Sirolimus monotherapy for Kasabach-Merritt phenomenon in a neonate; Case report.

INTRODUCTION AND IMPORTANCE: The Kasabach-Merritt Phenomenon (KMP), characterized by thrombocytopenia and consumptive coagulopathy due to endothelial cell growth in the infantile vascular tumor kaposiform hemangioendothelioma, presents a therapeutic challenge. This case highlights the novel use of sirolimus in a neonate, an approach less explored in this age group. CASE PRESENTATION: A female neonate presented with a right anterior chest mass, progressing to respiratory distress and congestive heart failure. Diagnosed with KMP, she exhibited low platelet count and coagulation abnormalities. Treatment with sirolimus (0.06 mg/day) led to mass reduction, improved bleeding, and a stable tumor after 12 months, without side effects. This case contrasts with existing literature advocating for combination therapy or higher sirolimus concentrations for effective treatment. Yet, our patient achieved favorable outcomes with low-dose monotherapy, suggesting a potentially safer approach in neonates with immature hepatic and renal metabolism. CLINICAL DISCUSSION: This case demonstrates the efficacy of low-dose sirolimus monotherapy in treating KMP in a neonate, challenging current preferences for combination therapies or higher doses. It emphasizes the need for further research into age-specific treatment protocols in KMP, considering the unique metabolic profiles of neonates and infants. CONCLUSION: Sirolimus has demonstrated potential in treating KMP in pediatric patients. While initial results are promising, determining optimal dosages and trough concentrations, especially in neonates and infants, remains essential.

Drug-induced Interstitial Nephritis in a Patient with Ulcerative Colitis Treated with 5-Aminosalicylic Acid.

This report describes the case of a 76-year-old man with ulcerative colitis who developed interstitial nephritis after starting 5-Aminosalicylic acid (5-ASA) therapy. The patient experienced an initial improvement in symptoms, but developed fatigue, anorexia, and severe renal dysfunction 2.5 months later. Renal biopsy confirmed drug-induced interstitial nephritis, and conservative treatment with fluid replacement and the discontinuation of 5-ASA improved the patient's condition. Clinicians should monitor patients receiving 5-ASA therapy for potential adverse effects, particularly renal injury, and promptly investigate symptoms of renal dysfunction. Early recognition and discontinuation of the offending agent may prevent further damage and improve patient outcomes.

A Natural Organic Compound "Decursin" Has Both Antitumor and Renal Protective Effects: Treatment for Osteosarcoma.

Osteosarcoma is a rare malignant tumor that commonly occurs in children. Anticancer drugs, for example, cisplatin, aid in postsurgery recovery but induce side effects such as renal damage, affecting the life prognosis of patients. Decursin which is one of the bioactive components has been reported for its anti-inflammatory, antioxidant, and antitumor effects, but the effect on osteosarcoma is unexplained. In this study, the research theme was to examine the sensitizing effect of decursin and its influence on cisplatin-induced nephrotoxicity. The cell viability and half maximal inhibitory concentration (IC50), apoptosis induction, and effect on cell cycle and Akt pathways were examined. In vivo, we examine the effects of decursin on tumors and mice bodies. Additionally, the effects of the cisplatin-decursin combination were evaluated in vitro and in vivo. Decursin suppressed cell viability and induced apoptosis via the cell cycle. Decursin also inhibited the Akt pathway by suppressing the phosphorylation of Akt. It enhanced apoptosis induction and lowered cell viability in combination with cisplatin. The increasing tumor volume was suppressed in the decursin-administrated group with further suppression in combination with cisplatin compared to sole cisplatin administration. The decrease in renal function and renal epithelial cell damage caused by cisplatin was improved by the combinatorial treatment with decursin. Therefore, decursin demonstrated an antitumor effect on the osteosarcoma cells and a renal protective effect in combination with cisplatin. Therefore, decursin is a prospective therapeutic agent against osteosarcoma.

Impact of Initial Body Weight Loss on Prognosis in Advanced Pancreatic Cancer: Insights From a Single-Center Retrospective Study.

