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.

Mixed hepatocellular carcinoma and high-grade neuroendocrine neoplasm with ambiguous histopathological features: a case report.

Well-differentiated neuroendocrine tumor (NET) and poorly differentiated neuroendocrine carcinoma (NEC) are distinct entities with different biological behavior. However, difficult cases showing equivocal morphology have been reported in some organs. Herein, we report a case of primary hepatic neuroendocrine neoplasm (NEN) with ambiguous histopathological features admixed with conventional hepatocellular carcinoma (HCC). A 70-year-old man with untreated chronic hepatitis B underwent left medial sectionectomy because of two incidental liver masses. On pathological examination, one of the resected tumors had intermingling NEN and HCC components. The NEN component consisted of relatively uniform tumor cells proliferating in trabecular, cord-like, or solid patterns with peripheral nuclear palisading. The tumor cells were immunopositive for synaptophysin, chromogranin A, cluster of differentiation 56 (CD56), and focally hepatocyte paraffin 1. p53 showed wild-type expression. The Ki-67 labeling index was 27% at the hot spot. Eleven months after the surgery, he died of a cerebral hemorrhage without evidence of recurrent liver cancer. The intermediate degree of differentiation and the modest proliferative activity can challenge the distinction between NEC and NET G3. While the coexisting HCC indicates NEC rather than NET in a pathogenetic viewpoint, such ambiguous tumor may not be as aggressive as typical NECs.

Prognostic significance of intraoperative peritoneal washing cytology for patients with potentially resectable pancreatic ductal adenocarcinoma.

BACKGROUND: The prognostic significance of intraoperative peritoneal washing cytology (IPWC) in pancreatic ductal adenocarcinoma (PDAC) remains controversial, and the treatment strategy for PDAC patients with positive cytology has not been established. OBJECTIVES: The objective of this study was to evaluate the clinical significance of IPWC in PDAC patients. METHODS: This study included a retrospective cohort of 166 patients with curatively resected PDAC who underwent IPWC. RESULTS: Overall, 17 patients (10%) had positive cytology (CY+), and 149 (90%) patients were negative (CY-). Tumor location in the pancreatic body and/or tail and pancreatic anterior capsular invasion were independent predictors of a CY+ status (P = 0.012 and 0.041, respectively). The initial recurrence occurred at the peritoneum with a significantly higher frequency in CY+ patients (50%) than in CY- patients (12%) (P = 0.003). The median overall survival (OS) for CY+ patients was 12 months. The OS rates at 1 and 3 years were significantly higher for CY- patients (75.1% and 35.3%, respectively) versus CY+ patients (47.1% and 17.6%, respectively; P = 0.012). However, one CY+ patient survived for 66 months, and another two CY+ patients have survived for more than three years after surgery without evidence of peritoneal recurrence. In the multivariate analysis, the independent predictors of OS were a CY+ status, lymph node metastasis, and adjuvant chemotherapy. CONCLUSIONS: This study demonstrates that positive IPWC predicts early peritoneal recurrence and a poor prognosis for PDAC patients. However, a small but not insignificant subset of CY+ patients with PDAC may avoid peritoneal carcinomatosis.

Clinical implications of the proliferative ability of the squamous component regarding tumor progression of adenosquamous carcinoma of the pancreas: A preliminary report.

OBJECTIVES: The objectives of this study were to examine the clinicopathological characteristics of patients with adenosquamous carcinoma of the pancreas (ASCP) and assess whether the proliferative ability of the squamous cell carcinoma (SCC) component contributes to either its proportion within the tumor or tumor progression. METHODS: We retrospectively reviewed 12 patients with resected ASCP and compared their clinicopathological characteristics with those of 161 patients with adenocarcinoma of the pancreas (ACP). The Ki-67 indexes of the separate ASCP components were assessed. RESULTS: All the clinicopathological characteristics and outcomes were similar between the ASCP patients and ACP patients. Among the 12 ASCP cases, nine exhibited higher Ki-67 levels in the SCC component than in the corresponding adenocarcinoma (AC) component at primary sites (P = 0.022). The component with a higher Ki-67 level coincided with the predominant component at the primary site in nine of 11 patients. In all 10 patients who presented lymph node metastasis, the metastases almost entirely consisted of either the SCC or AC component. The SCC component was absent from metastatic lymph nodes in five of 10 patients even though the Ki-67 levels at the primary site in four of these patients were higher in the SCC component than in the AC component. CONCLUSIONS: The enhanced proliferative ability of the SCC component of ASCP is reflected by its proportion within the tumor. However, other biological factors might contribute to metastasis in ASCP.

