Chordoma and chondrosarcoma gene profile: implications for immunotherapy

Developmental gene expression in skull-base chordomas and chondrosarcomas

PURPOSE

 Chordomas are malignant tumors of the axial spine and skull base, and they are notorious for their poor treatment response. Differentiating these tumors from comparatively less malignant chondrosarcomas is crucial for treatment and prognostication. Both tumor types differ in their developmental origin. Chordomas are considered to be derived from notochordal remnants and chondrosarcomas from mesenchymal cells. Here, we evaluated the differential expression of developmental transcription factors in these skull base tumors.

METHODS

 Histopathologically-confirmed tumor biopsies were obtained from 12 chordoma and 7 chondrosarcoma patients. Following RNA extraction, samples were submitted to real-time quantitative PCR (RT-qPCR) for the evaluation of 32 evolutionary conserved genes that are known to associate with notochord, mesoderm, and axial spine development. Gene expression levels were normalized to housekeeping genes ACTB and RS27a.

RESULTS

 Fifteen genes were either exclusively expressed (n = 12) or overexpressed (n = 3; 2.21-4.43 fold increase) in chordoma, compared to chondrosarcoma. Brachyury and CD24 were highly and exclusively expressed in chordoma. Other novel genes exclusive to chordomas included chordin, HOXA5 and ACAN. Vice versa, ten genes were either exclusively expressed (n = 2) or overexpressed (n = 8; 0.01-0.66 fold increase) in chondrosarcoma, compared to chordoma.

CONCLUSION

 As chordoma patients demonstrate a worse prognosis compared to chondrosarcoma patients, the differential expression of chordin, HOXA5 and ACAN and CD24 could be relevant for the pathophysiology of chordomas and may have diagnostic and treatment value. Further study on role of these genes in tumorigenesis is therefore warranted.

The novel developed and validated multiparametric MRI-based fusion radiomic and clinicoradiomic models predict the postoperative progression of primary skull base chordoma

Local progression of primary skull base chordoma (PSBC) is a sign of treatment failure. Predicting the postoperative progression of PSBC can aid in the development of individualized treatment plans to improve patients' progression-free survival (PFS) after surgery. This study aimed to develop a multiparametric MRI-based fusion radiomic model (FRM) and clinicoradiomic model (CRM) via radiomic and clinical analysis and to explore their validity in predicting postoperative progression in PSBC patients before surgery. In this retrospective study, a total of 129 patients with PSBC from our institution, including 57 patients with progression, were enrolled and randomized to the training set (TS) or the validation set (VS) at a 2:1 ratio. Radiomic features were extracted and dimensionally reduced from 3.0 T/axial T2-weighted imaging (T2WI), T1-weighted imaging (T1WI) and contrast-enhanced T1-weighted imaging (CE-T1WI) sequences for each patient, and the features were used for radiomic analysis. Univariate and multivariate Cox regression analyses were used to screen for key clinical factors. We constructed models on the basis of multivariate logistic regression analysis. Receiver operating characteristic (ROC) curve, calibration curve, and decision curve analyses were performed to evaluate the performance of the clinical model (CM), FRM and CRM. Through analysis, we found that blood supply was the only significantly different clinical factor in the CM. For the FRM, the area under the receiver operating characteristic curve (AUC) of the TS was 0.925, and the calibration curves were consistent across the TS. In the CRM, the AUC of the TS was 0.929, the calibration curve analysis was consistent for both the TS and the VS, and the DCA showed that the net benefit was greater at a threshold probability of > 0% for both the TS and the VS. Our proposed FRM can help clinicians better predict PSBC progression preoperatively, and the use of the CRM can lead to the development of more appropriate protocols to improve patients' PFS after surgery.

Role of immunotherapy in treatment refractory chordomas: review of current evidence

Introduction

Chordomas are aggressive tumors that are thought to arise from remnants of the embryological notochord. They can arise along the ventromedial aspect of the sacrum, mobile spine, and clivus-with most cases occurring in the sacrum or skull base. Despite surgery and radiation, chordomas often progress and become refractory to further treatment. The high recurrence rate of chordomas has created an urgent need to develop new systemic treatment options. Recent case reports and clinical trials have highlighted the use of immunotherapy for refractory chordomas. In this review, we summarize the results of these studies and discuss the potential role of immunotherapy for chordomas.

Methods

The PUBMED database was queried for studies mentioning both "Chordoma" and "Immunotherapy." All case series and case reports that involved administration of an immunotherapy for chordoma were included. Additional studies that were found during literature review were added. ClinicalTrials.Gov was queried for studies mentioning both "Chordoma" and "Immunotherapy." The final cohort consisted of all clinical trials that utilized immunotherapy for chordomas of any location.

Results

Eight case reports and series detailing the use of immunotherapy for treatment refractory chordoma were identified. Most patients received immunotherapy targeting the PD-1/PD-L1 interaction, and two patients received therapy targeting this interaction along with the tyrosine kinase inhibitor pazopanib. One patient received a vaccine derived from autologous tumor cells, and one patient received a viral vector that downregulated the effect of TGF-beta. One clinical trial utilized a brachyury vaccine in conjunction with standard of care radiotherapy.

Conclusions

Immunotherapy for chordoma is a promising area of investigation with increasing, but small, numbers of case series and clinical trials. Despite challenges in patient accrual, future directions in chordoma immunotherapy may lie in vaccine-based therapies and immune checkpoint inhibitors. Understanding chordoma heterogeneity and microenvironment will likely elucidate important chordoma features that will inform future clinical trial design.

Development of a Small Molecule Downmodulator for the Transcription Factor Brachyury

Brachyury is an oncogenic transcription factor whose overexpression drives chordoma growth. The downmodulation of brachyury in chordoma cells has demonstrated therapeutic potential, however, as a transcription factor it is classically deemed "undruggable". Given that direct pharmacological intervention against brachyury has proven difficult, attempts at intervention have instead targeted upstream kinases. Recently, afatinib, an FDA-approved kinase inhibitor, has been shown to modulate brachyury levels in multiple chordoma cell lines. Herein, we use afatinib as a lead to undertake a structure-based drug design approach, aided by mass-spectrometry and X-ray crystallography, to develop DHC-156, a small molecule that more selectively binds brachyury and downmodulates it as potently as afatinib. We eliminated kinase-inhibition from this novel scaffold while demonstrating that DHC-156 induces the post-translational downmodulation of brachyury that results in an irreversible impairment of chordoma tumor cell growth. In doing so, we demonstrate the feasibility of direct brachyury modulation, which may further be developed into more potent tool compounds and therapies.

Unraveling molecular signatures in rare bone tumors and navigating the cancer pathway landscapes for targeted therapeutics

Rare cancers (RCs), which account for over 20% of cancer cases, face significant research and treatment challenges due to their limited prevalence. This results in suboptimal outcomes compared to more common malignancies. Rare bone tumors (RBTs) constitute 5-10% of rare cancer cases and pose unique diagnostic complexities. The therapeutic potential of anti-cancer drugs for RBTs remains largely unexplored. Identifying molecular alterations in cancer-related genes and their associated pathways is essential for precision medicine in RBTs. Small molecule inhibitors and monoclonal antibodies targeting specific RBT-associated proteins show promise. Ongoing clinical trials aim to define RBT biomarkers, subtypes, and optimal treatment contexts, including combination therapies and immunotherapeutic agents. This review addresses the challenges in diagnosing, treating, and studying RBTs, shedding light on the current state of RBT biomarkers, potential therapeutic targets, and promising inhibitors. Rare cancers demand attention and innovative solutions to improve clinical outcomes.

