Molecular and Biochemical Analyses of Platelet-Derived Growth Factor Receptor (PDGFR) B, PDGFRA, and KIT Receptors in Chordomas

Integrated Molecular and Histological Insights for Targeted Therapies in Mesenchymal Sinonasal Tract Tumors

PURPOSE OF REVIEW

This review aims to provide a comprehensive overview of mesenchymal sinonasal tract tumors (STTs), a distinct subset of STTs. Despite their rarity, mesenchymal STTs represent a unique clinical challenge, characterized by their rarity, often slow progression, and frequently subtle or overlooked symptoms. The complex anatomy of the sinonasal area, which includes critical structures such as the orbit, brain, and cranial nerves, further complicates surgical treatment options. This underscores an urgent need for more advanced and specialized therapeutic approaches.

RECENT FINDINGS

Advancements in molecular diagnostics, particularly in next-generation sequencing, have significantly enhanced our understanding of STTs. Consequently, the World Health Organization has updated its tumor classification to better reflect the distinct histological and molecular profiles of these tumors, as well as to categorize mesenchymal STTs with greater accuracy. The growing understanding of the molecular characteristics of mesenchymal STTs opens new possibilities for targeted therapeutic interventions, marking a significant shift in treatment paradigms. This review article concentrates on mesenchymal STTs, specifically addressing sinonasal tract angiofibroma, sinonasal glomangiopericytoma, biphenotypic sinonasal sarcoma, and skull base chordoma. These entities are marked by unique histopathological and molecular features, which challenge conventional treatment approaches and simultaneously open avenues for novel targeted therapies. Our discussion is geared towards delineating the molecular underpinnings of mesenchymal STTs, with the objective of enhancing therapeutic strategies and addressing the existing shortcomings in the management of these intricate tumors.

The role of tumor immune microenvironment in chordoma: promising immunotherapy strategies

Chordoma is a rare malignant bone tumor with limited therapeutic options, which is resistant to conventional chemotherapy and radiotherapy, and targeted therapy is also shown with little efficacy. The long-standing delay in researching its mechanisms of occurrence and development has resulted in the dilemma of no effective treatment targets and no available drugs in clinical practice. In recent years, the role of the tumor immune microenvironment in driving tumor growth has become a hot and challenging topic in the field of cancer research. Immunotherapy has shown promising results in the treatment of various tumors. However, the study of the immune microenvironment of chordoma is still in its infancy. In this review, we aim to present a comprehensive reveal of previous exploration on the chordoma immune microenvironment and propose promising immunotherapy strategies for chordoma based on these characteristics.

A chronicle review of new techniques that facilitate the understanding and development of optimal individualized therapeutic strategies for chordoma

Chordoma is a rare malignant bone tumor that mainly occurs in the sacrum and the clivus/skull base. Surgical resection is the treatment of choice for chordoma, but the local recurrence rate is high with unsatisfactory prognosis. Compared with other common tumors, there is not much research and individualized treatment for chordoma, partly due to the rarity of the disease and the lack of appropriate disease models, which delay the discovery of therapeutic strategies. Recent advances in modern techniques have enabled gaining a better understanding of a number of rare diseases, including chordoma. Since the beginning of the 21st century, various chordoma cell lines and animal models have been reported, which have partially revealed the intrinsic mechanisms of tumor initiation and progression with the use of next-generation sequencing (NGS) techniques. In this study, we performed a systematic overview of the chordoma models and related sequencing studies in a chronological manner, from the first patient-derived chordoma cell line (U-CH1) to diverse preclinical models such as the patient-derived organoid-based xenograft (PDX) and patient-derived organoid (PDO) models. The use of modern sequencing techniques has discovered mutations and expression signatures that are considered potential treatment targets, such as the expression of Brachyury and overactivated receptor tyrosine kinases (RTKs). Moreover, computational and bioinformatics techniques have made drug repositioning/repurposing and individualized high-throughput drug screening available. These advantages facilitate the research and development of comprehensive and personalized treatment strategies for indicated patients and will dramatically improve their prognoses in the near feature.

Receptor Tyrosine Kinase Inhibitors for the Treatment of Recurrent and Unresectable Bone Sarcomas

Bone sarcomas are a heterogeneous group of rare tumors with a predominance in the young population. Few options of systemic treatment are available once they become unresectable and resistant to conventional chemotherapy. A better knowledge of the key role that tyrosine kinase receptors (VEGFR, RET, MET, AXL, PDGFR, KIT, FGFR, IGF-1R) may play in the pathogenesis of these tumors has led to the development of multi-target inhibitors (TKIs) that are progressively being incorporated into our therapeutic arsenal. Osteosarcoma (OS) is the most frequent primary bone tumor and several TKIs have demonstrated clinical benefit in phase II clinical trials (cabozantinib, regorafenib, apatinib, sorafenib, and lenvatinib). Although the development of TKIs for other primary bone tumors is less advanced, preclinical data and early trials have begun to show their potential benefit in advanced Ewing sarcoma (ES) and rarer bone tumors (chondrosarcoma, chordoma, giant cell tumor of bone, and undifferentiated pleomorphic sarcoma). Previous reviews have mainly provided information on TKIs for OS and ES. We aim to summarize the existing knowledge regarding the use of TKIs in all bone sarcomas including the most recent studies as well as the potential synergistic effects of their combination with other systemic therapies.

Emerging target discovery and drug repurposing opportunities in chordoma

The development of effective and personalized treatment options for patients with rare cancers like chordoma is hampered by numerous challenges. Biomarker-guided repurposing of therapies approved in other indications remains the fastest path to redefining the treatment paradigm, but chordoma's low mutation burden limits the impact of genomics in target discovery and precision oncology efforts. As our knowledge of oncogenic mechanisms across various malignancies has matured, it's become increasingly clear that numerous properties of tumors transcend their genomes - leading to new and uncharted frontiers of therapeutic opportunity. In this review, we discuss how the implementation of cutting-edge tools and approaches is opening new windows into chordoma's vulnerabilities. We also note how a convergence of emerging observations in chordoma and other cancers is leading to the identification and evaluation of new therapeutic hypotheses for this rare cancer.

