Establishment and characterization of TK-ALCL1: a novel NPM-ALK-positive anaplastic large-cell lymphoma cell line.

TK-ALCL1, a novel anaplastic lymphoma kinase (ALK)-positive anaplastic large-cell lymphoma (ALK+ ALCL) cell line, was established from the primary tumor site of a 59-year-old Japanese male patient. The immune profile of TK-ALCL1 corresponds to that seen typically in primary ALCL cells, i.e., positive for ALK, CD30, EMA, and CD4, but negative for CD2, CD3, CD5, CD8a, and EBV-related antigens. The rearrangement of the T cell receptor-gamma locus shows that TK-ALCL1 is clonally derived from T-lineage lymphoid cells. FISH and RT-PCR analysis revealed that TK-ALCL1 has the nucleophosmin (NPM)-ALK fusion transcript, which is typical for ALK+ ALCL cell lines. When TK-ALCL1 was subcutaneously inoculated into 6-week-old BALB/c Rag2-/-/Jak3-/- (BRJ) mice, it formed tumor masses within 4-6 weeks. Morphological, immunohistochemical, and molecular genetic investigations confirmed that the xenograft and the original ALCL tumor were identical. The ALK inhibitors Alectinib and Lorlatinib suppressed proliferation in a dose-dependent manner. Thus, TK-ALCL1 provides a useful in vitro and in vivo model for investigation of the biology of ALK+ ALCL and of novel therapeutic approaches targeting ALK.

Detection of Novel Tyrosine Kinase Fusion Genes as Potential Therapeutic Targets in Bone and Soft Tissue Sarcomas Using DNA/RNA-based Clinical Sequencing.

BACKGROUND: Approximately 1% of clinically treatable tyrosine kinase fusions, including anaplastic lymphoma kinase, neurotrophic tyrosine receptor kinase, RET proto-oncogene, and ROS proto-oncogene 1, have been identified in soft tissue sarcomas via comprehensive genome profiling based on DNA sequencing. Histologic tumor-specific fusion genes have been reported in approximately 20% of soft tissue sarcomas; however, unlike tyrosine kinase fusion genes, these fusions cannot be directly targeted in therapy. Approximately 80% of tumor-specific fusion-negative sarcomas, including myxofibrosarcoma and leiomyosarcoma, that are defined in complex karyotype sarcomas remain genetically uncharacterized; this mutually exclusive pattern of mutations suggests that other mutually exclusive driver oncogenes are yet to be discovered. Tumor-specific, fusion-negative sarcomas may be associated with unique translocations, and oncogenic fusion genes, including tyrosine kinase fusions, may have been overlooked in these sarcomas. QUESTIONS/PURPOSES: (1) Can DNA- or RNA-based analysis reveal any characteristic gene alterations in bone and soft tissue sarcomas? (2) Can useful and potential tyrosine kinase fusions in tumors from tumor-specific, fusion-negative sarcomas be detected using an RNA-based screening system? (3) Do the identified potential fusion tumors, especially in neurotrophic tyrosine receptor kinase gene fusions in bone sarcoma, transform cells and respond to targeted drug treatment in in vitro assays? (4) Can the identified tyrosine kinase fusion genes in sarcomas be useful therapeutic targets? METHODS: Between 2017 and 2020, we treated 100 patients for bone and soft tissue sarcomas at five institutions. Any biopsy or surgery from which a specimen could be obtained was included as potentially eligible. Ninety percent (90 patients) of patients were eligible; a further 8% (8 patients) were excluded because they were either lost to follow-up or their diagnosis was changed, leaving 82% (82 patients) for analysis here. To answer our first and second questions regarding gene alterations and potential tyrosine kinase fusions in eight bone and 74 soft tissue sarcomas, we used the TruSight Tumor 170 assay to detect mutations, copy number variations, and gene fusions in the samples. To answer our third question, we performed functional analyses involving in vitro assays to determine whether the identified tyrosine kinase fusions were associated with oncogenic abilities and drug responses. Finally, to determine usefulness as therapeutic targets, two pediatric patients harboring an NTRK fusion and an ALK fusion were treated with tyrosine kinase inhibitors in clinical trials. RESULTS: DNA/RNA-based analysis demonstrated characteristic alterations in bone and soft tissue sarcomas; DNA-based analyses detected TP53 and copy number alterations of MDM2 and CDK4 . These single-nucleotide variants and copy number variations were enriched in specific fusion-negative sarcomas. RNA-based screening detected fusion genes in 24% (20 of 82) of patients. Useful potential fusions were detected in 19% (11 of 58) of tumor-specific fusion-negative sarcomas, with nine of these patients harboring tyrosine kinase fusion genes; five of these patients had in-frame tyrosine kinase fusion genes ( STRN3-NTRK3, VWC2-EGFR, ICK-KDR, FOXP2-MET , and CEP290-MET ) with unknown pathologic significance. The functional analysis revealed that STRN3-NTRK3 rearrangement that was identified in bone had a strong transforming potential in 3T3 cells, and that STRN3-NTRK3 -positive cells were sensitive to larotrectinib in vitro. To confirm the usefulness of identified tyrosine kinase fusion genes as therapeutic targets, patients with well-characterized LMNA-NTRK1 and CLTC-ALK fusions were treated with tyrosine kinase inhibitors in clinical trials, and a complete response was achieved. CONCLUSION: We identified useful potential therapeutic targets for tyrosine kinase fusions in bone and soft tissue sarcomas using RNA-based analysis. We successfully identified STRN3-NTRK3 fusion in a patient with leiomyosarcoma of bone and determined the malignant potential of this fusion gene via functional analyses and drug effects. In light of these discoveries, comprehensive genome profiling should be considered even if the sarcoma is a bone sarcoma. There seem to be some limitations regarding current DNA-based comprehensive genome profiling tests, and it is important to use RNA testing for proper diagnosis and accurate identification of fusion genes. Studies on more patients, validation of results, and further functional analysis of unknown tyrosine kinase fusion genes are required to establish future treatments. CLINICAL RELEVANCE: DNA- and RNA-based screening systems may be useful for detecting tyrosine kinase fusion genes in specific fusion-negative sarcomas and identifying key therapeutic targets, leading to possible breakthroughs in the treatment of bone and soft tissue sarcomas. Given that current DNA sequencing misses fusion genes, RNA-based screening systems should be widely considered as a worldwide test for sarcoma. If standard treatments such as chemotherapy are not effective, or even if the sarcoma is of bone, RNA sequencing should be considered to identify as many therapeutic targets as possible.

