Establishment and characterization of NCC-PS1-C1: a novel cell line of pleomorphic sarcoma from a patient after neoadjuvant radiotherapy

Pleomorphic sarcoma (PS) is a heterogeneous group of malignant mesenchymal tumors without a specific histological lineage of differentiation. PS is genetically characterized by genetic instability and diversity and histologically characterized by morphological pleomorphism. PS is one of the most common soft tissue sarcomas. The only curative treatment for PS is complete surgical resection, in which neoadjuvant radiotherapy is frequently combined. PS demonstrates both local recurrence and metastasis after surgical treatment, and effective systemic chemotherapy has not yet been established. Patient-derived cancer cell lines are critical tools for basic and preclinical studies in the development of chemotherapy. However, only six PS cell lines are available from the public cell bank, and none of them are derived from PS after neoadjuvant radiotherapy, despite the fact that radiotherapy causes changes in the posttreatment cancer genome. Here, we reported a novel cell line of PS from a primary tumor specimen resected after neoadjuvant radiotherapy and named it NCC-PS1-C1. NCC-PS1-C1 cells showed a variety of copy number alterations and pathological mutations in TP53. NCC-PS1-C1 cells demonstrated constant proliferation, spheroid formation, and invasion capability in vitro. The screening of antitumor agents in NCC-PS1-C1 cells showed that bortezomib and romidepsin were effective against PS. In conclusion, we report a novel PS cell line from a primary tumor resected after neoadjuvant radiotherapy. We believe that NCC-PS1-C1 will be a useful tool for the development of novel chemotherapies for PS, especially for recurrent cases after neoadjuvant radiotherapy.

Clinical Outcome of Patients with Pelvic and Retroperitoneal Bone and Soft Tissue Sarcoma: A Retrospective Multicenter Study in Japan

Simple Summary

We aimed to clarify the clinical outcomes of patients with pelvic and retroperitoneal bone and soft tissue sarcoma. The 3-year overall survival (OS), local control (LC) rate, and progression-free survival (PFS) were 71.7%, 79.1%, and 48.6%, respectively. The most influential poor prognostic factor for OS was distant metastasis, and for PFS, this was higher age (≥60 years). Larger primary tumor size (≥10 cm) was the only poor prognostic factor for LC. In the histological analysis, osteosarcoma showed significantly worse OS and PFS than other sarcomas in the pelvis and retroperitoneum.

Abstract

This study aimed to retrospectively analyze the clinical outcomes of patients with pelvic and retroperitoneal bone and soft tissue sarcoma (BSTS). Overall, 187 patients with BSTS in the pelvis and retroperitoneal region treated at 19 specialized sarcoma centers in Japan were included. The prognostic factors related to overall survival (OS), local control (LC), and progression-free survival (PFS) were evaluated. The 3-year OS and LC rates in the 187 patients were 71.7% and 79.1%, respectively. The 3-year PFS in 166 patients without any distant metastases at the time of primary tumor diagnosis was 48.6%. Osteosarcoma showed significantly worse OS and PFS than other sarcomas of the pelvis and retroperitoneum. In the univariate analyses, larger primary tumor size, soft tissue tumor, distant metastasis at the time of primary tumor diagnosis, P2 location, chemotherapy, and osteosarcoma were poor prognostic factors correlated with OS. Larger primary tumor size, higher age, soft tissue tumor, chemotherapy, and osteosarcoma were poor prognostic factors correlated with PFS in patients without any metastasis at the initial presentation. Larger primary tumor size was the only poor prognostic factor correlation with LC. This study has clarified the epidemiology and prognosis of patients with pelvic and retroperitoneal BSTS in Japan.

Establishment and characterization of NCC-DDLPS5-C1: a novel patient-derived cell line of dedifferentiated liposarcoma

