Frequent mutations of genes encoding vacuolar H+ -ATPase components in granular cell tumors.

Granular cell tumors (GCTs) are rare mesenchymal tumors that exhibit a characteristic morphology and a finely granular cytoplasm. The genetic alterations responsible for GCT tumorigenesis had been unknown until recently, when loss-of-function mutations of ATP6AP1 and ATP6AP2 were described. Thus, we performed whole-exome sequencing, RNA sequencing, and targeted sequencing of 51 GCT samples. From these genomic analyses, we identified mutations in genes encoding vacuolar H+ -ATPase (V-ATPase) components, including ATP6AP1 and ATP6AP2, in 33 (65%) GCTs. ATP6AP1 and ATP6AP2 mutations were found in 23 (45%) and 2 (4%) samples, respectively, and all were truncating or splice site mutations. In addition, seven other genes encoding V-ATPase components were also mutated, and three mutations in ATP6V0C occurred on the same amino acid (isoleucine 136). These V-ATPase component gene mutations were mutually exclusive, with one exception. These results suggest that V-ATPase function is impaired in GCTs not only by loss-of-function mutations of ATP6AP1 and ATP6AP2 but also through mutations of other subunits. Our findings provide additional support for the hypothesis that V-ATPase dysfunction promotes GCT tumorigenesis.

Definitive surgery of primary lesion should be prioritized over preoperative chemotherapy to treat high-grade osteosarcoma in patients aged 41-65 years.

BACKGROUND: Recently, the number of osteosarcomas in middle-aged and older patients has demonstrated an increasing trend; moreover, their results are comparatively worse than those of young patients. In Europe and the USA, the prognosis for osteosarcoma in middle-aged and older patients has improved with adjuvant chemotherapy. In Japan, however, the prognosis has remained poor. MATERIALS AND METHODS: We retrospectively analyzed the outcomes of osteosarcoma, especially in regards to preoperative chemotherapy, from January 1980 to July 2014. A total of 29 patients with high-grade osteosarcoma between the age of 40 and 65 years were included. We included patients without distant metastasis and with primary lesions that were deemed resectable. The mean age was 52.8 years (range 41-65 years), and the mean follow-up period was 103.2 months (range 5-314 months). RESULTS: Adjuvant chemotherapy was administered to 27 of 29 patients (93%), and 8 of 15 cases (53%) were able to undergo preoperative chemotherapy as planned, including CDDP. A major complication of chemotherapy was acute kidney injury due to CDDP (26%). The 5-year OS and 5-year EFS were 64.9% and 57.1%, respectively. After 2006, a policy to prioritize the resection of the primary lesion was implemented, and if the primary lesion was deemed resectable, preoperative chemotherapy was either not administered or administered for only a short duration. The 5-year OS after 2006 improved to 78.8%. CONCLUSIONS: This study shows that administration of high-dose intensity preoperative chemotherapy was difficult in middle-aged and older patients due to their high rate of acute kidney injury by CDDP. For cases of osteosarcoma in middle-aged and older patients, if the primary lesion is resectable, preoperative chemotherapy should be minimized to prioritize the resection of the primary lesion. It was considered that, with appropriate measures to prevent complications, adjuvant chemotherapy may lead to improved prognosis. LEVEL OF EVIDENCE: V.

Case of mesenchymal tumor with the PPP6R3-USP6 fusion, possible nodular fasciitis with malignant transformation.

Nodular fasciitis (NF) is a self-limiting benign disease that is characterized by rapid proliferation of fibroblastic and myofibroblastic cells. The characteristic gene fusion containing the USP6 gene is a genetic hallmark of NF and MYH9-USP6 is the most frequent fusion, suggesting that NF is not a reactive condition but a neoplastic disease. Malignant transformation of NF has been reported rarely as a single case associated with the PPP6R3-USP6 fusion. Here we report a case of soft part tumor of which the histological feature was a typical NF but showed aggressive and non-regressing growth with local invasion. Targeted RNA sequencing and fluorescence in situ hybridization analysis identified PPP6R3-USP6 with gene amplification. These findings indicate that the present case is the second case of malignant NF, and we suggest potential malignant transformation in certain NF cases.

Giant cell tumor of the distal femur: Outcome beyond 20 years of follow-up after curettage with polymethylmethacrylate.