Cervical Paraspinal Chordoma: A Literature Review with a Novel Case Report

Chordomas are rare malignant neoplasms, accounting for 1–4% of all primary bone tumors. Most spinal chordomas occur in the sacrococcygeal region and the base of the skull; however, 6% of chordomas are observed in the cervical spine. In these cases, the lesion is mainly located in the midline. These tumors slowly grow before becoming symptomatic and encase the surrounding vascular and nerve structures. Patients with advanced chordoma have a poor prognosis due to local recurrence with infiltration and destruction of adjacent bone and tissues. Systemic chemotherapy options have not been fully effective in these tumors, especially for recurrent chordomas. Thus, new combinations of currently available targeted molecular and biological therapies with radiotherapy have been proposed as potential treatment modalities. Here, the present paper describes the case of a 41-year-old male with a C2–C4 chordoma located paravertebrally, who underwent surgical resection with a debulking procedure for a cervical chordoma. Computed tomography angiography revealed a paraspinal mass with bone remodeling and the MRI showed a paravertebral mass penetrating to the spinal canal with a widening of the intervertebral C2–C3 foramen. Initially, the tumor was diagnosed as schwannoma based on its localization and imaging features; however, the histopathology specimen confirmed the diagnosis of chordoma. This case study highlights the effectivity of radical surgical resection as a mainstay treatment for chordomas, discusses neuroimaging, diagnosis, and the use of currently available targeted therapies and forthcoming treatment strategies, as alternative treatment options for chordoma.

Advancement of PI3 Kinase Inhibitor Combination Therapies for PI3K-Aberrant Chordoma

Objectives  Targeted inhibitors of the PI3 kinase (PI3K) pathway have shown promising but incomplete antitumor activity in preclinical chordoma models. The aim of this study is to advance methodology for a high-throughput drug screen using chordoma models to identify new combination therapies for chordoma. Study Design  Present work is an in vitro study. Setting  The study conducted at an academic research laboratory. Materials and Methods  An in vitro study on automated high-throughput screening of chordoma cells was performed using a library of 1,406 drugs as both mono- and combination therapies with PI3K inhibitors. Combination indices were determined for dual therapies and synergistic outliers were identified as potential therapeutic agents. T (brachyury) siRNA knockdown in combination with PI3K pathway inhibition was also assessed. Results  Fifty-nine combination therapies were identified as having potential therapeutic efficacy. Effective combinations included PI3K inhibitors with GSK1838705A (ALK/IGF-1R inhibitor), LY2874455 (VEGFR/FGFR inhibitor), El1 (selective Ezh2 inhibitor), and (-)-p-bromotetramisole oxalate (alkaline phosphatase inhibitor). The top ranking targets identified included ALK, PDGFR, VEGFR, aurora kinase, and BCL-2. T (brachyury) inhibition produced significant reduction in cell viability and growth; however PI3K inhibition in combination with T (brachyury) knockdown did not result in further reduction in growth and viability in vitro. Conclusion  High throughput with in vitro combination screening is feasible with chordoma cells and allows for rapid identification of synergistic dual-therapies. Potential combination therapies and targetable pathways were identified. T (brachyury) knockdown produced significant reduction in cell viability, but did not show additional benefit with PI3K pathway inhibition in this model. Further in vitro and in vivo validation of these therapeutic combinations is warranted.

AZD8055 enhances in vivo efficacy of afatinib in chordomas

Chordomas are primary bone tumors that arise in the cranial base, mobile spine, and sacrococcygeal region, affecting patients of all ages. Currently, there are no approved agents for chordoma patients. Here, we evaluated the anti-tumor efficacy of small molecule inhibitors that target oncogenic pathways in chordoma, as single agents and in combination, to identify novel therapeutic approaches with the greatest translational potential. A panel of small molecule compounds was screened in vivo against patient-derived xenograft (PDX) models of chordoma, and potentially synergistic combinations were further evaluated using chordoma cell lines and xenograft models. Among the tested agents, inhibitors of EGFR (BIBX 1382, erlotinib, and afatinib), c-MET (crizotinib), and mTOR (AZD8055) significantly inhibited tumor growth in vivo but did not induce tumor regression. Co-inhibition of EGFR and c-MET using erlotinib and crizotinib synergistically reduced cell viability in chordoma cell lines but did not result in enhanced in vivo activity. Co-inhibition of EGFR and mTOR pathways using afatinib and AZD8055 synergistically reduced cell viability in chordoma cell lines. Importantly, this dual inhibition completely suppressed tumor growth in vivo, showing improved tumor control. Together, these data demonstrate that individual inhibitors of EGFR, c-MET, and mTOR pathways suppress chordoma growth both in vitro and in vivo. mTOR inhibition increased the efficacy of EGFR inhibition on chordoma growth in several preclinical models. The insights gained from our study potentially provide a novel combination therapeutic strategy for patients with chordoma. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

A clinical approach to parasellar lesions in the transition age

Many reviews have summarised the pathology and management of the parasellar region in adult patients, although an analysis of these aspects in the transition years, from puberty onset to the age of peak bone mass, has been lacking. A comprehensive search of English-language original articles, published from 2000 to 2020, was conducted in the MEDLINE database (December 2019 to March 2020). We selected all studies regarding epidemiology, diagnosis and management of the following parasellar lesions: germinoma, craniopharyngioma, Langerhans cell histiocytosis, optic glioma, hypothalamic hamartoma, tuber cinereum hamartoma, cranial chordoma, Rathke cleft cyst, hypophysitis and hypothalamitis during the transition age from childhood to adulthood. In the present review, we provide an overview of the principal parasellar lesions occurring in the transition age. Symptoms are usually a result of the mass effect of the lesions on nearby structures, as well as anterior pituitary deficits. Diabetes insipidus occurs frequently in these patients. In this age group, pubertal developmental disorders may be more evident compared to other stages of life. Parasellar lesions in the transition age mostly include neoplastic lesions such as germinomas, hamartomas, optic gliomas, craniopharyngiomas Langerhans cell histiocytosis and chordomas, and rarely inflammatory lesions (hypophysitis, hypothalamitis). There are limited data on the management of parasellar lesions in the transition age. Endocrine evaluation is crucial for identifying conditions that require hormonal treatment so that they can be treated early to improve the quality of life of the individual patient in this complex age range. The clinical approach to parasellar lesions involves a multidisciplinary effort.

