Clinicopathologic and genetic characterization of angiofibroma of soft tissue: a study of 12 cases including two cases with AHRR::NCOA3 gene fusion.

AIMS: Angiofibroma of soft tissue (AFST) is a benign tumour characterised by prominent arborizing blood vessels throughout the lesion. Approximately two-thirds of AFST cases were reported to have AHRR::NCOA2 fusion, and only two cases have been reported to have other gene fusions: GTF2I::NCOA2 or GAB1::ABL1. Although AFST is included in fibroblastic and myofibroblastic tumours in the World Health Organization's 2020 classification, histiocytic markers, especially CD163, have been reported to be positive in almost all examined cases, and it still remains the possibility of a fibrohistiocytic nature of the tumour. Therefore, we aimed to clarify the genetic and pathological spectrum of AFST and identify whether histiocytic marker-positive cells were true neoplastic cells. METHODS AND RESULTS: We evaluated 12 AFST cases, which included 10 cases with AHRR::NCOA2 and two with AHRR::NCOA3 fusions. Pathologically, nuclear palisading, which has not been reported in AFST, was detected in two cases. Furthermore, one tumour resected by additional wide resection revealed severe infiltrative growth. Immunohistochemical analysis indicated varying levels of desmin-positive cells in nine cases, whereas CD163- and CD68-positive cells were diffusely distributed in all 12 cases. We also performed double immunofluorescence staining and immunofluorescence in situ hybridisation in four resected cases with >10% desmin-positive tumour cells. The results suggested that the CD163-positive cells differed from desmin-positive cells with AHRR::NCOA2 fusion in all four cases. CONCLUSION: Our findings suggested that AHRR::NCOA3 could be the second most frequent fusion gene, and histiocytic marker-positive cells are not genuine neoplastic cells in AFST.

High prevalence of TERT aberrations in myxoid liposarcoma: TERT reactivation may play a crucial role in tumorigenesis.

Myxoid liposarcoma (MLPS) is genetically characterized by FUS-DDIT3 or EWSR1-DDIT3 gene fusion and the high frequency of hotspot mutations (C228T or C250T) in the promoter region of telomerase reverse transcriptase (TERT) that encodes the TERT protein. The latter leads to telomerase reactivation, a mechanism of telomere maintenance. Although the TERT promoter hotspot mutation is a poor prognostic factor in various tumors, its effect on MLPS has not been reported in detail. In the present study, we examined the clinicopathological characteristics, prognosis, and telomere maintenance mechanisms in 83 primary tumor samples of MLPS, which were resected surgically at the Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan, from 2008 to 2020. TERT promoter hotspot mutations were observed in 77% (63/82) cases, and alternative lengthening of telomeres (ALT) was absent in all cases. Among the cases without TERT promoter hotspot mutations, TERT rearrangements, and minor point mutations in the TERT promoter region were found in 3 and 2 cases, respectively. TERT mRNA expression was observed consistently even in patients for whom no genomic TERT aberrations were detected, and the presence of TERT promoter hotspot mutation did not correlate significantly with either overall and metastasis-free survival (P = .56, P = .83, respectively) or clinicopathological features. Therefore, patients with MLPS characteristically shows TERT expression and a high prevalence of TERT aberrations. Our findings suggest that TERT aberration is not prognostic factor, but might occur at an early stage and play a key role in tumorigenesis.

Prognostic significance of the MDM2/HMGA2 ratio and histological tumor grade in dedifferentiated liposarcoma.