BACKGROUND: Polymethymethacrylate (PMMA) is often used to reconstruct defects after curettage of Giant Cell Tumors (GCT). While GCTs usually originate in the epiphysis, the use of PMMA in distal femoral lesions may induce the risk of degenerative osteoarthritis (OA). We investigated the limb function of patients after curettage with PMMA beyond 20 years of follow-up. METHODS: Patients with more than 20 years of follow-up who underwent curettage with PMMA for distal femoral GCTs were observed. We retrospectively investigated the radiographic assessment of OA and functional assessment of the limb. The Kellgren and Lawrence (KL) grading system was used for radiographic evaluation. RESULTS: Five patients were included in this study. The mean age was 33 years, and the mean period from application of PMMA to final follow-up observation was 28.1 years. Four lesions were primary, and one lesion was recurrent. There were no patients with postoperative recurrence. There were no OA changes in preoperative radiographs. The shortest mean distance from PMMA to the articular cartilage was 4.6 mm on radiographs immediately after surgery. On radiographs at final follow-up observation, the KL grading were as follows: grade 1, 2 patients; grade 2, 1 patient; grade 3, 2 patients. All patients were able to independently ambulate without a crutch, and there was not enough pain to require nonsteroidal anti-inflammatory drugs. The mean flexion of the knee joint was 116°. CONCLUSIONS: Although PMMA used for distal femoral GCTs exhibited OA changes beyond a 20 year follow-up period, there were no cases requiring artificial joints, and the affected limbs demonstrated good function.

Pulmonary metastasis from giant cell tumor of bone: clinical outcome prior to the introduction of molecular target therapy.

OBJECTIVE: We analyzed the risk factors for pulmonary metastasis from giant cell tumor of bone and aimed to discuss their therapeutic strategy and appropriate follow-up period. METHODS: We analyzed 141 patients of giant cell tumor of bone. The variables analyzed included age, gender, primary site, Campanacci grading, surgical treatment on the primary lesion, radiotherapy and local recurrence. RESULTS: Pulmonary metastasis occurred in 12 patients. The risk factors were young age, Campanacci Grade III and local recurrence. Median time from initial surgery to metastasis was 1.3 years (0-3.1 years). Among them, eight patients experienced local recurrence of the primary tumor, and the median time from initial surgery to local recurrence was 0.8 years (0.3-2.9 years). Among seven patients who underwent wide resection, three patients showed local recurrence of the soft tissue. Nine patients underwent metastasectomy for pulmonary metastases. Of three patients who did not undergo metastasectomy, one patient died of uncontrollable metastases, and two patients showed no changes in their metastatic lesions. CONCLUSIONS: Although we found a correlation between local recurrence and pulmonary metastasis, we were still unable to prevent local or metastatic recurrence by wide resection. Local recurrence and metastasis have been found within ~3 years after initial surgery, and routine image examinations of the primary site and chest after initial surgical treatment should be considered for at least 3 years postoperatively.

Multicentric giant cell tumor of bone: Case series of 4 patients.

BACKGROUND: We aimed to retrospectively investigate patients with multicentric giant cell tumor (MCGCT) who were treated at our hospital and to clarify their clinical features, treatment policy, and follow-up method. METHODS: Four patients with two or more giant cell tumor (GCT) that occurred in the same patient were treated at our institution between 1978 and 2015. These patients were evaluated for the following: frequency, age of onset, number and site of occurrence, time to occurrence of the next lesion, treatment, recurrence, malignant transformation, metastasis, and oncological outcome. RESULTS: The rate of occurrence was 1.7%. The average age was 25.2 (17-44). The total number of lesions was three in two cases and two in two cases. All four cases had only one lesion during the initial visit. The most frequent site of occurrence was the proximal femur, followed by two lesions that occurred in the metaphysis. The interval between confirmation of the initial lesion and occurrence of the second lesion was in average 12.1 years (0.8-27.0). Initial presentations of lesions were treated by en bloc resection in one case and curettage in three cases. Local recurrences occurred in two cases that underwent curettage. The six lesions that occurred after the initial lesion were treated as follows: en bloc resection in four lesions, curettage and radiation therapy in one, and embolization and radiation therapy in one. Pathologically, no lesions presented malignancy. Pulmonary metastasis occurred in one case. The oncological outcome was NED in three cases and AWD in one case. CONCLUSIONS: No lesions were malignant, and by providing the same treatment as solitary GCT, the oncological outcome was good. It is unnecessary to be concerned of its risks and postoperatively conduct long-term searches for focal lesions across the body.