Chordoma-Current Understanding and Modern Treatment Paradigms

Chordoma is a low-grade notochordal tumor of the skull base, mobile spine and sacrum which behaves malignantly and confers a poor prognosis despite indolent growth patterns. These tumors often present late in the disease course, tend to encapsulate adjacent neurovascular anatomy, seed resection cavities, recur locally and respond poorly to radiotherapy and conventional chemotherapy, all of which make chordomas challenging to treat. Extent of surgical resection and adequacy of surgical margins are the most important prognostic factors and thus patients with chordoma should be cared for by a highly experienced, multi-disciplinary surgical team in a quaternary center. Ongoing research into the molecular pathophysiology of chordoma has led to the discovery of several pathways that may serve as potential targets for molecular therapy, including a multitude of receptor tyrosine kinases (e.g., platelet-derived growth factor receptor [PDGFR], epidermal growth factor receptor [EGFR]), downstream cascades (e.g., phosphoinositide 3-kinase [PI3K]/protein kinase B [Akt]/mechanistic target of rapamycin [mTOR]), brachyury—a transcription factor expressed ubiquitously in chordoma but not in other tissues—and the fibroblast growth factor [FGF]/mitogen-activated protein kinase kinase [MEK]/extracellular signal-regulated kinase [ERK] pathway. In this review article, the pathophysiology, diagnosis and modern treatment paradigms of chordoma will be discussed with an emphasis on the ongoing research and advances in the field that may lead to improved outcomes for patients with this challenging disease.

Mean platelet volume and platelet distribution width serve as prognostic biomarkers in skull base chordoma: a retrospective study

Background

Increasing studies have demonstrated that activated platelets play an essential role in tumour progression. However, the level and prognostic role of platelet indices in chordoma patients remain unclear. The aim of the current study was to characterize the prognostic performance of platelet count (PLT), mean platelet volume (MPV) and platelet distribution width (PDW) in skull base chordoma patients.

Methods

187 primary skull base chordoma patients between January 2008 and September 2014 were enrolled in this retrospective study. The optimal cut-off values were determined by X-tile software, and the correlations between PLT, MPV, PDW and clinicopathological features were further analysed. Kaplan-Meier curve and Cox regression analysis were used for survival analysis.

Results

The values of preoperative PTL, MPV and PDW ranged from 104 to 501 × 10⁹/L, 6.7 to 14.2 fl, and 7.8 to 26.2%, respectively. Elevated PLT was associated with larger tumour volume (p = 0.002). Kaplan-Meier survival analysis revealed that increased MPV and PDW were associated with shorter overall survival (p = 0.022 and 0.008, respectively). Importantly, multivariate Cox analysis demonstrated that elevated PDW was an independent unfavourable predictive factor for overall survival (hazard ratio (HR), 2.154, 95% confidence interval (CI), 1.258–3.688, p = 0.005).

Conclusions

Our data show that elevated MPV and PDW are associated with poor outcomes in skull base chordoma and that PDW may be helpful to identify patients with high risk.

Emerging Therapeutic Targets in Chordomas: A Review of the Literature in the Genomic Era

Chordomas are rare primary malignant tumors of the bones that occur along the skull base, spine, and sacrum. Long-term survival and neurological outcome continue to be challenging with continued low percentages of long-term survival. Recent studies have used genome, exome, transcriptome, and proteome sequencing to assess the mutational profile of chordomas. Most notably, Brachyury, or T-protein, has been shown to be an early mutational event in chordoma evolution. Clinically actionable mutations, including in the PI3K pathway, were identified. Preliminary evidence suggests that there may be mutational differences associated with primary tumor location. In this study, we review the therapeutic landscape of chordomas and discuss emerging targets in the genomic era.

Gene expression profile and bioinformatics analysis revealed key molecular characteristics of chordoma-before and after TNF- a treatment

BACKGROUND

Chordoma is a rare malignant tumor with limited treatment. Recent studies have shown that the proliferation and invasion ability of chordoma after Tumor necrosis factor alpha (TNF-α) treatment is enhanced, which may activate the gene pathway involved in the development of chordoma. This study tends to identify differentially expressed genes (DEGs) before and after treatment of TNF-α in chordoma cell line, providing a new target for future molecular therapy of chordoma.

METHODS

The gene expression profile of GSE101867 was downloaded from the Gene Expression Omnibus database, and the differentially expressed genes were obtained using GEO2R. Based on the CLUEGO plugin in Cytoscape, DEGs functionality and enrichment analysis. A protein-protein interaction (PPI) network was constructed using Cytoscape based on data collected from the STRING online dataset. The Hub genes are selected from the CytoHubba, the first 20 genes that coexist with the KEGG tumor-related pathway.

RESULTS

A total of 560 genes, including 304 up-regulated genes and 256 down-regulated genes, were selected as DEGs. Obviously, GO analysis shows that up-regulated and down-regulated DEGs are mainly enriched in biological processes such as synaptic tissue, cell adhesion, extracellular matrix organization and skeletal system development. DEGs are mainly enriched in tumor-associated pathways such as Pi3k-akt Signal path, Rap1 signal path. Three key genes were identified: PDGFRB, KDR, FGF2. All of these genes are involved in the tumor-associated pathways described previously.

CONCLUSION

This study is helpful in understanding the molecular characteristics of chordoma development. Hub genes PDGFRB, KDR, FGF2 and pi3k-akt signaling pathway, Rap1 signaling pathway will become a new target for the future treatment of chordoma.