Adenosquamous carcinoma in the biliary tract: association of the proliferative ability of the squamous component with its proportion and tumor progression.

OBJECTIVES: The purpose of this study was to evaluate the association of the proliferative ability of squamous cell carcinoma (SCC) component with its proportion and tumor progression in adenosquamous carcinoma (ASC) in the biliary tract. METHODS: Nine patients with ASC in the biliary tract (four each in the gallbladder and the extrahepatic bile duct and one in the ampulla of Vater) who underwent surgical resection were retrospectively reviewed. RESULTS: The proportion of the SCC component in the primary sites ranged from 30% to 95%. The Ki-67 index of the SCC component was higher than that of the adenocarcinoma component in all cases, regardless of the component ratio in the patients' primary lesions. Predominance of the SCC component in the advancing region of the tumor, in angiolymphatic invasion and in perineural invasion was observed in most of the cases. The component ratio in metastatic lymph nodes differed from that in the corresponding primary lesions in all six cases with lymph node metastasis. Among these cases, the proportion of the SCC component was increased in the metastatic lymph nodes compared with that in the corresponding primary lesion in two cases, whereas the proportion was decreased in four cases. CONCLUSIONS: The SCC component of ASC in the biliary tract displayed a relatively higher proliferative ability, which might be associated with local invasiveness. However, not only the high proliferative ability of the SCC component but also other biological factors might contribute to tumor progression and metastasis in ASC of the biliary tract.

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.

Collision tumors of hepatocellular carcinoma and malignant peritoneal mesothelioma.

We report a case of synchronous hepatocellular carcinoma (HCC) and malignant peritoneal mesothelioma (MM-per). A 56-year-old man with no past history of asbestos exposure, chronic viral hepatitis, or alcoholic liver injury was admitted to our hospital with left flank pain and abdominal tumor. Partial hepatectomy, splenectomy, partial diaphragm resection, and partial gastrectomy were performed. The tumor in the lateral segment of the liver was gray to white, massive in appearance, and contained focal bile-producing nodules and extensive fibrous firm lesion. It had directly invaded the spleen and diaphragm. Liver cirrhosis was not found. The peritoneum contained multiple small nodules especially around the diaphragm, which mimicked carcinoma dissemination. After histological examination, the liver tumor was diagnosed as HCC. It had trabecular and scirrhous patterns and positive immunoreactivities for Hep-Par-1 and α-fetoprotein. The peritoneal nodules were diagnosed as MM-per, epithelioid type, with positive immunoreactivities for calretinin and cytokeratin 5/6. The two tumors collided around the diaphragm. Cases of MM synchronous with other primary malignant tumors have been reported, but most had a history of asbestos exposure unlike the present case. The carcinogenic background was unclear for two tumors in this case. This is an extremely rare and valuable case.

[An autopsy case of unresectable colon cancer who developed lung injury by cetuximab].

We report the case of a woman in her 60s with unresectable advanced colon cancer. After the first course of cetuximab as second-line therapy, she had developed drug-induced lung injury. Steroid pulse therapy had been ineffective, and she died of respiratory failure on day 9. The pathological examination of autopsy lung specimens revealed diffuse alveolar damage(DAD). Details of the cetuximab-induced lung injury are unclear. However, in 3 previous reports of lung injury by cetuximab, the postmortem findings were similar to this case. We concluded that DAD seems to be one of the pathological features of lung injury caused by cetuximab.

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.

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.

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.

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.

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.