Multiple Recurrent Atypical Lipomatous Tumors/Well-Differentiated Liposarcomas and Dedifferentiated Liposarcomas Treated with Multiple Surgical Resections: A Case Report.

Atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDLPS) is usually a solitary adipocytic tumor. ALT/WDLPS shows no potential for metastasis unless it undergoes dedifferentiation. No case of multiple ALT/WDLPS has been reported in recent years. We present a rare case of multiple recurrent liposarcomas. A 71-year-old man with a history of scrotal ALT/WDLPS at 61 years presented with multiple large tumors spread throughout the body. The patient was bedridden and severely limited in his activities of daily living (ADL) due to multiple large tumors in the trunk and lower extremities. Radiological examination revealed multiple adipocytic tumors, mainly in the soft tissues of the trunk and extremities, with several visceral lesions. Tumors were resected in stages, starting with large tumors directly related to disability. Repeated palliative resections improved the patient's ADL; he regained ambulation and was discharged 18 months after admission. Twelve surgeries were performed to remove 44 adipocytic tumors from the testis, left chest wall, perigastric area, ileum, left inguinal region, both buttocks, thighs, and lower legs. Histological examination revealed dedifferentiated components in five tumors, while 39 tumors were diagnosed as ALT/WDLPS. At the age of 76 years, the patient developed an unresectable dedifferentiated liposarcoma between the heart and aorta, leading to fatality at 79 years. The patient's clinical course suggested multiple metastases of ALT/WDLPS of scrotal origin or ALT/WDLPS of multicentric origin. Although multicentric ALT/WDLPS or ALT/WDLPS metastases are rare, they should be considered when multiple large adipocytic tumors are found throughout the body. Despite the presence of numerous large malignant tumors, surgical treatments of the lesions can improve ADL and prolong life if the tumors are of low-grade malignancy.

Clinical Outcome of Low-Grade Myofibroblastic Sarcoma in Japan: A Multicenter Study from the Japanese Musculoskeletal Oncology Group.

