Cottus species and Baikalian sculpins. Morphological, life-historical, ecological, and karyological characteristics have also suggested that the fourspine sculpin so-called C. kazika is neither a member of Cottus nor Trachidermus. Therefore, the fourspine sculpin is transferred to the genus Rheopresbe. The genus and R. kazika are re-described. The genus Rheopresbe is discriminated from related genus Trachidermus by not having bony ridges on both nape and cheeks and also by presence of entopterygoid, and from the genus Cottus by having teeth on palatines and four spines on preopercle ridges.

Dedifferentiated liposarcoma (DDLS) has varying histopathological features, but their significance for the biological behaviour of this disease has not been fully clarified. The aim of this study was to elucidate the prognostic factors for DDLS by clinicopathologically reviewing a large case series.We clinicopathologically reviewed 123 cases of primary de-novo DDLS without preoperative treatment, including 81 in the internal trunk (internal DDLS) and 42 in peripheral sites (peripheral DDLS). Univariate and multivariate analyses of their features were also performed for all cases, the internal DDLS group, and the peripheral DDLS group. The results showed that, in all three groups, distant metastasis was significantly associated with shorter overall survival (OS) (univariate analysis, P 0.0001, P = 0.0011, and P = 0.0101, respectively), whereas local recurrence showed no significant effect on prognosis. Histopathologically, a high mitotic count and the presence of round tumour cells were significantly associated with shorter OS in multivariate analysis of the internal DDLS group [respectively: P = 0.0022, hazard ratio (HR) 4.39, 95% confidence interval (CI) 1.71-11.28; and P = 0.0014, HR 7.19, 95% CI 2.14-24.16]. In the peripheral DDLS group, necrosis and high-grade histological components were significantly associated with shorter OS (univariate analysis, P = 0.0068 and P = 0.0174, respectively).The presence of round tumour cells may be one of the histological factors associated with a worse prognosis of DDLS patients, as previous studies indicated. This study also suggests that distant metastasis may be predictive of prognosis for both internal and peripheral DDLS, rather than local recurrence.

Intimal sarcoma is one of the most common and well-known primary malignant neoplasms of the aorta and heart. The authors reviewed cases of intimal sarcoma from histological, immunohistochemical and genetic perspectives. Twenty cases of intimal sarcoma were retrieved. Immunohistochemistry and FISH of MDM2 and PDGFRA genes were performed. All 20 tumours were composed of spindle-shaped, stellate, oval or polygonal tumour cells with irregular hyperchromatic nuclei arranged in a haphazard pattern, accompanied by nuclear pleomorphism and frequent mitotic figures. Other histological findings were as follows: abnormal mitosis in 10 cases (50%), necrosis in 15 cases (75%), myxoid stroma in 12 cases (60%), cartilaginous formation in 1 case (5%), haemorrhage in 12 cases (60%) and fibrinous deposition in 14 cases (70%). The tumours were positive for MDM2 in 16 cases (80%), ERG in 4 cases (20%), alpha-smooth muscle actin in 6 cases (30%), desmin in 5 cases (25%) and AE1/AE3 in 4 cases (20%). Immunohistochemical positivity was focal in each case. Loss of H3K27me3 expression was noted in 2 cases (10%). MDM2 and PDGFRA gene amplifications were detected in 11 cases (55%) and 1 case (5%), respectively. Fisher's exact test revealed a significant correlation between MDM2 gene amplification and myxoid stroma (p = 0.0194). No parameters showed any association with the anatomical location of the tumours. It was suggested that myxoid histology of intimal sarcoma may be associated with MDM2 gene amplification and that intimal sarcoma may be divided into myxoid and non-myxoid types.