Skull Base Chordomas and Chondrosarcomas

Skull base chordomas account for less than 0.2% and chondrosarcomas for less than 0.15% of all intracranial tumors. Although their clinical and imaging presentations are similar, they derive from different origins. Chordomas arise from embryonic remnants of the primitive notochord and chondrosarcomas from primitive mesenchymal cells or from the embryonic rest of the cranial cartilaginous matrix. Both entities are characterized by infiltration and destruction of the surrounding bone and soft tissue and a high locoregional recurrence rate. Chondrosarcomas, when treated with similar complex strategies, display a much better prognosis than chordomas. The overall survival is approximately 65% for chordomas and 80% for chondrosarcomas at 5 years and 30 and 50%, respectively, at 10 years. Chordomas are divided into the following 3 histological types: classical (conventional), chondroid, and dedifferentiated. Chondrosarcomas have conventional, mesenchymal, clear cell, and dedifferentiated subgroups. Both tumor entities often present with nonspecific symptoms, and headaches are the most reported initial symptom. Computed tomography and magnetic resonance imaging are required to determine the tumor localization and the extent of tumor growth. The treatment philosophy is to maximize tumor resection, minimize morbidity, and preserve function. Neurosurgical approaches commonly used for the resection of intracranial chordomas and chondrosarcomas are transsphenoidal, transbasal, cranio-orbitozygomatic, transzygomatic extended middle fossa, transcondylar, and transmaxillary approaches. Chordomas and chondrosarcomas are not sensitive to chemotherapy and there are no approved drugs for their treatment. The present treatment concept is a combination of surgical resection with a maximal excision and preserving patients' quality of life by adjuvant radiotherapy for both chordomas and chondrosarcomas.

[From bench to bedside for new treatment paradigms in chordomas: An update]

Chordomas are rare malignant tumours, which typically occur in the axial skeleton and skull base. They arise from embryonic remnants of the notochord. They constitute less than 5 % of primary bone tumours. They are characterised by their locally aggressive potential with high frequency of recurrences and a median overall survival of 6 years. The initial therapeutic strategy must be discussed in an expert centre and may involve surgery, preoperative radiotherapy, exclusive radiotherapy or therapeutic abstention. Despite this, more than 50 % of patients will be facing recurrences with few therapeutic options available at this advanced stage. This review aims to outline current treatment options available in chordomas, as well as discussing potentiality of new therapeutic approaches through their molecular characterization and the comprehension of their immunological environment.

Long and Very-Long-Chain Ceramides Correlate with A More Aggressive Behavior in Skull Base Chordoma Patients

BACKGROUND

Skull base chordomas are rare tumors arising from notochord. Sphingolipids analysis is a promising approach in molecular oncology, and it has never been applied in chordomas. Our aim is to investigate chordoma behavior and the role of ceramides.

METHODS

Ceramides were extracted and evaluated by liquid chromatography and mass spectrometry in a cohort of patients with a skull base chordoma. Clinical data were also collected and correlated with ceramide levels. Linear regression and correlation analyses were conducted.

RESULTS

Analyzing the association between ceramides level and MIB-1, total ceramides and dihydroceramides showed a strong association (r = 0.7257 and r = 0.6733, respectively) with MIB-1 staining (p = 0.0033 and p = 0.0083, respectively). Among the single ceramide species, Cer C24:1 (r = 0.8814, p ≤ 0.0001), DHCer C24:1 (r = 0.8429, p = 0.0002) and DHCer C18:0 (r = 0.9426, p ≤ 0.0001) showed a significant correlation with MIB-1.

CONCLUSION

Our lipid analysis showed ceramides to be promising tumoral biomarkers in skull base chordomas. Long- and very-long-chain ceramides, such as Cer C24:1 and DHCer C24:1, may be related to a prolonged tumor survival and aggressiveness, and the understanding of their effective biological role will hopefully shed light on the mechanisms of chordoma radio-resistance, tendency to recur, and use of agents targeting ceramide metabolism.

Active receptor tyrosine kinases, but not Brachyury, are sufficient to trigger chordoma in zebrafish

The aberrant activation of developmental processes triggers diverse cancer types. Chordoma is a rare, aggressive tumor arising from transformed notochord remnants. Several potentially oncogenic factors have been found to be deregulated in chordoma, yet causation remains uncertain. In particular, sustained expression of TBXT – encoding the notochord regulator protein brachyury – is hypothesized as a key driver of chordoma, yet experimental evidence is absent. Here, we employ a zebrafish chordoma model to identify the notochord-transforming potential of implicated genes in vivo. We find that Brachyury, including a form with augmented transcriptional activity, is insufficient to initiate notochord hyperplasia. In contrast, the chordoma-implicated receptor tyrosine kinases (RTKs) EGFR and Kdr/VEGFR2 are sufficient to transform notochord cells. Aberrant activation of RTK/Ras signaling attenuates processes required for notochord differentiation, including the unfolded protein response and endoplasmic reticulum stress pathways. Our results provide the first in vivo evidence against a tumor-initiating potential of Brachyury in the notochord, and imply activated RTK signaling as a possible initiating event in chordoma. Furthermore, our work points at modulating endoplasmic reticulum and protein stress pathways as possible therapeutic avenues against chordoma.

Summary: An injection-based chordoma model in zebrafish shows that the hypothesized chordoma oncogene brachyury is insufficient, whereas EGFR and VEGFR2 are sufficient, to trigger notochord hyperplasia in our model.

Molecular foundations of primary spinal tumors-implications for surgical management

Primary spinal tumors are rare lesions that require careful clinical management due to their intimate relationship with critical neurovascular structures and the significant associated risk of morbidity. While the advent of molecular and genomic profiling is beginning to impact the management of the cranial counterparts, translation for spinal tumors has lagged behind. Maximal safe surgical resection remains the mainstay of patients with primary spinal tumors, with extent of resection and histology the only consistently identified independent predictors of survival. Adjuvant therapy has had limited impact. To develop targeted neoadjuvant and adjuvant therapies, improve prognostication, and enhance patient selection in spinal oncology, a thorough understanding of the current molecular and genomic landscape of spinal tumors is required. In this review, we detail the epidemiology, current standard-of-care, and molecular features of the most commonly encountered intramedullary spinal cord tumors (IMSCT), intradural extramedullary (IDEM) tumors, and primary spinal column malignancies (PSCM). We further discuss current efforts and future opportunities for integrating molecular advances in spinal oncology with clinical management.