BACKGROUND: Pancreatic cancer (PC) has a poor prognosis, with body weight loss commonly observed at diagnosis. However, the impact on PC prognosis of weight loss at the time of diagnosis on PC prognosis is unknown. METHODS: This retrospective, single-center study enrolled consecutively patients diagnosed with metastatic or locally advanced PC or resectable PC who were intolerant of or refused surgery. Patients who had lost more than 5% of their body weight or more than 2% and had a body mass index (BMI) of less than 20 kg/m2 at diagnosis were classified as experiencing body weight loss. Patients were subclassified into 2 groups: patients with and without weight loss. The study evaluated patient-related and PC-related factors affecting prognosis. Cox proportional hazards models were used to assess factors affecting prognosis. The primary endpoint was overall survival. Additionally, 1:1 propensity score matching was performed to reduce bias. RESULTS: In total, 220 patients were included in the study. The median age of the patients was 74 years, and 49.1% were male. Weight loss at diagnosis was observed in 43.2% of patients. There were no significant differences in clinical factors, except for anthropometric parameters, between the groups. The median survival time did not differ between the weight loss and no weight loss groups (149 and 173 days, respectively, P = .669). After matching, no significant differences in survival times were observed between the 2 groups. CONCLUSIONS: This study found no association between weight loss at diagnosis and prognosis in patients with advanced PC treated with best supportive care or chemotherapy.

Detection of transient abnormal myelopoiesis blasts in a liver biopsy specimen by double-immunostaining for full-length GATA1 and CD42b.

BACKGROUND: Transient abnormal myelopoiesis (TAM) is characterized by leukocytosis with increased circulating megakaryoblasts that harbor N-terminal truncating mutations in the GATA1 gene. Approximately 10% of affected patients experience early death. OBSERVATIONS: A 2-month-old boy with Down syndrome was diagnosed with TAM and followed without treatment. Although the blasts in the peripheral blood disappeared, liver failure progressed. A pathological examination revealed liver fibrosis, and double-immunostaining for full-length GATA1 and CD42b identified megakaryocytes with a GATA1 mutation. CONCLUSIONS: This simple and cost-effective method can be applied in routine practice to detect TAM blasts during assessment in a TAM crisis.

Structural phenotypes of knee osteoarthritis: potential clinical and research relevance.

A joint contains many different tissues that can exhibit pathological changes, providing many potential targets for treatment. Researchers are increasingly suggesting that osteoarthritis (OA) comprises several phenotypes or subpopulations. Consequently, a treatment for OA that targets only one pathophysiologic abnormality is unlikely to be similarly efficacious in preventing or delaying the progression of all the different phenotypes of structural OA. Five structural phenotypes have been proposed, namely the inflammatory, meniscus-cartilage, subchondral bone, and atrophic and hypertrophic phenotypes. The inflammatory phenotype is characterized by marked synovitis and/or joint effusion, while the meniscus-cartilage phenotype exhibits severe meniscal and cartilage damage. Large bone marrow lesions characterize the subchondral bone phenotype. The hypertrophic and atrophic OA phenotype are defined based on the presence large osteophytes or absence of any osteophytes, respectively, in the presence of concomitant cartilage damage. Limitations of the concept of structural phenotyping are that they are not mutually exclusive and that more than one phenotype may be present. It must be acknowledged that a wide range of views exist on how best to operationalize the concept of structural OA phenotypes and that the concept of structural phenotypic characterization is still in its infancy. Structural phenotypic stratification, however, may result in more targeted trial populations with successful outcomes and practitioners need to be aware of the heterogeneity of the disease to personalize their treatment recommendations for an individual patient. Radiologists should be able to define a joint at risk for progression based on the predominant phenotype present at different disease stages.

Update: Posttreatment Imaging of the Knee after Cartilage Repair.

Focal cartilage lesions are common pathologies at the knee joint that are considered important risk factors for the premature development of osteoarthritis. A wide range of surgical options, including but not limited to marrow stimulation, osteochondral auto- and allografting, and autologous chondrocyte implantation, allows for targeted treatment of focal cartilage defects. Arthroscopy is the standard of reference for the assessment of cartilage integrity and quality before and after repair. However, deep cartilage layers, intrachondral composition, and the subchondral bone are only partially or not at all visualized with arthroscopy. In contrast, magnetic resonance imaging offers noninvasive evaluation of the cartilage repair site, the subchondral bone, and the soft tissues of the joint pre- and postsurgery. Radiologists need to be familiar with the different surgical procedures available and their characteristic postsurgical imaging appearances to assess treatment success and possible complications adequately. We provide an overview of the most commonly performed surgical procedures for cartilage repair at the knee and typical postsurgical imaging characteristics.

Shoulder adhesive capsulitis in cancer patients undergoing positron emission tomography - computed tomography and the association with shoulder pain.