Malignant peripheral nerve sheath tumor (MPNST) is a very aggressive peripheral nerve sheath-derived sarcoma, which is one of the most difficult tumors to diagnose due to its wide spectrum of histological findings and lack of specific immunohistochemical markers. Recently, it has been reported that losses of expression of H3K27me3 and H3K27me2 caused by PRC2 dysfunction may be useful diagnostic markers for MPNST, but there is no consensus on their clinicopathological significance. Here, we investigated the relationship between loss of H3K27 methylation and various parameters and clarified the clinicopathological significance of such loss. We analyzed the clinicopathological and immunohistochemical features in 84 MPNST cases. Complete losses of H3K27me3 and H3K27me2 were observed in 37 (44%) and 29 (35%) cases, respectively. Losses of H3K27me3 and H3K27me2 were significantly correlated with myogenic immunopositivity (H3K27me3 vs. desmin, P = 0.0051; H3K27me3 vs. myogenin, P = 0.0009; H3K27me2 vs. myogenin, P = 0.042). Meanwhile, there were significant correlations between preservation of immunohistochemical neurogenic markers and intact H3K27me3 and H3K27me2 (H3K27me3 vs. S-100 protein, P = 0.0019; H3K27me3 vs. SOX10, P = 0.014; H3K27me2 vs. S-100 protein, P = 0.0011; H3K27me2 vs. SOX10, P = 0.0087). In multivariate analysis, local recurrence, distant metastasis, high FNCLCC grade, and loss of SOX10 expression were independent prognostic factors for overall survival. H3K27me3 and H3K27me2 expression was retained in all 26 cases of rhabdomyosarcoma non-alveolar subtype. In conclusion, we suggest that H3K27me3 and H3K27me2 immunonegativity is useful but not definitive for diagnosing MPNST. Complete loss of H3K27 methylation may be involved in aggressive transdifferentiation from neural differentiation to skeletal muscle differentiation in MPNST.

Solitary fibrous tumor (SFT) is a soft-tissue neoplasm of intermediate malignant potential, presenting a wide histopathological spectrum. Poorer prognosis of hemangiopericytoma of the central nervous system (CNS), hypoglycemic SFT, and dedifferentiation are well-known characters of SFT, but their clinical significance were not demonstrated enough by large-sized study. Here, the clinicopathological features of SFTs are reviewed and the relationship between genetics and clinicopathological features is examined using 145 SFT cases. All cases were STAT6 IHC-positive and/or NAB2-STAT6 fusion gene-positive. Tumor location was classified into three categories: 30 pleuropulmonary, 96 non-pleuropulmonary/non-central nervous system (CNS), and 18 CNS tumors. The tumor developed recurrence in 21 of 93 available cases (22.5%), metastasis in 11 of 93 (11.8%), and tumor death in 9 of 93 (9.6%). Hypoglycemia occurred in 2 primary tumors and 1 metastatic tumor among 63 reviewable cases, and dedifferentiation occurred in 10 cases (6.8%) including 6 primary tumors, 2 recurrent tumors, and 2 metastatic tumors. Recurrence was positively associated with CNS location (p = 0.0109) and hypoglycemia (p = 0.001); metastasis was positively associated with CNS location (p = 0.0231), hypoglycemia (p

Acanthopagruslatus and A.schlegelii (Sparidae) are closely related species distributed in northern tropical to temperate coastal waters of eastern Asia. Early life histories of the two species were investigated by seine net sampling in the Tien Yen estuary, northern Vietnam, which is probably the southernmost co-occurrence locality for these species. In northern Vietnam, early juveniles of both the Acanthopagrus species occurred in the Tien Yen estuary from December to March (A.schlegelii) or December to April (A.latus) when temperatures ranged from ca. 16 to 25 °C. The given temperature range is observed twice (spring and autumn) a year in Japan, and A.latus and A.schlegelii early juveniles are abundant respectively in each season. Thus, a thermoperiodicity of early juveniles of the two Acanthopagrus is common Asia-wide. The two species occurred as the same developmental stage, being markedly more abundant and having larger sizes in A.latus. The Acanthopagrus early juveniles inhabited bank waters of the estuary. Although waters continued to be mixed horizontally by temperatures but to be stratified by salinities during the study period, there was little variation in developmental stage and size among stations for both species. The two Acanthopagrus species from Vietnam spawn for the same season and their early juveniles simultaneously use the same nursery ground.

AIMS Complete loss of SMARCB1/INI1 in soft-tissue tumours such as malignant rhabdoid tumour, epithelioid sarcoma, myoepithelial tumour of soft tissue and extraskeletal myxoid chondrosarcoma is often associated with high-grade malignancy and poor prognosis. The diagnosis is sometimes challenging, owing to histological similarities, so careful differential diagnosis is required. Therefore, soft-tissue tumours with complete SMARCB1/INI1 loss could potentially include an unknown entity. METHODS AND RESULTS We analysed 160 cases of SMARCB1/INI1-deficient soft-tissue tumour, and found 14 cases that were not classifiable into already existing categories and had common clinical and histological features. These involved two male and 12 female patients, ranging in age from 20 years to 61 years. The tumours were located in the the puboinguinal region (n = 13) and pelvic cavity (n = 1). Histologically, the tumours showed relatively uniform epithelioid to spindle-shaped cells with myxoid stroma. All tumours showed immunoreactivity for brachyury, epithelial membrane antigen, and progesterone receptor, and 12 of 14 cases did so for oestrogen receptor. Variable positive staining for α-smooth muscle actin, S100 and glial fibrillary acidic protein (GFAP) was seen. NR4A3 and EWSR1 gene rearrangements were not detected in 13 and 11 examined cases, respectively. Clinical follow-up data for the 14 patients showed that 13 were alive without disease and one had been lost to follow-up; four patients developed local recurrence and/or metastases. CONCLUSION The designation 'myxoepithelioid tumour with choroid features' (METC) was proposed as a tumour with intermediate malignancy controllable with appropriate treatment, including the entity of myoepithelioma-like tumour of the vulvar region. METC represents a novel and independent subset that is histologically, biologically and clinically distinct from already existing SMARCB1/INI1-deficient soft-tissue tumours.