Advancing the Management of Skull Base Chondrosarcomas: A Systematic Review of Targeted Therapies

BACKGROUND

Chondrosarcomas rank as the second most common primary bone malignancy. Characterized by the production of a cartilaginous matrix, these tumors typically exhibit resistance to both radiotherapy (RT) and chemotherapy (CT), resulting in overall poor outcomes: a high rate of mortality, especially among children and adolescents. Due to the considerable resistance to current conventional therapies such as surgery, CT, and RT, there is an urgent need to identify factors contributing to resistance and discover new strategies for optimal treatment. Over the past decade, researchers have delved into the dysregulation of genes associated with tumor development and therapy resistance to identify potential therapeutic targets for overcoming resistance. Recent studies have suggested several promising biomarkers and therapeutic targets for chondrosarcoma, including isocitrate dehydrogenase (IDH1/2) and COL2A1. Molecule-targeting agents and immunotherapies have demonstrated favorable antitumor activity in clinical studies involving patients with advanced chondrosarcomas. In this systematic review, we delineate the clinical features of chondrosarcoma and provide a summary of gene dysregulation and mutation associated with tumor development, as well as targeted therapies as a promising molecular approach. Finally, we analyze the probable role of the tumor microenvironment in chondrosarcoma drug resistance.

METHODS

A systematic search was conducted across major medical databases (PubMed, Embase, and Cochrane Library) up to 10 November 2023. The search strategy utilized relevant Medical Subject Heading (MeSH) terms and keywords related to "chondrosarcomas", "target therapies", "immunotherapies", and "outcomes". The studies included in this review consist of randomized controlled trials, non-randomized controlled trials, and cohort studies reporting on the use of target therapies for the treatment of chondrosarcoma in human subjects.

RESULTS

Of the initial 279 articles identified, 40 articles were included in the article. The exclusion of 140 articles was due to reasons such as irrelevance, non-reporting of selected results, systematic literature review or meta-analysis, and lack of details on the method/results. Three tables highlighted clinical studies, preclinical studies, and ongoing clinical trials, encompassing 13, 7, and 20 studies, respectively. For the clinical study, a range of molecular targets, such as death receptors 4/5 (DR4 and DR5) (15%), platelet-derived growth factor receptor-alpha or -beta (PDGFR-α, PDGFR-β) (31%), were investigated. Adverse events were mainly constitutional symptoms emphasizing that to improve therapy tolerance, careful observation and tailored management are essential. Preclinical studies analyzed various molecular targets such as DR4/5 (28.6%) and COX-2 (28.6%). The prevalent indicator of antitumoral activity was the apoptotic rate of both a single agent (tumor necrosis factor-related apoptosis-inducing ligand: TRAIL) and double agents (TRAIL-DOX, TRAIL-MG132). Ongoing clinical trials, the majority in Phase II (53.9%), highlighted possible therapeutic strategies such as IDH1 inhibitors and PD-1/PD-L1 inhibitors (30.8%).

CONCLUSIONS

The present review offers a comprehensive analysis of targeted therapeutics for skull base chondrosarcomas, highlighting a complex landscape characterized by a range of treatment approaches and new opportunities for tailored interventions. The combination of results from molecular research and clinical trials emphasizes the necessity for specialized treatment strategies and the complexity of chondrosarcoma biology.

A Systematic Review of Adjuvant Chemotherapy in Localized Dedifferentiated Chondrosarcoma

Dedifferentiated chondrosarcoma (DDCS) is a high-grade subtype of chondrosarcoma with the bimorphic histological appearance of a conventional chondrosarcoma component with abrupt transition to a high-grade, non-cartilaginous sarcoma. DDCS can be radiographically divided into central and peripheral types. Wide resection is currently the main therapeutic option for localized DDCS. Moreover, the effectiveness of adjuvant chemotherapy remains controversial. Therefore, we performed a systematic review of available evidence to evaluate the effect of adjuvant chemotherapy on localized DDCS. The purpose was to compare the 5-year survival rate among patients treated with surgery plus adjuvant chemotherapy or surgery alone for localized DDCS. The search was conducted in PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases. Of the 217 studies shortlisted, 11 retrospective non-randomized studies (comprising 556 patients with localized DDCS) were selected. The 5-year survival rates were similar between the two treatment groups (28.2% (51/181) vs. 24.0% (90/375), respectively). The overall pooled odds ratio was 1.25 (95% confidence interval: 0.80-1.94; p = 0.324), and heterogeneity I2 was 2%. However, when limited to peripheral DDCS, adjuvant chemotherapy was associated with prolonged survival (p = 0.03). Due to the paucity of included studies and the absence of prospective comparative studies, no conclusions can be drawn regarding the effectiveness or ineffectiveness of adjuvant chemotherapy for localized DDCS.

Fibroblast Activation Protein Inhibitor (FAPI)-PET Imaging in Sarcoma

Advances in histopathologic and molecular genetic subtyping of sarcoma will potentially allow identification of novel diagnostic and therapeutic targets for specific subtypes, but a "pan-sarcoma" target is needed. This article provides an overview on expression of one potential candidate, fibroblast activation protein alpha in soft tissue and bone sarcoma, and the resulting application of 68Ga-FAPI as novel imaging probes in these rare tumor entities. Current preclinical and clinical data on 68Ga-FAPI-PET/CT in sarcomas are summarized. 68Ga-FAPI-PET-CT potentially offers important complementary information to be used in diagnostic work-up, assessment of therapy response, and prognostication of soft tissue and bone sarcomas.

Proton and carbon ion beam treatment with active raster scanning method in 147 patients with skull base chordoma at the Heidelberg Ion Beam Therapy Center-a single-center experience

BACKGROUND

This study aimed to compare the results of irradiation with protons versus irradiation with carbon ions in a raster scan technique in patients with skull base chordomas and to identify risk factors that may compromise treatment results.

METHODS

A total of 147 patients (85 men, 62 women) were irradiated with carbon ions (111 patients) or protons (36 patients) with a median dose of 66 Gy (RBE (Relative biological effectiveness); carbon ions) in 4 weeks or 74 Gy (RBE; protons) in 7 weeks at the Heidelberg Ion Beam Therapy Center (HIT) in Heidelberg, Germany. The median follow-up time was 49.3 months. All patients had gross residual disease at the beginning of RT. Compression of the brainstem was present in 38%, contact without compression in 18%, and no contact but less than 3 mm distance in 16%. Local control and overall survival were evaluated using the Kaplan-Meier Method based on scheduled treatment (protons vs. carbon ions) and compared via the log rank test. Subgroup analyses were performed to identify possible prognostic factors.

RESULTS

During the follow-up, 41 patients (27.9%) developed a local recurrence. The median follow-up time was 49.3 months (95% CI: 40.8-53.8; reverse Kaplan-Meier median follow-up time 56.3 months, 95% CI: 51.9-60.7). No significant differences between protons and carbon ions were observed regarding LC, OS, or overall toxicity. The 1‑year, 3‑year, and 5‑year LC rates were 97%, 80%, and 61% (protons) and 96%, 80%, and 65% (carbon ions), respectively. The corresponding OS rates were 100%, 92%, and 92% (protons) and 99%, 91%, and 83% (carbon ions). No significant prognostic factors for LC or OS could be determined regarding the whole cohort; however, a significantly improved LC could be observed if the tumor was > 3 mm distant from the brainstem in patients presenting in a primary situation.

CONCLUSION

Outcomes of proton and carbon ion treatment of skull base chordomas seem similar regarding tumor control, survival, and toxicity. Close proximity to the brainstem might be a negative prognostic factor, at least in patients presenting in a primary situation.

Immunotherapy as a Promising Option for the Treatment of Advanced Chordoma: A Systemic Review

OBJECTIVE

To summarize the function and efficacy of immunotherapy as an adjunctive therapy in the treatment of advanced chordoma.

METHODS

Literature search was conducted by two reviewers independently. Case reports, case series and clinical trials of immunotherapy for chordoma were retrieved systematically from Pubmed, Web of Science, Scoupus and Cochrane Library. Clinical outcome data extracted from the literature included median progression-free survival (PFS), median overall survival (OS), clinical responses and adverse events (AEs).

RESULTS

All studies were published between 2015 and 2022. Twenty-two eligible studies were selected for systemic review. PD-1/PD-L1 immune checkpoint inhibitors (ICIs) were the most common used immunotherapy agents in chordoma, among which Pembrolizumab was the most frequently prescribed. CTLA-4 antibody was only used as combination therapy in chordoma. Dose Limiting Toxicity (DLT) was not observed in any vaccine targeting brachyury, and injection site response was the most frequent AV. The response evaluation criteria in solid tumors (RECIST) were the most generally used evaluation standard in chordoma immunotherapy, and none of the included studies employed the Choi criteria.