This retrospective multicenter study aimed to analyze the clinical features and prognosis of 24 patients diagnosed with LGMS between 2002 and 2019 in the Japanese sarcoma network. Twenty-two cases were surgically treated and two cases were treated with radical radiotherapy (RT). The pathological margin was R0 in 14 cases, R1 in 7 cases, and R2 in 1 case. The best overall response in the two patients who underwent radical RT was one complete response and one partial response. Local relapse occurred in 20.8% of patients. Local relapse-free survival (LRFS) was 91.3% at 2 years and 75.4% at 5 years. In univariate analysis, tumors of 5 cm or more were significantly more likely to cause local relapse (p < 0.01). In terms of the treatment of relapsed tumors, surgery was performed in two cases and radical RT was performed in three cases. None of the patients experienced a second local relapse. Disease-specific survival was 100% at 5 years. A wide excision aimed at the microscopically R0 margin is considered the standard treatment for LGMS. However, RT may be a viable option in unresectable cases or in cases where surgery is expected to cause significant functional impairment.

A Case of GATA3 Positive Pleomorphic Liposarcoma, Epithelioid Variant: A Diagnostic Pitfall.

Pleomorphic liposarcoma is a rare malignant adipocytic tumor showing undifferentiated pleomorphic sarcoma morphology with various degrees of epithelioid features. It is sometimes difficult to distinguish from carcinoma metastasis. Immunohistochemical panel is very important for differential diagnosis; however, there is a risk that unexpected staining could lead to misinterpretation. We report a pleomorphic liposarcoma, epithelioid variant, in an 88-year-old man, with tricky-positive staining for GATA3. Histological examination revealed a tumor with epithelioid morphology. The tumor consists of solid sheets of epithelioid tumor cells with focal aggregates of pleomorphic lipoblasts. Immunohistochemically, the adipocytic tumor cell areas were positive for S100 protein, and the epithelioid tumor cells showed CAM 5.2 positivity. GATA3 was diffusely positive. The combination of CAM 5.2 and GATA3 staining suggested the possibility of metastatic cancer, but systemic clinical examinations did not detect any presence of a primary tumor, including urinary bladder, breasts, and salivary glands. The pathological diagnosis of pleomorphic liposarcoma, epithelioid variant, was made because of the presence of malignant lipoblasts. Our report may contribute for differential diagnosis of pleomorphic liposarcoma, epithelioid variant, with unexpected positive immunoreaction for GATA3.

Expression and localisation of MUC1 modified with sialylated core-2 O-glycans in mucoepidermoid carcinoma.

Mucoepidermoid carcinoma (MEC) is the most frequent of the rare salivary gland malignancies. We previously reported high expression of Mucin 1 (MUC1) modified with sialylated core-2 O-glycans in MEC by using tissue homogenates. In this study, we characterised glycan structures of MEC and identified the localisation of cells expressing these distinctive glycans on MUC1. Mucins were extracted from the frozen tissues of three patients with MEC, and normal salivary glands (NSGs) extracted from seven patients, separated by supported molecular matrix electrophoresis (SMME) and the membranes stained with various lectins. In addition, formalin-fixed, paraffin-embedded sections from three patients with MEC were subjected to immunohistochemistry (IHC) with various monoclonal antibodies and analysed for C2GnT-1 expression by in situ hybridisation (ISH). Lectin blotting of the SMME membranes revealed that glycans on MUC1 from MEC samples contained α2,3-linked sialic acid. In IHC, MUC1 was diffusely detected at MEC-affected regions but was specifically detected at apical membranes in NSGs. ISH showed that C2GnT-1 was expressed at the MUC1-positive in MEC-affected regions but not in the NSG. MEC cells produced MUC1 modified with α2,3-linked sialic acid-containing core-2 O-glycans. MUC1 containing these glycans deserves further study as a new potential diagnostic marker of MEC.

Epidemiologic Survey of Myxofibrosarcoma Using Data from the Bone and Soft Tissue Tumor Registry in Japan.