Background Undifferentiated pleomorphic sarcoma (UPS) is a sarcoma with a poor prognosis. A clinical trial, SARC028, revealed that treatment with anti-PD-1 drugs was effective against UPS. Studies have reported that UPS expresses PD-L1, sometime strongly (≥ 50%). However, the mechanism of PD-L1 expression in UPS has remained still unclear. CKLF-like MARVEL transmembrane domain containing 6 (CMTM6) was identified as a novel regulator of PD-L1 expression. The positive relationship between PD-L1 and CMTM6 has been reported in several studies. The aim of this study was to examine CMTM6 expression in UPS and evaluate the relationship between PD-L1 and CMTM6. Materials and methods Fifty-one primary UPS samples were subjected to CMTM6 and PD-L1 immunostaining. CMTM6 expression was assessed using proportion and intensity scores. CMTM6 gene copy number was also evaluated using a real-time PCR-based copy number assay. We also analyzed the mRNA expression and copy number variation of PD-L1 and CMTM6 in The Cancer Genome Atlas (TCGA) data. Results TCGA data indicated that the mRNAs encoded by genes located around 3p22 were coexpressed with CMTM6 mRNA in UPS. Both proportion and intensity scores of CMTM6 positively correlated with strong PD-L1 expression (≥ 50%) (both p = 0.023). CMTM6 copy number gain increased CMTM6 expression. Patients with UPS with a high CMTM6 intensity score had worse prognosis for overall survival. Conclusions CMTM6 expression was significantly correlated with PD-L1 expression. CMTM6 expression induced strong PD-L1 expression (≥ 50%). CMTM6 copy number gain promoted CMTM6 expression and increased PD-L1 expression in UPS.

Summary Loss of SMARCB1 protein expression has recently been identified in a variety of tumor types such as poorly differentiated chordoma (PCh) and malignant rhabdoid tumor (MRT) including atypical teratoid/rhabdoid tumor (AT/RT). PCh is characterized by poorly differentiated epithelioid tumor cells, sheet arrangement, and coexpression of nonepithelial and epithelial markers. Rhabdoid cells are sometimes present. Therefore, the differentiation of these tumors is often difficult. Brachyury is a transcription factor within the T-box family typically expressed in notochord tissue and chordomas. Some studies have reported high specificity and sensitivity of brachyury expression in chordomas. In the present study, we analyzed immunohistochemical brachyury expression in SMARCB1-deficient tumors and discuss important clinicopathological and diagnostic points, especially in cases of intracranial SMARCB1-deficient tumors with brachyury expression. Brachyury and cytokeratin immunoexpression status was examined in 42 formalin-fixed paraffin-embedded SMARCB1-deficient tumor specimens (PCh, 6 cases; extra-central nervous system [CNS] MRT, 26 cases; AT/RT, 10 cases) and 25 cases of conventional chordoma (CCh). All cases of PCh and CCh showed diffuse immunopositivities for cytokeratin 8, pan-cytokeratin, and brachyury. Brachyury immunoexpression was present in 2 extra-CNS MRT (8%) and 5 AT/RT (50%) cases, but immunopositivity was focal not diffuse. Indeed, in almost all cases of AT/RT (cytokeratin 8, 7/10 cases; pan-cytokeratin, 7/10 cases) and extra-CNS MRT (cytokeratin 8, 23/26 cases; pan-cytokeratin, 25/26 cases), fewer than 50% of cells showed immunoreactivity. Although the histological and clinical features of PCh resemble those of AT/RT, semiquantitative evaluations of the degree of brachyury and cytokeratin immunoexpressivity may help to distinguish PCh from AT/RT.