Molecular Targeted Therapy in the Treatment of Chordoma: A Systematic Review

Objectives: Chordoma is a rare bone malignancy that affects the spine and skull base. Treatment dilemma leads to a high rate of local relapse and distant metastases. Molecular targeted therapy (MTT) is an option for advanced chordoma, but its therapeutic efficacy and safety have not been investigated systematically. Therefore, a systematic review was conducted on studies reporting MTT regimens for chordoma. Methods: Clinical trials, case series and case reports on chordoma MTT were identified using MEDLINE, Cochrane library and EMBASE, and systematically reviewed. Data on clinical outcomes, such as median overall survival, progression-free survival, response rate and adverse events (AEs) were extracted and analyzed. Results: Thirty-three eligible studies were selected for the systematic review, which indicated that imatinib and erlotinib were the most frequently used molecular targeted inhibitors (MTIs) for chordoma. For PDGFR-positive and/or EGFR-positive chordoma, clinical benefits were achieved with acceptable AEs. Monotherapy is preferred as the first-line of treatment, and combined drug therapy as the second-line treatment. In addition, the brachyury vaccine has shown promising results. Conclusions: The selection of MTIs for patients with advanced or relapsed chordoma should be based on gene mutation screening and immunohistochemistry (IHC). Monotherapy of TKIs is recommended as the first-line management, and combination therapy (two TKIs or TKI plus mTOR inhibitor) may be the choice for drug-resistant chordoma. Brachyury vaccine is a promising therapeutic strategy and requires more clinical trials to evaluate its safety and efficacy.

Analysis of clinical factors and PDGFR-β in predicting prognosis of patients with clival chordoma

OBJECTIVE

In this study, the authors’ aim was to research clinical features and prognostic factors in patients harboring clival chordomas and explore the relationship between platelet-derived growth factor receptor-β (PDGFR-β) expression and tumor invasion and prognosis of clival chordoma.

METHODS

A total of 242 patients were retrospectively analyzed. Clinical information, including extent of resection, Al-Mefty classification, postoperative complications, and postoperative radiotherapy, was reviewed. Kaplan-Meier analysis was used to estimate survival time. Immunohistochemical analysis, quantitative reverse transcription polymerase chain reaction, and Western blotting were used to measure the expression level of proteins or mRNA. Transwell assaying was performed to measure the invasive ability of the tumor cells.

RESULTS

According to the Al-Mefty classification, there were 37, 112, and 93 type I, II, and III tumors, respectively. Gross-total resection (GTR) was achieved in 86 cases (35.5%), subtotal resection (STR) in 63 cases (26.0%), and partial resection (PR) in 93 cases (38.4%). The 5-year progression-free survival (PFS) and overall survival (OS) rates in the GTR group were significantly higher than those in the non–total resection (NTR; i.e., STR and PR) group (p < 0.001). The 5-year PFS and OS rates for patients with type I tumors were significantly higher than those for patients harboring types II and III tumors (p < 0.001). In the NTR group, the median PFS and OS of patients with lower PDGFR-β expression were significantly longer than those of patients with higher PDGFR-β expression. Reduction of PDGFR-β suppressed the invasion ability of cells in vitro. In addition, reduction of PDGFR-β can obviously downregulate the expression levels of mammalian target of rapamycin (mTOR) or phospho-mTOR.

CONCLUSIONS

Extent of resection, Al-Mefty classification, primary tumor, postoperative radiotherapy, and PDGFR-β expression level are valuable prognostic factors in patients with clival chordomas. PDGFR-β could regulate invasion through the mTOR pathway in clival chordoma cells.

The clinical outcome of recurrent sacral chordoma with further surgical treatment

To analyze the clinical results and related factors of further surgical treatment for recurrent sacral chordomas.Chordomas are rare primary malignant tumors with a high recurrence rate. The treatment of recurrent tumors is difficult and controversial. Contamination by previous operations and disturbed local anatomical structures may increase the risk of reoperation. Most previous studies have focused on the primary tumor; there are very few reports on the clinical diagnosis, treatment, and prognosis of recurrent sacral chordomas.Thirty-four patients with recurrent sacral chordomas from 1979 to 2014 were included in this study. The patients comprised 25 men and 9 women with an average age of 50.7 (24-75) years. The average time until recurrence was 19.4 (4-51) months postoperatively, and 85.3% of the recurrent tumors were located in bone. The patients had an average of 1.2 (1-3) recurrences before further operations were performed in our hospital. The mean maximum tumor diameter was 8.1 (4.6-12.0) cm. Thirty-one patients underwent further tumor resection in our hospital. The postoperative recurrence, metastasis, and survival results were followed and analyzed.The mean follow-up after surgical treatment of recurrence was 49.6 (12-144) months. Nine patients (37.5%) developed recurrence again after an average of 26.7 months. The 3-year and 5-year recurrence-free survival rate was 69.4% and 63.1%, respectively. Multivariate analysis showed that the tumor level within the sacrum (P = .001) and the surgical margin (P = .001) were significant recurrence-related factors. Four patients (16.7%) developed lung metastasis. Eighteen patients were alive at last follow-up. The 5-year and 10-year survival rate after surgical treatment of recurrence was 67.3% and 53.9%, respectively.Most recurrent tumors are located in bone, and a safe osteotomy margin is important. The surgical margin is the only controllable factor of further tumor recurrence. Some patients with recurrence achieve long survival and obtain a clinical benefit from repeated operations if complete resection is achieved.

Chordoma: a case series and review of the literature

BACKGROUND

Chordoma is a rare malignant tumor of the skull base and axial skeleton, with an incidence of less than 0.1/100,000 per year. Patients with advanced chordoma have a poor prognosis due to locoregional recurrence with infiltration and destruction of surrounding bone and soft tissue. Cytotoxic chemotherapy or other systemic therapies have not been proven to be effective for these diseases. Therefore, several molecularly targeted therapies have been proposed as potentially beneficial, including tyrosine kinase inhibitors such as imatinib, sorafenib, lapatinib, and others.

CASE PRESENTATION

We present three cases of advanced chordoma treated with molecular targeted therapies: a 52-year-old Caucasian man, a 72-year-old Caucasian woman, and a 38-year-old Caucasian woman.

CONCLUSIONS

Chordoma has few systemic treatment options and they have limited benefit. Randomized trials with large patient numbers are unfeasible in this rare disease. Targeted therapy might be a reasonable alternative treatment for chordoma. Still, new treatment strategies are needed for this rare disease.