Dedifferentiated liposarcoma (DDLPS) is a relatively common soft tissue sarcoma that results from the progression of well-differentiated liposarcoma (WDLPS). This study aimed to investigate the progression process and to clarify the pathological and genetic factors related to poor prognosis in DDLPS. In 32 DDLPS cases and five WDLPS cases, genetic factors were analyzed by custom comparative genomic hybridization (CGH) array, which was designed to densely cover gene regions known to be frequently amplified in WD/DDLPS. The analyses comparing primary and metastatic lesions and those comparing histologically different areas in the same tumor revealed intra-tumoral genetic heterogeneity and progression. According to a prognostic analysis comparing the good-prognosis and the poor-prognosis groups, we selected MDM2 and HMGA2 as candidate genes associated with poor and good prognosis, respectively. The ratios of the amplification or gain levels of MDM2 and HMGA2 expressed in log ratios (log[MDM2/HMGA2] = log[MDM2]-log[HMGA2]) were significantly associated with prognosis. An amplification or gain level of MDM2 that was more than twice that of HMGA2 (MDM2/HMGA2 > 2, log[MDM2/HMGA2] > 1) was strongly related to poor OS (P < .001) and poor distant metastasis-free survival (DMFS) (P < .001). In the pathological analysis of 44 cases of DDLPS, histological tumor grade, cellular atypia, and MDM2 immunoreactivity were related to overall survival (OS), while HMGA2 immunoreactivity tended to be associated with OS. Cellular atypia was also associated with DMFS. In conclusion, histological grade and MDM2 expression were determined to be prognostically important, and the MDM2/HMGA2 amplification or gain ratio was found to have significant prognostic value by the custom CGH array analysis.

Adult genitourinary sarcoma: The era of optional chemotherapeutic agents for soft tissue sarcoma.

OBJECTIVE: To report our institutional experience with treatment of primary genitourinary soft tissue sarcoma. METHODS: We retrospectively reviewed the medical records of adult soft tissue sarcoma patients treated between March 2005 and May 2019. The primary tumor sites included the prostate, kidney, urinary bladder and the paratesticular structures. RESULTS: A total of 19 patients - 16 men (84%) and three women (16%) - were enrolled in the study. The median age was 41 years (range 20-79 years). The most common primary site was the prostate (in eight patients; 42%), and prostatic sarcoma patients were younger than patients with sarcomas of other origins. The most common histological subtype was leiomyosarcoma (in five patients; 26%). The overall survival rates after 1, 3 and 5 years were 61.5%, 34.4% and 25.8%, respectively. The median survival time was 20.7 months (95% confidence interval 5.9-35.5 months). Univariate analysis showed that an absence of metastasis at diagnosis and complete surgical resection were predictive of favorable survival. In the chemotherapy group, the objective response rate was 20.5%. Pazopanib was administered to nine patients in the late-line setting, and the objective response rate was 11.1%; six grade ≥3 adverse events were observed in three patients. CONCLUSIONS: Inoperable metastatic genitourinary soft tissue sarcoma remains difficult to treat, as previously reported. Further investigation on this malignancy, including optimization of currently available antitumor drugs and the development of novel therapeutic agents, is required.

Primary intramucosal synovial sarcoma of the sigmoid colon in a patient with a germline mutation in the MSH2 gene: A case report.

Synovial sarcoma is a high-grade soft tissue sarcoma that occurs primarily in the deep soft tissue of extremities, and primary colorectal synovial sarcoma is extremely rare. In this report, we present a synovial sarcoma mostly located within the mucosa of the sigmoid colon. The patient was a man in his forties with a germline deletion in the MSH2 gene. He had experienced undifferentiated pleomorphic sarcoma of the left forearm 7 years before and adenocarcinoma of the transverse colon 6 years before, both of which were successfully treated and exhibited no recurrence to date. A surveillance colonoscopy for Lynch syndrome revealed the tumor which had a submucosal tumor-like appearance with central erosion and endoscopic resection was performed. Histologically, it was composed of monotonous proliferation of spindle cells arranged in cellular fascicles; these findings were compatible with monophasic fibrous synovial sarcoma. In the tumor cells, the presence of the SS18-SSX1 fusion gene was confirmed. Protein expression of mismatch repair genes was intact in the tumor cells, indicating the association between microsatellite instability and synovial sarcoma was weak. The present case highlights a rare primary site of synovial sarcoma in a patient with Lynch syndrome.

