Multicenter phase II trial assessing effectiveness of imatinib mesylate on relapsed or refractory KIT-positive or PDGFR-positive sarcoma

Molecular mechanisms underpinning sarcomas and implications for current and future therapy

Sarcomas are complex mesenchymal neoplasms with a poor prognosis. Their clinical management is highly challenging due to their heterogeneity and insensitivity to current treatments. Although there have been advances in understanding specific genomic alterations and genetic mutations driving sarcomagenesis, the underlying molecular mechanisms, which are likely to be unique for each sarcoma subtype, are not fully understood. This is in part due to a lack of consensus on the cells of origin, but there is now mounting evidence that they originate from mesenchymal stromal/stem cells (MSCs). To identify novel treatment strategies for sarcomas, research in recent years has adopted a mechanism-based search for molecular markers for targeted therapy which has included recapitulating sarcomagenesis using in vitro and in vivo MSC models. This review provides a comprehensive up to date overview of the molecular mechanisms that underpin sarcomagenesis, the contribution of MSCs to modelling sarcomagenesis in vivo, as well as novel topics such as the role of epithelial-to-mesenchymal-transition (EMT)/mesenchymal-to-epithelial-transition (MET) plasticity, exosomes, and microRNAs in sarcomagenesis. It also reviews current therapeutic options including ongoing pre-clinical and clinical studies for targeted sarcoma therapy and discusses new therapeutic avenues such as targeting recently identified molecular pathways and key transcription factors.

[New data on the molecular biology of soft tissue sarcoma]

Sarcoma consists in a group of rare malignant tumours of mesenchymal origin characterized by their vast clinical, pathological and biological heterogeneity. The pathological diagnosis of sarcoma relies classically of the differentiation features of tumour cells, with dozens of different tumour subtypes described in the last international classifications. Over the last decades, the advances in the development of new techniques of molecular biology have led to a major complexification of sarcoma classification, with the identification of multiple and specific molecular alterations that have led to significant changes for patients diagnostic, prognostic and therapeutic management. This review aims at giving an overview on the current knowledge of the molecular biology of soft tissue sarcoma, and emphasizes on their consequences for the daily management of patients.

Prognostic factors for patients with metastatic or recurrent thymic carcinoma receiving palliative-intent chemotherapy

BACKGROUND

Thymic malignancies are a model of rare cancer. However, little clinical data is available based on the large database. We aimed to clarify the prognostic factors, particularly the metastatic sites, for thymic malignancies using one of the largest, representative, multi-institutional databases, the NEJ023 database.

PATIENTS AND METHODS

Patients with Stage IVA/IVB or recurrent thymic carcinoma were enrolled between 1995 and 2014. Clinicopathologic information was evaluated, and the patients were subdivided according to the metastatic organs of involvement (serosal dissemination, liver, lymph node, pulmonary, and bone metastasis). A Kaplan-Meier analysis and multivariate Cox regression were used to evaluate survival.

RESULTS

Two hundred and seventy-nine patients with metastases and a predominantly squamous histology (66.7%) were included. Most patients (53.0%) had serosal dissemination, whereas 26.5%, 21.9%, 19.7%, and 15.8% had pulmonary, lymph node, bone and liver metastases, respectively. Over a median follow-up time of 21.5 months, the median overall survival (mOS) was 30.7 months. When the subjects were grouped according to involved metastatic sites, patients with more than 3 involved metastatic organs had the worst survival outcome. Among patients with isolated involvement, those with bone metastasis had the poorest survival, followed by patients with liver metastasis. Subjects with hypoalbuminemia also had poor survival outcomes. When patients treated with platinum and anthracycline-containing pharmacotherapy were compared with those treated with platinum and non-anthracycline-containing pharmacotherapy, no significant difference was observed. Bone metastasis (P = 0.0005), liver metastasis (P =  0.047), and hypoalbuminemia (P =  0.0021) were identified as prognostic factors in a multivariate analysis.