BACKGROUND: Myxofibrosarcoma is a common sarcoma among older patients, with locally infiltrative behavior and a predilection for local postoperative recurrence. Some studies have reported the factors affecting prognosis, although only a few have mentioned the previous staging classification systems. This study investigated the clinical overview and prognosis of myxofibrosarcoma to determine the optimal treatment. METHODS: This retrospective study analyzed the records of 349 patients with myxofibrosarcoma in the nationwide Bone and Soft Tissue Tumor Registry in Japan from 2006 to 2015. Clinical features, treatment options, and patient outcomes were investigated. RESULTS: Ultimately, 349 patients were identified. The overall survival rates were 93.1% at 2 years and 84.3% at 5 years. A multivariate analysis was performed using the Cox proportional hazards model. The study identified four significant prognostic factors for survival: tumor size, depth, compartment status, and location. The prognostic score was calculated by summing the scores of all the factors. The overall survival rate was 69.3% at 5 years for the patients with prognostic scores of 6 or higher. Conversely, the patients with prognostic scores of 2 or lower had a survival rate of 95.6% at 5 years. CONCLUSIONS: Among myxofibrosarcomas, those larger than 5 cm, deep-seated, invaded into the external compartment, or in axial body parts were associated with a significantly worse prognosis. Adjuvant radiotherapy and chemotherapy did not contribute significantly to a better prognosis. Previous staging classification systems are impractical for prognosis prediction. Therefore, new classifications are needed. Further research on new treatment methods for patients with a poor prognosis will be crucial in the future.

Dedifferentiation in low-grade osteosarcoma: a Japanese Musculoskeletal Oncology Group (JMOG) study.

BACKGROUND: Low-grade osteosarcomas, namely parosteal osteosarcoma (POS) and low-grade central osteosarcoma (LGCOS), occasionally dedifferentiate into high-grade malignancy, referred to as dedifferentiation in low-grade osteosarcoma (DLOS). This study aimed to elucidate the clinicopathologic features of DLOS, which are poorly described to date due to the extreme rarity of the disease. METHODS: A total of 33 patients with DLOS were included. Clinical characteristics, including the diagnostic accuracy of tumor biopsy, multimodal treatments, and clinical course, were retrospectively reviewed. Univariate analysis was performed to identify prognostic factors associated with overall survival (OS) and metastasis-free survival (MFS). RESULTS: The tumor subtypes comprised 10 cases (30.3%) of LGCOS and 23 cases (69.7%) of POS. The timing of dedifferentiation was synchronous in 25 (75.8%) and metachronous in 8 (24.2%) patients. The rates of preoperative diagnosis of DLOS were 40.0% and 65.4% for core needle biopsy and incisional biopsy, respectively. All patients underwent surgery and 25 patients received perioperative chemotherapy. Of the 13 patients who received neoadjuvant chemotherapy, 11 exhibited a poor histological response. The 5-year OS and MFS rates were 88.1% and 77.7%, respectively. Univariate analysis revealed that local recurrence was associated with poor OS (P < 0.01) and MFS (P < 0.01). Perioperative chemotherapy did not affect OS or MFS. CONCLUSIONS: The diagnostic accuracy of tumor biopsy for DLOS was lower than that for bone sarcomas, as reported previously. In contrast to conventional osteosarcomas with high chemosensitivity, both histological responses and survival analysis revealed low efficacy of chemotherapy for DLOS.

Establishment and characterization of a novel patient-derived cell line of dedifferentiated liposarcoma, NCC-DDLPS6-C1.

Dedifferentiated liposarcoma (DDLPS) is morphologically characterized by well-differentiated liposarcomas associated with high-grade non-lipogenic sarcoma and molecularly characterized by the coamplification of MDM2 and CDK4(12q14-15). DDLPS is highly aggressive, and effective systemic chemotherapy has not been developed yet. In this study, we established a novel DDLPS cell line, NCC-DDLPS6-C1, as a potential tool for the development of novel therapies. NCC-DDLPS6-C1 cells were established from surgically resected tumor tissues of a patient with DDLPS. Amplification and overexpression of MDM2 and CDK4 were observed in NCC-DDLPS6-C1 cells. NCC-DDLPS6-C1 cells proliferated rapidly, invaded aggressively, and formed spheroids. Moreover, NCC-DDLPS6-C1 cells formed tumors in mice. These observations suggested that the malignant potentials that may reflect the original features of DDLPS were retained in the NCC-DDLPS6-C1. Anticancer drugs that significantly reduced the proliferation of NCC-DDLPS6-C1 cells were identified by drug library screening. Thus, NCC-DDLPS6-C1 may recapitulate the original genotypes and phenotypes, and we conclude that the NCC-DDLPS6-C1 cell line is a useful resource for the study of DDLPS.

Establishment and characterization of two novel patient-derived myxoid liposarcoma cell lines.