Undifferentiated pleomorphic sarcoma (UPS) is a sarcoma with a poor prognosis. A clinical trial, SARC028, revealed that treatment with anti-PD-1 drugs was effective against UPS. Studies have reported that UPS expresses PD-L1, sometimes strongly (≥ 50%). However, the mechanism of PD-L1 expression in UPS has remained unclear. CKLF-like MARVEL transmembrane domain containing 6 (CMTM6) was identified as a novel regulator of PD-L1 expression. The positive relationship between PD-L1 and CMTM6 has been reported in several studies. The aim of this study was thus to examine CMTM6 expression in UPS and evaluate the relationship between PD-L1 and CMTM6 in this disease. Fifty-one primary UPS samples were subjected to CMTM6 and PD-L1 immunostaining. CMTM6 expression was assessed using proportion and intensity scores. CMTM6 gene copy number was also evaluated using a real-time PCR-based copy number assay. We also analyzed the mRNA expression and copy number variation of PD-L1 and CMTM6 in The Cancer Genome Atlas (TCGA) data. TCGA data indicated that the mRNAs encoded by genes located around 3p22 were coexpressed with CMTM6 mRNA in UPS. Both proportion and intensity scores of CMTM6 positively correlated with strong PD-L1 expression (≥ 50%) (both p = 0.023). CMTM6 copy number gain increased CMTM6 expression. Patients with UPS with a high CMTM6 intensity score had a worse prognosis for overall survival. UPS showed variation in CMTM6 copy number and CMTM6 expression. CMTM6 expression was significantly correlated with PD-L1 expression, especially with strong PD-L1 expression.

Giant cell tumor of bone (GCTB) is an intermediate malignant bone tumor that is locally aggressive and rarely metastasizes. Denosumab, which is a receptor activator of nuclear factor kappa B ligand (RANKL) inhibitor, can be used to treat GCTB. We focused on potential immunotherapy for GCTB and investigated the tumor microenvironment of GCTB. Programmed death-ligand 1 (PD-L1) and indoleamine 2,3-dioxygenase 1 (IDO1) expression and signal-regulatory protein alpha (SIRPα), forkhead box P3 (FOXP3), and cluster of differentiation 8 (CD8) infiltration were assessed by immunohistochemical studies of 137 tumor tissues from 96 patients. Of the naive primary specimens, 28% exhibited PD-L1 expression and 39% exhibited IDO1 expression. There was significantly more SIRPα+, FOXP3+, and CD8+ cell infiltration in PD-L1- and IDO1-positive tumors than in PD-L1- and IDO1-negative tumors. The frequency of PD-L1 expression and SIRPα+ cell infiltration in recurrent lesions treated with denosumab was significantly higher than in primary lesions and recurrent lesions not treated with denosumab. PD-L1 expression and higher SIRPα+ cell infiltration were significantly correlated with shorter recurrence-free survival. PD-L1 and SIRPα immune checkpoint inhibitors may provide clinical benefit in GCTB patients with recurrent lesions after denosumab therapy.

Malignant rhabdoid tumor (MRT) is a rare, highly aggressive sarcoma with an uncertain cell of origin. Despite the existing standard of intensive multimodal therapy, the prognosis of patients with MRT is very poor. Novel antitumor agents are needed for MRT patients. Forkhead box transcription factor 1 (FOXM1) is overexpressed and is correlated with the pathogenesis in several human malignancies. In this study, we identified the clinicopathological and prognostic values of the expression of FOXM1 and its roles in the progression of MRT. We investigated the FOXM1 expression levels and their clinical significance in 23 MRT specimens using immunohistochemistry and performed clinicopathologic and prognostic analyses. We also demonstrated correlations between the downregulation of FOXM1 and oncological characteristics using small interfering RNA (siRNA) and FOXM1 inhibitor in MRT cell lines. Histopathological analyses revealed that primary renal MRTs showed significantly low FOXM1 protein expression levels (p = 0.032); however, there were no significant differences in other clinicopathological characteristics or the survival rate. FOXM1 siRNA and FOXM1 inhibitor (thiostrepton) successfully downregulated the mRNA and protein expression of FOXM1 in vitro and the downregulation of FOXM1 inhibited cell proliferation, drug resistance to chemotherapeutic agents, migration, invasion, and caused the cell cycle arrest and apoptosis of MRT cell lines. A cDNA microarray analysis showed that FOXM1 regulated FANCD2 and NBS1, which are key genes for DNA damage repair. This study demonstrates that FOXM1 may serve as a promising therapeutic target for MRT.