Cystatin C as a p53-inducible apoptotic mediator that regulates cathepsin L activity.

In response to various cellular stresses, p53 is activated and inhibits malignant transformation through the transcriptional regulation of its target genes. However, the full picture of the p53 downstream pathway still remains to be elucidated. Here we identified cystatin C, a major inhibitor of cathepsins, as a novel p53 target. In response to DNA damage, activated p53 induced cystatin C expression through p53 binding sequence in the first intron. We showed that cathepsin L activity was decreased in HCT116 p53(+/+) cells after adriamycin treatment, but not in HCT116 p53(-/-) cells. We also found that knockdown of cystatin C reduced adriamycin-induced caspase-3 activation. Cystatin C expression was significantly downregulated in breast cancer cells with p53 mutations, and decreased cystatin C expression was associated with poor prognosis of breast cancer. Our findings revealed an important role of the p53-cystatin C pathway in human carcinogenesis.

Risk factors for distant metastasis of dermatofibrosarcoma protuberans.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) may recur locally but rarely metastasizes. Fibrosarcomatous transformation in dermatofibrosarcoma protuberans (FS-DFSP) is said to have worse prognosis compared with ordinary DFSP (O-DFSP). Since DFSP rarely metastasizes, there have been few reports summarizing data on distant metastasis cases at single institution. The aim of this retrospective study is to review DFSP cases in order to analyze risk factors for metastasis. PATIENTS AND METHODS: This retrospective study involved 67 patients. We analyzed O-DFSP and FS-DFSP metastasis rates, metastasis sites, time to metastasis, the relationship between frequency of local recurrence and metastasis, and the relationship between primary tumor size and metastasis. RESULTS: Distant metastasis was found in 5 (7.4 %) of 67 cases with DFSP. Of the five cases, the histopathological diagnosis was FS-DFSP in four cases and O-DFSP in one case. Out of five cases with metastasis, three had not recurred and two had recurred twice. No clear correlation was identified (Fisher's exact test: p = 0.216). The primary tumor diameters in the metastatic cases were 15.0, 12.6, 20.5, 13.0, and 5.0 cm, respectively. The tumor diameters in metastatic cases were significantly larger (Fisher's exact test: p < 0.0001). CONCLUSIONS: In this study, we identified a stronger correlation between DFSP metastasis and tumor size. There was a high possibility that the cases with large tumors might be FS-DFSP, having high rate of metastasis and poor prognosis. In treatment of DFSP, early diagnosis before primary tumor growth and wide resection is considered important.

Bipolar Head Perforation With Rhabdomyosarcoma of the Thigh: A Case Report With Literature Review.

Background/Aim: High complication rates during the perioperative management of sarcomas around the pelvis have been reported; however, few include the detailed clinical course or complications in the late postoperative period. Radiotherapy is a multidisciplinary strategy for treating sarcomas. However, irradiated bone and soft tissues show a permanent loss of repair and immunocompetence. We present a case of pleomorphic rhabdomyosarcoma of the thigh that resulted in acetabular collapse induced by radiation and intestinal perforation during long-term follow-up. Additionally, we discuss the risk factors for late complications and pelvic reconstruction methods. Case Report: A 75-year-old man presented with a 1-month history of a recurring fever. Ten years prior, he was diagnosed with pleomorphic rhabdomyosarcoma of the right thigh and underwent a wide resection and bipolar hip arthroplasty, followed by chemotherapy and radiotherapy. Radiographs showed central dislocation of the bipolar head. Computed tomography revealed free air in the hip joint and thickening of the colon wall. Colonoscopy revealed displacement of the bipolar head into the colon wall. Colon resection and hip disarticulation were performed, as the bipolar head was contaminated with intestinal contents. Currently, he is able to walk stably with a walker, and there is no evidence of recurrence or metastasis of the tumor. Conclusion: Irradiation of the periacetabular bone may induce resorptive destruction, resulting in future structural failure. Hardware should not be used for periacetabular bone reconstruction; the risk of pelvic organ damage should be considered when the acetabular collapse becomes deteriorated. Therefore, other reliable and permanent reconstruction options are required.