A Phase 1 Study of Nilotinib Plus Radiation in High-Risk Chordoma

PURPOSE

Chordomas are malignant tumors arising from remnant notochordal tissue. Despite improved local control with preoperative/postoperative radiation therapy (RT), progression-free survival and overall survival (OS) remain poor in patients with high-risk features. Chordoma has been identified to express and activate platelet-derived growth factor receptor signaling. We conducted a phase 1 trial to identify the maximum tolerated dose (MTD), safety, and feasibility of nilotinib with RT as either preoperative or definitive treatment for patients with high-risk chordoma.

METHODS AND MATERIALS

We recruited 23 patients with high-risk, nonmetastatic chordoma. High risk was defined as the presence of any of the following: local recurrence after surgery, previous intralesional resection, unplanned incomplete resection, unresectable or marginally resectable disease based on locally advanced stage, or declining surgery because of excessive morbidity. Patients were treated with nilotinib and concurrent RT to 50.4 Gy relative biological effectiveness (RBE) followed by surgery and postoperative RT to a cumulative dose up to 70.2 Gy RBE or definitively up to 77.4 Gy RBE without surgery. On completion of RT, patients were eligible to continue nilotinib until disease progression.

RESULTS

In patients receiving nilotinib 200 mg twice daily with RT, 3 dose-limiting toxicities (DLT) occurred in 5 patients. One DLT was seen among 6 patients receiving nilotinib 200 mg daily with RT. Therefore, 200 mg daily was declared the maximum tolerated dose. Eleven additional patients received nilotinib with RT at the maximum tolerated dose, and 1 additional DLT occurred. The objective best response rate was 6% (1 of 18 patients, 95% confidence interval [CI], 0.1%-27%). The median progression-free survival was 58.15 months (95% CI, 39.10-∞). The median OS was 61.5 months (43.1-∞), and the 2-year OS rate was 95%.

CONCLUSIONS

Nilotinib 200 mg/d with RT is safe and tolerated in patients with high-risk chordoma. Long-term follow-up is needed to understand whether nilotinib combined with RT, with or without surgery, adds greater improvement to progression-free survival or OS than with RT with or without surgery alone in patients with high-risk chordoma.

Poorly Differentiated Chordomas Showing Loss of INI1/SMARCB1: A Report of 2 Rare Cases With Diagnostic Implications

Poorly differentiated chordomas are rare musculoskeletal tumors. Case 1. A 42-year-old lady presented with quadriparesis of 2 months' duration. Radiologic imaging disclosed a soft tissue mass in her left prevertebral- and paravertebral cervical region. Case 2. A 4-year-old male child presented with neck pain and restricted head movements of 1-year duration. Radiologic imaging revealed a contrast enhancing, paraspinal soft tissue mass in his cervical region. Microscopic examination in both the cases revealed a cellular malignant tumor composed of moderate to markedly pleomorphic cells with interspersed mitotic figures, along with focal myxoid change and necrosis. By immunohistochemistry, tumor cells in both cases were diffusely positive for pan cytokeratin (AE1/AE3) and brachyury, whereas these were negative for INI1/SMARCB1. Tumor cells in the second case were also positive for glypican3. The first case developed pulmonary metastasis, while the second case developed recurrence. Poorly differentiated chordomas are uncommon tumors, invariably characterized by loss of INI1. These tumors can be rarely seen in adults and need to be differentiated from their diagnostic mimics, in view of treatment implications and their relatively aggressive clinical outcomes.

Circulating vascular endothelial growth factor (VEGF) as predictive factor of progression-free survival in patients with advanced chordoma receiving sorafenib: an analysis from a phase II trial of the french sarcoma group (GSF/GETO)

Background

Patients with advanced chordoma are often treated with tyrosine kinase inhibitors without any predictive factor to guide decision. We report herein an ancillary analysis of the the Angionext phase II trial (NCT 00874874).

Results

From May 2011 to January 2014, 26 were sampled. The 9-month PFS rate was 72.9% (95%-CI: 45.9-87.9). During sorafenib treatment, a significant increase in PlGF (18.4 vs 43.8 pg/mL, p<0.001) was noted along with a non-significant increase in VEGF (0.7 vs 1.0 ng/mL, p=0.07). VEGF at D1 >1.04 ng/mL (HR=12.5, 95%-CI: 1.37-114, p=0.025) and VEGF at D7 >1.36 ng/mL (HR=10.7, 95%-CI: 1.16-98, p=0.037) were associated with shorter PFS. The 9-month PFS rate was 92.3% (95%-CI: 56.6-98.9) when VEGF at D1 was ≤1.04 ng/mL versus 23.3% (95%-CI: 1.0-63.2) when >1.04 ng/mL.

Patients and Methods

Chordoma patients were treated with sorafenib 800 mg/day for 9 months, unless earlier occurrence of progression or toxicities. Six biomarkers (sE-Selectin, VEGF, VEGF-C, placental growth factor (PlGF), Thrombospondin, Stem Cell Factor (SCF)) were measured at baseline (day 1: D1) and day 7 (D7).

Conclusion

High levels of VEGF was associated with poor outcome.

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.

Establishment and genomic characterization of the new chordoma cell line Chor-IN-1

Chordomas are rare, slowly growing tumors with high medical need, arising in the axial skeleton from notochord remnants. The transcription factor “brachyury” represents a distinctive molecular marker and a key oncogenic driver of chordomas. Tyrosine kinase receptors are also expressed, but so far kinase inhibitors have not shown clear clinical efficacy in chordoma patients. The need for effective therapies is extremely high, but the paucity of established chordoma cell lines has limited preclinical research. Here we describe the isolation of the new Chor-IN-1 cell line from a recurrent sacral chordoma and its characterization as compared to other chordoma cell lines. Chor-IN-1 displays genomic identity to the tumor of origin and has morphological features, growth characteristics and chromosomal abnormalities typical of chordoma, with expression of brachyury and other relevant biomarkers. Chor-IN-1 gene variants, copy number alterations and kinome gene expression were analyzed in comparison to other four chordoma cell lines, generating large scale DNA and mRNA genomic data that can be exploited for the identification of novel pharmacological targets and candidate predictive biomarkers of drug sensitivity in chordoma. The establishment of this new, well characterized chordoma cell line provides a useful tool for the identification of drugs active in chordoma.