Demonstration of energy-saving membrane bioreactor (MBR) systems.

Membrane bioreactors (MBRs) have the advantages of achieving excellent effluent quality, a small footprint and smooth operation and maintenance. On the other hand, its high energy consumption remains a critical challenge for MBR application. Japan Sewage Works Agency has conducted a series of joint researches with several private companies since 2012 and developed four kinds of energy-saving MBR systems. Based on the results of long-term pilot-scale demonstrations, specific energy consumption (SEC) per unit treated effluent volume was calculated for each MBR system, resulting in all systems achieving SEC of 0.4 kWh/m3 or less. To meet an additional requirement for expanding MBR application, it is also necessary to establish the applicability of MBR systems to combined sewer systems, suffering from occasional inflow fluctuation caused by rainfall. The capability of temporary higher flux operation during and after rainy weather was also demonstrated with three of the four developed systems.

Phlebotomy as a preventive measure for crocidolite-induced mesothelioma in male rats.

Malignant mesothelioma (MM) is a rare but socially important neoplasm due to its association with asbestos exposure. Malignant mesothelioma is difficult to diagnose at an early stage, yet there are no particularly effective treatments available at the advanced stage, thus necessitating efficient strategies to prevent MM in individuals already exposed to asbestos. We previously showed that persistent oxidative damage caused by foreign body reaction and affinity of asbestos both to hemoglobin and histones is one of the major pathogeneses. Accordingly, as an effective strategy to prevent asbestos-induced MM, we undertook the use of an iron chelator, deferasirox, which decreased the epithelial-mesenchymal transition in a crocidolite-induced rat MM model. However, this agent may show adverse effects. Here, we studied the effects of iron removal by phlebotomy as a realistic measure on the same rat model. We injected a total of 5 mg crocidolite i.p. to F1 hybrid rats between the Fischer-344 and Brown-Norway strains at the age of 6 weeks. We repeated weekly or biweekly phlebotomy of 6-8 mL/kg/time from 10 to 60 weeks of age. The animals were observed until 120 weeks. In male rats, phlebotomy significantly decreased the weight and nuclear grade of MM, and modestly reduced the associated ascites and the fraction of more malignant sarcomatoid subtype. Weekly phlebotomy prolonged long-term survival. Our results indicate that appropriate phlebotomy may be a practical preventive measure to attenuate the initiation and promotion capacity of asbestos towards MM by reducing iron in individuals exposed to asbestos.

Osteogenic differentiation in dedifferentiated liposarcoma: a study of 36 cases in comparison to the cases without ossification.

AIMS: Ossification is found occasionally in dedifferentiated liposarcoma (DDLPS). The aims of this study were to elucidate whether the formed bone tissue is usually produced by tumour cells or by reactive non-neoplastic cells, and to reveal the clinicopathological characteristics of DDLPS with ossification. METHODS AND RESULTS: We examined 36 cases of ossified DDLPS by comparing them to 31 cases of non-ossified DDLPS. MDM2 amplification was confirmed in osteocytes and/or osteoblastic cells in all but one ossified DDLPS cases (27 of 28) using fluorescence in-situ hybridisation, although the morphological impression of ossification appeared to be mainly metaplastic (27 of 36) or high-grade osteosarcoma-like (six of 36). The bone tissue was often formed predominantly at the periphery of the DDLPS area near the well-differentiated liposarcoma component (18 of 36), and an organised structure such as bone marrow-like differentiation was not uncommon (12 of 36). According to a modified French Fédération Nationale des Centers de Lutte Contre le Cancer (FNCLCC) grading system, ossified DDLPS tended to be lower grade than non-ossified DDLPS (mean grade: 1.88 and 2.15, respectively). Ossification in DDLPS was associated significantly with shorter local recurrence-free survival by multivariate analysis (P = 0.02347), but metaplastic-appearing ossification tended to be associated with longer overall survival (P = 0.1400). CONCLUSIONS: The bone tissue formed in DDLPS was mainly neoplastic regardless of its morphology and maturity, which highlighted the osteogenic differentiation of the tumour cells. DDLPS patients with osteogenic differentiation tended to suffer from earlier local recurrences, which did not necessarily lead to poor life outcomes.