CONCLUSION

The site of metastatic involvement affects the survival outcomes of patients with thymic carcinoma, and this result may reflect the sensitivity of metastatic sites to pharmacotherapy. As a next step, controlling liver metastasis with pharmacotherapy could help to improve the prognosis of patients with thymic carcinoma.

Phase I-II trial of imatinib mesylate (Gleevec; STI571) in treatment of recurrent oligodendroglioma and mixed oligoastrocytoma. North central cancer treatment group study N0272 (ALLIANCE/NCCTG)

PURPOSE

To evaluate the pharmacokinetics and efficacy of imatinib in patients with recurrent oligodendroglial tumors.

METHODS

Patients with progressive WHO grade II-III recurrent tumors after prior RT and chemotherapy were eligible. A phase I dose-escalation study was conducted for patients on enzyme-inducing anticonvulsants (EIAC). A phase II study for non-EIAC patients utilized a fixed dose of 600 mg/D. Primary efficacy endpoint was 6-month progression-free survival (PFS6). A 2-stage design was utilized, with 90% power to detect PFS6 increase from 25 to 45%.

RESULTS

In the Phase I, maximum tolerated dose was not reached at 1200 mg/D. For phase II patients, overall PFS6 was 33% and median PFS 4.0 months (95% CI 2.1, 5.7). Median overall survival (OS) was longer in imatinib-treated patients compared with controls (16.6 vs. 8.0 months; HR = 0.64, 95% CI 0.41,1.0, p = 0.049), and longer in patients with 1p/19q-codeleted tumors (19.2 vs. 6.2 months, HR = 0.43, 95% CI 0.21,0.89, p = 0.019). Confirmed response rate was 3.9% (PR = 1; REGR = 1), with stable disease observed in 52.9%. At 600 mg/D, mean steady-state imatinib plasma concentration was 2513 ng/ml (95% CI 1831,3195). Grade 3-4 adverse events (hematologic, fatigue, GI, hypophosphatemia, or hemorrhage) occurred in 61%.

CONCLUSIONS

Although adequate plasma levels were achieved, the observed PFS6 of 33% did not reach our pre-defined threshold for success. Although OS was longer in imatinib-treated patients than controls, this finding would require forward validation in a larger cohort. Imatinib might show greater activity in a population enriched for PDGF-dependent pathway activation in tumor tissue.

Spotlight on olaratumab in the treatment of soft-tissue sarcoma: design, development, and place in therapy

Soft-tissue sarcoma (STS) is a heterogeneous group of tumors that arise from mesenchymal tissue. The prognosis of metastatic STS is poor with a life expectancy of 12–18 months. The mainstay of treatment is chemotherapy with an anthracycline. The addition of other chemotherapeutic agents to an anthracycline has been studied with limited success in improving outcomes for STS patients. Olaratumab is a fully human IgG1 monoclonal antibody that binds to platelet-derived growth factor receptor α (PDGFR-α) preventing binding of its ligands and receptor activation. This drug recently received the US Food and Drug Administration’s accelerated approval for the treatment of advanced STS when combined with doxorubicin. This approval was based upon an improvement in overall survival of patients receiving the combination of doxorubicin and olaratumab compared to those receiving doxo-rubicin alone. In this review, we have analyzed the available literature on the development of olaratumab, its clinical utility, and its place in therapy. Based on early-phase clinical trials, olaratumab appears to be a promising agent for the treatment of STS.

Managing sarcoma: where have we come from and where are we going?