BACKGROUND: Adhesive capsulitis is a relatively common condition that can develop in cancer patients during treatment. Positron emission tomography - computed tomography (PET-CT) is routinely performed as a follow-up study in cancer patients after therapy. Being aware of PET-CT findings to suggest shoulder adhesive capsulitis may help to alert clinicians for the diagnosis of unsuspected shoulder capsulitis. AIM: To assess the association of shoulder adhesive capsulitis with cancer/therapy type and symptoms in cancer patients undergoing PET-CT. METHODS: Our prospective study received Institutional Review Board approval. Written informed consent was obtained from all patients, who answered a questionnaire regarding shoulder pain/stiffness at the time of PET-CT study, between March 2015 and April 2019. Patients with advanced glenohumeral arthrosis, metastatic disease or other mass in the shoulder, or shoulder arthroplasty were excluded. Patterns of shoulder capsule 18F-fluorodeoxyglucose (FDG) uptake were noted. Standard Uptake Value (SUV)max and SUVmean values were measured at rotator interval (RI) and deltoid muscle in bilateral shoulders. Normalized SUV (SUV of RI/SUV of deltoid muscle) was also calculated. We assessed if SUV values are different between symptomatic and asymptomatic patients in both shoulders. Covariates were age, gender, and therapy type (surgery, chemotherapy, radiation). Wilcoxon rank sum tests were used to compare unadjusted marginal differences for age, SUV measurements between symptomatic and asymptomatic patients. Multiple linear regression models were used to examine the relationship between right or left shoulder SUV measurements and symptom status, after adjusting for covariates. Statistical significance level was set at P < 0.05. RESULTS: Of 252 patients initially enrolled for the study (mean age 66 years, 67 symptomatic), shoulder PET-CT data were obtained in 200 patients (52 were excluded due to exclusion criteria above). The most common cancer types were lymphoma (n = 61), lung (n = 54) and breast (n = 53). No significant difference was noted between symptomatic and asymptomatic patients in terms of age, gender, proportion of patients who had surgical therapy and radiation therapy. A proportion of patients who received chemotherapy was higher in patients who were asymptomatic in the right shoulder compared to those symptomatic in the right shoulder (65% vs 48%, P = 0.012). No such difference was seen for the left shoulder. In both shoulders, SUVmax and SUVmean were higher in symptomatic shoulders than asymptomatic shoulders (Left SUVmax 2.0 vs 1.6, SUVmean 1.6 vs 1.3, both P < 0.002; Right SUVmax 2.2 vs 1.8, SUVmean 1.8 vs 1.5, both P < 0.01). For lung cancer patients, bilateral RI SUVmax and SUVmean values were higher in symptomatic shoulders than asymptomatic shoulders. For other cancer patients, symptomatic patients had higher left RI SUVmax/mean than asymptomatic patients after adjustment. CONCLUSION: In symptomatic patients metabolic activities in RI were higher than asymptomatic patients. Adhesive capsulitis should be considered in cancer patients with shoulder symptoms and positive FDG uptake in RI.

Pristimerin inhibits the proliferation of HT1080 fibrosarcoma cells by inducing apoptosis.

Fibrosarcoma is a soft tissue sarcoma that is classified as a rare cancer. Therefore, no standard anti-tumor drug therapy has been established for fibrosarcoma. Although pristimerin (PM) has been reported to exert an anti-tumor effect on various types of cancer, no studies have examined the therapeutic effect of PM on soft tissue sarcoma. The purpose of the current study was to investigate the anti-tumor effect of PM on human fibrosarcoma cells (HT1080). The present study examined the cell viability, IC50 values and ability to induce apoptosis of PM in HT1080 and normal human dermal fibroblast (aHDF) cells. The effect of PM on the following signaling pathways associated with cell proliferation was also evaluated: AKT and mitogen-activated protein kinase (MAPK). Using mice subcutaneously transplanted with fibrosarcoma cells, the effect of PM treatment was investigated on tumor growth inhibition, body weight and liver and renal function. The results revealed that PM administration reduced cell viability and induced apoptosis in a dose-dependent matter. In HT1080 cells, the IC50 value of PM was 0.16 µM at 24 h and 0.13 µM at 48 h. PM treatment also decreased the levels of phosphorylated AKT, mTOR, NF-κB and phosphorylated ERK in a dose-dependent manner. In the PM injection group, the increase in tumor volume was significantly reduced and the effect on weight loss and liver and renal function were revealed to be insignificant. PM exerted little effect on normal human dermal fibroblasts and was highly effective against human fibrosarcoma cells. The results indicated that PM may be used as a potential therapeutic agent against fibrosarcoma.