Cytotoxic molecule-positive classical Hodgkin's lymphoma: a clinicopathological comparison with cytotoxic molecule-positive peripheral T-cell lymphoma of not otherwise specified type.

BACKGROUND: Classical Hodgkin's lymphoma is characterized by Hodgkin and Reed Sternberg cells, which are of B-cell origin in many cases. We recently highlighted the adverse prognostic significance of cytotoxic molecule expression in patients with classical Hodgkin's lymphoma. However, the clinical characteristics of cytotoxic molecule-positive classical Hodgkin's lymphoma remain controversial. DESIGN AND METHODS: We investigated the clinicopathological profiles of 32 patients with cytotoxic molecule-positive Hodgkin's lymphoma, comprising 23 with nodular sclerosis and 9 with mixed cellularity, and compared these profiles with those of 55 patients with cytotoxic molecule-positive nodal peripheral T-cell lymphoma, not otherwise specified and 439 patients with cytotoxic molecule-negative Hodgkin's lymphoma. RESULTS: The patients with cytotoxic molecule-positive Hodgkin's lymphoma consisted of 20 men and 12 women with a median age of 50 years (range, 19 to 81). All these patients had lymphadenopathy at presentation, and 14 showed mediastinal involvement. Physical findings included hepatomegaly and splenomegaly in six patients each. Four patients had a bulky mass, and nine showed stage IV disease. The tumor cells of patients with cytotoxic molecule-positive Hodgkin's lymphoma had a prototypic immunophenotype of CD15(+) CD30(+) CD45RO(-) fascin(+), with positivity for Epstein-Barr virus in 39% of cases. All patients were negative for Pax5. In comparison with patients with cytotoxic molecule-positive nodal peripheral T-cell lymphomas, not otherwise specified, patients with cytotoxic-positive Hodgkin's lymphoma had relatively mild clinical symptoms, similar to those of patients with cytotoxic molecule-negative Hodgkin's lymphoma. Regarding prognosis, the survival of patients with cytotoxic molecule-positive Hodgkin's lymphoma was worse than that of patients with cytotoxic molecule-negative Hodgkin's lymphoma (P = 0.0003) but better than that of patients with cytotoxic molecule-positive peripheral T-cell lymphomas, not otherwise specified (P = 0.002). CONCLUSIONS: Cytotoxic molecule-positive Hodgkin's lymphoma is characterized by an unfavorable prognosis, even if its clinicopathological features are within the boundaries of classical Hodgkin's lymphoma. More effective chemotherapy for cytotoxic molecule-positive Hodgkin's lymphoma is clearly required.

[Clinical analysis of 3 cases with primary splenic diffuse large B-cell lymphoma].

The definition of primary splenic lymphoma is controversial, but it has been reported to be a rare disease that comprises less than 1% of all malignant lymphomas. Three cases of primary splenic diffuse large B-cell lymphoma treated at our institution are described here. Median follow-up was 34.6 months (range 8.7∼39.2) and median age at diagnosis was 72 years old (range 65∼73). In all three cases, the diagnosis was definitively established not by splenectomy but by ultrasonically guided percutaneous splenic tissue core biopsy. Using the Hans classifier, one of the cases was subclassified as the germinal center B-cell like (GCB) subtype and two as non-GCB subtype. One case was CD5-positive diffuse large B-cell lymphoma. Two patients were in Ann Arbor stage II and one was in stage III. Using the International Prognostic Index, one was categorized as Low/intermediate risk, one as high/intermediate risk, and one as high risk. All patients underwent eight cycles of rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisolone followed by irradiation therapy. These three patients attained complete response. Although the follow-up period to date has been short, all patients have maintained a complete response and are currently alive. To determine whether our management protocol is valid, further observations are needed.

Establishment and characterization of NCC-MLPS1-C1: a novel patient-derived cell line of myxoid liposarcoma.