Dedifferentiated liposarcoma (DDLPS) is a highly aggressive subtype of liposarcoma that is morphologically defined as a transition from a well-differentiated lipomatous component to a non-lipogenic one. Curative therapy for DDLPS is complete resection, and the benefits of current systemic chemotherapy remain marginal. Although DDLPS is molecularly characterized by co-amplification of MDM2 and CDK4 (12q14-15) and detailed genomic analyses have been conducted by multiple research groups, the effects of molecular targeted drugs are marginal, and novel therapeutic modalities are required. Although patient-derived cell lines are pivotal for cancer research, no DDLPS cell lines are currently available from public cell repositories. Accordingly, in this study, we established a novel DDLPS cell line, NCC-DDLPS5-C1, using surgically resected tumor tissues from a patient with DDLPS. NCC-DDLPS5-C1 cells exhibited typical gene amplification, overexpression of MDM2 and CDK4, and other DNA copy number alterations. The NCC-DDLPS5-C1 cells were capable of rapid cell proliferation, aggressive invasion, and spheroid formation, but not tumor formation in mice. We reported the utility of NCC-DDLPS5-C1 cells for a drug-response assay to detect anticancer drugs that significantly attenuated cell proliferation. Thus, we concluded that the NCC-DDLPS5-C1 cell line could be a useful resource for the study of DDLPS. Considering the diversity of disease in terms of clinical outcomes, continuous efforts are required to develop more patient-derived cancer models with different clinical and pathological backgrounds.

Establishment and Characterization of NCC-MFS5-C1: A Novel Patient-Derived Cell Line of Myxofibrosarcoma

Myxofibrosarcoma (MFS) is a highly aggressive malignancy with complex karyotypes and a postoperative recurrence tendency, owing to its strong invasiveness. Although systemic chemotherapy is considered in patients with unresectable MFS, the efficacy of conventional chemotherapy is hitherto unclear. Recently, drug screening analysis using a large number of tumor cell lines has been attempted to discover novel therapeutic candidate drugs for common cancers. However, the number of MFS cell lines is extremely small because of its low incidence-this hinders the conduction of screening studies and slows down the development of therapeutic drugs. To overcome this problem, we established a novel MFS cell line, NCC-MFS5-C1, which was shown to harbor typical MFS genetic abnormalities and thus had useful properties for in vitro studies. We conducted the largest integrated screening analysis of 210 drugs using NCC-MFS5-C1 cells along with four MFS cell lines, which we previously reported. Bortezomib (a proteasome inhibitor) and romidepsin (a histone deacetylase inhibitor) showed stronger antitumor effects than the standard drug, doxorubicin. Therefore, the NCC-MFS5-C1 cell line can potentially contribute to elucidating MFS pathogenesis and developing a novel MFS treatment.

Establishment and characterization of NCC-MPNST6-C1: a novel patient-derived cell line of malignant peripheral nerve sheath tumors

Malignant peripheral nerve sheath tumors (MPNSTs) are a rare subtype of mesenchymal tumors that arise from the sheath of peripheral nerves. MPNSTs exhibit strong metastatic potential, leading to poor clinical outcomes. The clinical utility of radiation therapy and chemotherapy is marginal with respect to overall survival and effective systematic therapies for MPNSTs are still needed to improve patient outcome. Although patient-derived cell lines are an essential tool for the development of novel therapies, only a limited number of cell lines have been reported and are available from cell banks. Thus, we established the novel MPNST cell line, NCC-MPNST6-C1, using surgically resected MPNST tissue. The NCC-MPNST6-C1 cells retained copy-number alterations similar to those of the original tumors and demonstrated constant proliferation, spheroid formation, and invasion capability in vitro, which reflected the malignant features of the original tumor tissue. While the NCC-MPNST6-C1 cells did not exhibit tumorigenesis in nude mice, their use in drug screening resulted in anti-cancer agents with low IC50 values. Hence, we conclude that the NCC-MPNST6-C1 cell line is a useful resource for the study of MPNSTs.

Establishment and characterization of NCC-UPS3-C1: a novel patient-derived cell line of undifferentiated pleomorphic sarcoma

Undifferentiated pleomorphic sarcoma (UPS), previously termed malignant fibrous histiocytoma, is one of the most aggressive sarcomas with no identifiable line of differentiation. Although the molecular mechanism of oncogenesis in UPS has not been clarified, radiation exposure is considered to be a risk factor in the development of UPS. In the treatment of UPS, surgical treatment remains the most important modality. While chemotherapy is considered in unresectable or metastatic cases, UPS is known to be refractory to conventional chemotherapy, leading to an unfavorable prognosis. To improve the clinical outcome of this condition, novel treatment methods are urgently needed. Patient-derived cell lines are essential tools in preclinical studies. However, owing to the rarity of UPS, only four UPS cell lines are publicly available. Thus, we established a novel UPS cell line, NCC-UPS3-C1, using a surgically resected tumor from a patient with radiation-associated UPS. NCC-UPS3-C1 cells had multiple genomic deletions including the tumor suppressor genes CDKN2A and CDKN2B. NCC-UPS3-C1 cells demonstrated constant growth, spheroid formation, and aggressive invasion ability. We also conducted a screening test using 214 drugs and identified that the histone deacetylase inhibitor, romidepsin, is highly effective on NCC-UPS3-C1 cells. Thus, we concluded that the NCC-UPS3-C1 cell line is a useful tool in preclinical studies for UPS.