CONCLUSIONS

No clinical data have demonstrated that CTLA-4 ICIs combined with PD-1/PD-L1 ICIs is more effective than ICIs monotherapy in treating chordoma, and ICIs in combination with other therapies exhibit more toxicity than monotherapy. PD-1/PD-L1 ICIs monotherapy is recommended as an immunotherapy in patients with advanced chordoma, which may even benefit PD-L1-negative patients. The brachyury vaccine has shown good safety in chordoma patients, and future clinical trials should focus on how to improve its therapeutic efficacy. The use of immunomodulatory agents is a promising therapeutic option, though additional clinical trials are required to evaluate their safety and effectiveness. RECIST does not seem to be an appropriate standard for assessing medications of intratumoral immunotherapy.

Chondroitin Sulfate Proteoglycan 4 as a Marker for Aggressive Squamous Cell Carcinoma

Chondroitin sulfate (CS) proteoglycan 4 (CSPG4) is a cell surface proteoglycan that is currently under investigation as a marker of cancer malignancy, and as a potential target of anticancer drug treatment. CSPG4 acts as a driver of tumourigenesis by regulating turnover of the extracellular matrix (ECM) to promote tumour cell invasion, migration as well as inflammation and angiogenesis. While CSPG4 has been widely studied in certain malignancies, such as melanoma, evidence is emerging from global gene expression studies, which suggests a role for CSPG4 in squamous cell carcinoma (SCC). While relatively treatable, lack of widely agreed upon diagnostic markers for SCCs is problematic, especially for clinicians managing certain patients, including those who are aged or infirm, as well as those with underlying conditions such as epidermolysis bullosa (EB), for which a delayed diagnosis is likely lethal. In this review, we have discussed the structure of CSPG4, and quantitatively analysed CSPG4 expression in the tissues and pathologies where it has been identified to determine the usefulness of CSPG4 expression as a diagnostic marker and therapeutic target in management of malignant SCC.

Chondroitin sulfate proteoglycan 4 expression in chondrosarcoma: A potential target for antibody-based immunotherapy

Chondrosarcoma is a common primary bone malignancy whose phenotype increases with its histologic grade. They are relatively resistant to chemotherapy and radiation therapy limiting curative options for disseminated disease. Chondroitin sulfate proteoglycan 4 (CSPG4) is a cell surface proteoglycan that is highly expressed across various human cancers, including chondrosarcoma, and has restricted distribution in healthy tissues, making it an attractive target for the antibody-based therapy. CSPG4 specific chimeric antigen receptor (CAR) T cell therapies have been shown to be effective in treating other cancers such as melanoma and triple negative breast cancer. The goal of this study was to assess the prevalence of CSPG4 in human chondrosarcoma and to assess the efficacy of CSPG4 specific CAR T cells in lysing chondrosarcoma cells in vitro. Using immunohistochemistry (IHC), we stained a tissue microarray containing primary conventional and dedifferentiated chondrosarcoma from 76 patients with CSPG4 specific monoclonal antibodies (mAbs). In addition, we incubated 2 chondrosarcoma cell lines with CSPG4-targeting CAR T cells and subsequently evaluated cell survival. Our results showed medium to high expression of CSPG4 in 29 of 41 (71%) conventional chondrosarcoma tumors and in 3 of 20 (15%) dedifferentiated chondrosarcoma tumors. CSPG4 expression showed a positive association with time to metastasis and survival in both subtypes. CSPG4 CAR T treated cell lines showed a lysis of respectively >80% and 70% demonstrating CSPG4-targeted CAR T cells effective in killing CSPG4-positive chondrosarcoma tumors.

Immunotherapeutic treatments for spinal and peripheral nerve tumors: a primer

OBJECTIVE

Spinal and peripheral nerve tumors are a heterogeneous group of neoplasms that can be associated with significant morbidity and mortality despite the current standard of care. Immunotherapy is an emerging therapeutic option to improve the prognoses of these tumors. Therefore, the authors sought to present an updated and unifying review on the use of immunotherapy in treating tumors of the spinal cord and peripheral nerves, including a discussion on mechanism of action, drug delivery, current treatment techniques, and preclinical and clinical studies.

METHODS

Current data in the literature regarding immunotherapy were collated and summarized. Targeted tumors included primary and secondary spinal tumors, as well as peripheral nerve tumors.

RESULTS

Four primary modalities of immunotherapy (CAR T cell, monoclonal antibody, viral, and cytokine) have been reported to target spine and peripheral nerve tumors. Of the primary spinal tumors, spinal cord astrocytomas had the most preclinical evidence supporting immunotherapy success with CAR T-cell therapy targeting the H3K27M mutation, whereas spinal schwannomas and ependymomas had the most evidence reported for monoclonal antibody therapy preclinically. Of the secondary spinal tumors, primary CNS lymphomas demonstrated some clinical response to immunotherapy, whereas multiple myeloma and bone tumor experiences with immunotherapy were largely limited to concept only. Within peripheral nerve tumors, the use of immunotherapy to treat neurofibromas in the setting of syndromes has been suggested in theory, and possible immunotherapeutic targets have been identified in malignant peripheral nerve tumors. To date, there have been 2 clinical trials involving spine tumors and 2 clinical trials involving peripheral nerve tumors that have reported results, all of which are promising but require validation.

CONCLUSIONS

Immunotherapy to treat spinal and peripheral nerve tumors has become an emerging area of research and interest. A large amount of preclinical data supporting the translation of this therapy into practice, aimed at ameliorating the poor prognoses of specific tumors, have been reported. Future clinical studies for translation will focus on the optimal therapy type and administration route to best target these tumors, which often preclude total surgical resection given their proximity to the neural and vascular elements of the spine.

The Ascidia Ciona robusta Provides Novel Insights on the Evolution of the AP-1 Transcriptional Complex

The Activator Protein-1 transcription factor family (AP-1) transcriptional complex is historically defined as an early response group of transcription factors formed by dimeric complexes of the Jun, Fos, Atf, and Maf bZIP proteins that control cell proliferation and differentiation by regulating gene expression. It has been greatly investigated in many model organisms across metazoan evolution. Nevertheless, its complexity and variability of action made its multiple functions difficult to be defined. Here, we place the foundations for understanding the complexity of AP-1 transcriptional members in tunicates. We investigated the gene members of this family in the ascidian Ciona robusta and identified single copies of Jun, Fos, Atf3, Atf2/7, and Maf bZIP-related factors that could have a role in the formation of the AP-1 complex. We highlight that mesenchyme is a common cellular population where all these factors are expressed during embryonic development, and that, moreover, Fos shows a wider pattern of expression including also notochord and neural cells. By ectopic expression in transgenic embryos of Jun and Fos genes alone or in combination, we investigated the phenotypic alterations induced by these factors and highlighted a degree of functional conservation of the AP-1 complex between Ciona and vertebrates. The lack of gene redundancy and the first pieces of evidence of conserved functions in the control of cell movements and structural organization exerted by these factors open the way for using Ciona as a helpful model system to uncover the multiple potentialities of this highly complex family of bZIP transcription factors.

Immunotherapy for Chordoma and Chondrosarcoma: Current Evidence

Chordomas and chondrosarcomas are rare but devastating neoplasms that are characterized by chemoradiation resistance. For both tumors, surgical resection is the cornerstone of management. Immunotherapy agents are increasingly improving outcomes in multiple cancer subtypes and are being explored in chordoma and chondrosarcoma alike. In chordoma, brachyury has been identified as a prominent biomarker and potential molecular immunotherapy target as well as PD-1 inhibition. While studies on immunotherapy in chondrosarcoma are sparse, there is emerging evidence and ongoing clinical trials for PD-1 as well as IDH inhibitors. This review highlights potential biomarkers and targets for immunotherapy in chordoma and chondrosarcoma, as well as current clinical evidence and ongoing trials.