Background/aim Malignant peripheral nerve sheath tumor (MPNST) is a rare soft-tissue tumor, and its diagnosis is usually made histopathologically. The effectiveness of chemotherapy and radiotherapy has not been established. We elucidated prognostic factors, diagnostic markers, and therapeutic targets. Materials and methods Cases of MPNST were studied using next-generation sequencing. A total of 24 tumor samples, 11 from von Recklinghausen's disease-associated MPNST (vRH-MPNST), 11 from sporadic non-vRH MPNST, and two neurofibroma (NF) cases were retrieved, on which next-generation sequencing and survival analysis were performed. Results We identified NF1 gene mutations, including three mutations in two NFs, and 10 mutations in eight MPNSTs (five vRH-MPNSTs and three sporadic MPNSTs). Meningioma 1 (MN1) gene alteration was detected in six cases of vRH-MPNST. It is considered that MN1 gene alteration is related to the tumorigenesis of vRH-MPNST. Conclusion MN1 gene mutation was detected in more than half of our cases, it may have potential for use as a therapeutic target in vRH-MPNST.

Synovial sarcoma (SS) is a malignant soft tissue neoplasm harboring SS18-SSX fusion gene and is histologically characterized by spindle cells and epithelial components. Some investigations have demonstrated that desmoplastic reaction (DR) is an independent prognostic factor of cancers. However, it remains unknown whether DR is of predictive value for the prognosis of synovial sarcoma patients. Here, we reviewed the clinical and histological findings of 88 patients with SS. We defined DR as hyalinized collagenous structures and classified the degree of DR as follows: none, mild, moderate, and severe. Overall, 23 SS cases (24%) showed moderate or severe DR histologically. Statistically, the cases with moderate or severe degree of DR showed poorer prognosis than those with no or mild DR (local recurrence: P = 0.0059, distant metastasis: P = 0.0002, tumor death: P = 0.0382). The findings of the study suggest that the DR of synovial sarcoma could be an important prognostic factor.

Ischemic fasciitis is a benign myofibroblastic lesion, occurring in the sacral region or proximal thigh of elderly or bedridden individuals. The pathogenesis of ischemic fasciitis is thought to be based on ischemic condition; however, it has never been demonstrated. In this study, we examined the expression of ischemia-associated proteins in ischemic fasciitis by immunohistochemical and genetic methods. Specifically, this study aimed to reveal the expression of HIF-1α, MDM2, CDK4, p16, and gene amplification of MDM2 gene. Seven cases of ischemic fasciitis from among the soft-tissue tumors registered at our institution were retrieved. Histopathological findings were as follows: poorly demarcated nodular masses, a proliferation of spindle-shaped fibroblastic or myofibroblastic cells with oval nuclei and eosinophilic or pale cytoplasm, zonal fibrinous deposition, pseudocystic degeneration, granulation-like proliferation of capillary vessels, ganglion-like cells, myxoid or hyalinized stroma, and chronic inflammatory infiltration. Immunohistochemically, the spindle cells were positive for HIF-1α (7/7 cases), MDM2 (4/7 cases), CDK4 (4/7 cases), p16 (7/7 cases), p53 (2/7 case), cyclin D1 (7/7 cases), and alpha-smooth muscle actin (6/7 cases). Neither MDM2 gene amplification nor USP6 gene split signal was detected in any case. Overexpression of the above proteins may be associated with the pathogenic mechanism of ischemic fasciitis. It is noted that the immunohistochemical positivity of MDM2, CDK4, and p16 do not necessarily indicate malignant neoplasm such as dedifferentiated liposarcoma.

The original version of this article unfortunately contained mistakes introduced during the production process. Tables 1 and 2 were presented incorrectly. The original article has been corrected.

Aims Inflammatory myofibroblastic tumour (IMT) is a spindle cell neoplasm of intermediate malignancy, and the diagnosis is often challenging due to the morphological overlap with other spindle cell neoplasms and reactive lesions. More than half of IMTs have the ALK gene rearrangement, and a minor subset have ROS1, NTRK3 or RET gene rearrangements. We sought to determine the potential diagnostic utility of pan-Trk immunohistochemistry for IMTs. Methods and results We retrospectively examined 40 cases of IMT using immunohistochemistry with a rabbit monoclonal pan-Trk antibody. Gene rearrangement was confirmed by fluorescence in-situ hybridisation and/or reverse transcription-polymerase chain reaction. The IMTs were classified as the ALK (n = 29), ROS1 (n = 2), NTRK3 (n = 2), RET (n = 0) and 'quadruple-negative' (n = 7) genotypes by molecular analyses. Both of the ETV6-NTRK3 fusion-positive cases showed nuclear and cytoplasmic staining for pan-Trk in the majority of tumour cells. None of the ALK, ROS1 or quadruple-negative-type IMTs showed nuclear staining for pan-Trk, but approximately one-third of these IMTs showed focal and weak cytoplasmic staining. One exceptional case of a RANBP2-ALK-positive epithelioid inflammatory myofibroblastic sarcoma (an aggressive variant of IMT) showed moderate cytoplasmic staining for pan-Trk. Conclusions These results suggest that pan-Trk immunoreactivity with a nuclear and cytoplasmic staining pattern may be useful to identify ETV6-NTRK3-positive IMTs and may be helpful in selecting patients for Trk-targeted therapy.