Establishment and characterization of NCC-LGFMS1-C1: a novel patient-derived cell line of low-grade fibromyxoid sarcoma

Low-grade fibromyxoid sarcoma (LGFMS) is a rare soft-tissue sarcoma genetically characterized by the presence of the FUS-CREB3L2 gene fusion. While LGFMS exhibits indolent features during its early stages, the rates of recurrence, metastasis, and death from the disease are high. Presently, the role of FUS-CREB3L2 gene fusions in the unique features of LGFMS is not clear, and there is no modality to improve the clinical outcomes of patients with LGFMS; thus, extensive studies on LGFMS are required. Patient-derived cancer cell lines are critical tools for cancer research. However, no cell line has been established for LGFMS. Here, we aimed to develop a novel cell line for LGFMS and successfully established it using surgically resected tumor tissues. The cells, named NCC-LGFMS1-C1, possessed the same fusion genes as their original tumor and visible copy number variations. The cells had a fibroblastic appearance, formed spheroids when they were seeded in a low-attachment dish, and exhibited constant growth and invasion. Additionally, we demonstrated the feasibility of high-throughput drug screening using these cells. In conclusion, the NCC-LGFMS1-C1 cell line is a useful tool for studying LGFMS.

Establishment and characterization of novel patient-derived cell lines from giant cell tumor of bone

Giant cell tumor of bone (GCTB) is a locally aggressive and rarely metastasizing tumor. GCTB is characterized by the presence of unique giant cells and a recurrent mutation in the histone tail of the histone variant H3.3, which is encoded by H3F3A on chromosome 1. GCTB accounts for ~ 5% of primary bone tumors. Although GCTB exhibits an indolent course, it has the potential to develop aggressive behaviors associated with local recurrence and distant metastasis. Currently, complete surgical resection is the only curative treatment, and novel therapeutic strategies are required. Patient-derived cancer cell lines are critical tools for basic and pre-clinical research. However, only a few GCTB cell lines have been reported, and none of them are available from public cell banks. Therefore, we aimed to establish novel GCTB cell lines in the present study. Using curetted tumor tissues of GCTB, we established two cell lines and named them NCC-GCTB2-C1 and NCC-GCTB3-C1. These cells harbored a typical mutation in histones and exhibited slow but constant growth, formed spheroids, and had invasive capabilities. We demonstrated the utility of these cell lines for high-throughput drug screening using 214 anticancer agents. We concluded that NCC-GCTB2-C1 and NCC-GCTB3-C1 cell lines were useful for the in vitro study of GCTB.

Establishment and characterization of NCC-ssRMS2-C1: a novel patient-derived cell line of spindle cell/sclerosing rhabdomyosarcoma

Spindle cell/sclerosing rhabdomyosarcoma (ssRMS) is a rare subtype of rhabdomyosarcoma (RMS) that has fascicular spindle cell and/or sclerosing morphology. SsRMS has a diverse molecular background and is categorized into three groups: congenital/infantile ssRMS with a gene fusion involving the NCOA2 and VGLL2, ssRMS with the MYOD1 mutation, and ssRMS with no recurrent identifiable genetic alterations. Because ssRMS is a newly defined disease concept of RMS, the optimal treatment methods have not been determined. This results in unfavorable prognosis and consequently signals the urgent need for continuous research. Patient-derived cell lines are essential tools in basic and translational research. However, only two ssRMS cell lines with the MYOD1 mutation have been reported to date. Thus, we established a novel ssRMS cell line named NCC-ssRMS2-C1 using a surgically resected tumor tissue from an adult ssRMS patient. NCC-ssRMS2-C1 cells retained the copy number alterations corresponding to the original tumor and are categorized into the group with no recurrent identifiable genetic alterations. NCC-ssRMS2-C1 cells demonstrated constant proliferation, spheroid formation, and capability for invasion in vitro, reflecting the malignant features of the original tumor tissue. In a drug screening test, ssRMS demonstrated remarkable sensitivity to romidepsin, trabectedin, actinomycin D, and bortezomib. Hence, we conclude that the NCC-ssRMS2-C1 cell line is the first ssRMS cell line which belongs to the group with no recurrent identifiable genetic alterations, and it will be a useful resource in both basic and translational studies for ssRMS.