Notochordal Tumors: An Update on Molecular Pathology with Therapeutic Implications

Recent molecular investigations of chordoma show common expression of various receptor tyrosine kinases and activation of downstream signaling pathways contributing to tumor growth and progression. The transcription factor brachyury (also known as T) is important in notochord differentiation, and germline duplication of the gene is often found in familial chordomas. Nuclear expression of brachyury is consistent in chordoma and in benign notochordal cell tumor. Based on the molecular evidence, targeting of several kinds of molecular agents has been attempted for the treatment of uncontrolled chordomas and achieved partial response or stable condition in many cases.

Genetic aberrations and molecular biology of skull base chordoma and chondrosarcoma

Chordomas and chondrosarcomas are two major malignant bone neoplasms located at the skull base. These tumors are rarely metastatic, but can be locally invasive and resistant to conventional chemotherapies and radiotherapies. Accordingly, therapeutic approaches for the treatment of these tumors can be difficult. Additionally, their location at the skull base makes them problematic. Although accurate diagnosis of these tumors is important because of their distinct prognoses, distinguishing between these tumor types is difficult due to overlapping radiological and histopathological findings. However, recent accumulation of molecular and genetic studies, including extracranial location analysis, has provided us clues for accurate diagnosis. In this report, we review the genetic aberrations and molecular biology of these two tumor types. Among the abundant genetic features of these tumors, brachyury immunohistochemistry and direct sequencing of IDH1/2 are simple and useful techniques that can be used to distinguish between these tumors. Although it is still unclear why these tumors, which have such distinct genetic backgrounds, show similar histopathological findings, comparison of their genetic backgrounds could provide essential information.

STAT3 Inhibition as a Therapeutic Strategy for Chordoma

Objective Signal transducer and activator of transcription (STAT) proteins regulate key cellular fate decisions including proliferation and apoptosis. STAT3 overexpression induces tumor growth in multiple neoplasms. STAT3 is constitutively activated in chordoma, a tumor with a high recurrence rate despite maximal surgical and radiation treatment. We hypothesized that a novel small molecule inhibitor of STAT3 (FLLL32) would induce significant cytotoxicity in sacral and clival chordoma cells. Methods Sacral (UCh1) and clival (UM-CHOR-1) chordoma cell lines were grown in culture (the latter derived from primary tumor explants). FLLL32 dosing parameters were optimized using cell viability assays. Antitumor potential of FLLL32 was assessed using clonal proliferation assays. Potential mechanisms underlying observed cytotoxicity were examined using immunofluorescence assays. Results FLLL32 induced significant cytotoxicity in UCh1 and UM-CHOR-1 chordoma cells, essentially eliminating all viable cells, correlating with observed downregulation in activated, phosphorylated STAT3 upon administration of FLLL32. Mechanisms underlying the observed cytotoxicity included increased apoptosis and reduced cellular proliferation through inhibition of mitosis. Conclusion As a monotherapy, FLLL32 induces potent tumor kill in vitro in chordoma cell lines derived from skull base and sacrum. This effect is mediated through inhibition of STAT3 phosphorylation, increased susceptibility to apoptosis, and suppression of cell proliferation.

The potential function of microRNA in chordomas

Little is known about the molecular biology of chordomas, which are rare, chemoresistant tumors with no well-established treatment. miRNAs regulate gene networks and pathways. We aimed to evaluate the effects of dysregulated miRNA in chordomas would help reveal the underlying mechanisms of chordoma initiation and progression. In this study, miR-31, anti-miR-140-3p, anti-miR148a, and miR-222 were transiently transfected to chordoma cell lines and an MTS assay, apoptosis assay, and cell-cycle analysis were conducted to evaluate the effects. The mRNA level of predicted and confirmed targets of each miRNA, as well as the EMT and MET markers of U-CH1 and MUG-Chor1, were assessed with real-time polymerase chain reaction. Transient transfection of miRNA mimics was achieved, as each mimic increased or decreased the level of its corresponding miRNA. miR-31 decreased cell viability in MUG-Chor1 and U-CH2 after 72h, which is consistent with previous findings for U-CH1. Both miR-31 and anti-miR-148a induced apoptosis in all three cell lines. Although each miRNA had a similar pattern, miR-31 had the most effective S-phase arrest in all three cell lines. RDX, MET, DNMT1, DNMT3B, TRPS1, BIRC5, and KIT were found to be targeted by the selected miRNAs. The level of miR-222 in chordoma cell lines U-CH1 and MUG-Chor1 correlated positively with EMT markers and negatively with MET markers. This study uncovered the potential of miR-31, miR-140-3p, miR-148a, and miR-222-3p to be key molecules in the cell viability, cell cycle, and apoptosis in chordomas, as well as initiation, differentiation, and progression.

Targeted next-generation sequencing of cancer genes in advanced stage malignant pleural mesothelioma: a retrospective study

INTRODUCTION

Malignant pleural mesothelioma (MPM) is a rare malignant disease, and the understanding of molecular pathogenesis has lagged behind other malignancies.

METHODS

A series of 123 formalin-fixed, paraffin-embedded tissue samples with clinical annotations were retrospectively tested with a commercial library kit (Ion AmpliSeq Cancer Hotspot Panel v.2, Life Technologies, Grand Island, NY) to investigate 50 genes plus other two, BRCA1-associated protein-1 (BAP-1) and neurofibromatosis-2 (NF2), frequently altered in MPM. DNA was obtained from tissues after manual microdissection and enriched for at least 50% cancer cells. Variations affecting protein stability or previously correlated to cancer, more frequently identified (≥ 25 patients with at least 10% of allelic frequency), were subsequently evaluated by Sanger sequencing. Immunohistochemistry staining for BAP1 and NF2 proteins was also performed.