Histopathological and genetic review of phosphaturic mesenchymal tumours, mixed connective tissue variant.

AIMS: 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. METHODS AND RESULTS: 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. CONCLUSIONS: 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.

Leydig cell tumor of the testis, presenting with azoospermia.

Case: A case of Leydig cell tumor, associated with azoospermia, is presented. Outcome: The levels of sex hormones obviously were decreased, including luteinizing hormone (LH) and follicle-stimulating hormone (FSH), with elevated testosterone. Computed tomography revealed no adrenal gland tumor, but a significant calcification in the right scrotal content was observed. He received a right radical orchiectomy and then he was unable to ejaculate. An endocrine panel revealed significantly decreased levels of testosterone and the low LH level had remained. Hormone replacement therapy with combined LH and FSH successfully recovered and preserved spermatogenesis. Conclusions: Although the patient's sexual function deteriorated after surgery, hormone replacement therapy was successful in establishing spermatogenesis.

Histological spectrum of angiofibroma of soft tissue: histological and genetic analysis of 13 cases.

AIMS: Angiofibroma of soft tissue (AFST) is a rare soft tissue neoplasm characterized by a fibroblastic cytomorphology and a prominent vascular structure. AFSTs possess a novel fusion gene, i.e. NCOA2-AHRR/AHRR-NCOA2 or GTF2I-NCOA2, providing a useful approach to diagnosing AFST. Morphologically, AFSTs span a wide spectrum, making diagnosis a challenge. The aim of this study was to review AFST cases and to report previously unknown histological features, which we confirmed by genetic analysis. METHODS AND RESULTS: We reviewed 276 cases diagnosed as solitary fibrous tumours/haemangiopericytomas (232 cases), unclassified tumours of fibroblastic differentiation (36 cases), and recently diagnosed AFSTs (eight cases), and retrieved 13 cases compatible with AFST. Immunohistochemical staining was performed for these cases, all 13 of which were analysed by reverse transcription polymerase chain reaction and fluorescence in-situ hybridization. The histological findings were as follows: amianthoid fibres, extravasation of red blood cells, haemosiderin deposition, aggregates of foamy histiocytes, cystic change, necrosis, and haemorrhage. Immunohistochemically, the tumour cells were positive for epithelial membrane antigen (four of 13 cases), desmin (six of 13 cases), CD163 (13 of 13 cases), CD68 (seven of 13 cases), oestrogen receptor (13 of 13 cases), progesterone receptor (three of 13 cases), and STAT6 (one of 13 cases, weak nuclear staining), but they were negative for CD34, α-smooth muscle actin, muscle-specific actin, S100, pan-cytokeratin, MDM2, and CDK4. The AHRR-NCOA2 fusion gene was detected in eight cases, and NCOA2 gene rearrangement in nine cases. CONCLUSION: We revealed the previously unreported histological variation and immunohistochemical findings of AFST, and confirmed them by using genetic methods. The results suggested that AFST should be considered in the diagnosis of fibrous or fibrohistiocytic tumours with the above histological features.

Receptor role of the annexin A2 in the mesothelial endocytosis of crocidolite fibers.