Chondrosarcoma-from Molecular Pathology to Novel Therapies

Chondrosarcoma (CHS) is the second most common primary malignant bone sarcoma. Overall survival and prognosis of this tumor are various and often extreme, depending on histological grade and tumor subtype. CHS treatment is difficult, and surgery remains still the gold standard due to the resistance of this tumor to other therapeutic options. Considering the role of differentiation of CHS subtypes and the need to develop new treatment strategies, in this review, we introduced a multidisciplinary characterization of CHS from its pathology to therapies. We described the morphology of each subtype with the role of immunohistochemical markers in diagnostics of CHS. We also summarized the most frequently mutated genes and genome regions with altered pathways involved in the pathology of this tumor. Subsequently, we discussed imaging methods and the role of currently used therapies, including surgery and the limitations of chemo and radiotherapy. Finally, in this review, we presented novel targeted therapies, including those at ongoing clinical trials, which can be a potential future target in designing new therapeutics for patients with CHS.

[Interdisciplinary surgery to the central skull base-current status]

Hintergrund

Die Schädelbasis stellt eine chirurgisch hochkomplexe Einheit dar und ist häufig nur über kombinierte Zugangswege erreichbar. Neu entwickelte Operationstechniken mit Verwendung von mikrochirurgischen Visualisierungsverfahren und aktiven Instrumenten („powered instruments“) sowie „Multi-Port-Zugänge“ ermöglichen neue, weniger traumatische Operationskorridore. Hierfür ist eine enge interdisziplinäre Zusammenarbeit zwischen dem Chirurgen aus dem Fachgebiet der Hals-Nasen-Ohren-Heilkunde sowie dem Neurochirurgen notwendig. Die aktuell etablierten Zugangsverfahren zur zentralen Schädelbasis werden aufgrund eigener klinischer Erfahrungen und unter Berücksichtigung der Entität systematisiert und in Bezug auf die aktuelle Studienlage erörtert.

Material und Methode

Es erfolgte eine retrospektive, qualitative und deskriptive Auswertung der Operationsberichte einzelner Patienten, die in der Zeit zwischen 2006 und 2019 mit Pathologien an der zentralen Schädelbasis chirurgisch gemeinsam von der Neurochirurgie und der Hals-Nasen-Ohren-Heilkunde/Kopf- und Halschirurgie behandelt wurden.

Ergebnisse

Die chirurgischen Zugangswege zur zentralen Schädelbasis ließen sich nachfolgend kategorisieren, teilweise auch in Kombination derselben, als sog. Multi-Port-Zugänge: transnasal-transsphenoidal, subfrontal, subtemporal, transzygomatisch, transpterygonal, transpetrös, translabyrinthär und subokzipital. Maßgebend für die Wahl des Zugangswegs waren die Lokalisation und Art der Pathologie, sowie der mögliche Anspruch auf Funktionserhalt und Komplettentfernung.

Schlussfolgerung

Aufgrund der Komplexität der Strukturen der zentralen Schädelbasis, der unterschiedlichsten Tumorentitäten und der benötigten Fachkompetenz unterschiedlicher Facharztdisziplinen bleibt die Chirurgie der zentralen Schädelbasis eine Herausforderung, der man sich nur an speziellen, nach den Kriterien der Gesellschaft für Schädelbasischirurgie e. V. zertifizierten Kompetenzzentren stellen sollte.

GD2 or HER2 targeting T cell engaging bispecific antibodies to treat osteosarcoma

BACKGROUND

The cure rate for metastatic osteosarcoma has not substantially improved over the past decades. Clinical trials of anti-HER2 trastuzumab or anti-GD2 dinutuximab for metastatic or refractory osteosarcoma were not successful, and neither was immune checkpoint inhibitors (ICIs).

METHODS

We tested various target antigen expressions on osteosarcoma cell lines using flow cytometry and analyzed in vitro T cell engaging BsAb (T-BsAb)-dependent T cell-mediated cytotoxicity using 4-h ⁵¹Cr release assay. We tested in vivo anti-tumor activities of T-BsAb targeting GD2 or HER2 in established osteosarcoma cell line or patient-derived xenograft (PDX) mouse models carried out in BALB-Rag2^-/-IL-2R-γc-KO (BRG) mice. We also generated ex vivo BsAb-armed T cells (EATs) and studied their tumor-suppressive effect against osteosarcoma xenografts. In order to improve the anti-tumor response, ICIs, anti-human PD-1 (pembrolizumab) or anti-human PD-L1 (atezolizumab) antibodies were tested their synergy with GD2- or HER2-BsAb against osteosarcoma.

RESULTS

GD2 and HER2 were chosen from a panel of surface markers on osteosarcoma cell lines and PDXs. Anti-GD2 BsAb or anti-HER2 BsAb exerted potent anti-tumor effect against osteosarcoma tumors in vitro and in vivo. T cells armed with anti-GD2-BsAb (GD2-EATs) or anti-HER2-BsAb (HER2-EATs) showed significant anti-tumor activities as well. Anti-PD-L1 combination treatment enhanced BsAb-armed T cell function in vivo and improved tumor control and survival of the mice, when given sequentially and continuously.

CONCLUSION

Anti-GD2 and anti-HER2 BsAbs were effective in controlling osteosarcoma. These data support the clinical investigation of GD2 and HER2 targeted T-BsAb treatment in combination with immune checkpoint inhibitors, particularly anti-PD-L1, in patients with osteosarcoma to improve their treatment outcome.

miR-1290 inhibits chordoma cell proliferation and invasion by targeting Robo1

BACKGROUND

Chordoma is a low-grade aggressive bone tumor with a high local recurrence. MicroRNAs (miRNAs) have been reported to play crucial roles in the development of chordoma. Our previous study has shown miR-1290 is associated with muscle invasion and the prognosis of chordoma. However, the underlying mechanism of miR-1290 in chordoma remains unclear. In this study, we aimed to explore the function of miR-1290 in the biological behaviors of chordoma.

METHODS

Sixteen sacral chordoma samples and 10 fetal nucleus pulposus specimens were collected for the detection of miR-1290 and Robo1 at the First Affiliated Hospital of Soochow University. Bioinformatic analysis and a luciferase reporter assay was used to verify the interaction between miR-1290 and the target gene robo1 in chordoma. Effects of miR-1290 expression on chordoma cell proliferation and invasion were explored by clone formation and Transwell assay in vitro. The underlying mechanisms of miR-1290 and Robo1 in chordoma cell proliferation and invasion were also explored in the U-CH1 cell line.

RESULTS

In vitro functional analysis, including clone formation, and Transwell assays indicated overexpression of miR-1290 significantly suppressed chordoma cell proliferation and invasion. Bioinformatic analysis revealed Robo1 as a potential target of miR-1290, and luciferase reporter assays demonstrated the association between miR-1290 and the Robo1 gene in U-CH1 cells. Robo1 was further confirmed to be up-regulated in chordoma tissues by immunohistochemistry (IHC), which is negatively correlated with miR-1290 expression in chordoma tissue. Additionally, we found down-regulation of miR-1290 could induce the expression of Robo1 in chordoma cells, while the elevation of miR-1290 expression could inhibit Robo1 expression in chordoma cells.

CONCLUSIONS

miR-1290 inhibits chordoma cell proliferation and invasion by negatively regulating the Robo1 gene.

Small-molecule targeting of brachyury transcription factor addiction in chordoma

Chordoma is a primary bone cancer with no approved therapy1. The identification of therapeutic targets in this disease has been challenging due to the infrequent occurrence of clinically actionable somatic mutations in chordoma tumors2,3. Here we describe the discovery of therapeutically targetable chordoma dependencies via genome-scale CRISPR-Cas9 screening and focused small-molecule sensitivity profiling. These systematic approaches reveal that the developmental transcription factor T (brachyury; TBXT) is the top selectively essential gene in chordoma, and that transcriptional cyclin-dependent kinase (CDK) inhibitors targeting CDK7/12/13 and CDK9 potently suppress chordoma cell proliferation. In other cancer types, transcriptional CDK inhibitors have been observed to downregulate highly expressed, enhancer-associated oncogenic transcription factors4,5. In chordoma, we find that T is associated with a 1.5-Mb region containing 'super-enhancers' and is the most highly expressed super-enhancer-associated transcription factor. Notably, transcriptional CDK inhibition leads to preferential and concentration-dependent downregulation of cellular brachyury protein levels in all models tested. In vivo, CDK7/12/13-inhibitor treatment substantially reduces tumor growth. Together, these data demonstrate small-molecule targeting of brachyury transcription factor addiction in chordoma, identify a mechanism of T gene regulation that underlies this therapeutic strategy, and provide a blueprint for applying systematic genetic and chemical screening approaches to discover vulnerabilities in genomically quiet cancers.