Establishment and characterization of NCC-MFS3-C1: a novel patient-derived cell line of myxofibrosarcoma

Myxofibrosarcoma (MFS) is one of the most aggressive sarcomas with highly complex karyotypes and genomic profiles. Although a complete resection is required in the treatment of MFS, it is often not achieved due to its strong invasive nature. Additionally, MFS is refractory to conventional chemotherapy, leading to poor prognosis. Therefore, it is necessary to develop novel treatment modalities for MFS. Patient-derived cell lines are important tools in basic research and preclinical studies. However, only 10 MFS cell lines have been reported to date. Furthermore, among these cell lines, merely two MFS cell lines are publicly available. Hence, we established a novel MFS cell line named NCC-MFS3-C1, using a surgically resected tumor specimen from a patient with MFS. NCC-MFS3-C1 cells had copy number alterations corresponding to the original tumor. NCC-MFS3-C1 cells demonstrate constant proliferation, spheroid formation, and aggressive invasion. In drug screening tests, the proteasome inhibitor bortezomib and the histone deacetylase inhibitor romidepsin demonstrated significant antiproliferative effects on NCC-MFS3-C1 cells. Thus, the NCC-MFS3-C1 cell line is a useful tool in both basic and preclinical studies for MFS.

Establishment and characterization of NCC-DDLPS3-C1: a novel patient-derived cell line of dedifferentiated liposarcoma

Dedifferentiated liposarcoma (DDLPS) is a highly malignant subtype of liposarcoma, with characteristic amplification of MDM2 and CDK4 (12q14-15). It is caused by the dedifferentiation of well-differentiated liposarcoma. DDLPS is refractory to conventional chemotherapy; thus, surgical resection is the primary treatment modality. However, complete resection of DDLPS is difficult because of its deep location, which results in poor prognosis. Therefore, novel systemic chemotherapy is required to improve the clinical outcome. Patient-derived cell lines are important tools in the development of novel chemotherapy. However, there are no DDLPS cell lines available from public cell banks. In this study, we established a novel DDLPS cell line, NCC-DDLPS3-C1, using a surgically resected specimen from a patient with DDLPS. NCC-DDLPS3-C1 cells retained the characteristic gene amplification of MDM2 and CDK4. In addition, other gene amplifications and losses related to the poor prognosis of DDLPS were also observed in concordance with the original tumor. The cells also exhibited rapid cell proliferation, aggressive invasion ability, spheroid formation ability, and tumorigenic ability in nude mice. Furthermore, a drug-screening test showed significant antiproliferative effects of proteasome inhibitors and HDAC inhibitors. Thus, the NCC-DDLPS3-C1 cell line should be a useful tool for the development of novel chemotherapy for DDLPS.

Establishment and characterization of NCC-SS4-C1: a novel patient-derived cell line of synovial sarcoma

Synovial sarcoma (SS) is defined as a monomorphic blue spindle cell sarcoma showing variable epithelial differentiation, and is characterized by a specific fusion gene, SS18-SSX. Although SS is rare, it accounts for approximately 8% of all soft tissue sarcomas, which occupies a significant proportion of soft tissue tumors. The prognosis of SS is unfavorable, with 5-year survival rate of 50-60%, and only a few anti-cancer agents are recommended for its treatment. Thus, we need to urgently establish novel treatment methods. Patient-derived cell lines are essential tools in basic research and pre-clinical studies. However, there are only 4 publicly available SS cell lines. Therefore, we established a novel SS cell line, NCC-SS4-C1, using surgically resected tumor tissues of a patient with SS. The cell line maintained the characteristic fusion gene, SS18-SSX1, and copy number alteration, in concordance with the original tumor. The cells also exhibited moderate cell proliferation, invasion ability, and spheroid formation ability. Moreover, a drug-screening test using 4 SS cell lines, including NCC-SS4-C1, demonstrated the significant anti-proliferative effects of ALK and HDAC inhibitors. Thus, we concluded that the NCC-SS4-C1 cell line is a useful tool for basic and pre-clinical studies of SS.