Myxoid liposarcoma (MLPS) is a lipogenic sarcoma, characterized by myxoid appearance histology and the presence of the FUS-DDIT3 fusion gene. MLPS shows frequent recurrence and poor prognosis after standard treatments, such as surgery. Therefore, novel therapeutic approaches for MLPS are needed. Development of novel treatments requires patient-derived cell lines to study the drug responses and their molecular backgrounds. Presently, only three cell lines of MLPS have been reported, and no line is available from public cell banks. Thus, this study aimed to establish and characterize novel MLPS cell lines. Using surgically resected tumor tissue from two patients with MLPS, two novel lines NCC-MLPS2-C1 and NCC-MLPS3-C1 were established. The presence of FUS-DDIT3 fusion, slow growth, spheroid formation, and invasive capability in these cell lines was confirmed. Growth retardation was monitored for 213 anti-cancer agents using NCC-MLPS2-C1 and NCC-MLPS3-C1 cells, and the results were integrated with the response to treatments in an MLPS cell line, NCC-MLPS1-C1, which was previously established in our laboratory. We found that romidepsin suppressed cell proliferation at considerably low concentrations in all three examined cell lines. NCC-MLPS2-C1 and NCC-MLPS3-C1 cell lines developed here represent a useful tool for basic and preclinical studies of MLPS.

Establishment and characterization of a novel patient-derived Ewing sarcoma cell line, NCC-ES2-C1.

Ewing sarcoma (ES) is a small round cell sarcoma that is characterized by the unique gene translocation EWSR1-FLI1. It is the second most common primary bone and soft tissue malignancy in children and adolescents. It constitutes 10-15% of all bone sarcomas and is highly aggressive and rapidly recurring. Although intensive treatments have improved the clinical outcome of ES patients, 20-25% of them exhibit metastases during diagnosis. Thus, the prognoses of these patients remain poor. Cell lines are pivotal resources to investigate the molecular background of disease progression and to develop novel therapeutic modalities. In this study, we established and characterized a novel ES cell line, NCC-ES2-C1. The presence of the EWSR1-FLI1 fusion gene in these cells was confirmed in the NCC-ES2-C1 cells. Furthermore, these cells exhibited constant proliferation, and invasion, but did not form tumors in mice. We screened the anti-tumor effects of 214 anti-cancer drugs in NCC-ES2-C1 cells and found that the drugs which effectively reduced the proliferation of NCC-ES2-C1 cells. We concluded that NCC-ES2-C1 cells are a useful resource to study functions of the EWSR1-FLI1 fusion gene, investigate phenotypic changes caused by genes and proteins, and evaluate the anti-tumor effects of novel drugs.

Preoperative Denosumab Therapy Against Giant Cell Tumor of Bone is Associated with an Increased Risk of Local Recurrence After Curettage Surgery.

INTRODUCTION: Denosumab has been shown to be highly effective at suppressing the progression of giant cell tumor of bone (GCTB). However, recent studies have observed a potential increased risk of local recurrence after surgery following the use of denosumab, raising concerns on the use of this agent against GCTB in combination with surgery. METHODS: We retrospectively reviewed the medical records of 234 patients with GCTB who were surgically treated at multiple institutions from 1990 to 2017. Patient background, tumor characteristics, treatment methods, local recurrence-free survival rate, distant metastasis rate, oncologic outcome, and limb function at final follow-up were analyzed and compared between cases treated with and without denosumab. RESULTS: The 3-year local recurrence-free survival rate was significantly lower in patients who underwent preoperative denosumab therapy (35.3%) compared with those treated without denosumab (79.9%) (P < 0.001). Among patients who were preoperatively treated with denosumab, those who had a local recurrence all underwent curettage surgery. CONCLUSIONS: Preoperative denosumab therapy in combination with curettage surgery was significantly associated with an increased risk of local recurrence in Campanacci grade 3 tumors. Our data suggest that clinicians seeing GCTB patients should be aware to this increased risk when planning preoperative denosumab therapy.

Recurrent malignant peripheral nerve sheath tumor presenting as an asymptomatic intravenous thrombus extending to the heart: a case report.