Benign notochordal cell tumour: clinicopathology and molecular profiling of 13 cases

Aims

To study the clinicopathological and molecular features of benign notochordal cell tumours (BNCTs) and their differential diagnosis from chordoma.

Methods

13 cases of BNCT were investigated. The genome-wide copy number imbalances were performed using Oncoscan CNV array in three cases and fluorescence in situ hybridisation (FISH) detection of epidermal growth factor receptor (EGFR)/chromosome 7 enumeration probe (CEP7), LSI1p36/1q21, LSI19p13/19q13, CEP3/CEP12 and Telvysion 6 P was performed in 13 cases.

Results

All 13 BNCTs were symptomatic and eight cases showed a close relationship with the bones of the skull base. The important histological character for differential diagnosis with chordoma was the absence of extracellular matrix and eosinophil cells and the presence of vacuoles in most tumour cells. Immunohistochemical staining of AE1/AE3, vimentin, epithelial membrane antigen, S-100 and brachyury (100% each) were positive in BNCTs. Gain of chromosome 7 occurred in 10 cases (76.9%), gain of 1p in four (30.8%), gain of 1q in five (38.5%), gain of 19p and 19q in five (38.5%), gain of chromosome 12 in 11 cases (84.6%), gain of 6p in eight (61.5%) and gain of chromosome 3 in four cases (30.8%).

Conclusions

In contrast to chordoma, chromosome gain or normal copy number was more common while chromosome loss was infrequent in BNCTs. This may be a differential diagnosis clue for chordoma and may be an important characteristic in the progression of notochordal cell tumours.

Response to PD1 inhibition in conventional chondrosarcoma

Background

Chondrosarcoma is one of the most common malignant bone tumors in adults. Conventional chondrosarcoma represents around 85% of all chondrosarcomas and is notoriously difficult to treat with chemotherapy.

Case presentation

We describe a 67-year-old man with metastatic conventional chondrosarcoma who was treated with nivolumab. Treatment was discontinued after restaging showed increased tumor burden, which later proved to be pseudoprogression. The patient restarted nivolumab and continues to have a near complete response.

Conclusion

Conventional chondrosarcoma may be sensitive to checkpoint inhibitors. Further, this case demonstrates clearly the phenomenon of pseudo-progression in this disease, a factor that must be considered in the design of clinical trials and clinical care. This case supports additional study of immunomodulatory agents in this deadly disease.

Lymphocyte-Related Inflammation and Immune-Based Scores Predict Prognosis of Chordoma Patients After Radical Resection

The inflammatory microenvironment plays a critical role in the development and progression of malignancies. In the present study, we aimed to evaluate the prognostic value of lymphocyte-related inflammation and immune-based prognostic scores in patients with chordoma after radical resection, including the neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), monocyte-lymphocyte ratio (MLR), and systemic immune-inflammation index (SII). A total of 172 consecutive patients with chordoma who underwent radical resection were reviewed. R software was used to randomly select 86 chordoma patients as a training set and 86 chordoma patients as a validation set. Potential prognostic factors were also identified, including age, sex, tumor localization, KPS, Enneking stage, tumor size, and tumor metastasis. Overall survival (OS) was calculated using the Kaplan–Meier method and multivariate Cox regression analyses. NLR, PLR, SII, Enneking stage, tumor differentiation and tumor metastasis were identified as significant factors from the univariate analysis in both the training and validation sets and were subjected to multivariate Cox proportional hazards analysis. The univariate analysis showed that NLR ≥1.65, PLR ≥121, and SII ≥370×10⁹/L were significantly associated with poor OS. In the multivariate Cox proportional hazard analysis, SII, Enneking stage and tumor metastasis were significantly associated with OS. As noninvasive, low-cost, reproducible prognostic biomarkers, NLR, PLR and SII could help predict poor prognosis in patients with chordoma after radical resection. This finding may contribute to the development of more effective tailored therapy according to the characteristics of individual tumors.

Chondrosarcoma: A Rare Misfortune in Aging Human Cartilage? The Role of Stem and Progenitor Cells in Proliferation, Malignant Degeneration and Therapeutic Resistance

Unlike other malignant bone tumors including osteosarcomas and Ewing sarcomas with a peak incidence in adolescents and young adults, conventional and dedifferentiated chondrosarcomas mainly affect people in the 4th to 7th decade of life. To date, the cell type of chondrosarcoma origin is not clearly defined. However, it seems that mesenchymal stem and progenitor cells (MSPC) in the bone marrow facing a pro-proliferative as well as predominantly chondrogenic differentiation milieu, as is implicated in early stage osteoarthritis (OA) at that age, are the source of chondrosarcoma genesis. But how can MSPC become malignant? Indeed, only one person in 1,000,000 will develop a chondrosarcoma, whereas the incidence of OA is a thousandfold higher. This means a rare coincidence of factors allowing escape from senescence and apoptosis together with induction of angiogenesis and migration is needed to generate a chondrosarcoma. At early stages, chondrosarcomas are still assumed to be an intermediate type of tumor which rarely metastasizes. Unfortunately, advanced stages show a pronounced resistance both against chemo- and radiation-therapy and frequently metastasize. In this review, we elucidate signaling pathways involved in the genesis and therapeutic resistance of chondrosarcomas with a focus on MSPC compared to signaling in articular cartilage (AC).

Proteoglycans remodeling in cancer: Underlying molecular mechanisms

Extracellular matrix is a highly dynamic macromolecular network. Proteoglycans are major components of extracellular matrix playing key roles in its structural organization and cell signaling contributing to the control of numerous normal and pathological processes. As multifunctional molecules, proteoglycans participate in various cell functions during morphogenesis, wound healing, inflammation and tumorigenesis. Their interactions with matrix effectors, cell surface receptors and enzymes enable them with unique properties. In malignancy, extensive remodeling of tumor stroma is associated with marked alterations in proteoglycans' expression and structural variability. Proteoglycans exert diverse functions in tumor stroma in a cell-specific and context-specific manner and they mainly contribute to the formation of a permissive provisional matrix for tumor growth affecting tissue organization, cell-cell and cell-matrix interactions and tumor cell signaling. Proteoglycans also modulate cancer cell phenotype and properties, the development of drug resistance and tumor stroma angiogenesis. This review summarizes the proteoglycans remodeling and their novel biological roles in malignancies with particular emphasis to the underlying molecular mechanisms.

Comprehensive analysis of mRNA-lncRNA co-expression profile revealing crucial role of imprinted gene cluster DLK1-MEG3 in chordoma

Chordoma is a rare bone tumor with high recurrence rate, but the mechanism of its development is unclear. Long non-coding RNAs(lncRNAs) are recently revealed to be regulators in a variety of biological processed by targeting on mRNA transcription. Their expression profile and function in chordoma have not been investigated yet. In this study, we firstly performed the comprehensive analysis of the lncRNA and coding genes expression analysis with three chordoma samples and three fetal nucleus pulposus tissues. lncRNA and gene microarrays were used to determine the differentially expressed lncRNAs and protein coding genes. 2786 lncRNAs and 3286 coding genes were significantly up-regulated in chordoma, while 2042 lncRNAs and 1006 coding genes were down-regulated. Pearson correlation analysis was conducted to correlate differentially expressed lncRNAs with protein coding genes, indicating a comprehensive lncRNA-coding gene co-expression network in chordoma. Cis-correlation analysis showed that various transcripts of MEG3 and MEG8 were paired with the most differentially expressed gene DLK1. As located in the same locus, we further analyzed the miRNA clusters in this region, and identified that 61.22% of these miRNAs were significantly down-regulated, implying the silence of the imprinted gene cluster DLK1-MEG3. Overexpression of MEG3 suppressed the proliferation of chordoma cells. Our study pointed out the potential role of lncRNAs in chordoma, presented the lncRNA-coding genes co-expression profile, and revealed that imprinted gene cluster DLK1-MEG3 contributes to the pathogenesis of chordoma development.