Melorheostosis With Uniform Rib Thickening.

ABSTRACT: A 16-year-old girl presented with left chest pain. Radiography and CT revealed localized abnormal calcification in the left sixth rib and sixth thoracic vertebra. Bone scintigraphy confirmed abnormal uptake of 99m Tc in the same area. An open biopsy of the sixth rib was performed, leading to the diagnosis of melorheostosis. This case showed uniformly thickened calcification throughout the rib, unlike the typical "dripping candle wax" radiography finding associated with melorheostosis. This case implies the importance of open biopsy for diagnostic confirmation in cases with atypical imaging features.

A New Deep Learning Algorithm for Detecting Spinal Metastases on Computed Tomography Images.

STUDY DESIGN: Retrospective diagnostic study. OBJECTIVE: To automatically detect osteolytic bone metastasis lesions in the thoracolumbar region using conventional computed tomography (CT) scans, we developed a new deep learning (DL)-based computer-aided detection model. SUMMARY OF BACKGROUND DATA: Radiographic detection of bone metastasis is often difficult, even for orthopedic surgeons and diagnostic radiologists, with a consequent risk for pathologic fracture or spinal cord injury. If we can improve detection rates, we will be able to prevent the deterioration of patients' quality of life at the end stage of cancer. MATERIALS AND METHODS: This study included CT scans acquired at Tokyo Medical and Dental University (TMDU) Hospital between 2016 and 2022. A total of 263 positive CT scans that included at least one osteolytic bone metastasis lesion in the thoracolumbar spine and 172 negative CT scans without bone metastasis were collected for the datasets to train and validate the DL algorithm. As a test data set, 20 positive and 20 negative CT scans were separately collected from the training and validation datasets. To evaluate the performance of the established artificial intelligence (AI) model, sensitivity, precision, F1-score, and specificity were calculated. The clinical utility of our AI model was also evaluated through observer studies involving six orthopaedic surgeons and six radiologists. RESULTS: Our AI model showed a sensitivity, precision, and F1-score of 0.78, 0.68, and 0.72 (per slice) and 0.75, 0.36, and 0.48 (per lesion), respectively. The observer studies revealed that our AI model had comparable sensitivity to orthopaedic or radiology experts and improved the sensitivity and F1-score of residents. CONCLUSION: We developed a novel DL-based AI model for detecting osteolytic bone metastases in the thoracolumbar spine. Although further improvement in accuracy is needed, the current AI model may be applied to current clinical practice. LEVEL OF EVIDENCE: Level III.

Prevalence of Precursory Signs of Atypical Femoral Fractures in Patients Receiving Bone-Modifying Agents for Bone Metastases: A Cross-Sectional Study.

Patients on bone-modifying agents (BMAs) for bone metastases are at risk of atypical femoral fractures (AFFs), which can lead to a sudden deterioration in performance status. In this study, we sought to determine the prevalence of radiographic precursory signs of AFF in patients on oncologic BMAs. Forty-two patients (23 men, 19 women; mean age 68.8 ± 10.0 years) on oncologic BMAs (zoledronate for >3 years and/or denosumab for >1 year) and without clinical symptoms were enrolled between 2019 and 2021. All patients were receiving denosumab at enrollment and 5 had previously used zoledronate. The mean duration of BMA use was 31.2 ± 18.5 months. Radiographs of both femurs were screened for precursory signs of AFF (e.g., thickening of the lateral cortex). The patients were divided into two groups according to thickening status and compared by duration of BMA use. They were also divided into three groups by duration of BMA use (12-23 months, n = 18; 24-59 months, n = 19; ≥60 months, n = 5), and the prevalence of apparent thickenings was examined. As a result, 18 patients (42.9%) showed minute local or diffuse thickening and 10 (23.8%) showed apparent local thickening. The duration of BMA use was significantly longer in patients with apparent thickening than in those without (47.3 ± 23.6 months [n = 10] versus 26.2 ± 13.5 months [n = 32]; p < 0.05). The prevalence of apparent thickening increased with increasing duration of BMA use (12-23 months, 5.6%; 24-59 months, 31.6%; ≥60 months, 60.0%). In conclusion, radiographic precursory signs of AFF are common in patients on oncologic BMAs. Radiographic screening for AFF could be relevant in patients who have been on long-term oncologic BMAs, even if asymptomatic. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

S100-negative epithelioid malignant peripheral nerve sheath tumor with possible perineurial differentiation.