BACKGROUND: Malignant peripheral nerve sheath tumor (MPNST) is a rare soft tissue sarcoma mainly treated via surgical resection. Herein, we report a case of MPNST wherein a massive tumor thrombus extended to the major veins and heart. CASE PRESENTATION: A 39-year-old female with a history of neurofibromatosis type 1 developed MPNST from the right radial nerve. In addition to adjuvant chemotherapy, she underwent wide tumor resection and concomitant radial nerve resection, followed by postoperative radiotherapy. Histological evaluation revealed marked venous invasion. The 2-year follow-up CT revealed an asymptomatic recurrent tumor thrombus extending from the right subclavian vein to the heart. An urgent life-saving operation was performed to ligate the base of the right subclavian vein and remove the entire intravenous thrombus that extended to the right ventricle. The remaining tumor in the right subclavian vein increased in size 3 months after thrombectomy. After confirming the absence of any metastatic lesions, the patient underwent extended forequarter amputation to achieve surgical remission. One year later, a new metastasis to the right diaphragm was safely resected. The patient remains alive without any evidence of disease 2 years after the extended forequarter amputation. CONCLUSIONS: In cases of a previous history of microscopic venous invasion, recurrence can occur as a massive tumor thrombus that extends to the great vessels.

Establishment and characterization of the NCC-GCTB4-C1 cell line: a novel patient-derived cell line from giant cell tumor of bone.

Giant cell tumor of bone (GCTB) is a rare osteolytic intermediate bone tumor that harbors a pathogenic H3F3A gene mutation and exhibits characteristic histology. The standard curative treatment for GCTB is complete surgical resection, but it frequently results in local recurrence and, more rarely, metastasis. Therefore, effective multidisciplinary treatment is needed. Although patient-derived tumor cell lines are promising tools for preclinical and basic research, there are only four available cell lines for GCTB in public cell banks. Thus, the aim of this study was to establish a novel GCTB cell line. Using surgically resected tumor tissues from a patient with GCTB, we established a cell line named NCC-GCTB4-C1. The cells harbored the typical H3F3A gene mutation and exhibited constant proliferation and invasive capabilities. After characterizing NCC-GCTB4-C1 cell behaviors, we conducted high-throughput screening of 214 anti-tumor drugs and identified seven effective drugs. Comparing the results of high-throughput screening using NCC-GCTB4-C1 cell line with the results using NCC-GCTB1-C1, NCC-GCTB2-C1, and NCC-GCTB3-C1 cell lines that we previously established, four drugs were in common effective. This study showed potential drugs for the treatment of GCTB. These data indicate that NCC-GCTB4-C1 has the potential to be a powerful tool in preclinical and basic research on GCTB.

Complications of surgery for giant cell tumor of bone in the extremities: Incidence, risk factors, management modality, and impact on functional and oncological outcomes.

BACKGROUND: Due to the wide variations in location, size, local invasiveness, and treatment options, the complications associated with surgery for giant cell tumor of bone have been sporadically reported. For quality assessment, fundamental data based on large-scale surveys of complications under a universal evaluation system is needed. The Dindo-Clavien classification is an evaluation system for complications based on severity and required intervention type and is suitable for the evaluation of surgery in a heterogeneous cohort. METHODS: A multi-institutional retrospective survey of 141 patients who underwent surgery for giant cell tumor of bone in the extremity was performed. The incidence and risk factors of complications, type of intervention for complication control, and impact of complications on functional and oncological outcomes were analyzed using the Dindo-Clavien classification. RESULTS: Forty-six cases (32.6%) had one or more complications. Of them, 18 (12.8%), 11 (7.8%), and 17 (12.1%) cases were classified as Dindo-Clavien classification grade I, II, and III complications, respectively. There were no cases with grade IV or V complications. Progression in Campanacci grading (p = 0.04), resection (over curettage, p < 0.0001), reconstruction with prosthesis (p = 0.0007), and prolonged operative duration (p = 0.0002) were significant risk factors for complications. Complications had a significant impact on function (p < 0.0001). Differences in the impact of complication types and tumor location on function were confirmed. Complications had no impact on local recurrence and metastasis development. CONCLUSION: The Dindo-Clavien classification could provide fundamental information, under a uniform definition and classification system, on postoperative complications in patients with giant cell tumor of bone in terms of incidence, type of intervention for complication control, risk factors, and impact on functional outcome. The data are useful not only for preoperative evaluation for the risk of complications under specific conditions but also for quality assessment of surgery for giant cell tumor of bone.

Dedifferentiated Osteosarcoma of the Distal Ulna: A Case Report.