Asbestos-induced mesothelioma is a worldwide problem. Parietal mesothelial cells internalize asbestos fibers that traverse the entire lung parenchyma, an action that is linked to mesothelial carcinogenesis. Thus far, vitronectin purified from serum reportedly enhances the internalization of crocidolite by mesothelial cells via integrin αvß5. To reveal another mechanism by which mesothelial cells endocytose (phagocytose) asbestos, we first evaluated the effects of serum on asbestos uptake, which proved to be nonessential. Thereafter, we undertook a study to identify proteins on the surface of mesothelial cells (MeT5A) that act as receptors for asbestos uptake based on the assumption that receptors bind to asbestos with physical affinity. To this end, we incubated the membrane fraction of MeT5A cells with crocidolite or chrysotile and evaluated the adsorbed proteins using sodium dodecyl sulfate polyacrylamide gel analysis. Next, we extensively identified the proteins using an in-solution or in-gel digestion coupled with mass spectrometry. Among the identified proteins, annexin A2 (ANXA2) and transferrin receptor protein 1 (TFRC) were distinguished because of their high score and presence at the cell surface. Crocidolite uptake by MeT5A cells was significantly decreased by shRNA (short hairpin RNA)-induced knockdown of ANXA2 and direct blockade of cell surface ANXA2 using anti-ANXA2 antibody. In addition, abundant ANXA2 protein was present on the cell membrane of mesothelial cells, particularly facing the somatic cavity. These findings demonstrate that ANXA2 has a role in the mesothelial phagocytosis of crocidolite and may serve as its receptor.

Cancer-promoting role of adipocytes in asbestos-induced mesothelial carcinogenesis through dysregulated adipocytokine production.

Like many other human cancers, the development of malignant mesothelioma is closely associated with a chronic inflammatory condition. Both macrophages and mesothelial cells play crucial roles in the inflammatory response caused by asbestos exposure. Here, we show that adipocytes can also contribute to asbestos-induced inflammation through dysregulated adipocytokine production. 3T3-L1 preadipocytes were differentiated into mature adipocytes prior to use. These cells took up asbestos fibers (chrysotile, crocidolite and amosite) but were more resistant to asbestos-induced injury than macrophages and mesothelial cells. Expression microarray analysis followed by reverse transcription-PCR revealed that adipocytes respond directly to asbestos exposure with an increased production of proinflammatory adipocytokines [e.g. monocyte chemoattractant protein-1 (MCP-1)], whereas the production of anti-inflammatory adipocytokines (e.g. adiponectin) is suppressed. This was confirmed in epididymal fat pad of mice after intraperitoneal injection of asbestos fibers. Such dysregulated adipocytokine production favors the establishment of a proinflammatory environment. Furthermore, MCP-1 marginally promoted the growth of MeT-5A mesothelial cells and significantly enhanced the wound healing of Y-MESO-8A and Y-MESO-8D human mesothelioma cells. Our results suggest that increased levels of adipocytokines, such as MCP-1, can potentially contribute to the promotion of mesothelial carcinogenesis through the enhanced recruitment of inflammatory cells as well as a direct growth and migration stimulatory effect on mesothelial and mesothelioma cells. Taken together, our findings support a potential cancer-promoting role of adipocytes in asbestos-induced mesothelial carcinogenesis.

Diameter and rigidity of multiwalled carbon nanotubes are critical factors in mesothelial injury and carcinogenesis.

Multiwalled carbon nanotubes (MWCNTs) have the potential for widespread applications in engineering and materials science. However, because of their needle-like shape and high durability, concerns have been raised that MWCNTs may induce asbestos-like pathogenicity. Although recent studies have demonstrated that MWCNTs induce various types of reactivities, the physicochemical features of MWCNTs that determine their cytotoxicity and carcinogenicity in mesothelial cells remain unclear. Here, we showed that the deleterious effects of nonfunctionalized MWCNTs on human mesothelial cells were associated with their diameter-dependent piercing of the cell membrane. Thin MWCNTs (diameter ∼ 50 nm) with high crystallinity showed mesothelial cell membrane piercing and cytotoxicity in vitro and subsequent inflammogenicity and mesotheliomagenicity in vivo. In contrast, thick (diameter ∼ 150 nm) or tangled (diameter ∼ 2-20 nm) MWCNTs were less toxic, inflammogenic, and carcinogenic. Thin and thick MWCNTs similarly affected macrophages. Mesotheliomas induced by MWCNTs shared homozygous deletion of Cdkn2a/2b tumor suppressor genes, similar to mesotheliomas induced by asbestos. Thus, we propose that different degrees of direct mesothelial injury by thin and thick MWCNTs are responsible for the extent of inflammogenicity and carcinogenicity. This work suggests that control of the diameter of MWCNTs could reduce the potential hazard to human health.