Standard Treatment Remains the Recommended Approach for Patients with Bone Sarcoma Who Underwent Unplanned Surgery: Report from the Japanese Musculoskeletal Oncology Group

Background

The outcomes of unplanned surgery for bone sarcomas have not been frequently discussed. However, it is important to recognize patterns, treatment, and clinical outcomes of unplanned surgeries for patients with bone sarcomas. This multicenter study aimed to characterize the clinical outcomes of patients with bone sarcomas who underwent unplanned surgeries.

Patients and Methods

Data of 43 patients with bone sarcomas who underwent unplanned surgery between 2006 and 2017 were obtained from 23 hospitals in Japan. These included 18 cases of osteosarcoma, 9 of Ewing sarcoma, 8 of chondrosarcoma, and 6 of undifferentiated pleomorphic sarcoma. The study included 28 men and 15 women, with a mean age of 46 years. The mean follow-up duration was 59 months.

Results

The main primary tumor sites were the femur (n = 19), spine (n = 6), pelvis (n = 5), tibia (n = 3), and humerus (n = 3). The primary diagnoses were benign bone tumor (n = 24), trauma (n = 7), bone metastasis (n = 5), osteomyelitis (n = 4), degeneration (n=2), and unknown (n = 1). As unplanned surgeries, curettage, with or without bone graft, was performed in 26 patients; internal fixation was performed in 7; spinal surgery in 5; arthroplasty in 4; and arthroscopy in one. Thirty-eight patients received additional standard treatments. Thirty-four of these patients underwent surgical tumor resections, including amputation (n = 10), and the remaining 4 received radiotherapy or carbon ion radiotherapy as additional standard treatments. The 5-year disease-specific survival (DSS) rates in patients with osteosarcoma, Ewing sarcoma, and chondrosarcoma were 65.5%, 58.3%, and 72.9%, respectively. Twelve (27.9%) patients developed local recurrences (LR); among the total 43 patients studied, the 5-year DSS rates were significantly worse for those who developed LR compared to those who did not (p = 0.03). The 5-year DSS rates in patients with and without LR were 44% and 73.8%, respectively.

Conclusion

We recommend that patients who have undergone unplanned surgery be administered standard treatment, including the option of amputation because herein, LR was shown to be a risk factor for decreased DSS.

Establishment and characterization of NCC-DDLPS1-C1: a novel patient-derived cell line of dedifferentiated liposarcoma

Dedifferentiated liposarcoma (DDLPS) is one of the four subtypes of liposarcomas; it is characterized by the amplification of the 12q13-15 region, which includes MDM2 and CDK4 genes. DDLPS has an extremely high local recurrence rate and is refractory to chemotherapy and radiation, which leads to poor prognosis. Therefore, a novel therapeutic strategy should be urgently established for improving the prognosis of DDLPS. Although patient-derived cell lines are important tools for basic research, there are no DDLPS cell lines available from public cell banks. Here, we report the establishment of a novel DDLPS cell line. Using the surgically resected tumor tissue from a patient with DDLPS, we established a cell line and named it NCC-DDLPS1-C1. The NCC-DDLPS1-C1 cells contained 12q13-15, 1p32, and 1q23 amplicons and highly expressed MDM2 and CDK4 proteins. NCC-DDLPS-C1 cells exhibited constant growth, spheroid formation, aggressive invasion, and tumorigenesis in mice. By screening a drug library, we identified that the proteasome inhibitor, bortezomib, had inhibitory effects on the proliferation of NCC-DDLPS1-C1 cells. We concluded that the NCC-DDLPS1-C1 cell line may serve as a useful tool for basic and pre-clinical studies of DDLPS.

Establishment and characterization of NCC-ASPS1-C1: a novel patient-derived cell line of alveolar soft-part sarcoma