Osteosarcoma is the most common malignant primary bone tumor that occurs most frequently in the second decade of life but rarely in patients over 40 years of age. The most common primary sites of osteosarcoma are the distal femur followed by proximal tibia and proximal humerus, and involvement of the wrist is extremely rare. Moreover, dedifferentiated osteosarcoma is also a rare condition that progresses to high-grade osteosarcoma from low-grade osteosarcoma, usually central low-grade osteosarcoma or parosteal osteosarcoma that bears MDM2 and/or CDK4 gene amplifications. We herein report an extremely rare case of dedifferentiated osteosarcoma arising in the distal ulna of an adult over 40 years of age. The patient was a 46-year-old man with a 2-month history of pain in his left swollen wrist. The initial radiological findings suggested a benign bone tumor in the distal ulna, and the lesion was marginally excised at the nearby hospital. Although the pathological diagnosis at the nearby hospital suggested a benign cartilaginous tumor, the tumor recurred in an aggressive manner 8 months after the initial surgery. The patient was referred to our hospital, and an incisional biopsy showed a high-grade osteosarcoma. The primary tumor was retrospectively re-evaluated at our hospital and diagnosed as low-grade osteosarcoma. Since neoadjuvant chemotherapy failed to shrink the tumor, the patient had to undergo below the elbow amputation to cure the disease. Although the tumor was negative for MDM2 nor CDK4, the definitive diagnosis of dedifferentiated osteosarcoma was made according to the clinical course and the histological findings. Lung metastases were found 10 months after the amputation, which were successfully treated by neoadjuvant chemotherapy and surgery. The patient has been doing well with no evidence of disease for 1 year and 6 months. Surprisingly, the literature review revealed that many low-grade osteosarcomas of the distal ulna progressed to high-grade dedifferentiated osteosarcomas. One should bear in mind that the diagnosis and treatment for bone-forming tumors of the distal ulna should be made very carefully because, although rare, it is possible that the tumor may initially appear as a benign or low-grade malignant tumor and may progress to high-grade osteosarcoma.

Characterization of tumor-associated MUC1 and its glycans expressed in mucoepidermoid carcinoma.

Mucoepidermoid carcinoma (MEC) is one of the most frequently misdiagnosed tumors. Glycans are modulated by malignant transformation. Mucin 1 (MUC1) is a mucin whose expression is upregulated in various tumors, including MEC, and it has previously been investigated as a diagnostic and prognostic tumor marker. The present study aimed to reveal the differences in the mucin glycans between MEC and normal salivary glands (NSGs) to discover novel diagnostic markers. Soluble fractions of salivary gland homogenate prepared from three MEC salivary glands and 7 NSGs were evaluated. Mucins in MEC and NSGs were separated using supported molecular matrix electrophoresis, and stained with Alcian blue and monoclonal antibodies. The glycans of the separated mucins were analyzed by mass spectrometry. MUC1 was found in MEC but not in NSGs, and almost all glycans of MUC1 in MEC were sialylated, whereas the glycans of mucins in NSGs were less sialylated. The core 2 type glycans, (Hex)2(HexNAc)2(NeuAc)1 and (Hex)2(HexNAc)2(NeuAc)2, were found to be significantly abundant glycans of MUC1 in MEC. MEC markedly produced MUC1 modified with sialylated core 2 glycans. These data were obtained from the soluble fractions of salivary gland homogenates. These findings provide a basis for the utilization of MUC1 as a serum diagnostic marker for the preoperative diagnosis of MEC.

Establishment and characterization of a novel cell line, NCC-DDLPS2-C1, derived from a patient with dedifferentiated liposarcoma.

Dedifferentiated liposarcoma (DDLPS) is a highly aggressive subtype of liposarcoma that is histologically a transition form between an atypical lipomatous tumor/well-differentiated liposarcoma and a non-lipogenic sarcoma. DDLPS is genetically characterized by a complex karyotype with copy number variations and genomic complexity. DDLPS has a poor prognosis, a high local recurrence rate, and refractory behaviors for chemotherapy and radiation, which indicate a requirement for a novel therapeutic strategy for better clinical outcomes. We report here, a novel DDLPS cell line (NCC-DDLPS2-C1) developed from a tumor tissue. NCC-DDLPS2-C1 cells showed an amplified 12q13-15 region and exhibited constant growth, spheroid formation, and invasion. High-throughput drug screening revealed distinct sensitivity between monolayer- and three-dimensional cells. Romidepsin and trabectedin especially showed high anti-proliferative effects in both culture methods of NCC-DDLPS2-C1. Thus, the NCC-DDLPS2-C1 cell line may serve as a useful resource for DDLPS studies.