Epithelioid malignant peripheral nerve sheath tumor (MPNST) is a rare subtype of MPNST composed of epithelioid cells with abundant cytoplasm. Currently, strong and diffuse immunostaining for S100 protein and SOX10 is generally regarded as a characteristic feature of epithelioid MPNST. However, malignant tumors with epithelioid morphology that arise from a peripheral nerve or a pre-existing benign nerve sheath tumor should be regarded as epithelioid MPNSTs when they do not show characteristic features that definitively lead to other specific diagnoses. Here, we describe 3 cases of epithelioid MPNST in the peripheral nerve or schwannoma that was negative for S100 protein and SOX10 expression. Instead, these tumors were positive for EMA, GLUT1, claudin 1, and cytokeratin to varying degrees, while all of them retained SMARCB1 and H3K27me3 by immunohistochemistry. EMA, GLUT1, and claudin 1 are known markers of perineurial cell differentiation; thus, they could possibly represent epithelioid MPNST with perineurial cell differentiation.

Targeting Podoplanin for the Treatment of Osteosarcoma.

PURPOSE: Osteosarcoma, the most common bone malignancy in children, has a poor prognosis, especially when the tumor metastasizes to the lungs. Therefore, novel therapeutic strategies targeting both proliferation and metastasis of osteosarcoma are required. Podoplanin (PDPN) is expressed by various tumors and is associated with tumor-induced platelet activation via its interaction with C-type lectin-like receptor 2 (CLEC-2) on platelets. We previously found that PDPN contributed to osteosarcoma growth and metastasis through platelet activation; thus, in this study, we developed an anti-PDPN humanized antibody and evaluated its effect on osteosarcoma growth and metastasis. EXPERIMENTAL DESIGN: Nine osteosarcoma cell lines and two osteosarcoma patient-derived cells were collected, and we evaluated the efficacy of the anti-DPN-neutralizing antibody PG4D2 and the humanized anti-PDPN antibody AP201, which had IgG4 framework region. The antitumor and antimetastasis effect of PG4D2 and AP201 were examined in vitro and in vivo. In addition, growth signaling by the interaction between PDPN and CLEC-2 was analyzed using phospho-RTK (receptor tyrosine kinase) array, growth assay, or immunoblot analysis under the supression of RTKs by knockout and inhibitor treatment. RESULTS: We observed that PG4D2 treatment significantly suppressed tumor growth and pulmonary metastasis in osteosarcoma xenograft models highly expressing PDPN. The contribution of PDGFR activation by activated platelet releasates to osteosarcoma cell proliferation was confirmed, and the humanized antibody, AP201, suppressed in vivo osteosarcoma growth and metastasis without significant adverse events. CONCLUSIONS: Targeting PDPN with a neutralizing antibody against PDPN-CLEC-2 without antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity is a novel therapeutic strategy for PDPN-positive osteosarcoma.

Surgical Treatment of Intramuscular Myxoma.

PURPOSE: Intramuscular myxoma (IM) is a rare benign myxoid tumor that may be challenging to differentiate from sarcoma in small amounts of biopsied material. Although IM appears to be well-circumscribed macroscopically, it infiltrates the adjacent edematous muscle microscopically. The recommended treatment is resection, but there is controversy with regard to the appropriate surgical margin. This study aimed to clarify which surgical procedure that should be applied when the preoperative diagnosis is IM and how to manage treatment if the postoperative diagnosis turns out to be a sarcoma. METHODS: We retrospectively examined 55 IM patients treated from January 1982 to December 2014. Patient characteristics, tumor location, tumor size, radiograph, preoperative and postoperative pathological reports, surgical techniques, treatment outcome, and complications were reviewed. The patients were followed up on for at least 5 years. All patients were confirmed not to have Mazabraud syndrome. RESULTS: In the 55 IM patients examined, the mean patient age was 48 years and most were female. The most common tumor locations were in the muscles of the thighs (47%) and buttocks (20%). The mean tumor diameter was 5 cm. Wide resection and marginal resection were performed in 24 and 31 patients, respectively. The mean follow-up duration was 19 years. No local recurrence, malignant transformation, or complications were observed. CONCLUSIONS: Marginal resection is suitable in patients whose preoperative diagnosis is IM, as it is able to prevent local recurrence and allows for the preservation of muscle and muscle fascia. If the postoperative diagnosis turns out to be myxoid sarcoma, minimum surgical contamination makes additional wide resection less invasive.