The tetraspanin CD81 mediates the growth and metastases of human osteosarcoma.

PURPOSE: CD81 is a member of the tetraspanin family of membrane proteins. Recently, it has been shown that CD81 may be involved in cancer cell proliferation and metastasis. As yet, however, there have been few reports on the expression and role of CD81 in osteosarcoma. METHODS: The expression of CD81 was investigated in human osteoblast cell line hFOB1.19 and in human osteosarcoma cell lines Saos2, MG63 and 143B. The expression of CD81 was inhibited in osteosarcoma cells using siRNA after which cell proliferation, migration and invasion were assessed. We also used Western blotting to investigate the phosphorylation status of Akt, Erk, JNK and p38, and measured the expression of MMP-2, MMP-9 and MT1-MMP. In addition, we used a CRISPR/Cas9 system to stably knock out CD81 expression in 143B cells, transplanted the cells into mice, and assessed tumor formation and lung metastasis in these mice compared to those in the control group. RESULTS: We found that CD81 was expressed in the human osteoblast cell line and in all osteosarcoma cell lines tested. The osteosarcoma cell line 143B exhibited a particularly high level of expression. In addition, we found that osteosarcoma cell proliferation, migration and invasion were decreased after CD81 inhibition, and that the phosphorylation of Akt and Erk was suppressed. Also, the expression levels of MMP-2, MMP-9 and MT1-MMP were found to be suppressed, with MMP-9 showing the greatest suppression. In vivo, we found that mice transplanted with CD81 knockout 143B cells exhibited significantly less tumor formation and lung metastasis than mice in the control group. CONCLUSION: Based on our findings we conclude that inhibition of CD81 suppresses intracellular signaling and reduces tumorigenesis and lung metastasis in osteosarcoma cells.

Severity of heterotopic ossification in patients following surgery for hip fracture: a retrospective observational study.

BACKGROUND: Heterotopic ossification (HO) is a relatively common complication following hip surgery treated with open reduction and internal fixation, total arthroplasty or hemiarthroplasty. Development of HO after hip surgery is an important clinical issue as it can affect functional status. We aimed to determine whether there was association between severity of heterotopic ossification about the hip and the interval between the time of hip fracture and surgery. MATERIALS AND METHODS: Our retrospective study included 151 patients (age range 33-95 years) treated for hip fractures by hemiarthroplasty. Medical records were reviewed for time interval to surgery, laterality, surgical approach, and patient age. Patients who had any post-operative complications were excluded. Radiographs were semiquantitatively assessed for the degree of heterotopic ossification based on Brooker Classification (5-point scale). Statistical analysis was performed utilizing Chi-square, Kruskal-Wallis, and Score tests, and also a proportional odds model (significance level set at 0.05). RESULTS: Thirty eight patients had no heterotopic ossification, 43 had class 1, 55 had class 2, and 15 had class 3 or greater heterotopic ossification. The majority of patients (59.6%) had surgery within 2 days of acute injury. Severe heterotopic ossification (HO 3+) was associated with the longer interval between the time of acute hip fracture and surgery (median 6 days) vs. median 2 days in all other groups (HO classes 0-2) (p = 0.0015). The odds ratio and 95% CI for one level higher HO class was 1.296 (1.152, 1.459), which meant that the odds of having HO class one level higher increased by about 29.6% for every one-day increase in the days to surgery. No significant association was found for other variables. CONCLUSION: Class 3 or greater HO was associated with longer time interval between time of acute hip fracture and surgery compared to all other groups (HO class 0-2).

[Cell surface pH imaging using poly(ethylene glycol)-phospholipid: its potential as the core structure of membrane anchored-probes].