We describe a Case of a 74-year-old Japanese man with poorly differentiated carcinoma of the anterior mediastinum. The patient underwent anterior mediastinal tumor resection through median sternotomy. The tumor, 7.0 × 5.0 cm, had invaded surrounding tissues (pericardium, right lung, right and left brachiocephalic veins, and superior vena cava). Complete resection of the tumor was not performed. One month after the operation, the patient developed multiple pulmonary metastases, right pleural dissemination, and carcinomatous pleurisy. He was treated with lenvatinib, a novel multi-kinase inhibitor, to which the metastasis responded favorably. This case reports for the first time the clinical usefulness of lenvatinib for poorly differentiated carcinoma of the anterior mediastinum. Management of side effects by several methods, including suspending use of medication on weekends (called a weekends-off strategy), is another strong argument to continue lenvatinib administration.

The RNA-binding protein HuC/D displays a neuron-specific expression and is involved in neuronal differentiation and the maintenance of the nervous system. Here we investigated the diagnostic value of HuC/D in neuroblastomas. We evaluated 85 neuroblastic tumors: 81 neuroblastomas; 3 ganglioneuroblastomas, intermixed; 1 ganglioneuroma, maturing; and 101 other tumors consisting of 34 Ewing sarcomas, 14 nephroblastomas, 11 rhabdomyosarcomas, 15 pulmonary small cell carcinomas, 18 pancreatic neuroendocrine tumors, and 9 pheochromocytomas. Immunohistochemistry for HuC/D, PHOX2B, and tyrosine hydroxylase was performed. The immunoreactivity for HuC/D was semiquantified using the total score (TS; range, 0-8). HuC/D positivity was defined as a TS ≥6. The TS of the neuroblastic tumors (mean TS, 7.94) was significantly higher than those of the other small round cell tumors and neuroendocrine tumors (P < .001) except for the pheochromocytomas (mean TS, 6.89; P = .074). HuC/D was positive in all 85 neuroblastic tumors, 1 (2.9%) Ewing sarcoma, 1 (6.7%) pulmonary small cell carcinoma, and 8 (89%) pheochromocytomas. PHOX2B was positive in all of the neuroblastic tumors and pheochromocytomas. Tyrosine hydroxylase was positive in 80 (94%) neuroblastic tumors, 1 (9.1%) rhabdomyosarcoma, and all of the pheochromocytomas. Therefore, HuC/D serves as a highly sensitive diagnostic marker to distinguish neuroblastomas from other small round cell tumors. The combination of HuC/D and PHOX2B staining may be valuable for the diagnosis of neuroblastic tumors, especially in the assessment of small sections. HuC/D expression in tumors may be related to catecholamine production or a neural crest-derived cell origin.

The SWI/SNF chromatin-remodeling complex, which is composed of evolutionarily conserved core subunits such as SMARCB1/INI1 (INI1), SMARCA4/BRG1 (BRG1), SMARCC1/BAF155 (BAF155), and SMARCC2/BAF170 (BAF170), can be viewed as the prototype of an epigenetic regulator of gene expression that is involved in tumor suppression. Epithelioid sarcoma, which classified as a tumor of uncertain differentiation, shows an almost complete loss of INI1. However, some cases of epithelioid sarcoma have preserved INI1, and the clinicopathologic features of these cases are uncertain. To date, there has been no investigation focused on the SWI/SNF chromatin-remodeling complex in INI1-preserved epithelioid sarcoma cases. First, an investigation of INI1 immunoexpression statuses in 60 formalin-fixed paraffin-embedded epithelioid sarcoma specimens (proximal type, 29 cases; conventional type, 31 cases) was performed. In the available INI1-preserved epithelioid sarcoma cases, we analyzed the BRG1, BAF155, and BAF170 protein expressions. INI1 preservation was observed in 6 of 29 (21%) proximal-type and 2 of 31 (6%) conventional-type epithelioid sarcoma cases. Six cases of INI1-preserved epithelioid sarcomas of proximal type were available for further immunohistochemical study. One proximal type showed loss of BAF170, and 2 proximal-type cases revealed loss of BRG1 with preservation of the other remaining core subunit proteins. One proximal-type case showed a mosaic pattern of BRG1 and loss of BAF155. However, in the remaining 2 proximal-type cases, all core subunit proteins were preserved. Overall, these results suggest that loss of expression of SWI/SNF chromatin-remodeling complex proteins has an important role in tumorigenesis. The remaining 2 INI1-preserved epithelioid sarcoma cases may have had other abnormalities causing dysfunction of SWI/SNF chromatin remodeling.