Sarcomas are a heterogeneous group of neoplasms of mesenchymal origin. Approximately 80% arise from soft tissue and 20% originate from bone. To date more than 100 sarcoma subtypes have been identified and they vary in molecular characteristics, pathology, clinical presentation and response to treatment. While sarcomas represent <1% of adult cancers, they account for approximately 21% of paediatric malignancies and thus pose some of the greatest risks of mortality and morbidity in children and young adults. Metastases occur in one-third of all patients and approximately 10-20% of sarcomas recur locally. Surgery in combination with preoperative and postoperative therapies is the primary treatment for localized sarcoma tumours and is the most promising curative possibility. Metastasized sarcomas, on the other hand, are treated primarily with single-agent or combination chemotherapy, but this rarely leads to a complete and robust response and often becomes a palliative form of treatment. The heterogeneity of sarcomas results in variable responses to current generalized treatment strategies. In light of this and the lack of curative strategies for metastatic and unresectable sarcomas, there is a need for novel subtype-specific treatment strategies. With the more recent understanding of the molecular mechanisms underlying the pathogenesis of some of these tumours, the treatment of sarcoma subtypes with targeted therapies is a rapidly evolving field. This review discusses the current management of sarcomas as well as promising new therapies that are currently underway in clinical trials.

Multi-platform profiling of over 2000 sarcomas: identification of biomarkers and novel therapeutic targets

Background: Drug development in sarcoma has been hampered by the rarity and heterogeneity of the disease and lack of predictive biomarkers to therapies. We assessed protein expression and gene alterations in a large number of bone and soft tissue sarcomas in order to categorize the molecular alterations, identify predictive biomarkers and discover new therapeutic targets. Methods: Data from sarcoma specimens profiled for protein expression, gene amplification/translocation and DNA sequencing was reviewed. Results: 2539 sarcoma specimens of 22 subtypes were included. TOPO2A was the most overexpressed protein at 52.8%. There was overexpression or loss of other sarcoma relevant proteins such as SPARC, PTEN and MGMT. Approximately 50% of the sarcomas expressed PD-L1 by IHC and presented with PD-1+ TILs, notably the LMS, chondrosarcomas, liposarcomas and UPS. Gene amplification/rearrangement of ALK, cMYC, HER2, PIK3CA, TOPO2A and cMET was relatively uncommon. EGFR gene amplification occurred at a rate of 16.9%. DNA sequencing of 47 genes identified mutations in 47% of the samples. The most commonly mutated genes were TP53 (26.3%) and BRCA2 (17.6%). Overexpression of TOPO2A was associated with TP53 mutation (P = 0.0001). Conclusion: This data provides the landscape of alterations in sarcoma. Future clinical trials are needed to validate these targets.

Effectiveness of Imatinib Mesylate Treatment in a Patient with Dermatofibrosarcoma Protuberans with Pulmonary and Pancreatic Metastases

We herein encountered a case of abdominal wall dermatofibrosarcoma protuberans (DFSP) that developed pulmonary and pancreatic metastases 5 years after complete resection. Because specific rearrangements of the platelet-derived growth factor beta (PDGFB) locus by a novel fluorescence in situ hybridization method was detected, the patient was treated with imatinib mesylate at 400 mg/day. A partial response was achieved by imatinib without any specific toxicity. Although metastatic DFSP is an extremely rare disease, an evaluation of PDGFB fusion is essential and imatinib mesylate should be considered as an optimal therapeutic choice in patients with metastatic or locally advanced DFSP.

Targeted Chemotherapy in Bone and Soft-Tissue Sarcoma

Historically surgical intervention has been the mainstay of therapy for bone and soft-tissue sarcomas, augmented with adjuvant radiation for local control. Although cytotoxic chemotherapy revolutionized the treatment of many sarcomas, classic treatment regimens are fraught with side effects while outcomes have plateaued. However, since the approval of imatinib in 2002, research into targeted chemotherapy has increased exponentially. With targeted therapies comes the potential for decreased side effects and more potent, personalized treatment options. This article reviews the evolution of medical knowledge regarding sarcoma, the basic science of sarcomatogenesis, and the major targets and pathways now being studied.