Alveolar soft-part sarcoma is a mesenchymal malignancy characterized by the rearrangement of ASPSCR1 and TFE3 and a histologically distinctive pseudoalveolar pattern. Although alveolar soft-part sarcoma takes an indolent course, its long-term prognosis is poor because of late distant metastases. Currently, curative treatments have not been found for alveolar soft-part sarcoma, and hence, a novel therapeutic strategy has long been required. Patient-derived cell lines comprise an important tool for basic and preclinical research. However, few cell lines from alveolar soft-part sarcoma have been reported in the literature because it is an extremely rare malignancy, accounting for less than 1% of all soft-tissue sarcomas. This study aimed to establish a novel alveolar soft-part sarcoma cell line. Using surgically-resected tumor tissue of alveolar soft-part sarcoma, we successfully established a cell line and named it NCC-ASPS1-C1. The NCC-ASPS1-C1 cells harbored an ASPSCR1-TFE3 fusion gene and exhibited slow growth, and spheroid formation. On the other hand, NCC-ASPS1-C1 did not show the capability of invasion. We screened the antiproliferative effects of 195 anticancer agents, including Food and Drug Administration-approved anticancer drugs. We found that the MET inhibitor tivantinib and multi-kinase inhibitor orantinib inhibited the proliferation of NCC-ASPS1-C1 cells. The clinical utility and molecular mechanisms of antitumor effects of these drugs are worth investigating in the further studies, and NCC-ASPS1-C1 cells will be a useful tool for the in vitro study of alveolar soft-part sarcoma.

Establishment and characterization of NCC-ssRMS1-C1: a novel patient-derived spindle-cell/sclerosing rhabdomyosarcoma cell line

Spindle-cell/sclerosing rhabdomyosarcoma (ssRMS) is a rare subtype of rhabdomyosarcoma, characterized by unique pathological features. Although distinctive molecular backgrounds such as frequent mutations in MyoD1 have been reported, optimized therapy has not been fully developed, and further investigations are required. Patient-derived cancer models are critical tools for basic and pre-clinical studies. However, there is no model for ssRMS. Thus, this study aimed to develop a novel cell line from the tumor tissue of a patient with ssRMS. Using surgically resected tissue, we successfully established this cell line, named NCC-ssRMS1-C1. These cells exhibited spindle-shape morphology, consistent with the pathological observations of the original tumor tissue. Genetic studies demonstrated that NCC-ssRMS1-C1 cells retained original copy number alterations and the typical point mutation in MyoD1. Malignant phenotypes such as proliferation, spheroid formation, and invasion were confirmed in vitro by studying NCC-ssRMS1-C1 cells. Upon screening an anti-cancer agent library, sensitivity to conventional chemotherapeutic agents such as actinomycin D was revealed. We conclude that the NCC-ssRMS1-C1 cell line will be a useful resource for basic and pre-clinical studies.

Establishment and characterization of NCC-SS3-C1: a novel patient-derived cell line of synovial sarcoma

Synovial sarcoma is a rare malignancy of mesenchymal origin, characterized by a chromosomal translocation, t(X;18) (p11.2;q11.2). Wide surgical resection with radiation and cytotoxic chemotherapy is established as a standard treatment; however synovial sarcoma remains a high-grade sarcoma with poor prognosis, and novel anti-cancer agents and immunological approaches are currently being developed. The patient-derived cell line is a critical tool for basic and pre-clinical research. However, only a few patient-derived synovial sarcoma cell lines are publicly available from cell banks. Thus, the aim of this study was to establish and characterize a novel cell line for synovial sarcoma. Using a surgically resected tumor tissue from a 48-year-old female patient, we successfully established a cell line, named NCC-SS3-C1. NCC-SS3-C1 cells harbor an SS18-SSX1 fusion gene and exhibit moderate growth, spheroid formation, and invasion. We examined a range of proliferation-inhibiting effects of small molecule anti-cancer compounds, including FDA-approved anti-cancer drugs, using NCC-SS3-C1 cells, and identified anti-cancer drugs which inhibited the proliferation of NCC-SS3-C1 cells at the low concentration. We concluded that NCC-SS3-C1 would be a useful tool for basic and pre-clinical synovial sarcoma research.

Establishment and characterization of NCC-CDS2-C1: a novel patient-derived cell line of CIC-DUX4 sarcoma