Pre-treatment Neutrophil-to-Lymphocyte Ratio Predicts Efficacy of Eribulin for Soft-tissue Sarcoma.

BACKGROUND: Eribulin is widely used for the treatment of breast cancer and soft-tissue sarcoma (STS). Previous studies identified the pre-treatment absolute lymphocyte count, baseline neutrophil-to-lymphocyte ratio (NLR) and C-reactive protein concentration as potential prognostic markers in patients with breast cancer treated with eribulin. However, prognostic factors for eribulin treatment in patients with STS have not been identified. PATIENTS AND METHODS: This was a retrospective analysis of data collected prospectively from 53 patients who were treated with eribulin for recurrent or metastatic STS between March 2016 and August 2019. Univariate and multivariate analyses were performed to determine the predictive factors of durable clinical benefit, progression-free survival, and overall survival. RESULTS: L-Sarcoma histology [hazard ratio (HR)=28.20, 95% confidence intervaI (CI)=1.67-476.00; p=0.021] and pre-treatment NLR <3.0 (HR=9.96, 95% CI=1.28-77.7; p=0.028) were independent factors predictive of durable clinical benefit. In addition, pre-treatment NLR <3.0 (HR=0.34, 95% CI=0.16-0.74; p=0.0059) and male sex (HR=0.23, 95% CI=0.10-0.52; p<0.001) were independent factors predictive of better progression-free survival. CONCLUSION: This retrospective study found that baseline NLR predicts the efficacy of eribulin for STS.

Differences in the efficacy and safety of eribulin in patients with soft tissue sarcoma by histological subtype and treatment line.

Clinical evidence regarding eribulin treatment for patients with soft tissue sarcoma (STS) is limited to those with L-sarcoma (leiomyosarcoma and liposarcoma) who have completed at least two chemotherapies. Whether histological subtypes and treatment lines affect the efficacy and safety of eribulin for patients with STS has yet to be elucidated. The current study retrospectively reviewed patients with STS receiving eribulin at the Cancer Institute Hospital of JFCR and evaluated the prognostic factors affecting its efficacy and safety by histological diagnoses and treatment lines. A total of 41 patients with STS, including 26 with L-sarcoma, underwent eribulin treatment. Additionally, a total of and 14 patients, including 12 with L-sarcoma, received eribulin as a second-line treatment. The results revealed that patients with L-sarcoma demonstrated longer progression-free survival (PFS) rates compared with patients without L-sarcoma (4.5 vs. 2.3 months; P=0.005). Furthermore, differences in treatment line significantly affected PFS (4.5 months in second-line treatment vs. 2.4 months in later lines; P=0.037). A high number of patients with L-sarcoma received eribulin as a second-line treatment. Regarding safety, several adverse events were reported, such as neutropenia, which were more frequently observed in patients with L-sarcoma or other patients receiving eribulin as a second-line treatment. However, most adverse events were tolerable. The clinical efficacy of eribulin was increased in patients with L-sarcoma, which was similar to previous clinical trials. However, treatment lines could also affect its efficacy. When evaluating the clinical value of eribulin to STS, it is important to consider treatment lines.

Platelet-derived lysophosphatidic acid mediated LPAR1 activation as a therapeutic target for osteosarcoma metastasis.