TGF-β signalling and PEG10 are mutually exclusive and inhibitory in chondrosarcoma cells

Histological distinction between enchondroma and chondrosarcoma is difficult because of a lack of definitive biomarkers. Here, we found highly active transforming growth factor-β (TGF-β) and bone morphogenetic protein (BMP) signalling in human chondrosarcomas compared with enchondromas by immunohistochemistry of phosphorylated SMAD3 and SMAD1/5. In contrast, the chondrogenic master regulator SOX9 was dramatically down-regulated in grade 1 chondrosarcoma. Paternally expressed gene 10 (PEG10) was identified by microarray analysis as a gene overexpressed in chondrosarcoma SW1353 and Hs 819.T cells compared with C28/I2 normal chondrocytes, while TGF-β1 treatment, mimicking higher grade tumour conditions, suppressed PEG10 expression. Enchondroma samples exhibited stronger expression of PEG10 compared with chondrosarcomas, suggesting a negative association of PEG10 with malignant cartilage tumours. In chondrosarcoma cell lines, application of the TGF-β signalling inhibitor, SB431542, increased the protein level of PEG10. Reporter assays revealed that PEG10 repressed TGF-β and BMP signalling, which are both SMAD pathways, whereas PEG10 knockdown increased the level of phosphorylated SMAD3 and SMAD1/5/9. Our results indicate that mutually exclusive expression of PEG10 and phosphorylated SMADs in combination with differentially expressed SOX9 is an index to distinguish between enchondroma and chondrosarcoma, while PEG10 and TGF-β signalling are mutually inhibitory in chondrosarcoma cells.

Petroclival Chondrosarcoma: A Multicenter Review of 55 Cases and New Staging System

OBJECTIVE

To analyze clinical outcomes after treatment of petroclival chondrosarcoma and to propose a novel staging system.

STUDY DESIGN

Retrospective case review, 1995 to 2015.

SETTING

Multicenter study.

PATIENTS

Consecutive patients with histopathologically proven petroclival chondrosarcoma.

INTERVENTION(S)

Microsurgery, endoscopic endonasal surgery, radiation therapy, observation.

MAIN OUTCOME MEASURES

Disease- and treatment-associated morbidity, recurrence, mortality.

RESULTS

Fifty-five patients (mean age 42 years; 56% women) presenting with primary or recurrent petroclival chondrosarcoma were analyzed. The mean duration of follow-up was 74 months. Among 47 primary cases, the most common presenting symptoms were headache (55%) and diplopia (49%) and the mean tumor size at diagnosis was 3.3 cm. Subtotal resection was performed in 33 (73%) patients and gross total resection in 12 (27%). Adjuvant postoperative radiation was administered in 30 (64%) cases. Preoperative cranial neuropathy improved in 13 (29%), worsened in 11 (24%), and remained stable in 21 (47%) patients; notably, 11 preoperative sixth nerve palsies resolved after treatment. Nine recurrences occurred at a mean of 42 months. The 1-, 3-, 5- and 10-year recurrence-free survival rate for all 45 patients who underwent primary microsurgery with or without adjuvant radiation therapy was 97%, 89%, 70%, and 56%, respectively. Higher tumor stage, larger categorical size (<4 versus ≥4 cm), lack of adjuvant radiation, and longer duration of follow-up were associated with greater risk of recurrence. The overall mortality rate was 2% for patients presenting with primary disease.Analyzing the cohort of 17 cases with 20 recurrences, 3 received salvage surgery alone, 5 radiation therapy alone, 11 multimodality treatment, and one patient has been observed. Tumor control was ultimately achieved in 15 of 17 patients with recurrent disease. One patient (6%) with grade 3 petroclival chondrosarcoma died as a result of rapidly progressive disease within 6 months of salvage treatment. The overall mortality rate was 6% for patients with recurrent disease.

CONCLUSION

Gross total or subtotal resection with adjuvant radiation provides durable tumor control with minimal morbidity in most patients. Surgery may improve preoperative cranial nerve dysfunction, particularly in the case of cranial nerve 6 paralysis.

Role of the ECM in notochord formation, function and disease

The notochord is a midline structure common to all chordate animals; it provides mechanical and signaling cues for the developing embryo. In vertebrates, the notochord plays key functions during embryogenesis, being a source of developmental signals that pattern the surrounding tissues. It is composed of a core of vacuolated cells surrounded by an epithelial-like sheath of cells that secrete a thick peri-notochordal basement membrane made of different extracellular matrix (ECM) proteins. The correct deposition and organization of the ECM is essential for proper notochord morphogenesis and function. Work carried out in the past two decades has allowed researchers to dissect the contribution of different ECM components to this embryonic tissue. Here, we will provide an overview of these genetic and mechanistic studies. In particular, we highlight the specific functions of distinct matrix molecules in regulating notochord development and notochord-derived signals. Moreover, we also discuss the involvement of ECM synthesis and its remodeling in the pathogenesis of chordoma, a malignant bone cancer that originates from remnants of notochord remaining after embryogenesis.

Immunotherapy as a Potential Treatment for Chordoma: a Review

Chordoma is a locally aggressive primary malignancy of the axial skeleton. The gold standard for treatment is en bloc resection, with some centers now advocating for the use of radiation to help mitigate the risk of recurrence. Local recurrence is common, and salvaging local failures is quite difficult. Chemotherapy has been ineffective and small molecule targeted therapy has had only marginal benefits in small subsets of patients with rare tumor phenotypes or refractory disease. Recent successes utilizing immunotherapy in a variety of cancers has led to a resurgence of interest in modifying the host immune system to develop new ways to treat tumors. This review will discuss these studies and will highlight the early studies employing immune strategies for the treatment of chordoma.

Medical treatment of advanced chordomas

Chordoma is a very rare bone sarcoma that can arise from any site along the spine and from the skull base. En bloc resection is the gold standard for treatment while radiation therapy has been shown to provide both curative and palliative benefit. Unfortunately, local recurrences are common, even after a complete surgical resection, and up to 40% of patients suffer from distant metastases, while salvage treatments are challenging. Patients carrying an advanced disease need a systemic treatment. Unluckily, conventional chordoma are insensitive to cytotoxic chemotherapy that is considered the standard treatment option in patients with metastatic sarcoma. In the last decade, innovative therapies have been introduced, positively impacting disease control and patients' quality of life. In addition, a better understanding of the molecular characteristics of chordoma allowed to detect new potential targets. This review is focused on the pharmacological management of patients affected by an advanced disease, starting with a summary of data available on conventional chemotherapy, then moving to a deeper analysis of available data on molecular agents and immunotherapy, and finally providing an update on ongoing clinical trials and future prospective.

First report of clinical responses to immunotherapy in 3 relapsing cases of chordoma after failure of standard therapies

Chordoma is a rare tumor of notochordal origin, currently principally treated by surgery and/or irradiation. Here, we describe the clinical outcome of 3 consecutive patients with metastatic and locally advanced chordoma, treated with different immunotherapeutic approaches. All patients presented fast growing tumors and failure of standard therapies. One was treated with a tumor-based vaccine, the 2 others with anti-PD1 antibodies, all with impressive clinical and radiological responses. We therefore propose that chordoma is an immunogenic tumor and thus that translational and clinical research is necessary to develop rationally designed immunotherapy approaches.

Recent advances in understanding and managing chordomas

Chordomas are rare primary bone tumors arising from embryonic remnants of the notochord. They are slow-growing, locally aggressive, and destructive and typically involve the axial skeleton. Genetic studies have identified several mutations implicated in the pathogenesis of these tumors. Treatment poses a challenge given their insidious progression, degree of local invasion at presentation, and high recurrence rate. They tend to respond poorly to conventional chemotherapy and radiation. This makes radical resection the mainstay of their treatment. Recent advances in targeted chemotherapy and focused particle beam radiation, however, have improved the management and prognosis of these tumors.