Various physiological and pathological processes are accompanied with the local acidification of extracellular local pH. However, imaging tools to investigate the spatio-temporal dynamics as well as the functional significance of cell surface pH are limitedly available. We established a novel method of in vitro cell surface pH imaging by using a membrane-anchored pH probe, poly(ethylene glycol)-phospholipid conjugated with fluorescein isothiocyanate (FITC-PEG-lipid). PEG-lipid, amphiphilic synthetic polymer, is a biomaterial originally synthesized for cell-surface engineering for transplantation therapy. When added into the cell culture medium, FITC-PEG-lipid was spontaneously inserted into the plasma membrane via its phospholipid moiety. FITC-PEG-lipid was retained at the extracellular surface due to the hydrophobic PEG moiety. The ratiometric readout of FITC fluorescence was unique to the extracellular pH in the range of weakly alkaline and acidic pH (pH 5.0-7.5). The pH measurement with FITC-PEG-lipid was accurate enough to distinguish the difference of 0.1 pH unit for the external solutions at pH 5.9, 6.0 and 6.1, near the inflection point of fluorescence ratio. The response of FITC-PEG-lipid to the extracellular pH was reversible. Continuous alteration of extracellular pH was successfully visualized by time-lapse imaging analysis. Our study demonstrated that FITC-PEG-lipid is useful as a sensitive and reversible cell surface-anchored pH probe. The simple labeling procedure of FITC-PEG-lipid is advantageous especially when considering its application to high-throughput in vitro assay. Furthermore, PEG-lipid holds a great potential as the membrane anchor of various analytical probes to approach the juxtamembrane environments.

DEVELOPMENT OF RADIATION DOSE CALCULATION SOFTWARE USING THE SIZE-SPECIFIC DOSE ESTIMATE.

We aimed to develop a software for facilitating absorbed dose per pixel (pixel dose) calculation using a size-specific dose estimate (SSDE). We calculated the pixel dose at nine equal points inserted into the radiophotoluminescence glass dosemeter (RPLD) and compared the pixel dose with the measured doses using RPLD. With this method, the relative errors of average pixel dose was -0.1% for adults and 2.86, 3.36 and 1.17% for those aged 10, 5 and 1 years without tube current modulation, respectively. In contrast, the relative error of SSDE was 17.37% for adults and 20.38, 20.73 and 19.20% for those aged 10, 5 and 1 years, respectively. In other words, the pixel dose was almost equal to the measured doses. Therefore, our software can be useful for determining arbitrary point.

Limb saving surgery for Ewing's sarcoma of the distal tibia: a case report.

BACKGROUND: Ewing's sarcoma is a primary malignant tumor of bone occurring mostly in childhood. Few effective reconstruction techniques are available after wide resection of Ewing's sarcoma at the distal end of the tibia. Reconstruction after wide resection is especially difficult in children, as it is necessary to consider the growth and activity of the lower limbs. CASE PRESENTATION: A 12-year-old Japanese boy had presented with right lower leg pain at age 8 years. Imaging examination showed a bone tumor accompanied by a large extra-skeletal mass in the distal part of his tibia. The tumor was histologically diagnosed as Ewing's sarcoma. The patient received chemotherapy, followed by wide resection. Reconstruction consisted of a bone transport method involving external fixation of Taylor Spatial Frame. To prevent infection after surgery, the external fixation pin was coated with iodine. One year after surgery, the patient showed poor consolidation of bone, so iliac bone transplantation was performed on the extended bones and docking site of the distal tibia. After 20 months, tibia formation was good. Three years after surgery, there was no evidence of tumor recurrence or metastases; bone fusion was good, and he was able to run. CONCLUSIONS: The bone transport method is an effective surgical method of reconstruction after wide resection of a bone tumor at the distal end of the tibia, if a pin can be inserted into the distal bone fragment. Coating external fixation pins with iodine may prevent postoperative infection.

Hepatic metastases from primary extremity leiomyosarcomas: Two case reports.

INTRODUCTION: Leiomyosarcoma is a highly malignant soft tissue sarcoma. Most leiomyosarcomas of the extremities metastasize initially to the lungs, with few metastasizing to the liver. Also, it is difficult to diagnose metastases to other regions of the lung during follow-up. CASE PRESENTATION: The first patient was a 51-year-old Japanese woman diagnosed with a leiomyosarcoma of the left distal femur. She underwent chemotherapy, followed by wide tumor excision and reconstruction using frozen autograft with total knee arthroplasty. Eleven months later, a focal lesion was observed in her right liver, despite the absence of lung metastases. Partial hepatic resection was performed, and the hepatic lesion was diagnosed a metastasis of leiomyosarcoma. Two years later, there has been no evidence of local recurrence. The second patient was a 60-year-old Japanese male diagnosed with a leiomyosarcoma of the left thigh. He underwent preoperative chemotherapy followed by wide excision. Three years later, a focal lesion was found in his medial liver, despite the absence of lung metastases. Partial hepatic resection was performed, and the hepatic lesion was diagnosed as a metastasis of leiomyosarcoma. At the latest follow-up, there has been no evidence of local recurrence. CONCLUSIONS: The lung is the most common site of metastases from leiomyosarcomas of the extremeties, because these metastases are hematogenous. Both our patients presented with metastases of the liver, despite the absence of lung metastases. Hepatic metastasis is commonly found in computed tomography (CT) scan. Periodic CT scans of the chest and abdomen are necessary in following-up patients who undergo resection of primary leiomyosarcomas of the extremities.