Myxoid liposarcoma is a rare mesenchymal malignancy, which is characterized by a FUS-DDIT3 fusion known as chromosomal translocation t(12;16)(q13;p11) and arises in the fat tissue. Although surgery with radiation has been established as a standard treatment, myxoid liposarcoma shows frequent recurrence and poor prognosis, thus requiring new therapeutic approaches. Patient-derived cell lines represent a critical tool for basic and preclinical research. However, only two such myxoid liposarcoma cell lines have been reported, and they are not available in cell banks. The aim of this study was to establish and characterize a novel myxoid liposarcoma cell line. Using surgically resected tumor tissue from a 47-year-old male patient, we established the NCC-MLPS1-C1 cell line. NCC-MLPS1-C1 cells were characterized by FUS-DDIT3 fusion, slow growth, spheroid formation, and invasive capability. We screened the effect of anti-cancer agents on the proliferation of NCC-MLPS1-C1 cells. The cells displayed a remarkable response to multitarget kinase inhibitors of RET, PDGFR-ß, VEGFR, or FGFR. NCC-MLPS1-C1 cells and the tumor tissue shared common profiles of kinase activity including identified drug targets, such as RET and PDGFR-ß. We believe that NCC-MLPS1-C1 cells will represent a useful tool for basic and preclinical studies of myxoid liposarcoma.

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.

Establishment and characterization of a novel cell line, NCC-TGCT1-C1, derived from a patient with tenosynovial giant cell tumor.

Tenosynovial giant cell tumor (TGCT) is a mesenchymal tumor arising from the synovium of tendon sheath and joints, characterized by translocation t(1;2)(p13;q37). Clinical behaviors of TGCT range from favorable to locally aggressive and further research is required to lead the identification of novel therapeutic avenues for TGCT. Patient-derived cell lines are an indispensable tool for interrogating molecular mechanisms underlying the progression of disease. However, only one TGCT cell line is currently available from cell banks, and a paucity of adequate patient-derived cells hinders basic and translational research. This study aimed to establish a novel cell line of TGCT. To this end, a novel cell line, NCC-TGCT1-C1 was established from the primary tumor tissue of a 40-year-old female patient with TGCT. The cells exhibited translocation t(1;2)(p13;q37), generating COL6A3-CSF1 fusion gene. The cells were maintained as a monolayer culture through more than 30 passages over 12 months. The cells exhibited continuous growth and the ability for spheroid formation and invasion. When used in a high-throughput assay to evaluate the anti-proliferative effects of 164 anticancer drugs, the cells responded strongly to a kinase inhibitor such as gefitinib, and mitoxantrone. Our results indicate that the novel TGCT cell line, designated NCC-TGCT1-C1, was successfully established and could be used to study TGCT development and the effects of anticancer agents.

Establishment and characterization of NCC-MFS2-C1: a novel patient-derived cancer cell line of myxofibrosarcoma.

Myxofibrosarcoma (MFS) is among the most aggressive and complex sarcoma types that require novel therapeutic approaches for improved clinical outcomes. MFS displays highly complex karyotypes, and frequent alterations in p53 signaling and cell cycle checkpoint genes as well as loss-of-function mutations in NF1 and PTEN have been reported. The effects of radiotherapy and chemotherapy on MFS are limited, and complete surgical resection is the only curative treatment. Thus, the development of novel therapeutic strategies for MFS has long been long desired for MFS. Patient-derived cell lines are an essential tool for basic and translational research in oncology. However, public cell banks provide only a limited number of MFS cell lines. In this study, we aimed to develop a novel patient-derived MFS cell line, which was established from the primary tumor tissue of a 71-year-old male patient with MFS and was named NCC-MFS2-C1. A single-nucleotide polymorphism assay revealed that NCC-MFS2-C1 cells exhibited gain and loss of genetic loci. NCC-MFS2-C1 cells were maintained as a monolayer culture for over 24 passages for 10 months. The cells exhibited spindle-like morphology, continuous growth, and capacity for spheroid formation and invasion. Screening of 213 anticancer agents revealed that bortezomib, gemcitabine, romidepsin, and topotecan at low concentrations inhibited the proliferation of NCC-MFS2-C1 cells. In conclusion, we established a novel MFS cell line, NCC-MFS2-C1, which can be used for studying the molecular mechanisms underlying tumor development and for the in vitro screening of anti-cancer drugs.