Cloning and expression profile of the alanine aminotransferase gene from kuruma shrimp Penaeus japonicus exposed to different salinities.

Several crustaceans including shrimps change the amount of specific free amino acids to regulate the osmotic pressure in their bodies. Kuruma shrimp Penaeus japonicus also increases the concentration of alanine (Ala) in the abdominal muscle following the increase of environmental salinity. In the present study, to elucidate the mechanisms of changes in Ala accumulation of kuruma shrimp depending on salinity, we cloned the gene encoding alanine aminotransferase (ALT), an enzyme involved in Ala biosynthesis, and examined its expression profile. It was found that the full-length kuruma shrimp ALT1 cDNA consisted of 3,301 bp, encoding 514 amino acids, and that all amino acid residues important for ALT activity were conserved. Phylogenetic analysis also indicated that the ALT gene cloned in this study was classified as ALT1. Moreover, we examined the expression levels of the ALT1 gene in the abdominal muscle and the hepatopancreas of kuruma shrimp acclimated at 17‰, 34‰, and 40‰ salinities, resulting that the mRNA levels of the ALT1 genes in both tissues of the shrimp acclimated at 40‰ were significantly higher than those at 17‰ for 12 h (p < 0.05). The mRNA levels of the ALT1 gene in the abdominal muscle of the shrimp acclimated for more than 24 h tended to increase following the increase of environmental salinity. These results indicate that ALT1 is responsible for the increase of free Ala concentration in the abdominal muscle of kuruma shrimp to regulate osmotic pressure at high salinity.

Lewis y antigen is expressed in oral squamous cell carcinoma cell lines and tissues, but disappears in the invasive regions leading to the enhanced malignant properties irrespective of sialyl-Lewis x.

Expression and implication of carbohydrate antigens in squamous cell carcinomas (SCCs) in oral cavity was examined. In the cell lines, type 2H and Lewis y antigens were markedly expressed. In the tissues from SCC patients and benign disorders, type 2H was highly expressed in hyperplasia (96.4 %), displasia (92.9 %) and SCC (100 %). Lewis y was, in turn, expressed mainly in cancer tissues (91.3 %), suggesting that Lewis y is a cancer-associated antigen. Normal oral mucosa showed no expression of these blood group antigens. Surprisingly, Lewis y antigen disappeared in the invasion sites where Ki-67 was definitely stained. Over-expression of Lewis y with manipulation of a fucosyltransferase cDNA resulted in suppression of cell growth and invasion, and knockdown of Lewis y also brought about increased cell growth and invasion. In either situations, no changes in the expression of sialyl-Lewis x could be found. Lowered tumor growth and invasion into surrounding tissues were also shown in Lewis y-positive SCC grafts in nu/nu mice. All these results together with alternative staining between Lewis y and Ki-67 in cancer tissues and FUT1 transfectants suggested that loss of Lewis y is a crucial event for the late stage of SCCs.

Evaluation of two distinct methods to quantify the uptake of crocidolite fibers by mesothelial cells.

Exposure to asbestos fibers increases the risk of mesothelioma in humans. One hypothetical carcinogenic mechanism is that asbestos fibers may directly induce mutations in mesothelial cells. Although the uptake of asbestos fibers by mesothelial cells is recognized, methods for the quantification of the uptake have not been well established. In the present study, we evaluated two distinct methods, using crocidolite fibers and MeT5A mesothelial cells. One method is histological evaluation using the cell-block technique, which allows for the direct cross-sectional observation of cells and fibers. We found the bright field observation with ×1000 magnification (oil-immersion) of the sample with Kernechtrot staining was most suitable for this purpose. The other method is flow cytometric analysis, which permits the evaluation of a much larger number of cells. We observed that the side scatter (SSC) increased with the intracellular fibers, and that the "mean SSC ratio (treated/control)" was useful for quantification. We could collect the cells with abundant internalized crocidolite fibers by sorting. Results of the two methodologies were correlated well in the experiments. The quantities of internalized fibers increased with incubation time and loaded dosage, but they were inversely associated with cellular density in culture.