Osteosarcoma is the most common primary malignant bone cancer, with high rates of pulmonary metastasis. Osteosarcoma patients with pulmonary metastasis have worse prognosis than those with localized disease, leading to dramatically reduced survival rates. Therefore, understanding the biological characteristics of metastatic osteosarcoma and the molecular mechanisms of invasion and metastasis of osteosarcoma cells will lead to the development of innovative therapeutic intervention for advanced osteosarcoma. Here, we identified that osteosarcoma cells commonly exhibit high platelet activation-inducing characteristics, and molecules released from activated platelets promote the invasiveness of osteosarcoma cells. Given that heat-denatured platelet releasate maintained the ability to promote osteosarcoma invasion, we focused on heat-tolerant molecules, such as lipid mediators in the platelet releasate. Osteosarcoma-induced platelet activation leads to abundant lysophosphatidic acid (LPA) release. Exposure to LPA or platelet releasate induced morphological changes and increased invasiveness of osteosarcoma cells. By analyzing publicly available transcriptome datasets and our in-house osteosarcoma patient-derived xenograft tumors, we found that LPA receptor 1 (LPAR1) is notably upregulated in osteosarcoma. LPAR1 gene KO in osteosarcoma cells abolished the platelet-mediated osteosarcoma invasion in vitro and the formation of early pulmonary metastatic foci in experimental pulmonary metastasis models. Of note, the pharmacological inhibition of LPAR1 by the orally available LPAR1 antagonist, ONO-7300243, prevented pulmonary metastasis of osteosarcoma in the mouse models. These results indicate that the LPA-LPAR1 axis is essential for the osteosarcoma invasion and metastasis, and targeting LPAR1 would be a promising therapeutic intervention for advanced osteosarcoma.

Changes in Neutrophil-to-lymphocyte Ratio Predict Efficacy of Trabectedin for Soft-tissue Sarcoma.

Background/Aim: Trabectedin and eribulin are widely used for the treatment of soft-tissue sarcoma (STS). Previously it was shown that the baseline neutrophil-to-lymphocyte ratio (NLR) predicts the efficacy of eribulin for STS. However, prognostic factors for trabectedin on STS have not been identified to date. Patients and Methods: We conducted a retrospective study of data collected prospectively from 39 patients treated with trabectedin for recurrent or metastatic STS between October 2012 and December 2019. To determine the predictive factors of overall survival (OS) and progression-free survival (PFS), univariate and multivariate analyses were performed. Results: Age ≥40 (HR=0.33, 95% CI=0.15-0.71; p=0.0050) and changes in NLR (ΔNLR) <0.5 (HR=2.40, 95% CI-1.01-5.72; p=0.048) were independent factors predictive of longer OS. In addition, age ≥40 (HR=0.23, 95% CI=0.10-0.52; p<0.001) was an independent predictor of longer PFS. Conclusion: Changes in NLR and age ≥40 years were able to predict the efficacy of trabectedin for STS.

Pre-Treatment Neutrophil-to-Lymphocyte Ratio (NLR) as a Predictive Marker of Pazopanib Treatment for Soft-Tissue Sarcoma.

Pazopanib with trabectedin and eribulin is widely used to treat soft-tissue sarcoma (STS). We have shown that baseline neutrophil-to-lymphocyte ratio (NLR) may predict the efficacy and patient prognosis of eribulin. Changes in NLR, but not baseline NLR, can predict patient prognosis of trabectedin. However, prognostic factors of pazopanib for STS have not been identified. We present a retrospective analysis of 141 patients treated with pazopanib for recurrent or metastatic non-round cell STS. Univariate and multivariate analyses were performed to determine the predictive factors of durable clinical benefit (DCB), overall survival (OS), and progression-free survival. L-sarcoma histology (odds ratio [OR] = 0.31, 95% CI = 0.12-0.79; p = 0.014) and pre-treatment NLR < 3.0 (OR = 2.03, 95% CI = 1.02-6.67; p = 0.045) were independent predictive factors of DCB. Pre-treatment NLR < 3.0 (hazard ratio [HR] = 0.55, 95% CI = 0.36-0.84; p = 0.0057), liposarcoma histology (HR = 1.78, 95% CI = 1.09-2.91; p = 0.022), primary extremity site (HR = 0.48, 95% CI = 0.31-0.75; p = 0.0010), ECOG PS ≥ 1 (HR = 1.62, 95% CI = 1.08-2.42; p = 0.019), and CRP < 0.3 (HR = 0.52, 95% CI = 0.33-0.82; p = 0.0050) were independent predictive factors of OS. These findings indicate that baseline NLR predicts the efficacy and patient prognosis of pazopanib for STS.