CIC-DUX4 sarcoma (CDS), an aggressive soft tissue sarcoma, is characterized by a CIC and DUX4 rearrangement. It has a dismal clinical course and high metastatic rate and shows chemotherapy resistance; therefore, a novel therapeutic strategy is required. Patient-derived cell lines are indispensable tools for basic and preclinical research. However, only a few patient-derived CDS cell lines have been currently reported. Therefore, in this study, we aimed to establish and characterize a novel cell line of CDS. We successfully established the NCC-CDS2-C1 cell line by using surgically resected tumor tissue from a patient with CDS. The NCC-CDS2-C1 cells harbored a CIC-DUX4 fusion gene without insertion and exhibited rapid growth, spheroid formation, and invasion. We screened the antiproliferative effects of small anticancer agent compounds, which included FDA-approved anticancer drugs, on NCC-CDS2-C1 cells in comparison with those on the two previously reported patient-derived CDS cell lines, NCC-CDS1-X1-C1 and NCC-CDS1-X3-C1. The response profile of NCC-CDS2-C1 was similar to but distinct from those of the other cell lines for the small anticancer agent compounds. Therefore, we conclude that the NCC-CDS2-C1 cell line will be a useful tool for basic and preclinical studies of CDS.

Lymphatic routes of the stomach demonstrated by gastric carcinomas with solitary lymph node metastasis

To clarify whether or not the lymphatic routes that have long been generally accepted are indeed correct, we retrospectively examined the clinical records of patients with solitary lymph node metastasis from gastric carcinoma. From 735 patients gastrectomized with lymph node dissection (more than D1), 51 (7%) were histologically proven to have only one lymph node involved. In 44 of these 51 patients, the involved nodes were all in the perigastric region (N1). There were also 7 patients with a jumping metastasis to the N2-N3 nodes. Three of them were found along the left gastric artery (#7 according to Japanese classification) and the other 4 were found along either the common hepatic artery (#8) or the proper hepatic artery (#12). The depth of invasion was submucosal in 2, proper-muscular in 2, subserosal in 1, and serosa-exposed in 2, and the conclusive stage was II in 2, IIIa in 3, and IIIb in 2. However, 1 of these patients died of liver cirrhosis and 2 died of pneumonia, while the other 4 were still alive at the time of this report more than 5 years after surgery. These results suggest that not every sentinel node is located in the perigastric region near the primary tumor and that, if the preoperative examination indicates submucosal invasion, then a systematic regional lymph node dissection should therefore be carried out.

[Evaluation of intra-arterial infusion chemotherapy for advanced gastric cancer]

We evaluated the therapeutic efficacy of intraarterial infusion chemotherapy in advanced gastric cancer, its side effect and patient prognosis, in comparison with systemic infusion. Of 125 cases of advanced gastric cancer, 41 cases received intraarterial chemotherapy (A group) and the rest were given systemic infusion (S group). Protocols of chemotherapy were 5-FU + MTX in 49 cases, 5-FU + cisplatin in 62, and 5-FU + MMC in 14. Location of the disease was the peritoneum in 69 cases, nodes in 59, liver in 38, and other sites, 33. The response rate of A group was significantly higher than that of S group, at 31% and 13% respectively. Although 41% of cases showed side effects (> or = grade 2), there was no significant difference between the 2 groups. The median survival period and 1-year survival rate were 8.4 months and 35%, respectively, and there was no significant difference between the 2 groups. In cases with liver metastasis, the prognosis of A group was better than that of S group. The results suggest that intra-arterial infusion chemotherapy is an effective treatment for liver metastasis from gastric cancer.

[Effect of low-dose CDDP/5-FU therapy on thymidylate synthase content]

Low-dose therapy consisting of cisplatin plus 5-fluorouracil was given to 20 patients with advanced gastric cancer, and specimens were obtained to evaluate levels of 5-fluorodeoxyuridine (FdUMP) and thymidylate synthase (TS), indices of DNA, and proliferating nuclear cell antigen (PCNA). There was a significant correlation between the levels of FdUMP, total TS and free TS in cancer and in normal gastric mucosa, respectively. Total TS of cancer was higher than that of normal tissue, at 5.3 +/- 4.8 and 3.4 +/- 2.2 pmol/g, respectively. On the other hand, there was no relationship nor difference between The TSIR ratio of cancer and normal mucosa. The FdUMP levels of far advanced cancer showed a tendency to be lower than those of the less advanced one, especially in liver metastasis. The total TS was higher in intestinal type and in INF alpha or beta. The free TS was higher in invasive type, liver metastasis and curability C. The TSIR ratio showed a tendency to be lower in far advanced cases, such as invasive type and INF gamma. The correlation between DNA index and TS values and between PCNA labeling index and TS values were good. These results suggest that TS levels would be a predictor for malignant potential as well as for chemosensitivity.