Functional roles of CSPG4/NG2 in chondrosarcoma

CSPG4/NG2 is a multifunctional transmembrane protein with limited distribution in adult tissues including articular cartilage. The purpose of this study was to investigate the possible roles of CSPG4/NG2 in chondrosarcomas and to establish whether this molecule may have potential for targeted therapy. Stable knock-down of CSPG4/NG2 in the JJ012 chondrosarcoma cell line by shRNA resulted in decreased cell proliferation and migration as well as a decrease in gene expression of the MMP (matrix metalloproteinase) 3 protease and ADAMTS4 (aggrecanase). Chondrosarcoma cells in which CSPG4/NG2 was knocked down were more sensitive to doxorubicin than wild-type cells. The results indicate that CSPG4/NG2 has roles in regulating chondrosarcoma cell function in relation to growth, spread and resistance to chemotherapy and that anti-CSPG4/NG2 therapies may have potential in the treatment of surgically unresectable chondrosarcoma.

CSPG4 as a prognostic biomarker in chordoma

BACKGROUND

There are currently no generally accepted biomarkers used in the clinical treatment of chordoma tumors. CSPG4 has been associated with disease severity in other tumors.

PURPOSE

This study aimed to characterize the frequency of CSPG4 expression in chordoma tumors and to correlate it with disease severity and clinical outcome.

STUDY DESIGN

A retrospective review of clinical outcomes and immunohistochemical staining using tissue micro-array was carried out.

PATIENT SAMPLE

The sample comprised 86 patients treated for chordoma at a single center (1985-2007).

OUTCOME MEASURES

Survival and incidence of metastases were the outcome measures.

METHODS

Pathologic specimens of chordoma tumors were evaluated for the expression of CSPG4 by immunohistochemical staining with mAbs. Chi-square testing and Cox proportional hazard regression analysis were used to evaluate the impact of CSPG4 expression on survival and incidence of metastases, while controlling for patient age, sex, and surgical margins.

RESULTS

Average patient age at the time of presentation was 59.8 years (standard deviation [SD] 13.7). Average follow-up was 6.5 years (SD 4.8). Twenty (23%) patients developed metastatic disease. At the time of final follow-up, 57 patients (66%) had died. Chordoma tumors from 62 patients (72%) stained positive for CSPG4. CSPG4 expression more than doubled the risk of death (hazard ratio [HR] 2.3; 95% CI 1.04, 5.17). CSPG4 positive tumors were also associated with an increased risk of metastatic disease (31% for CSPG4 positive tumors vs. 0% in CSPG4 negative, p=.02).

CONCLUSIONS

Results presented here support the consideration of using CSPG4 as a biomarker establishing the prognosis for chordoma tumors. A positive CSPG4 stain may be associated with an increased risk of metastasis and mortality from disease.

Three-dimensional endoscopy in transnasal transsphenoidal approach to clival chordomas

BACKGROUND

The purpose of this prospective, observational study was to evaluate the management of skull base chordomas surgically resected via a 3D-endoscopic transnasal approach.

METHODS

Thirteen consecutive patients were observed and only 9 were surgically treated using a 3D-endoscopic transnasal approach assisted by a novel 3D visualization system.

RESULTS

Nine consecutive male patients (mean age, 57.4 years) underwent exclusive 3D-endoscopic transnasal transsphenoidal resection of clival chordomas; gross total resection was achieved in 66.6% of cases (6 of 9 patients), near-total resection in 11.2% (1 of 9 patients), and partial resection in 22.2% (2 of 9 patients). The complications observed were 2 cases of postoperative cerebrospinal fluid (CSF) leaks and 1 case of temporary VI cranial nerve palsy.

CONCLUSION

No discomfort was recorded; when a dura opening was required, 3D vision allowed an accurate intradural sharp dissection and a precise repair of the skull base. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1814-E1819, 2016.

α-methylacyl-CoA racemase (AMACR) expression in chordomas differentiates them from chondrosarcomas

Aims: Chordomas and chondrosarcomas are malignant mesenchymal tumours with overlapping morphological and immunohistochemical (IHC) characteristics. Our aim was to evaluate the IHC expression of α-methylacyl-CoA racemase (AMACR/P504S), β-catenin and E-cadherin in chordomas relative to chondrosarcomas and assess the utility of these markers for differential diagnosis. Methods: Archival sections of 18 chordomas, 19 chondrosarcomas and 10 mature cartilage samples were immunostained and scored for AMACR, β-catenin and E-cadherin and the relative differential capacity of each marker was calculated. In addition, AMACR mRNA level was assessed in 5 chordomas by RT-PCR and evaluated by comparative C_T method. Results: AMACR and β-catenin stained 88.9% and 94.1% of the chordomas respectively, 21.1% and 10.5% of the chondrosarcomas correspondingly and none of the mature cartilage samples. E-cadherin stained positively 82.4% of the chordomas, 36.8% of the chondrosarcomas and 42.9% of the mature cartilage cases. Both AMACR and β-catenin showed statistically significant difference between chordomas and chondrosarcomas (p < 0.001 for both), unlike E-cadherin. AMACR was detected at the mRNA level. Conclusions: AMACR is expressed in most of the chordomas but only in a minority of chondrosarcomas. AMACR may serve as IHC marker of chordoma with differentiating ability comparable to that of β-catenin.

Intradural prepontine chordoma in an 11-year-old boy. A case report

CASE REPORT

The authors report a case of an 11-year-old boy that presented with headache and vomiting that was present for several months. CT and MR imaging revealed a large prepontine mass and an obstructive hydrocephalus. A ventriculoperitoneal shunt was inserted, and in a second operation, a radiologically proven total resection was performed, using a left frontotemporal transsylvian approach. The tumour showed no involvement of the dura or clivus. Histological examination showed the characteristics of a chordoma. No further adjuvant treatment was given. The patient remained disease or tumour free after a 6-year follow-up.

DISCUSSION

Intradural chordomas are extremely rare tumours that originate from notochordal remnants. Only three other cases have been reported in the paediatric population. Ecchordosis physaliphora (EP) is an ectopic notochordal remnant that has a similar biological behaviour and is difficult to distinguish from intradural chordomas. They might exist in a continuum from benign notochordal tumour to malignant chordoma. A surgical resection without adjuvant radiation therapy is suggested to be the treatment of choice in the paediatric population.

CONCLUSION

The authors describe a rare case of an intradural prepontine chordoma in an 11-year-old boy that stayed disease free after a 6-year follow-up.

Contemporary management of clival chordomas

PURPOSE OF REVIEW

Clival chordomas are rare malignant tumors associated with a poor prognosis. In this article, we review the current literature to identify a variety of strategies that provide guidelines toward the optimal management for this aggressive tumor.

RECENT FINDINGS

Molecular disease, particularly, the development of characterized chordoma cell lines, has become one of the new cornerstones for the histological diagnosis of chordomas and for the development of effective chemotherapeutic agents against this tumor. Brachyury, a transcription factor in notochord development, seems to provide an excellent diagnostic marker for chordoma and may also prove to be a valuable target for chordoma therapy. Aggressive cytoreductive surgery aiming for gross total resection with maintenance of key neurovascular structures, followed by proton beam or hadron radiation, provides the best local recurrence and overall survival rates.

SUMMARY

Clival chordomas are locally aggressive tumors that are challenging to treat because of their unique biology, proximity to key neurovascular structures and poor prognosis. Currently, chordomas are optimally managed with aggressive surgery, whilst preserving key structures, and postoperative radiation in a multidisciplinary setting with an experienced team. The advancement of molecular techniques offers exciting future diagnostic and therapeutic options in the management of chordomas.

The molecular aspects of chordoma

Chordomas are one of the rarest bone tumors, and they originate from remnants of embryonic notochord along the spine, more frequently at the skull base and sacrum. Although they are relatively slow growing and low grade, chordomas are highly recurrent, aggressive, locally invasive, and prone to metastasize to the lungs, bone, and the liver. Chordomas highly and generally show a dual epithelial-mesenchymal differentiation. These tumors resist chemotherapy and radiotherapy; therefore, radical surgery and high-dose radiation are the most used treatments, although there is no standard way to treat the disease. The molecular biology process behind the initiation and progression of a chordoma needs to be revealed for a better understanding of the disease and to develop more effective therapies. Efforts to discover the mysteries of these molecular aspects have delineated several molecular and genetic alterations in this tumor. Here, we review and describe the emerging insights into the molecular landscape of chordomas.