Marine fish generally show higher genetic diversity and shallower population structure than freshwater fish, but data for rare species are lacking. A latid fish, akame (Lates japonicus), is a rare, large predatory fish endemic to Japan, occurring mainly in the estuaries and coastal waters of Kochi and Miyazaki prefectures. Among species of Lates, akame is the only one adapted to temperate waters, while the others are distributed in tropical waters. Despite conservation concerns for this species, almost nothing is known about its population genetic characteristics. We used amplified fragment length polymorphism (AFLP) and mitochondrial DNA (mtDNA) markers to describe the genetic variation and its partitioning among juvenile samples collected from multiple localities and over different years. Twenty-four primer combinations detected a total of 522 AFLP loci, only 40 (7.7 %) of which were polymorphic. Sequence analysis of the entire mtDNA control region identified only five haplotypes defined by four variable sites. The level of genetic diversity revealed by both genetic markers was unusually low compared to other marine fish and comparable to levels observed for some endangered freshwater fish exhibiting some of the lowest levels of genetic diversity among vertebrate populations. Analysis of molecular variance for the AFLP data indicated a weak but significant population structure (F CT = 0.07, P

To examine reproduction of Coilia nasus, an engraulid endemic fish to Ariake Bay, in the freshwaters upstream of the reclamation dike of Isahaya inlet, ichthyoplankton was collected at the surface with a larva net. Eggs and larvae of this species were captured in abundance, especially in the retention basin. All eggs had reached middle or late embryonic stages, and larvae from the preflexion with yolk to the juvenile stage (4.1–39.3 mm) were found. This suggests that the freshwaters of retention basin supply spawning and nursery grounds for C. nasus.

Phosphaturic mesenchymal tumour, mixed connective tissue variant (PMT-MCT), is a tumour of uncertain differentiation, characterised by 'smudgy/grungy' calcification and vitamin D-resistant phosphaturic osteomalacia. Fibroblast growth factor (FGF)23 is recognised as a reliable marker of PMT-MCT, but quantitative evaluation has never been performed. We reviewed cases of tumour-associated osteomalacia or histologically definitive PMT-MCT without osteomalacia using histological, immunohistochemical and genetic methods and evaluated the diagnostic significance of these findings.A total of 19 tumours from 14 cases diagnosed previously as PMT-MCT were retrieved, on which immunohistochemical staining, reverse transcription-polymerase chain reaction (RT-PCR) and fluorescence in-situ hybridisation (FISH) analysis were performed. Histologically, fibrous capsule, calcification and giant cell reaction tended to be observed in soft-tissue PMT-MCT, while PMT-MCT of bone and multiple PMT-MCT showed an infiltrative growth pattern. The immunohistochemical results were as follows: the tumour cells were positive for FGF23 (nine of 12, 75%), FGFR1 (11 of 11, 100%), CD56 (12 of 14, 85.7%) and E26 oncogene homologue (ERG) (5 of 13, 38.4%). The sole malignant tumour was positive for p53. FGF23 mRNA was detected in seven of 14 formalin-fixed paraffin-embedded (FFPE) specimens and all five frozen specimens by RT-PCR. The level of FGF23 mRNA, which was determined by real-time PCR, varied among the phosphaturic cases. Two of 17 tumours were positive for FGFR1 gene rearrangement.It was considered that PMT-MCT is a histopathological entity with or without phosphaturia, with varying levels of FGF23 mRNA, and with or without fibronectin 1 (FN1)-FGFR1 fusion gene. The authors propose that the histology of PMT-MCT differs depending on its location, such as bone or soft tissue, which could complicate the differential diagnosis.