[Radiation therapy for advanced gastric cancer]

Thirteen patients with advanced gastric cancer treated by palliative radiotherapy were retrospectively analyzed. The radiation sites were abdominal cavities in 8 cases, superficial masses in 5 and lung metastasis in one. The purposes were to diminish mass size in 5 cases, to relieve pain in 3 and to reduce stenosis in 6. The total doses were more than 40 Gy in 10 patients. In 2 cases, the intracavitary irradiation was performed using 192Ir. In one case, radiation had to be stopped at the dose of 22.5 Gy because of poor general condition. Partial response was obtained in 6 of 12 cases (RP, 50%). The sites of responders were superficial lesions in 4 and hepatic hilar mass in 2, which were given intracavitary as well as external radiation. Pain relief was achieved in all patients suffering from it. One of 3 cases with esophageal stenosis showed marked improvement in swallowing. Two patients showed a decrease in the levels of tumor markers. Five patients had side effects of more than grade 2. Two of them were grade 3, one thrombocytopenia and one diarrhea. The median survival time of all cases was 9 months, and 5 patients could shift to home care. These results suggest that palliative radiotherapy could be one of the most useful locoregional therapies for advanced gastric cancer, in the aspect of improvement of patient's QOL.

[A study of arterial infusion chemotherapy for gastric cancer patients with peritoneal metastasis]

We analyzed the clinical response, toxicities, out-patient and overall survival time among 41 gastric cancer patients with peritoneal metastasis to evaluate chemotherapies and drug delivery routes. Sixteen patients were treated by arterial infusion (AI) and 25 by systemic therapy (ST), with either 5-FU/MTX (FMTX) therapy or 5-FU/CDDP (FP) therapy. Partial response was observed in 8 patients (50%) among 16 with AI and in 6 (24%) among 25 with ST (p = 0.09). There were no differences in the incidence of side effects (> or = grade 2 according to WHO criteria) between AI and ST group, at 25% and 36%, respectively. No significant differences were observed in either survival time or home care duration among patients with AI chemotherapy and those with ST procedure.

[A study of chemotherapy for patients with severely advanced gastric cancer--comparison of chemotherapy and route]

We analyzed the clinical response, toxicities, ambulatory and overall survival time among 51 patients with inoperable gastric cancer, to evaluate chemotherapies and drug delivery routes. Twenty-nine patients were treated by Methotrexate/5-FU (FMTX) therapy and 22 by 5-FU/CDDP (FP) therapy. Twenty-five patients were treated by intra-arterial (IA) route and 26 by intra-venous (IV). The response rate of IA therapy was higher than that of IV therapy (p < 0.05), 48% and 19%, respectively. Median survival times of FMTX and FP were 361 and 289 days, respectively, and the 1-year survival rates of FMTX and FP were 44% and 33%, respectively, with no significant differences. Duration of home chemotherapy with FMTX was longer than that with FP, at 130 and 85 days, respectively. There was no difference between duration of home chemotherapy of IA and that of IV. IA chemotherapy showed a higher response rate than IV, but there were no differences in the incidence of side effects and ambulatory and overall survival time.

[Effect of low dose CDDP/5-fluorouracil therapy on PCNA labeling index and TS inhibition rate of gastric cancer]

The response of gastric cancer to intravenous application of low-dose CDDP plus 5-fluorouracil (FP) was assessed by changes in DNA indices (DIs) and PCNA labeling indices (LIs) by flow cytometry, and by the thymidylate synthetase inhibition rate (TSIR). Pretherapy samples were compared to specimens resected at operation. FP therapy was performed in 10 of 26 specimens and not in the others (C). There was no difference between change in DIs of FP group and that of C group. In FP group, PCNA LI of resected specimen was higher than that of biopsy, although they showed almost the same values in C group. Change in PCNA LIs correlated to TSIR in FP group. These results suggest that FP therapy affects gastric cancer cells in PCNA LIs and TSIR, and that PCNA LIs could be an indicator of the effect of FP therapy as TSIR.

[Methotrexate/5-fluorouracil therapy in gastric cancer with peritoneal metastasis]

Eighteen patients with gastric cancer with peritoneal metastasis were treated with methotrexate/5-fluorouracil sequential therapy. In four patients, a partial response was obtained and in another four, symptomatic relief was obtained by the therapy. As side effects, BM suppression was seen in 9 and GI symptoms in 6 patients. Intraaortic, low-dose and 3-hour-interval procedure are recommended in the therapy.