Imaging findings of NTRK­rearranged spindle cell neoplasms: A case series.

NTRK-rearranged spindle cell neoplasms (NTRK-RSCNs) are a new category of soft tissue tumors with NTRK gene fusions. The present study aimed to investigate the radiological features of NTRK-RSCNs and their association with histopathological findings. The present study included six patients with NTRK-RSCNs, whose fusion genes were confirmed using next-generation sequencing. All patients underwent surgery, and their diagnosis and clinical outcomes were investigated. In addition, the magnetic resonance imaging (MRI) features of all tumors and histopathological findings of the resected specimens were assessed. The present study included three women and three men, with a mean age of 22 years (range, 2-43 years). The NTRK gene fusions included four NTRK1 and two NTRK3 fusions. Three patients were preoperatively diagnosed with solitary fibrous tumors. One patient with NTRK3 fusion experienced local recurrence and distant metastases, whereas the other five patients had no local recurrence or metastasis. MRI revealed that all tumors were highly vascular with intra- and peritumoral flow voids of differing degrees. Furthermore, a partially ill-defined border, suggesting infiltration of tumors into the surrounding tissues, particularly fat tissue, was observed in five patients, which was confirmed by histopathological findings. In conclusion, NTRK-RSCNs are highly vascular tumors that can infiltrate the surrounding tissues. These findings suggested that NTRK-RSCNs should be considered in the differential diagnosis of highly vascular-rich mesenchymal tumors, including solitary fibrous tumors and alveolar soft part sarcomas. Furthermore, wide resection may be preferred to completely resect this type of tumor, considering its invasive nature.

HEY1-NCOA2 expression modulates chondrogenic differentiation and induces mesenchymal chondrosarcoma in mice.

Mesenchymal chondrosarcoma affects adolescents and young adults, and most cases usually have the HEY1::NCOA2 fusion gene. However, the functional role of HEY1-NCOA2 in the development and progression of mesenchymal chondrosarcoma remains largely unknown. This study aimed to clarify the functional role of HEY1-NCOA2 in transformation of the cell of origin and induction of typical biphasic morphology of mesenchymal chondrosarcoma. We generated a mouse model for mesenchymal chondrosarcoma by introducing HEY1-NCOA2 into mouse embryonic superficial zone (eSZ) followed by subcutaneous transplantation into nude mice. HEY1-NCOA2 expression in eSZ cells successfully induced subcutaneous tumors in 68.9% of recipients, showing biphasic morphologies and expression of Sox9, a master regulator of chondrogenic differentiation. ChIP sequencing analyses indicated frequent interaction between HEY1-NCOA2 binding peaks and active enhancers. Runx2, which is important for differentiation and proliferation of the chondrocytic lineage, is invariably expressed in mouse mesenchymal chondrosarcoma, and interaction between HEY1-NCOA2 and Runx2 is observed using NCOA2 C-terminal domains. Although Runx2 knockout resulted in significant delay in tumor onset, it also induced aggressive growth of immature small round cells. Runx3, which is also expressed in mesenchymal chondrosarcoma and interacts with HEY1-NCOA2, replaced the DNA-binding property of Runx2 only in part. Treatment with the HDAC inhibitor panobinostat suppressed tumor growth both in vitro and in vivo, abrogating expression of genes downstream of HEY1-NCOA2 and Runx2. In conclusion, HEY1::NCOA2 expression modulates the transcriptional program in chondrogenic differentiation, affecting cartilage-specific transcription factor functions.