Efficacy and Biological Activity of Imatinib in Metastatic Dermatofibrosarcoma Protuberans (DFSP)

PURPOSE

To report on imatinib mesylate (IM) in patients with metastatic dermatofibrosarcoma protuberans (DFSP)/fibrosarcomatous (FS)-DFSP and on the impact of the treatment on tumor biology.

EXPERIMENTAL DESIGN

Ten consecutive patients treated with IM from 2007 to 2015 for a metastatic relapse from DFSP/FS-DFSP were identified. FISH analysis for COL1A1-PDGFB was performed. Two IM-treated and 4 naïve FS-DFSP were transcriptionally profiled by RNAseq on HiScanSQ platform. Differential gene expression was analyzed with edgeR (Bioconductor), followed by hierarchical clustering and Principal Component Analysis.

RESULTS

All cases featured fibrosarcomatous in the metastasis and retained the COL1A1-PDGFB. Best RECIST response was: 8 partial response, 1 stable disease, and 1 progressive disease. Median progression-free survival was 11 months. Five patients received surgery after IM and all relapsed. IM was restored in 4 patients with a new response. After IM, the most upregulated genes included those encoding for immunoglobulins and those affecting functions and differentiation of endothelial cells. Pathway enrichment analysis revealed upregulation in genes involved in antigen processing and presentation, natural killer-mediated cytotoxicity, and drug and xenobiotics metabolism. Conversely, a significant down-regulation of kinase signaling pathways was detected.

CONCLUSIONS

All metastatic cases were fibrosarcomatous. Most patients responded to IM, but PFS was shorter than reported in published series which included both DFSP and FS-DFSP. All patients operated after IM had a relapse, suggesting that IM cannot eradicate metastatic cases and that the role of surgery is limited. Transcriptional profile of naïve and posttreatment samples pointed the contribution of immune infiltrates in sustaining the response to IM.

Synergistic antiproliferative effect of imatinib and adriamycin in platelet-derived growth factor receptor-expressing osteosarcoma cells

Osteosarcoma (OS) is the most frequent primary solid malignant tumor of bone. Its prognosis remains poor in the substantial proportion of patients who do not respond to chemotherapy and novel therapeutic options are therefore needed. We previously established a mouse model that mimics the aggressive behavior of human OS. Enzyme-linked immunosorbent assay-based screening of such mouse tumor lysates identified platelet-derived growth factor–BB (PDGF-BB) as an abundant soluble factor, the gene for which was expressed dominantly in surrounding non-malignant cells of the tumor, whereas that for the cognate receptor (PDGF receptor β) was highly expressed in OS cells. Platelet-derived growth factor-BB induced activation of both MEK–ERK and phosphatidylinositol 3-kinase–protein kinase B signaling pathways and promoted survival in OS cells deprived of serum, and these effects were blocked by the PDGF receptor inhibitor imatinib. However, these actions of PDGF-BB and imatinib were mostly masked in the presence of serum. Whereas imatinib alone did not manifest an antitumor effect in mice harboring OS tumors, combined treatment with imatinib and adriamycin exerted a synergistic antiproliferative effect on OS cells in vivo. These results suggest that treatment of OS with imatinib is effective only when cell survival is dependent on PDGF signaling or when imatinib is combined with another therapeutic intervention that renders the tumor cells susceptible to imatinib action, such as by inducing cellular stress.

Targeted therapy in sarcomas other than GIST tumors

Non-GIST soft tissue sarcomas are a heterogeneous grouping of mesenchymal tumors that comprise less than 1% of adult malignancies. Treatment continues to be based on cytotoxic chemotherapy regimens. However, characterization of the molecular pathway deregulations that drive these tumors has led to the emergence of more customized treatment options. In this review, we focus on the multitude of molecular inhibitors targeting angiogenesis and cell cycle pathways being tested in clinical trials.