To examine regional specific diversity in development and growth of Ayu (Plecoglossus altivelis) larvae, we collected and compared collections from the Kalong estuary in Vietnam, and the Shimanto and Muko estuary, and the Niigata coast in Japan. Among the four areas, most of the morphometrics through ontogeny were similar except that the snout tended to be shorter and the anus hardly migrated in Kalong larvae. The snout length increased gradually with growth in the Vietnamese larvae, while this value increased significantly until ca. 10 mm BL, subsequently being constant up to 30 mm body length (BL) in the Japanese larvae. The water temperature when the larvae were collected was higher in the Kalong than in most of the Japan sites. Growth-rates estimated from otolith increments were from highest to lowest, Niigata (mean = 0.54 mm/day), Kalong (0.47), Shimanto (0.38) and Muko (0.34). The higher growth-rates were obtained not in Niigata of highest latitudinal region, but in Kalong of lowest latitudinal region. This indicates that Ayu could experience their early developmental stages from the cool temperate to tropical regions, implying the potential biodiversity of this fish species in the world.

The early life history of Ayu (Plecoglossus altivelis) was investigated in the Kalong and Tien Yen River systems, northern Vietnam, which is probably the most southern distribution locality for this species, during the period of November 2010 to February 2011. A total of 248 larvae were captured in the Kalong, and none were collected in the Tien Yen. There was little difference in development between the Kalong larvae and those of P. a. altivelis and P. a. ryukyuensis. Temperatures and salinities when the larvae were collected ranged from ca. 12 to 21°C and from ca. 3.5 to 30 psu. The preflexion to flexion larvae (primarily preflexion with yolk, 5.2–12.9 mm BL) occurred in the central current from December to February, with a peak abundance in early January. The flexion to postflexion (primarily postflexion, 14.1–23.8 mm BL) larvae occurred in the bank waters from early January to late February. The larval occurrence in the Kalong was 1–2 months later than for P. a. altivelis in Japan and P. a. ryukyuensis in the Ryukyu Islands, probably because of the delay until a reasonable photoperiod for the start of spawning in the lower latitudinal region. The larvae were never collected from the sea, where the temperatures were lower than in the river and estuary in January and February, unlike in Japan.

To examine the importance of the upper estuarine areas of Ariake Bay as a nursery ground for fish, assemblages of larvae and juveniles were compared among various aquatic habitats. The upper estuaries of the bay (the Rokkaku and Hayatsue estuaries) are brackish, highly turbid waters with high tidal velocities, and differ substantially from the Isahaya area, which has been separated from the bay by a man-made dike, to the middle estuary (the Kikuchi estuary). Abundances of larvae and juveniles were higher in the estuaries than in the open bay and Isahaya areas. Abundant species in the upper estuaries were similar to each other, but differed from those of the middle estuary. This was primarily due to larvae and juveniles of fishes that occurred almost entirely in the upper estuaries, such as Acanthogobius hasta, Boleophthalmus pectinirostris, Coilia nasus, Cynoglossus abbreviatus, Nibea albiflora, Odontamblyopus lacepedii, Trachidermus fasciatus and Tridentiger barbatus. These results suggest that the upper estuaries play an important role as nursery grounds for fishes.

Little is known about where anguilliform fishes complete metamorphosis from the leptocephalus to juvenile stage. Conger myriaster leptocephali in the final stages of metamorphosing were collected from the estuarine portions of the lower Rokkaku River and in the northwest region of Ariake Bay. Three metamorphosing leptocephali with PAM/TM ratios of 0.27–0.34 were collected in the lower river, and five (PAM/TM, 0.30–0.46) were collected at sea stations in the bay. The collection of metamorphosing larvae of this species in a river estuary with lower salinity and high turbidity raises the question of how much these habitats are used by the metamorphosing larvae of this marine eel species.

To clarify the fragmentation mechanism of a molten metallic fuel jet in a sodium pool under highejection-velocityconditions that correspond to the medium- and high-burnup conditions in the metallic fuel core of liquid-metal-cooled fast breeder reactors, a series of experiments with molten copper as a metallic fuel simulant and a sodium pool was carried out. Under low-ejection-velocity conditions in the range of an ambient Weber number (Wea ) < 200, the fragmentation of the molten copper jet depends on the initial superheating of the jet. The size of copper fragments decreases with increasing initial superheating. Under high-ejection-velocity conditions in the range of Wea ≥ 200, the size of the fragments is confirmed to be almost independent of the initial superheating of the jet. Furthermore, the size of the fragments agrees well with that evaluated using the Rayleigh-Taylor instability model, in which the fragment size is assumed to be equal to half the fastest growing wavelength. This result is qualita...

Preflexion to postflexion larvae (2.1–8.0 mm) of Diagramma pictum (Haemulidae) occur in coastal Tosa Bay, Japan from May to September. They can be distinguished from the other haemulid larvae by head spination, location of anus, and melanophore patterns. Compared with larvae identified as the same species from Australia, there are significantly morphological differentiations between the two areas. Thus, these significant differences are likely a reflection of subspecific differences.