RESULTS

The commonest genetic variations were clustered in two main pathways: the p53/DNA repair (TP53, SMACB1, and BAP1) and phosphatidylinositol 3-kinase-AKT pathways (PDGFRA, KIT, KDR, HRAS, PIK3CA, STK11, and NF2). PIK3CA:c.1173A>G mutation, STK11:rs2075606 (T>C), or TP53:rs1042522 (Pro/Pro) was significantly associated with time to progressive disease (TTPD; all p values < 0.01). Furthermore, the accumulation of genetic alterations correlated with shorter TTPD and reduced overall survival (TTPD p value = 0.02, overall survival p value = 0.04). BAP1 genetic variations identified were mainly located in exons 13 and 17, and BAP1 nonsynonymous variations were significantly correlated with BAP1 protein nuclear localization.

CONCLUSION

Next-generation sequencing was applied to a relatively large retrospective series of MPM using formalin-fixed, paraffin-embedded archival material. Our results indicate a complex mutational landscape with a higher number of genetic variations in the p53/DNA repair and phosphatidylinositol 3-kinase pathways, some of them with prognostic value.

Chordoma: an update on the pathophysiology and molecular mechanisms

Chordoma is a rare low-grade primary malignant skeletal tumor, which is presumed to derive from notochord remnants. The pathogenesis of chordoma has not been fully elucidated. However, recent advances in the molecular biology studies have identified brachyury underlying the initiation and progression of chordoma cells. More efforts have been made on accumulating evidence of the notochordal origin of chordoma, discovering signaling pathways and identifying crucial targets in chordomagenesis. In this review, we summarize the most recent research findings and focus on the pathophysiology and molecular mechanisms of chordoma.

Paediatric Chordomas

Paediatric chordomas are rare malignant tumours arising from primitive notochordal remnants with a high rate of recurrence. Only 5 % of them occur in the first two decades such less than 300 paediatric cases have been reported so far in the literature. In children, the average age at diagnosis is 10 years with a male-to-female ratio closed to 1. On the opposite to adults, the majority of paediatric chordomas are intracranial, characteristically centered on the sphenooccipital synchondrosis. Metastatic spread seems to be the prerogative of the under 5-year-old children with more frequent sacro-coccygeal locations and undifferentiated histology. The clinical presentation depends entirely on the tumour location. The most common presenting symptoms are diplopia and signs of raised intracranial pressure. Sacrococcygeal forms may present with an ulcerated subcutaneous mass, radicular pain, bladder and bowel dysfunctions. Diagnosis is suspected on computerised tomography showing the bone destruction and with typically lobulated appearance, hyperintense on T2-weighted magnetic resonance imaging. Today, treatment relies on as complete surgical resection as possible (rarely achieved because of frequent invasiveness of functional structures) followed by adjuvant radiotherapy by proton therapy. The role of chemotherapy has not been proven. Prognosis is better than in adults and depends on the extent of surgical resection, age and histology subgroup. Biological markers are still lacking to improve prognosis by developing targeted therapy.

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.

Combined PDGFR and HDAC Inhibition Overcomes PTEN Disruption in Chordoma

BACKGROUND

The majority of chordomas show activation of the platelet-derived growth factor receptor (PDGFR). Based on in vitro intertumoral variation in response to recombinant PDGF protein and PDGFR inhibition, and variable tumor response to imatinib, we hypothesized that chordomas resistant to PDGFR inhibition may possess downstream activation of the pathway.

METHODS

Molecular profiling was performed on 23 consecutive chordoma primary tissue specimens. Primary cultures established from 20 of the 23 specimens, and chordoma cell lines, UCH-1 and UCH-2, were used for in vitro experiments.

RESULTS

Loss of heterozygosity (LOH) at the phosphatase and tensin homolog (PTEN) locus was observed in 6 specimens (26%). PTEN disruption statistically correlated with increased Ki-67 proliferation index, an established marker of poor outcome for chordoma. Compared to wild type, PTEN deficient chordomas displayed increased proliferative rate, and responded less favorably to PDGFR inhibition. PTEN gene restoration abrogated this growth advantage. Chordomas are characterized by intratumoral hypoxia and local invasion, and histone deacetylase (HDAC) inhibitors are capable of attenuating both hypoxic signaling and cell migration. The combination of PDGFR and HDAC inhibition effectively disrupted growth and invasion of PTEN deficient chordoma cells.

CONCLUSIONS

Loss of heterozygosity of the PTEN gene seen in a subset of chordomas is associated with aggressive in vitro behavior and strongly correlates with increased Ki-67 proliferative index. Combined inhibition of PDGFR and HDAC attenuates proliferation and invasion in chordoma cells deficient for PTEN.

Sorafenib in patients with locally advanced and metastatic chordomas: a phase II trial of the French Sarcoma Group (GSF/GETO)

BACKGROUND

There is no consensual treatment of locally advanced or metastatic chordomas.

PATIENTS AND METHODS

We conducted a multicenter, open-label, uncontrolled phase II trial of sorafenib (800 mg/day). The primary end point was the 9-month progression-free rate according to RECIST 1.1. All patients had documented progressive disease at the time of study entry.

RESULTS

Twenty-seven patients were enrolled between May 2011 and January 2014. The median age was 64 (range, 30-86) years. There were 17 men and 10 women. Twelve patients had been previously treated with chemotherapy and molecularly targeted agents. The maximum toxicity grade per patient was grade 3 in 21 cases (77.8%) and grade 4 in 4 cases (14.8%). Sorafenib provided an intent-to-treat best objective response of 1/27 [3.7%; 95% confidence interval (CI) 0.1% to 19.0%], a 9-month progression-free rate of 73.0% (95% CI 46.1-88.0) and a 12-month overall survival rate of 86.5% (95% CI 55.8-96.5). Survival curves were similar in pretreated and not pretreated patients.

DISCUSSION

Additional clinical trials further exploring sorafenib as a treatment of locally advanced or metastatic chordomas are warranted.

Metastatic Chordoma: Report of the Two Cases and Review of the Literature

Chordomas are rare malignant bone tumours with a predilection for the axial skeleton, especially the sacrum and skull base. Median survival in patients with metastatic disease is usually dismal. Treatment is challenging due to the propensity for local recurrence, metastatic disease as well as lack of clear consensus regarding the optimal management. Our case report highlights two cases of sacral chordoma with locally recurrent and widespread metastatic disease, stable on molecular targeted therapy.

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.

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.