Key components of chemotherapy for thymic malignancies: a systematic review and pooled analysis for anthracycline-, carboplatin- or cisplatin-based chemotherapy

Purpose

Thymic malignancies, comprising thymoma and thymic carcinoma, are rare. Consequently, optimal chemotherapy for advanced thymic malignancies remains controversial. Platinum-based chemotherapy is currently the consensus treatment based on the results of single-arm phase II trials and retrospective investigations. However, comparison of cisplatin-based and carboplatin-based chemotherapy has yet to be undertaken; the effectiveness of the addition of anthracycline also remains uncertain.

Methods

In the present study, clinical trials and retrospective data regarding platinum-based chemotherapy were analyzed. The endpoint was the response rate to each chemotherapy. For advanced thymoma, we compared platinum with anthracycline-based chemotherapy and platinum with non-anthracycline-based chemotherapy. For advanced thymic carcinoma, anthracycline-based versus non-anthracycline-based chemotherapy and carboplatin-based versus cisplatin-based chemotherapy were compared. This analysis included a retrospective study of response of advanced thymic carcinoma to irinotecan and cisplatin in our institution.

Results

The response rate for the 314 patients from 15 studies with advanced thymoma, including both prospective and retrospective data, was 69.4 % [95 % confidence interval (CI) 63.1–75.0 %] for platinum with anthracycline-based chemotherapy and 37.8 % (95 % CI 28.1–48.6 %; p < 0.0001) for platinum with non-anthracycline-based chemotherapy. The response rates after anthracycline-based and non-anthracycline-based chemotherapy for advanced thymic carcinoma were similar (41.8 vs. 40.9 %; p < 0.91), whereas the response rates after cisplatin-based and carboplatin-based chemotherapy for advanced thymic carcinoma differed significantly (53.6 vs. 32.8 %; p = 0.0029) in 206 patients from 10 studies.

Conclusions

Platinum with anthracycline-based chemotherapy is an optimal combination for advanced thymoma. For advanced thymic carcinoma, cisplatin-based chemotherapy may be superior to carboplatin-based chemotherapy.

Neoadjuvant treatment of Dermatofibrosarcoma Protuberans of pancreas with Imatinib: case report and systematic review of literature

Dermatofibrosarcoma Protuberans (DFSP) is a rare skin tumor, characterized by frequent local recurrence but is seldom metastatic. It is histologically characterized by storiform arrangement of spindle cells. Cytogenetically, most tumors are characterized by translocation 17:22 leading to overexpression of tyrosine kinase PDGFB which can be targeted with tyrosine kinase inhibitor, Imatinib. We describe the first case of unresectable pancreatic metastases from DFSP treated with neoadjuvant Imatinib and subsequently R0 metastectomy. Additionally, a comprehensive systematic review of DFSP pancreatic metastases and the current published data on the use of Imatinib in DFSP is summarized.

Clinicopathological analysis of thymic malignancies with a consistent retrospective database in a single institution: from Tokyo Metropolitan Cancer Center

BACKGROUND

Thymic epithelial tumors (TETs), which comprise thymoma and thymic carcinoma, are rare cancers with specific morphological and clinical features. Their clinical characteristics and outcomes have gradually been clarified by assessing large-scale, retrospective data obtained with international cooperation.

METHODS

The study is a retrospective review of 187 Japanese patients with TETs who attended our institution from 1976 to 2012. Relevant clinical features of patients with TETs and their tumors, including histology, staging, treatment strategies, and overall survival, were investigated. Differences in survival were assessed by the Kaplan-Meier method and uni- and multi-variate Cox proportional hazards regression analyses.