Multi-parametric muscle and fat correlation of computed tomography parameters to outcomes in a total hip arthroplasty population.

BACKGROUND: Cross-sectional imaging is not currently used in planning Total Hip Arthroplasty (THA). The aim of our study is to determine correlations between CT parameters and outcomes following THA. METHODS: A prospective registry of patients who underwent total joint arthroplasty was reviewed for patients who: (1) underwent THA, (2) had a CT between 1 year before and 6 months after surgery, and (3) completed perioperative WOMAC and Harris Hip Score (HHS) questionnaires. Two readers measured CT parameters, yielding mean Hounsfield Units, area, average diameter, and perimeter of the psoas major, gluteus medius and minimus muscles. A segmentation algorithm determined visceral and subcutaneous fat area, and waist circumference. ICC was calculated for each measurement to examine inter-reader agreement. Regression analyses were performed to select measurements with most impact on outcome scores. RESULTS: Twenty-eight patients met inclusion criteria (17 female, 11 male), having mean (+/- standard deviation) age of 54.4 +/- 14.8 years and BMI 29.0 +/- 6.3 kg/m2. Correlations were found between HHS and age (0.650, p = 0.018), height (-1.263, p = 0.009), visceral-to-subcutaneous fat area ratio at the psoas level (0.511, p = 0.018), and waist circumference at the psoas level (1.759, p = 0.002). Inter-reader analysis showed ICC > 0.850 for all measurements. CONCLUSION: Age and height, as well as CT-derived visceral-to-subcutaneous fat area ratio and waist circumference significantly correlate with postsurgical HHS scores following THA. Our study suggests that parameters derived from cross-sectional CT imaging can be useful additional preoperative planning tool for THA.

Understanding Magnetic Resonance Imaging of Knee Cartilage Repair: A Focus on Clinical Relevance.

The aims of this review article are (a) to describe the principles of morphologic and compositional magnetic resonance imaging (MRI) techniques relevant for the imaging of knee cartilage repair surgery and their application to longitudinal studies and (b) to illustrate the clinical relevance of pre- and postsurgical MRI with correlation to intraoperative images. First, MRI sequences that can be applied for imaging of cartilage repair tissue in the knee are described, focusing on comparison of 2D and 3D fast spin echo and gradient recalled echo sequences. Imaging features of cartilage repair tissue are then discussed, including conventional (morphologic) MRI and compositional MRI techniques. More specifically, imaging techniques for specific cartilage repair surgery techniques as described above, as well as MRI-based semiquantitative scoring systems for the knee cartilage repair tissue-MR Observation of Cartilage Repair Tissue and Cartilage Repair OA Knee Score-are explained. Then, currently available surgical techniques are reviewed, including marrow stimulation, osteochondral autograft, osteochondral allograft, particulate cartilage allograft, autologous chondrocyte implantation, and others. Finally, ongoing research efforts and future direction of cartilage repair tissue imaging are discussed.

Antitumor effects of pristimerin on human osteosarcoma cells in vitro and in vivo.

There are very few treatments for musculoskeletal tumors, compared to other cancers; thus, novel therapeutic drugs are needed. Pristimerin (PM) is a triterpene compound isolated from plant extracts that reportedly has antitumor effects on various cancers, such as of the breast and prostate. The purpose of this study was to evaluate the antitumor effects of PM on human osteosarcoma cells. Treatment of the human osteosarcoma cell lines, MNNG and 143B, with PM led to a dose-dependent decrease in cell viability. The effects of PM on apoptosis were evaluated with the Annexin V/propidium iodide assay and analysis of caspases 3, 8, and 9 activities. Western blot analysis showed that PM caused a decrease in the expression of Akt, mTOR, and NF-κB. The volumes and weights of human osteosarcoma xenografts decreased significantly with PM treatment. The results of this study revealed that PM can inhibit human osteosarcoma growth in vitro and in vivo, and may be a novel therapeutic agent for the disease.