The notochord: structure and functions

The notochord is an embryonic midline structure common to all members of the phylum Chordata, providing both mechanical and signaling cues to the developing embryo. In vertebrates, the notochord arises from the dorsal organizer and it is critical for proper vertebrate development. This evolutionary conserved structure located at the developing midline defines the primitive axis of embryos and represents the structural element essential for locomotion. Besides its primary structural function, the notochord is also a source of developmental signals that patterns surrounding tissues. Among the signals secreted by the notochord, Hedgehog proteins play key roles during embryogenesis. The Hedgehog signaling pathway is a central regulator of embryonic development, controlling the patterning and proliferation of a wide variety of organs. In this review, we summarize the current knowledge on notochord structure and functions, with a particular emphasis on the key developmental events that take place in vertebrates. Moreover, we discuss some genetic studies highlighting the phenotypic consequences of impaired notochord development, which enabled to understand the molecular basis of different human congenital defects and diseases.

Novel targeted therapies in chordoma: an update

Chordomas are rare, locally aggressive skull base neoplasms known for local recurrence and not-infrequent treatment failure. Current evidence supports the role of maximal safe surgical resection. In addition to open skull-base approaches, the endoscopic endonasal approach to clival chordomas has been reported with favorable albeit early results. Adjuvant radiation is prescribed following complete resection, alternatively for gross residual disease or at the time of recurrence. The modalities of adjuvant radiation therapy reported vary widely and include proton-beam, carbon-ion, fractionated photon radiotherapy, and photon and gamma-knife radiosurgery. As of now, no direct comparison is available, and high-level evidence demonstrating superiority of one modality over another is lacking. While systemic therapies have yet to form part of any first-line therapy for chordomas, a number of targeted agents have been evaluated to date that inhibit specific molecules and their respective pathways known to be implicated in chordomas. These include EGFR (erlotinib, gefitinib, lapatinib), PDGFR (imatinib), mTOR (rapamycin), and VEGF (bevacizumab). This article provides an update of the current multimodality treatment of cranial base chordomas, with an emphasis on how current understanding of molecular pathogenesis provides a framework for the development of novel targeted approaches.

Nuances in the treatment of malignant tumors of the clival and petroclival region

Introduction Malignancies of the clivus and petroclival region are mainly chordomas and chondrosarcomas. Although a spectrum of malignancies may present in this area, a finite group of commonly encountered malignant pathologies will be the focus of this review, as they are recognized to be formidable pathologies due to adjacent critical neurovascular structures and challenging surgical approaches.

Objectives The objective is to review the literature regarding medical and surgical management of malignant tumors of the clival and petroclival region with a focus on clinical presentation, diagnostic identification, and associated adjuvant therapies. We will also discuss our current treatment paradigm using endoscopic, open, and combined approaches to the skull base.

Data Synthesis A literature review was conducted, searching for basic science and clinical evidence from PubMed, Medline, and the Cochrane Database. The selection criteria encompassed original articles including data from both basic science and clinical literature, case series, case reports, and review articles on the etiology, diagnosis, treatment, and management of skull base malignancies in the clival and petroclival region.

Conclusions The management of petroclival malignancies requires a multidisciplinary team to deliver the most complete surgical resection, with minimal morbidity, followed by appropriate adjuvant therapy. We advocate the combination of endoscopic and open approaches (traditional or minimally invasive) as required by the particular tumor followed by radiation therapy to optimize oncologic outcomes.

Theranostic impact of NG2/CSPG4 proteoglycan in cancer

NG2/CSPG4 is an unusual cell-membrane integral proteoglycan widely recognized to be a prognostic factor, a valuable tool for ex vivo and non-invasive molecular diagnostics and, by virtue of its tight association with malignancy, a tantalizing therapeutic target in several tumour types. Although the biology behind its involvement in cancer progression needs to be better understood, implementation of NG2/CSPG4 in the routine clinical practice is attainable and has the potential to contribute to an improved individualized management of cancer patients. In this context, its polymorphic nature seems to be particularly valuable in the effort to standardize informative diagnostic procedures and consolidate forcible immunotherapeutic treatment strategies. We discuss here the underpinnings for this potential and highlight the benefits of taking advantage of the intra-tumour and inter-patient variability in the regulation of NG2/CSPG4 expression. We envision that NG2/CSPG4 may effectively be exploited in therapeutic interventions aimed at averting resistance to target therapy agents and at interfering with secondary lesion formation and/or tumour recurrence.

Chordoma: the entity

Chordomas are malignant tumors of the axial skeleton, characterized by their locally invasive and slow but aggressive growth. These neoplasms are presumed to be derived from notochordal remnants with a molecular alteration preceding their malignant transformation. As these tumors are most frequently observed on the skull base and sacrum, patients suffering from a chordoma present with debilitating neurological disease, and have an overall 5-year survival rate of 65%. Surgical resection with adjuvant radiotherapy is the first-choice treatment modality in these patients, since chordomas are resistant to conventional chemotherapy. Even so, management of chordomas can be challenging, as chordoma patients often present with recurrent disease. Recent advances in the understanding of the molecular events that contribute to the development of chordomas are promising; the most novel finding being the identification of brachyury in the disease process. Here we present an overview of the current paradigms and summarize relevant research findings.

Molecular characterization of chordoma xenografts generated from a novel primary chordoma cell source and two chordoma cell lines

OBJECT

Chordoma cells can generate solid-like tumors in xenograft models that express some molecular characteristics of the parent tumor, including positivity for brachyury and cytokeratins. However, there is a dearth of molecular markers that relate to chordoma tumor growth, as well as the cell lines needed to advance treatment. The objective in this study was to isolate a novel primary chordoma cell source and analyze the characteristics of tumor growth in a mouse xenograft model for comparison with the established U-CH1 and U-CH2b cell lines.

METHODS

Primary cells from a sacral chordoma, called "DVC-4," were cultured alongside U-CH1 and U-CH2b cells for more than 20 passages and characterized for expression of CD24 and brachyury. While brachyury is believed essential for driving tumor formation, CD24 is associated with healthy nucleus pulposus cells. Each cell type was subcutaneously implanted in NOD/SCID/IL2Rγ(null) mice. The percentage of solid tumors formed, time to maximum tumor size, and immunostaining scores for CD24 and brachyury (intensity scores of 0-3, heterogeneity scores of 0-1) were reported and evaluated to test differences across groups.

RESULTS

The DVC-4 cells retained chordoma-like morphology in culture and exhibited CD24 and brachyury expression profiles in vitro that were similar to those for U-CH1 and U-CH2b. Both U-CH1 and DVC-4 cells grew tumors at rates that were faster than those for U-CH2b cells. Gross tumor developed at nearly every site (95%) injected with U-CH1 and at most sites (75%) injected with DVC-4. In contrast, U-CH2b cells produced grossly visible tumors in less than 50% of injected sites. Brachyury staining was similar among tumors derived from all 3 cell types and was intensely positive (scores of 2-3) in a majority of tissue sections. In contrast, differences in the pattern and intensity of staining for CD24 were noted among the 3 types of cell-derived tumors (p < 0.05, chi-square test), with evidence of intense and uniform staining in a majority of U-CH1 tumor sections (score of 3) and more than half of the DVC-4 tumor sections (scores of 2-3). In contrast, a majority of sections from U-CH2b cells stained modestly for CD24 (scores of 1-2) with a predominantly heterogeneous staining pattern.

CONCLUSIONS

This is the first report on xenografts generated from U-CH2b cells in which a low tumorigenicity was discovered despite evidence of chordoma-like characteristics in vitro. For tumors derived from a primary chordoma cell and U-CH1 cell line, similarly intense staining for CD24 was observed, which may correspond to their similar potential to grow tumors. In contrast, U-CH2b tumors stained less intensely for CD24. These results emphasize that many markers, including CD24, may be useful in distinguishing among chordoma cell types and their tumorigenicity in vivo.