RESULTS

The 187 patients included 52 patients with stage I, 37 with stage II, 22 with stage III, and 76 with stage IVa/IVb tumors according to the Masaoka-Koga Staging System. As to histological type, five patients had type A, 33 type AB, 19 type B1, 39 type B2, and 15 type B3 thymomas, whereas 68 patients had thymic carcinoma, including 11 with neuroendocrine carcinomas according to the 2004 WHO classification. Either insufficient data were available to classify the tumors of the remaining eight patients or they had rare types. Immunological abnormalities were present in 26 patients, most of whom had thymomas (21.8% of the thymoma group). Most of the patients who presented with symptoms had myasthenia gravis or extensive thymic carcinoma. Secondary cancers were present in 25 patients (13.3%). The overall 5- and 10-year survival rates for thymoma were 85.4 and 71.5%, respectively, and those for thymic carcinoma were 33.8 and 2.3%, respectively. OS differed significantly between stage IVa thymomas and thymic carcinomas. The stage and whether the tumors were thymomas or thymic carcinomas were significant determinants of survival according to multivariate analysis.

CONCLUSION

The efficacy of treatments for thymoma and thymic carcinoma should be investigated separately because these tumors differ in their clinical features and prognosis.

Serum protein acidic and rich in cysteine (SPARC) as a prognostic marker in soft tissue sarcomas

BACKGROUND

Serum protein acidic and rich in cysteine (SPARC) is a matricellular secreted glycoprotein that performs several cellular functions and has been implicated in tumorigenesis in a variety of tumor types. The chemotherapeutic agent nanoparticle albumin-encapsulated (NAB)-paclitaxel has been postulated to exploit SPARC expression to target neoplastic cells. SPARC's role, and potentially the role of NAB-paclitaxel, in the highly heterogeneous class of soft-tissue sarcomas (STS) has not been investigated. Our objective was to explore the pattern of SPARC expression and its prognostic significance in STS.

METHODS

27 tissue specimens representing various STS histologies were stained for SPARC expression by immunohistochemistry (IHC). Staining intensity was scored blindly. Survival was determined from patients' medical records and analyzed using Kaplan-Meier and log-rank with respect to SPARC expression level.

RESULTS

Elevated SPARC expression was observed in 15/27 (56%) specimens. Overall patient survival segregated strongly based on levels of SPARC expression. Patients who expressed low-to-moderate levels of SPARC exhibited median survival of 22.1 months, while the median survival of patients with moderate-to-high expression levels was 4.4 months (log rank; p = 0.0016).

CONCLUSIONS

SPARC expression is elevated in a significant proportion of STS specimens analyzed in this study, but it does not appear to correlate with specific STS histologies. Given our limited sample size, we cannot draw definitive conclusions regarding association of SPARC with STS subtype. Overall survival segregates strongly by degree of SPARC expression, with elevated expression being adverse. If validated in a larger study, our results suggest that trials in STS with agents potentially targeting SPARC, such as NAB-paclitaxel, should be stratified by SPARC expression level.

Dermatofibrosarcoma protuberans in a 10-year-old child

BACKGROUND

Dermatofibrosarcoma protuberans is a rare mesenchymal malignancy in childhood and adolescence. The tumor is characterized by dermal spindle cell proliferation with infiltration of subcutaneous tissue, expression of CD34, and a specific fusion of the platelet-derived growth factor beta with the collagen type 1alpha1 gene.

MAIN OBSERVATION

We observed a 10-year-old girl with a medaillon-like, asymptomatic plaque on the chest that was diagnosed as DSFP. The tumor was completely removed by delayed Mohs surgery. Follow-up so far has shown a complete response.

CONCLUSIONS

The prognosis of dermatofibrosarcoma protuberans in children is excellent as long as early diagnosis is followed by complete excision with Mohs surgery as a golden standard.

Therapeutic targeting of platelet-derived growth factor receptors in solid tumors

INTRODUCTION

Genetic aberrations that are associated with platelet-derived growth factor receptor (PDGFR) activity are frequently found in glioblastomas (10 - 15%), dermatofibrosarcoma protuberans (≤ 100%) and gastrointestinal stromal tumors (5%). Sequencing studies have also identified mutations at lower frequency in common cancer types. Preclinical evidence further suggests tumor stimulatory roles of PDGFRs expressed by tumor stroma cells and indicates a deleterious effect of stromal PDGFRs on intratumoral drug uptake.

AREAS COVERED

This review summarizes the present understanding of PDGF signaling in solid tumors based on experimental studies and clinical findings. It also provides a discussion of selected ongoing efforts to develop novel cancer therapies involving PDGFR inhibition with tyrosine kinase inhibitors or PDGFR-targeting monoclonal antibodies.

EXPERT OPINION

An increased molecular understanding of response and resistance mechanisms will be essential for therapeutic advances in PDGFR-directed cancer therapy. Further developments rely on clinical studies where systematic analyses of target status in malignant cells and in cells of the tumor stroma are included. Studies with combination therapies will be facilitated by selective PDGFR inhibitors with reduced side effects. Finally, development of improved companion diagnostics is of critical importance for patient selection and monitoring of therapeutic effects.

Activation of abl family kinases in solid tumors

Although c-Abl and Arg non-receptor tyrosine kinases are well known for driving leukemia development, their role in solid tumors has not been appreciated until recently. Accumulating evidence now indicates that c-Abl and/or Arg are activated in some solid tumor cell lines via unique mechanisms that do not involve gene mutation/translocation, and c-Abl/Arg activation promotes matrix degradation, invasion, proliferation, tumorigenesis, and/or metastasis, depending on the tumor type. However, some data suggest that c-Abl also may suppress invasion, proliferation, and tumorigenesis in certain cell contexts. Thus, c-Abl/Arg may serve as molecular switches that suppress proliferation and invasion in response to some stimuli (e.g., ephrins) or when inactive/regulated, or as promote invasion and proliferation in response to other signals (e.g., activated growth factor receptors, loss of inhibitor expression), which induce sustained activation. Clearly, more data are required to determine the extent and prevalence of c-Abl/Arg activation in primary tumors and during progression, and additional animal studies are needed to substantiate in vitro findings. Furthermore, c-Abl/Arg inhibitors have been used in numerous solid tumor clinical trials; however, none of these trials were restricted to patients whose tumors expressed highly activated c-Abl/Arg (targeted trial). Targeted trials are critical for determining whether c-Abl/Arg inhibitors can be effective treatment options for patients whose tumors are driven by c-Abl/Arg.

Systematic therapy for unresectable or metastatic soft-tissue sarcomas: past, present, and future

Unresectable or metastatic disease occurs in 40% to 60% of soft-tissue sarcoma (STS) patients and portends a poor prognosis. For decades, doxorubicin has formed the backbone of systemic treatment, with response rates of approximately 26%. Patients progressing following first-line therapy were left with few proven options. No other cytotoxic chemotherapy agent or combination has demonstrated superiority to doxorubicin. Advances in targeted therapy of STS have been hindered by STS heterogeneity and poorly understood disease biology. Despite challenges, progress has been made in specific STS subtypes. Here, we highlight the challenges, progress, and lessons learned from STS trials published in the last 20 to 25 years.

Cryoimmunology for malignant bone and soft-tissue tumors

Several new methods have recently been developed for the treatment of malignant bone and soft-tissue tumors, and many of these targeted therapies have yielded promising initial results in clinical settings. As more sarcomas become amenable to effective molecular-targeting therapy, the need to evaluate the synergistic effects of combination therapies with anticancer drugs will grow. Other immunologic therapies have also been reported, such as exogenous cytokines, dendritic cell (DC) therapy and peptide vaccines. Cryoimmunology has shown promising results in some malignant tumors after cryosurgery and is expected to influence the next generation of tumor immunotherapy. In this report, we describe the induction of a systemic antitumor immune response following liquid nitrogen cryotreatment of a destructive murine osteosarcoma. Combining tumor cryotreatment with DCs to promote tumor-specific immune responses enhanced systemic immune responses and inhibited metastatic tumor growth. We also describe the induction of a systemic antitumor immune response following reconstruction for malignant bone tumors using frozen autografts treated with liquid nitrogen.